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We designed a trigonal symmetric imine-linked covalent organic framework (COF), TFPC-DAB, with control over the angularity of the building units, where a bent C2-symmetric diamine, such as 1,3-diaminobenzene (1,3-DAB or DAB), with an exo-angle of 120° was used instead of those with an exo-angle of 180°, in combination with a C3-symmetric trialdehyde, such as tri(4-formylphenoxy)cyanurate (TFPC). Its synthesis was accomplished by reacting the building units in a mixture of mesitylene/dioxane/6 M acetic acid under solvothermal conditions. The phase purity, thermal stability, and porosity of TFPC-DAB were established by various analytical techniques. Utilizing the Density Functional Tight Binding (DFTB+) simulation and Pawley refinement, the best fit of the small angle x-ray pattern was found to have an AA stacking of TFPC-DAB in the trigonal space group P3 with low refinement parameters. Such smart materials are in huge demand to detect hazardous corrosive chemicals, such as HCl and NH3. The dual features of electron deficient π-acidic triazine moiety and heteroatoms (N/O) from TFPC and electron rich phenyl units from DAB embodied in the framework enhance its luminescent property and thereby make it suitable for solvent-based HCl and NH3 sensing. The detection limits for HCl and NH3 in methanol were found to be 14 and 82 ppb, respectively. The effect of solvent polarity on the sensing studies was observed with much lower detection limits in dioxane: 2.5 and 11 ppb for HCl and NH3, respectively. A detailed theoretical calculation using density functional theory and configurational bias Monte Carlo modules was conducted for understanding interactions between the COF and HCl or NH3 analytes. [ABSTRACT FROM AUTHOR]

We investigate the sensitivity of co-linear three-photon electromagnetically induced transparency (EIT) in 133 Cs Rydberg atoms to radio frequency electric fields and compare against the conventional two-photon system. Specifically, we model the 4-level and 5-level atomic systems and compare how the transmission of the probe changes with different laser powers and RF field strengths. In this model, we define a sensitivity metric that relates to the current best experimental implementation and assumes photon shot noise limited detection. We find that the three-photon system boasts much narrower linewidths compared to the conventional two-photon EIT. These narrow line features, however, do not align with the regions of the best sensitivity. In addition to this, we calculate the expected sensitivity for the two-photon Rydberg sensor and find that the best achievable sensitivity is over an order of magnitude better than the current measured values of 5 μ Vm − 1 Hz − 1 / 2 . However, by accounting for additional noise sources in the experiment and the quantum efficiency of the photo-detectors, the values are in good agreement. [ABSTRACT FROM AUTHOR]

Ice I has three forms depending on the stacking arrangements of its layers: hexagonal ice Ih, cubic ice Ic, and stacking disordered ice Isd. Below ∼60 K, amorphous water becomes metastable, and the formation of any form of ice I is often implicitly precluded. Using a newly developed low-temperature reflection high-energy electron diffraction (RHEED) technique, we show that crystalline ice with cubic stacking sequences (i.e., ice Ic) formed through Ne sublimation from a solid H2O/Ne (1:1000 ratio) matrix at 13 K. The extent of stacking disorder (disordered cubic and hexagonal stacking sequences) in the ice formed by Ne matrix sublimation is smaller than that in vapor-deposited ice Isd prepared at 143 K and below the limit of detection of low-temperature RHEED. Dependence of the resulting ice structures on the thickness of the H2O/Ne matrix shows that amorphous water first forms in the early stages of Ne sublimation, and the cubic stacking sequence subsequently takes place. As the cubic ice Ic formed here at a much lower temperature (13 K) than previously observed (typically above 78 K), Ne matrix sublimation represents a novel route to the formation of cubic ice Ic under low-temperature and low-pressure conditions. [ABSTRACT FROM AUTHOR]

The dynamic characteristics (i.e. autocorrelation and cross-correlation) in modern industrial systems have raised great challenges to process fault detection. To cope with the dynamics and uncertainty of dynamic industrial processes, this paper proposes a new process control method, dynamic convolutional gated recurrent unit attention auto-encoder (DCGRUA-AE) for fault detection in dynamic processes. Firstly, DCGRUA-AE integrates a convolutional gated recurrent unit (CGRU) with a local convolution layer to learn both global and local features of dynamic process data in an unsupervised fashion. Secondly, a dual attention module is embedded in the deep network to preserve effective features. Finally, DeconvGRU combined with a dense layer is used as the encoder to reconstruct the original process data. Two statistics (i.e. T-square (T2) and squared prediction error (SPE)) based on DCGRUA-AE are used to set the control limits for fault detection. The feasibility and superiority of DCGRUA-AE-based fault detection method have been verified on four industrial processes. The experimental results indicate that the CGRU and dual attention mechanism can significantly improve the fault detection performance of DCGRUA-AE in dynamic processes. The hybrid of CGRU, attention mechanism and auto-encoder provides a new method for fault detection in dynamic industrial processes. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: A monolithic column‐based mass spectrometry (MS) analysis kit was prepared for whole blood analysis with MS. The kit is disposable and can be used for purification, storage, transportation and direct analysis of whole blood. The kit mainly consists of a capillary for quantitative microsampling, a cation exchange monolithic column for purification and storage, and a syringe for loading sample. This kit is very friendly to various users that one can easily siphon the blood in the kit followed by rapid clean‐up. We established a quantitative method using the kit with a limit detection as low as 0.33 nmol/L, and achieved more than five orders of magnitude enhancement in sensitivity compared to direct nanoelectrospray ionization MS analysis. The column can avoid analyte exposure to environment, which helps the storage of the sample for laboratory analysis. The relative standard deviation of immediate blood analysis and storage blood analysis within 10 d was less than 10%. This method has been successfully applied to the quantitative analysis of procainamide hydrochloride in 2 μL rat blood. These results indicate that this disposable kit does have the potential to achieve highly sensitive quantitative MS analysis in biological samples, which is expected to become a cost‐effective and powerful tool for in vitro diagnostics. [ABSTRACT FROM AUTHOR]

Simple, low-cost, and fast determination of cysteine and glutathione with high sensitivity is an essential problem to evaluate the physiological processes in living organisms. Artificial nanozymes have provided considerable opportunities in biosensing. In this work, using a graphene-based ternary nanozyme, we present a simple but efficient colorimetric method for the determination of cysteine and glutathione. The nanozyme exhibits excellent and stable catalytic performance toward H2O2 and catalyzes the 3,3′,5,5′-tetramethylbenzidine chromogenic reaction. However, this reaction is significantly suppressed by cysteine and glutathione. Thus, a sensitive colorimetric method is presented based upon this inhibition. Excellent performance with low detection limits, good selectivity, and rapid analysis suggests potential bioanalytical applications for the determination of cysteine and glutathione. [ABSTRACT FROM AUTHOR]

Volumetric absorptive micro-sampling (VAMS) has emerged as a simple and safe tool for collecting and storing blood samples in clinical and bioanalytical fields. This study presents a novel method for determining essential and non-essential trace elements (As, Be, Cd, Cs, Cu, Fe, Mg, P, Pb, S, Sb, Se, Tl, V, U) in VAMS-collected blood samples using microwave-assisted digestion with diluted acid as sample preparation method and an inductively coupled plasma triple quadrupole mass spectrometry (ICP-QQQ) as determination technique. While certain elements posed challenges due to VAMS tip background issues (Al, Ti, Cr, Mn, Co, Ni, Sn, Mo, Ba), the method demonstrated high precision and accuracy for the targeted analytes. It was demonstrated that 4.5 mol L−1 HNO3 plus 100 µL H2O2 30% (w/w) was suitable for an efficiency of digestion for further elemental determination using micro-analysis (spending less than 300 µL analytical solution) by ICP-QQQ, given that the residual carbon content (RCC) after the digestion procedure was lower than 5%. All the results higher than limit of quantification (LOQ) were in agreement with reference values for all analytes. Accuracy was assessed through reference material analysis and recovery tests using spiked samples. Moreover, suitable agreements (p > 0.05) between this method (VAMS-M) and the comparative method (liquid sampling method) were obtained for all analytes >LOQ. Furthermore, all results >LOQ showed good precision according to precision requirements (Horwitz equation). In this way, with the use of dilute acid, low dilution factor (30-fold), and excellent digestion efficiency (>95%), the proposed method was able to achieve an excellent detection limit, precision, and accuracy for 15 elements: As, Be, Cd, Cs, Cu, Fe, Mg, P, Pb, S, Sb, Se, Tl, V, and U using ICP-MS/MS, without the need for matrix-matched calibration curves. This research showcases an innovative analytical approach using VAMS for blood samples, offering biosafety, practicality, sensitivity, versatility, and robustness. This method contributes to the advancement of trace element analysis in biomedical research and clinical applications. [ABSTRACT FROM AUTHOR]

Cutting-edge printed circuit board (PCB) technology shows promise either as an automated detection unit or as an alternative sensor matrix, and has opened a new avenue in the diagnostic industry. The PCB-based platform is superior to conventional benchtop instruments in terms of its miniaturization, user-friendly operation, and ease of handling. Flexible PCBs have revolutionized wearable approaches to integrate multiple components within the same circuit or different electronic gadgets, reducing space and production costs. An effective packaging approach combining microfluidics and biosensing modules on Lab-on-PCB technology has been demonstrated, introducing additive devising and manufacturing techniques. Circuit integration has revolutionized the diagnostic sector by improving the sensing ability and rapidity of biosensors. Bioelectronics has led to the development of point-of-care (PoC) devices, offering superior performance compared with conventional biosensing systems. These devices have lower production costs, are smaller, and have greater reproducibility, enabling the construction of compact sensing modules. Flexible upgrades to the fabrication pattern of the printed circuit board (PCB) remains the most reliable and consistent means so far, offering portability, wearability, a lower detection limit, and smart output integration to these devices. This review summarizes the advances in PCB technology for biosensing devices for introducing automation and their emerging application as an alternative matrix material for detecting various analytes. [ABSTRACT FROM AUTHOR]

A novel chemosensor has been developed for the precise detection of Zn2+ in cosmetics creams and water samples, exhibiting remarkable accuracy. This new chemosensor is composed of NH2–UiO–MOF serving as the base MOF, with 2‐acetyl‐6‐bromopyridine acting as the ligand, referred to as the 2A6BrP=N–UiO–MOF chemosensor. Extensive studies have been conducted to optimize the spectrophotometric and fluorometric detection of Zn2+ ions using this new chemosensor. Achieving a consistent and stable spectroscopic signal with the 2A6BrP=N–UiO–MOF chemosensor necessitated a response time of less than 30 s. Validation of the proposed methods followed ICH (International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use) guidelines, ensuring precision in determining limits of detection (LODs), limits of quantification (LOQs), linearity, and precision. The spectrophotometric and fluorometric techniques yielded highly sensitive LOD values of 15.50 (ppb) and 8.70 ppb, respectively, for Zn2+ ions. Furthermore, research indicated that the 2A6BrP=N–UiO–MOF chemosensor can be efficiently recycled up to eight times by treating it with 0.1 M HCl, showcasing its potential for sustainability. Subsequently, the application of the 2A6BrP=N–UiO–MOF chemosensor demonstrated its remarkable efficacy in detecting Zn2+ in various real water samples. Its exceptional sensitivity and selectivity make it a valuable tool for accurate Zn2+ detection in practical environmental settings. [ABSTRACT FROM AUTHOR]

Cronobacter sakazakii in powdered infant formula (PIF) can infect infants with a mortality rate of up to 80%. In this study, a propidium monoazide–loop‐mediated isothermal amplification (PMA‐LAMP) assay was developed for fast and cost‐effective visual detection of viable C. sakazakii. The detection could be finished in 75 min and the results could be identified by the naked eye. The detection limits of the assay were as low as 1.2 × 101 cfu/mL and 1.2 × 102 cfu/mL for gel electrophoresis and naked eyes respectively. Finally, the assay also showed good reliability in the artificially contaminated PIF. [ABSTRACT FROM AUTHOR]

The present investigation demonstrates a simple, sensitive and selective colorimetric probe for the detection of Hg2+ in milk samples employing redox interaction of Hg2+ ions with citrate‐stabilised silver nanoparticles, inducing colour change from yellow to colourless. Milk samples were pretreated by ultrasound assistance in acidic media. The detection limit (LOD) was 6.17 ppb using UV–Visible spectrophotometer with linear correlation (R2 = 0.9901) at 10–2000 ppb solution of Hg2+ ions. Developed probe was highly selective to Hg2+ over different interfering metal ions and can be effectively employed to identify Hg2+ in milk samples. [ABSTRACT FROM AUTHOR]

A novel ratiometric electrochemical aptasensor based on split aptamer and Au-reduced graphene oxide (Au-rGO) nanomaterials was proposed to detect aflatoxin M1 (AFM1). In this work, Au-rGO nanomaterials were coated on the electrode through the electrodeposition method to increase the aptamer enrichment. We split the aptamer of AFM1 into 2 sequences (S1 and S2), where S1 was immobilized on the electrode due to the Au-S bond, and S2 was tagged with methylene blue (MB) and acted as a response signal. A complementary strand to S1 (CS1) labeled with ferrocene (Fc) was introduced as another reporter. In the presence of AFM1, CS1 was released from the electrode surface due to the formation of the S1-AFM1-S2 complex, leading to a decrease in Fc and an increase in the MB signal. The developed ratiometric aptasensor exhibited a linear range of 0.03 μg L−1 to 2.00 μg L−1, with a detection limit of 0.015 μg L−1 for AFM1 detection. The ratiometric aptasensor also showed a linear relationship from 0.2 μg L−1 to 1.00 μg L−1, with a detection limit of 0.05 μg L−1 in natural milk after sample pretreatment, indicating the successful application of the developed ratiometric aptasensor. Our proposed strategy provides a new way to construct aptasensors with high sensitivity and selectivity. [ABSTRACT FROM AUTHOR]

The low sensitivity of working electrodes is usually the bottleneck of the electrochemical testing method. In this work, bismuth antimonate nanosheets have excellent electrochemical performance and are used as the modified materials for glassy carbon electrodes. Bismuth antimonate nanosheets were prepared by a simple coprecipitation method. By changing the calcination temperature and holding time, the effects of these factors on the morphology and structure of the bismuth antimonate nanosheets were investigated. The bismuth antimonate-modified electrode was used for the electrochemical detection of benzoic acid. The results showed that a pair of semi-reversible redox peaks appeared at − 0.48 V and + 0.05 V, and the intensity of the redox peaks gradually increased with the increase of benzoic acid concentration and scan rate. The bismuth antimonate nanomaterial-modified glassy carbon electrode has a wide linear detection range (0.0002–2 mM), low detection limit (0.053 µM) and good cycling performance for detecting benzoic acid. The good electrochemical performance shows that bismuth antimonate nanomaterials have potential application value in the detection of benzoic acid. The glassy carbon electrode modified by bismuth antimonate nanosheets can effectively detect benzoic acid, with linear detection range (0.0002–2 mM) and detection limit (0.053 µM) and good repeatability [ABSTRACT FROM AUTHOR]

Point-of-care sensors targeting blood marker analysis must be designed to function with very small volumes since acquiring a blood sample through a simple, mostly pain-free finger prick dramatically limits the sample size and comforts the patient. Therefore, we explored the potential of converting a conventional lateral flow assay (LFA) for a significant biomarker into a self-contained and compact polymer channel-based LFA to minimize the sample volume while maintaining the analytical merits. Our primary objective was to eliminate the use of sample-absorbing fleece and membrane materials commonly present in LFAs. Simultaneously, we concentrated on developing a ready-to-deploy one-step LFA format, characterized by dried reagents, facilitating automation and precise sample transport through a pump control system. We targeted the detection of the heart failure biomarker NT-proBNP in only 15 µL human whole blood and therefore implemented strategies that ensure highly sensitive detection. The biosensor combines streptavidin-functionalized magnetic beads (MNPs) as a 3D detection zone and fluorescence nanoparticles as signal labels in a sandwich-based immunoassay. Compared to the currently commercialized LFA, our biosensor demonstrates comparable analytical performance with only a tenth of the sample volume. With a detection limit of 43.1 pg∙mL−1 and a mean error of 18% (n ≥ 3), the biosensor offers high sensitivity and accuracy. The integration of all-dried long-term stable reagents further enhances the convenience and stability of the biosensor. This lateral flow channel platform represents a promising advancement in point-of-care diagnostics for heart failure biomarkers, offering a user-friendly and sensitive platform for rapid and reliable testing with low finger-prick blood sample volumes. [ABSTRACT FROM AUTHOR]

The recent clinical success of messenger RNA (mRNA) technology in managing the Covid pandemic has triggered an unprecedented innovation in production and analytical technologies for this therapeutic modality. mRNA is produced by enzymatic transcription of plasmid DNA (pDNA) using polymerase in a cell-free process of in vitro transcription. After transcription, the pDNA is considered a process-related impurity and is removed from the mRNA product enzymatically, chromatographically, or by precipitation. Regulatory requirements are currently set at 10 ng of template pDNA per single human dose, which typically ranges between 30 and 100 µg. Here, we report the development of a generic procedure based on enzymatic digestion and chromatographic separation for the determination of residual pDNA in mRNA samples, with a limit of quantification of 2.3 ng and a limit of detection of less than 0.1 ng. The procedure is based on enzymatic degradation of mRNA and anion exchange HPLC separation, followed by quantification of residual pDNA with a chromatographic method that is already widely adopted for pDNA quality analytics. The procedure has been successfully applied for in-process monitoring of three model mRNAs and a self-amplifying RNA (saRNA) and can be considered a generic substitution for qPCR in mRNA in-process control analytical strategy, with added benefits that it is more cost-efficient, faster, and sequence agnostic. [ABSTRACT FROM AUTHOR]

Laser interference lithography (LIL) was used to fabricate gold nanodisk arrays on glass which was studied as surface-enhanced Raman spectroscopy (SERS) substrates. The Raman response of varying array periods (250 nm, 300 nm, 344 nm, 395 nm, and 446 nm) was compared using the chemical rhodamine 6G. The 300-nm period displayed the highest SERS enhancement among the tested LIL substrates. Experimental transmission measurements and their finite element method (FEM) simulations were taken to understand the optical response of the LIL substrates. The 300-nm-period LIL substrate was used to detect urea to confirm its practical use as a SERS substrate. The enhancement factor of the 300-nm-period substrate was 2.3 × 106. Furthermore, the detection limit of urea was 0.05 mM for the optimized substrate. [ABSTRACT FROM AUTHOR]

Nanozymes have been widely used as enzyme substitutes. Based on a comprehensive literature survey of 261 publications, we report the significant differences in the Michaelis–Menten constants (Km) between peroxidase-mimicking nanozymes and horseradish peroxidase (HRP). Further, these differences were not considered in more than 60% of the publications for analytical developments. As a result, nanozymes' catalytic activity is limited, resulting in a potentially higher limit of detection (LOD). We used a peroxidase-mimicking Au@Pt nanozyme, which has Km for TMB comparable with HRP and three orders of magnitude higher Km for H2O2. Using the Au@Pt nanozyme as a label for immunoassays, non-optimized nanozyme substrate concentrations led to 30 times higher LOD compared to optimized conditions. The results confirm the necessity of measuring nanozymes' kinetic parameters and the corresponding adjustment of substrate concentrations for highly sensitive detection. [ABSTRACT FROM AUTHOR]

A phthalonitrile‐based bent shaped push‐pull dibenzodioxin was synthesized using an efficient and rapid monowave reactor‐assisted protocol in acceptable yields. When aqueous Fe3+ ion solution was added to the bent dibenzodioxin in dimethyl sulfoxide (DMSO), the fluorescence intensity of bent dibenzodioxin at 450 nm was quenched significantly. UV‐visible and fluorimetric measurements displayed high selectivity and sensitivity towards Fe3+ over other metal ions, with a low detection limit of 0.67 μM. Fluorimetric investigations like interference and reversibility test of bent‐dibenzodioxin with Fe3+ led to proving it as a potential canditate for chemosensor application. Job's plot showed 1 : 2 stoichiometry between the bent‐dibenzodioxin and Fe3+ ions respectively and it was proposed that the the binding of one of the Fe3+ ion is from the phenanthroline‐like bent pocket, featuring two oxygen atoms and the other Fe3+ ions binds with the two ortho‐dinitrile units of the bent‐dibenzodioxin. [ABSTRACT FROM AUTHOR]

This study demonstrates a facile solvothermal approach to synthesizing green fluorescent carbon dots (G‐CDs) using baby pumpkin as a natural precursor. The G‐CDs exhibit strong fluorescence emission at 547 nm under excitation at 467 nm, and the highest quantum yield reaching 17.5 % in acetone, making them suitable for a range of applications including sensing, bioimaging, catalysis, and drug delivery. The G‐CDs demonstrate excellent stability under various conditions, such as prolonged light exposure, high salt concentration, extended periods, and elevated temperatures. Furthermore, the G‐CDs show a good linear relationship with Cd2+ within the concentration range of 0 to 16.5 μmol/L, with a linear correlation coefficient of 0.9920. The detection limit (LOD) was calculated to be 0.68 μmol/L. The recovery rate ranges between 85.66% to 97.43%, indicating their potential for use in environmental metal ion detection. This study provides a convenient and economical method for the synthesis of G‐CDs using baby pumpkin as a precursor, offering a sustainable alternative for various applications in sensing, imaging, catalysis, and drug delivery. [ABSTRACT FROM AUTHOR]

The abnormally expressed microRNAs (miRNAs) serve as crucial indicators for disease diagnosis and are strongly associated with the progression of various diseases. The quantification of miRNAs is highly significant for the clinical diagnosis and treatment of various types of cancers. This study utilizes the CRISPR/Cas13a system, which combines CRISPR RNA (crRNA) and CRISPR-associated Cas13a, to recognize the miRNA directly and specifically, thus activating the trans-cleavage activity of Cas13a. By integrating the CRISPR-Cas13a system with an exonuclease-iii (Exo-iii)-assisted chain cleavage of silver ions (Ag+)-aptamer and an Ag+ -based color reaction, a method for the detection of miRNA that is specific and sensitive is developed. This approach demonstrated exceptional sensitivity in detecting miRNA, with a low detection limit of 5.12 fM. Moreover, the suggested method was effectively utilized to precisely measure the amount of miRNA in intricate biological samples, demonstrating its practical applicability. Furthermore, due to its elevated sensitivity and simple probe design and fluorophore labeling, the suggested colorimetric technique holds great potential for use in clinical diagnostics. [ABSTRACT FROM AUTHOR]

In this study, a fast and simple method has been developed for the determination of nitrite in different aqueous samples. The method, which can be applied for on-site as well as off-site analyses, is based on the reaction of nitrite with potassium iodide in an acid medium to liberate triiodide ions. These liberated triiodide ions react with starch adhesive to form a dark blue complex, which is quantified by digital imaging using an ordinary smartphone and a freely available mobile application. Image analysis was done in the RGB color space, and the B-channel values were used to obtain the analytical signal. Under the optimum conditions, the method showed a linear range of 0.05–1 mg/L and a detection limit of 0.013 mg/L. The relative standard deviation for the determination of 0.5 mg/L nitrite was found to be 2.2% (n = 6). The results obtained using the proposed method were evaluated by comparing them to those obtained by a commercial UV-Vis spectrophotometer and also by analyzing spiked samples to calculate recovery percentages. [ABSTRACT FROM AUTHOR]

Substitution reactions in carbocyanine dyes are used to determine nucleophilic compounds. The interaction of a chlorine-containing carbocyanine dye with a number of medicinal substances is studied. It is shown that, in the reaction with isoniazid in the presence of a surfactant, this dye selectively changes color from yellow-green to violet. The formation of a product of the substitution of chlorine for isoniazid is proven by chromatography–mass spectrometry. The reaction proceeds in 20 min in the presence of 1 mM cetyltrimethylammonium bromide. The limit of detection for isoniazid in water by the photometric method is 10 μg/mL and in diluted artificial urine using fluorimetry, 0.3 μg/mL. The procedure does not use full-spectrum equipment, which simplifies the determination. [ABSTRACT FROM AUTHOR]

Considering the application prospects of a cascade catalytic system in biomedical analysis, it remains significant to develop a cascade catalytic system for one-step rapid colorimetric detection. Herein, PVP/NH2-MIL-101(Fe) possessing enhanced peroxidase (POD)-like activity was successfully synthesized by microwave-assisted and polyvinylpyrrolidone (PVP) modification strategies. Then, PVP/NH2-MIL-101(Fe) and glucose oxidase (GOx) were covalently coupled via the bifunctional cross-linker glutaraldehyde, the GOx@PVP/NH2-MIL-101(Fe) with dual enzymatic functional activities (POD-like and GOx activities) was subsequently synthesized. GOx@PVP/NH2-MIL-101(Fe) had strong affinities for the substrates glucose, 3,3',5,5'-tetramethylbenzidine, and hydrogen peroxide. Based on this specific nanozyme GOx@PVP/NH2-MIL-101(Fe), a one-step colorimetric assay for rapid glucose determination was built. This detection method not only took 20 min to analyze but also possessed a linear range of 10–250 µM with a detection limit of 1.05 µM. Furthermore, the cascade catalytic system was applied to determine glucose concentrations in human serum samples. Compared with commercial blood glucose meters, the proposed method was also accurate and effective, making it a candidate method for determining blood glucose. [ABSTRACT FROM AUTHOR]

Background In 2022, the global dissemination of mpox virus (MPXV) outside endemic regions prompted the expansion of diagnostic testing worldwide. This study assesses the performance characteristics of 5 real-time polymerase chain reaction (PCR) assays in detecting MPXV during the 2022 outbreak. Methods Clinical specimens collected from patients across Ontario, Canada, were tested on the following assays: RealStar Orthopoxyvirus PCR and FlexStar Monkeypox virus PCR (Altona Diagnostics), Novaplex MPXV (Seegene), VIASURE Monkeypox virus Real Time PCR Reagents (CerTest Biotec), and a laboratory-developed test. Positive percent agreement (PPA), negative percent agreement (NPA), relative limit of detection (LOD), and precision were evaluated and MPXV lineages were determined using an amplicon-based whole-genome sequencing (WGS) assay. Results Swabs were collected from various anatomic sites (65 positive and 30 negative). All assays demonstrated 100% NPA (95% confidence interval, 88.4%/88.1%–100.0%), with PPA ranging from 92.2% (82.7%–97.4%) to 96.9% (89.3%–99.6%). LOD and precision were comparable across assays, with coefficient of variations <3%. WGS analysis identified 6 lineages, all belonging to subclade IIb. Conclusions The assays exhibited excellent PPA, NPA, LOD, and precision. Ongoing performance monitoring is essential to detect assay escape mutants and ensure universal detection of evolving MPXV strains. [ABSTRACT FROM AUTHOR]

Background The 2022 outbreak of the clade IIb monkeypox virus and subsequent global spread lead to an urgent need for the development of high-throughput, sensitive, and reproducible diagnostic tests. Methods We developed 3 assays to detect monkeypox virus, 2 (MPXV+ and MPXV) for m2000 RealTime and 1 (MPXV) for Alinity m platforms. Dual targets in E9L and B6R (MPXV+) and J2L and B7R (MPXV) increased mutation resistance. In silico prediction indicates MPXV+ cross-reactivity with orthopox viruses and specific monkeypox virus detection with MPXV. Results m2000 RealTime MPXV+ and MPXV assay sensitivity was determined to be 3.2 plaque-forming units/mL using a reference virus culture diluted into universal transport medium (UTM). Alinity m MPXV lower limit of detection was 200 copies/mL using monkeypox virus plasmids in pooled UTM matrix. m2000 RealTime MPXV+ and MPXV assays were validated with lesion swabs in UTM and 1:1 saliva to UTM mixtures. Commercially available and remnant clinical lesion specimens in UTM were tested with RealTime MPXV+, RealTime MPXV and Alinity m MPXV assays and demonstrated high agreement to known mpox (MPX)-positive specimens. Conclusions RealTime MPXV+, RealTime MPXV, and Alinity MPXV are high throughput and sensitive assays used for the detection of monkeypox virus. These assays maybe useful during MPX outbreaks. [ABSTRACT FROM AUTHOR]

A self-standable, transparent, self-adhesive, bending resistant and highly adaptive SERS substrate has been fabricated by depositing Ag nanoparticles (AgNPs) on CdS nanowires (CdSNWs) embedded in a specially prepared nanofilm matrix, and further used for the in-situ, at real-time, sensitive and selective detection of urea in human sweat and plant leaves. [Display omitted] Wearable SERS substrates have gained substantial attention for health monitoring and other applications. Current designs often rely on conventional polymer substrates, leading to discomfort and complexity due to the need of additional adhesive layers. To address the issues, we fabricate a flexible, uniform, ultrathin, transparent and porous SERS substrate via depositing Ag nanoparticles (AgNPs) onto the CdS nanowires (CdSNWs) grown on the surface of a prepared nanofilm (AgNPs-CdSNWs/nanofilm). Unlike the wearable SERS substrates reported in literature, the one presented in this work is self-adhesive to a variety of surfaces, which simplifies structure, enhances comfort and improves performance. Importantly, the new SERS substrate as developed is highly stable and reusable. Artificial sample tests revealed that the substrate showed a great enhancement factor (EF) of 4.2 × 107 and achieved a remarkable detection limit (DL) of 1.0 × 10−14 M for rhodamine 6G (R6G), which are among the highest records observed in wearable SERS substrates reported in literature. Moreover, the substrate enables at real-time and in-situ reliable monitoring of urea dynamics in human sweat and plant leaves, indicating its applicability for health analysis and in precision agriculture. [ABSTRACT FROM AUTHOR]

We designed a novel ratiometric fluorescence immunoassay based on bioorthogonal nanozymes for carcinoembryonic antigen detection. The analytical performance of our designed immunoassay showed a wide linear range, a low detection limit, good reproducibility, selectivity and stability. Thus, bioorthogonal nanozymes hold great potential applications in clinical diagnoses. [ABSTRACT FROM AUTHOR]

Herein, Mn‐doped ZnS quantum dots/gelatin (QDs‐G) composite gel beads were directly prepared by a green and novel method. The method shows a range of benefits, such as the green and convenient process, mild conditions, and simple post‐processing. The resulting QDs‐G gel beads are transparent, homogeneous and stable. These gel beads exhibit clear orange‐red fluorescence under 302 nm UV light, which is associated with Mn‐doped ZnS QDs. Additionally, the QDs‐G gel beads possess a reversible thermo‐responsive sol‐gel transition property. TEM observation shows that there are QDs in the QDs‐G gel beads, and their average particle size is 4.0 nm. The QDs‐G gel beads can be innovatively used for both fluorescent detection and colorimetric detection, which show advantages such as simple operation, direct observation (no need for instruments), wide detection range, and good anti‐interference ability. Moreover, the more accurate fluorescence detection toward Cu2+ can be conducted through QDs/gelatin solution (the detection limit is 0.16 μM) based on the thermo‐responsive sol‐gel transition property of the gel beads. Therefore, the as‐fabricated QDs‐G gel bead is a promising candidate for application in the detection field. [ABSTRACT FROM AUTHOR]

In this work, we developed a rapid and sensitive label-free ratiometric fluorescent (FL) probe for the detection of bleomycin (BLM). The probe consists of a DNA sequence (D6) and two fluorophore groups, 2-amino-5,6,7-trimethyl-1,8-naphthalene (ATMND) and SYBR Green I (SGI). The D6 sequence could be folded into a three-way junction structure containing a C–C mismatch position in the junction pocket. The unique "Y" structure not only could entrap ATMND in the mismatch pocket with high affinity, leading to FL quenching at 408 nm, but also embed SGI in the grooves of the double-stranded portion, resulting in FL enhancement at 530 nm. In the presence of BLM–Fe(II), the "Y" structure of D6 was destroyed due to the specific cleavage of the BLM recognition site, the 5′-GT-3′ site in D6. This caused the release of ATMND and SGI and thus the ratiometric signal change of FL enhancement by ATMND and FL quenching by SGI. Under optimal conditions, the ratiometric probe exhibited a linear correlation between the intensity ratio of F408/F530 and the concentration of BLM in the range of 0.5–1000 nM, with a detection limit of 0.2 nM. In addition, the probe was applied to detect BLM in human serum samples with satisfactory results, indicating its good clinical application potential. [ABSTRACT FROM AUTHOR]

Background: Clinical samples are irreplaceable, and their transformation into searchable and reusable digital biobanks is critical for conducting statistically empowered retrospective and integrative research studies. Currently, mainly data-independent acquisition strategies are employed to digitize clinical sample cohorts comprehensively. However, the sensitivity of DIA is limited, which is why selected marker candidates are often additionally measured targeted by parallel reaction monitoring. Methods: Here, we applied the recently co-developed hybrid-PRM/DIA technology as a new intelligent data acquisition strategy that allows for the comprehensive digitization of rare clinical samples at the proteotype level. Hybrid-PRM/DIA enables enhanced measurement sensitivity for a specific set of analytes of current clinical interest by the intelligent triggering of multiplexed parallel reaction monitoring (MSxPRM) in combination with the discovery-driven digitization of the clinical biospecimen using DIA. Heavy-labeled reference peptides were utilized as triggers for MSxPRM and monitoring of endogenous peptides. Results: We first evaluated hybrid-PRM/DIA in a clinical context on a pool of 185 selected proteotypic peptides for tumor-associated antigens derived from 64 annotated human protein groups. We demonstrated improved reproducibility and sensitivity for the detection of endogenous peptides, even at lower concentrations near the detection limit. Up to 179 MSxPRM scans were shown not to affect the overall DIA performance. Next, we applied hybrid-PRM/DIA for the integrated digitization of biobanked melanoma samples using a set of 30 AQUA peptides against 28 biomarker candidates with relevance in molecular tumor board evaluations of melanoma patients. Within the DIA-detected approximately 6500 protein groups, the selected marker candidates such as UFO, CDK4, NF1, and PMEL could be monitored consistently and quantitatively using MSxPRM scans, providing additional confidence for supporting future clinical decision-making. Conclusions: Combining PRM and DIA measurements provides a new strategy for the sensitive and reproducible detection of protein markers from patients currently being discussed in molecular tumor boards in combination with the opportunity to discover new biomarker candidates. [ABSTRACT FROM AUTHOR]

X‐ray detectors utilizing 2D/3D heterodimensional perovskites have achieved great success. However, the labile nature of halide perovskites generally results in structures with random orientations and interfaces, which in turn increases the dark noise of X‐ray detectors, hindering their use in low‐dose X‐ray detection. Here, it is shown that both anisotropy and ultralow dark current can be achieved in self‐powered X‐ray detectors using well‐oriented 2D/3D heterodimensional perovskite crystals (HPCs). A halide diffusion‐promoted welding approach is devised to create the oriented HPCs, enabling two distinct configurations: A lateral orientation where the inorganic frameworks of the two phases are perpendicular, and a vertical orientation with parallel inorganic slabs. The different crystalline orientations produce unique anisotropic X‐ray detecting performance of 2D/3D HPCs, with a large anisotropic ratio of 4. Moreover, a self‐powered X‐ray detector using vertical HPC exhibits a greatly suppressed dark current density of 0.17 nA cm−2 and a low detection limit of 77 nGyair s−1, enabling high‐resolution X‐ray imaging. In contrast, the lateral devices show higher X‐ray sensitivity (1850 µC Gyair−1cm−2) at zero bias. This work reveals the interplay between crystalline orientation and X‐ray detection performance, opening new possibilities for developing low‐cost, low‐noise X‐ray detectors. [ABSTRACT FROM AUTHOR]

The design and development of ultra‐accurate probe is of great significance to chemical sensing in complex practical scenarios. Here, a self‐accelerating naphthalimide‐based probe with fast response and high sensitivity toward hydrogen peroxide (H2O2) is designed. By coupling with the specially selected upconversion nanoparticles (UCNPs), an ultra‐accurate colorimetric‐fluorescent‐upconversion luminescence (UCL) tri‐mode platform is constructed. Owing to the promoted reaction process, this platform demonstrates rapid response (< 1 s), an ultra‐low detection limit (4.34 nM), and superb anti‐interferent ability even in presence of > 21 types of oxidants, explosives, metallic salts, daily compounds, colorful or fluorescent substances. In addition, the effectiveness of this design is further verified by a sponge‐based sensing chip loaded with the UCNPs/probe in recognizing trace H2O2 vapor from interferents with the three characteristic colors existing simultaneously. The proposed design of probe and tri‐mode visualization detection platform is expected to open up a brand‐new methodology for ultra‐accurate sensing. [ABSTRACT FROM AUTHOR]

Hydrothermal synthesis has been effectively used to create pure and Europium (Eu3+) doped (1, 3 & 5%) ZnO nanostructures. The as-synthesized structures were analyzed using a range of spectroscopic and microscopic techniques such as X-ray, UV–Vis, FTIR, PL, and SEM analysis. It was discovered that the shape of the fabricated flower-like ZnO nanostructures made of mixed compact clustered nanorods could be meticulously governed by changing the Eu3+ dopant amount within the desired threshold. The distinctive photoluminescence (PL) properties indicate that energy is transferred from excited ZnO material, precisely at its band-gap (3.17 eV), to the Eu3+ states through the luminescent defects present in the nanoparticles. Considering, the increasing presence of heavy metal ions poses a continuous risk to both human health and ecosystems, we introduced for the first time, an electrochemical spectroscopy analysis of Europium-doped ZnO (Eu3+: ZnO) as modifications to the glassy carbon electrodes for lead (Pb2+) heavy metal ion detection. Electrochemical impedance spectroscopy, cyclic voltammetry, and square wave voltammetry were used to test the sensor’s sensing ability. Differential pulse voltammetry reveals the remarkable sensitivity towards Pb2+ ions with a 0.002 µM detection limit. [ABSTRACT FROM AUTHOR]

An easily synthesizable indole‐derived chromofluorogenic probe InNS has been demonstrated for recognition of trivalent metal ions (i. e. Al3+, Ga3+, In3+ and Fe3+). Both UV‐Vis and emission spectral studies have been employed to assess the cation sensing ability of InNS in semi‐aqueous medium. This probe exhibited a chromogenic response for these metal ions, and the related change was accompanied with the appearance of a new absorption near 376 nm. An obvious color change from pale yellow to dark yellow could also be noticed upon addition of the aforementioned metal ions to the probe's solution. Distinctively from the UV‐Vis analysis, the fluorescence behavior of InNS was completely different; it displayed a 'turn‐on' fluorescence response for only Al3+ among all the studied cations. The detection limit and the association constant (Ka) for Al3+ were determined to be 12.5 nM and 6.85×106 M−1, respectively. A potential 1 : 1 binding mode of Al3+‐InNS has been established based on Job's plot, 1H NMR and DFT analyses. The reversibility experiment was conducted using strongly chelating EDTA ion, and a corresponding logic gate has been devised. In terms of practical applications, the InNS has been utilized to detect Al3+ in human breast carcinoma (MCF‐7) cell lines displaying promising 'turn‐on' bioimaging experiments. [ABSTRACT FROM AUTHOR]

Nanozymes possess major advantages in catalysis and biosensing compared with natural nanozymes. In this study, the AuPt@BaTiO3 bimetallic alloy Schottky junction is prepared to act as oxidase mimetics, and its photo−piezoelectric effect is investigated. The synergy between the photo−piezoelectric effect and the local surface plasmon resonance enhances the directional migration and separation of photogenerated electrons, as well as hot electrons induced by the AuPt bimetallic alloy. This synergy significantly improves the oxidase−like activity. A GSH colorimetric detection platform is developed based on this fading principle. Leveraging the photo−piezoelectric effect allows for highly sensitive detection with a low detection limit (0.225 μM) and reduces the detection time from 10 min to 3 min. The high recovery rate (ranging from 99.91% to 101.8%) in actual serum detection suggests promising potential for practical applications. The development of bimetallic alloy heterojunctions presents new opportunities for creating efficient nanozymes. [ABSTRACT FROM AUTHOR]

The application of statistical estimation theory to Hong–Ou–Mandel interferometry led to enticing results in terms of the detection limit for photon reciprocal delay and polarisation measurement. In the following paper, a fully fibre-coupled setup operating in the telecom wavelength region proves to achieve, for the first time, in common-path Hong–Ou–Mandel-based interferometry, a detection limit for photon phase delay at the zeptosecond scale. The experimental results are then framed in a theoretical model by calculating the Cramer–Rao bound (CRB) and, after comparison with the obtained experimental results, it is shown that our setup attains the optimal measurement, nearly saturating CRB. [ABSTRACT FROM AUTHOR]

Aspergillus species create major postharvest problems due to the food losses caused by their mere presence and the hazardous mycotoxins they produce, such as aflatoxin B1 (AFB1) and ochratoxin A (OTA). These mycotoxins are mainly produced by A. flavus and A. carbonarius, respectively. In this study, we developed a rapid detection method for the two aforementioned species based on loop-mediated isothermal amplification (LAMP). The primers were designed to target genes belonging to the mycotoxin clusters pks and aflT for A. carbonarius and A. flavus, respectively. Result visualization was carried out in real time via the detection of fluorescent signals. The method developed showed high sensitivity and specificity, with detection limits of 0.3 and 0.03 pg/reaction of purified DNA of A. carbonarius and A. flavus, respectively. The assays were further implemented on inoculated nuts, including pistachios and almonds, after one-step crude DNA extraction. These tests revealed a detection level of 0.5 spore/g that shows the effectiveness of LAMP as a rapid method for detecting potentially toxigenic Aspergillus spp. directly in food. The validation of the assays included tests on a larger scale that further confirmed their sensitivity and specificity, as well as enabling the production of ready-to-use LAMP prototype kits. These kits are easy to use and aim to simplify the screening of food samples in order to monitor the presence of specific Aspergillus contaminations. [ABSTRACT FROM AUTHOR]

The primary goal of the proposed study is to establish and validate a low‐cost, sensitive, reliable, and trouble‐free RP‐UPLC process with improved performance for the direct estimation of Lixisenatide in pure powder and fixed‐dose tablet form. The proposed method is optimized by implementing quality by design studies. The method is optimized using quadratic model of central composite design (CCD) of randomized response surface study. Successful separation of Lixisenatide is obtained by the use of Phenyl‐XBD (1.7 µm, 2.1 mm × 100 mm) column and a mobile phase of acetonitrile: 0.1% w/v OPA (60:40) with 0.5 mL min−1 flow rate. The separated Lixisenatide and its degradants are explorated with PDA detector which has the ability to provide comprehensive spectral information, rapid data acquisition, quantitative analysis, and peak purity analysis of all compounds simultaneously. The RT of Lixisenatide is found to be 1.34 min. The lowest concentration of Lixisenatide's limit of detection and limit of quantification makes guarantees regarding the method's sensitivity. For the provided range of linear concentrations (1.25–7.5 µg mL−1), the regression coefficient is found to be 0.999. The computed average percentage recoveries of Lixisenatide in spiked solutions ranged from 98.9% to 101.2%. The % degradation of Lixisenatide in the presence of a variety of forced conditions confirms the existing method's stability. Lixisenatide is significantly photo sensitive when compared to other stressful conditions such as acid, base hydrolysis, and oxidation. The proposed UPLC approach separates Lixisenatide with high sensitivity, a short retention time, and an affordable solvent system. [ABSTRACT FROM AUTHOR]

In this work, an inelastic neutron scattering system was developed for element analysis in limestone with a D–T neutron generator and a 3*3 inch LaBr3 detector. Six sets of simulated limestone samples were prepared by proportionally mixing high-purity CaCO3, SiO2, and MgO powders and measured in situ with Inelastic Neutron Scattering (INS) facility. Empirical mode decomposition (EMD) technique is used for noise reduction and filtering of the original gamma energy spectrum. The energy window method was used for quantitative analysis. The minimum detection limits for Ca, Si, and Mg in the samples were determined to be 0.019%, 0.021%, and 0.026%, respectively. The linear relationship between elemental content and the gamma-ray counts has been studied. [ABSTRACT FROM AUTHOR]

Presented is an infrared-induced sensor constructed of upconversion nanoparticles and DNAzyme for ultra-sensitive, and rapid detection of uranyl ions. The detection method eliminates the use of chemically labeled nucleic acid probes, possesses high selectivity, and a uranyl detection limit of 39 nM. The technique is successfully applied to the detection of uranyl in various water samples as well as human serum, illustrating the excellent sensitivity and specificity of the quantification platform. [ABSTRACT FROM AUTHOR]

The rational design of covalent organic frameworks (COFs) with hydrochromic properties is of significant value because of the facile and rapid detection of water in diverse fields. In this report, we present a thiazole-linked COF (TZ-COF-6) sensor with a large surface area, ultrahigh stability, and excellent crystallinity. The sensor was synthesized through a simple three-component reaction involving amine, aldehyde, and sulfur. The thiazole and methoxy groups confer strong basicity to TZ-COF-6 at the nitrogen sites, making them easily protonated reversibly by water. Therefore, TZ-COF-6 displayed color change visible to the naked eye from yellow to red when protonated, along with a red shift in absorption in the ultraviolet-visible diffuse reflectance spectra (UV-vis DRS) when exposed to water. Importantly, the water-sensing process was not affected by polar organic solvents, demonstrating greater selectivity and sensitivity compared to other COF sensors. Therefore, TZ-COF-6 was used to detect trace amounts of water in organic solvents. In strong polar solvents, such as N,N-dimethyl formamide (DMF) and ethanol (EtOH), the limit of detection (LOD) for water was as low as 0.06% and 0.53%, respectively. Even after 8 months of storage and 15 cycles, TZ-COF-6 retained its original crystallinity and detection efficiency, displaying high stability and excellent cycle performance. [ABSTRACT FROM AUTHOR]

This research centers on the development and synthesis of a longwave fluorescence probe, labeled as 60T, designed for the simultaneous detection of hydrogen sulfide, cysteine/homocysteine, and glutathione. The probe showcases a swift response, good linearity range, and heightened sensitivity, boasting that the detection limits of the probe for Cys, Hcy, GSH and H2S were 0.140, 0.202, 0.259 and 0.396 μM, respectively. Notably, its efficacy in monitoring thiol status changes in live MCF-7 cells is underscored by a substantial decrease in fluorescence intensity upon exposure to the thiol trapping reagent, N-ethyl maleimide (NEM). With an impressive red emission signal at 630 nm and a substantial Stokes shift of 80 nm, this probe exhibits remarkable sensitivity and selectivity for biothiols and H2S, indicating promising applications in the diagnosis and surgical navigation of relevant cancers. [ABSTRACT FROM AUTHOR]

Membrane-based sensors (MePSs) exhibit remarkable precision and sensitivity in detecting pressure changes. MePSs are commonly used to monitor catalytic reactions in solution, generating gas products crucial for signal amplification in bioassays. They also allow for catalyst quantification by indirectly measuring the pressure generated by the gaseous products. This is particularly interesting for detecting enzymes in biofluids associated with disease onset. To enhance the performance of a MePS, various structural factors influence membrane flexibility and response time, ultimately dictating the device's pressure sensitivity. In this study, we fabricated MePSs using polydimethylsiloxane (PDMS) and investigated how structural modifications affect the Young's modulus (E) and residual stress (σ0) of the membranes. These modifications have a direct impact on the sensors' sensitivity to pressure variations, observed as a function of the volume of the chamber (Σ) or of the mechanical properties of the membrane itself (S). MePSs exhibiting the highest sensitivities were then employed to detect catalyst quantities inducing the dismutation of hydrogen peroxide, producing dioxygen as a gaseous product. As a result, a catalase enzyme was successfully detected using these optimized MePSs, achieving a remarkable sensitivity of (22.7 ± 1.2) µm/nM and a limit of detection (LoD) of 396 pM. [ABSTRACT FROM AUTHOR]

In this paper, we study the drift behavior of organic electrochemical transistor (OECT) biosensors in a phosphate-buffered saline (PBS) buffer solution and human serum. Theoretical and experimental methods are illustrated in this paper to understand the origin of the drift phenomenon and the mechanism of ion diffusion in the sensing layer. The drift phenomenon is explained using a first-order kinetic model of ion adsorption into the gate material and shows very good agreement with experimental data on drift in OECTs. We show that the temporal current drift can be largely mitigated using a dual-gate OECT architecture and that dual-gate-based biosensors can increase the accuracy and sensitivity of immuno-biosensors compared to a standard single-gate design. Specific binding can be detected at a relatively low limit of detection, even in human serum. [ABSTRACT FROM AUTHOR]

We propose a segmentation-based bounding box generation method for omnidirectional pedestrian detection that enables detectors to tightly fit bounding boxes to pedestrians without omnidirectional images for training. Due to the wide angle of view, omnidirectional cameras are more cost-effective than standard cameras and hence, suitable for large-scale monitoring. However, state-of-the-art pedestrian detectors cannot directly be applied to omnidirectional pedestrian detection because pedestrians' appearance in omnidirectional images may be rotated to any angle, which substantially degrades the performance of standard pedestrian detectors. Existing methods mitigate this issue by transforming images during inference, though the methods have limited detection accuracy and slow detection speed. A recently proposed method obviates the transformation at the cost of laborious annotation works and trains detectors with omnidirectional pedestrian detection datasets. We propose instead leveraging an existing large-scale object detection dataset to obviate both the transformation and annotation works. We train a detector with rotated images and tightly fitted bounding box annotations generated from the segmentation annotations in the object detection dataset, which enable detectors to detect pedestrians in omnidirectional images with tightly fitted bounding boxes. We also develop pseudo-fisheye distortion augmentation, which deforms images of perspective view to imitate the fisheye distortion and further enhances the performance. Extensive analysis shows that our detector successfully fits bounding boxes to pedestrians and demonstrates substantial performance improvement over existing methods. [ABSTRACT FROM AUTHOR]

Large-geometry secondary ion mass spectrometry (LG-SIMS) is routinely used to determine the elemental and isotopic compositions, thanks to its high sensitivity and in situ micro-analysis capability. Its large volumes of transfer and coupling column, however, might bring low vacuum and high background of volatile elements (esp. H), which hampers its application in ultralow H2O content measurement. In this study, we report a modified analytical procedure to accurately analyze samples with ultralow-level H2O content by using a LG-SIMS of type CAMECA IMS 1280-HR. Based on four new water content working reference materials of quartz glasses with H2O contents ranging from ca. 0 to 39 ppm, the estimated detection limit of LG-SIMS is 0.15 ppm for H2O. This ultralow detection limit is achieved mainly by the intrinsic high sensitivity of the instrument and the conjunctive usage of a stabilized temperature-controlled cooling trap device and a novel tin–bismuth alloy mount preparation technology, which are able to maintain a vacuum pressure at 1.7 × 10−9 mbar in the analysis chamber. Based on these new improvements, our approach can potentially become a routine choice for analyses of H2O content and oxygen–hydrogen isotopes for (extra)terrestrial materials with ultralow-level water content. [ABSTRACT FROM AUTHOR]

Time-of-flight ICP-mass spectrometry (ICP-ToF-MS) allows acquisition of almost the entire periodic table in only a few tens of microseconds, with several mass spectra combined into a single readout. When hyphenated with a low-dispersion laser ablation (LA) unit, it allows for 2D elemental mapping at a laser repetition rate of several hundred hertz, with each laser shot recorded as a single pixel. Although its use in geosciences is increasing, the technique is often referred to as semi-quantitative. Here, we present the outcomes of ultra-fast high-resolution 2D mapping and quantification of the constituting elements of geological reference materials and micrometeorites with LA-ICP-ToF-MS, carried out in a period of over a year. Quantitative data for each pixel were obtained through a combination of multi-point external calibration and normalization of the sum of all element oxide contents to 100%. Detection limits ranging from 0.1 to 10 μg g−1 were attained for most elements when using a 5 μm × 5 μm square laser spot. Repeated analysis of reference materials in a period of over one year demonstrates an intermediate precision down to 3% RSD. [ABSTRACT FROM AUTHOR]

A novel ionic responsive Schiff base organic gelator was successfully designed and synthesized. The solvent selection experiment showed that the gelator showed good thermoreversible gelator behavior in aniline, valerate alcohol and isopropyl alcohol. FT-IR studies have shown that C=O and N–H of molecules participate in the formation of intermolecular hydrogen bonds, thus promoting the formation of gelator states. The XRD and SEM results show that the molecules self-assemble in the dry gelator to form the entangled network structure. In addition, the fluorescence spectrum test of gelling agent G showed that gelling agent G could specifically recognize Cu2+. Gelator G has good selectivity, low detection limit (2.92 × 10–8 M) and high sensitivity, which can be applied to the detection of Cu2+ in biology, environment and other fields. The results show that gelator G has broad application prospects in materials science, chemistry, biomedicine and other fields. It also confirms that benzopyran-derived hydrazone Schiff base compounds have far-reaching research significance. [ABSTRACT FROM AUTHOR]

Purpose: This article aims to establish a rapid visual method for the detection of Streptococcus pyogenes (GAS) based on recombinase polymerase amplification (RPA) and lateral flow strip (LFS). Methods: Utilizing speB of GAS as a template, RPA primers were designed, and basic RPA reactions were performed. To reduce the formation of primer dimers, base mismatch was introduced into primers. The probe was designed according to the forward primer, and the RPA-LFS system was established. According to the color results of the reaction system, the optimum reaction temperature and time were determined. Thirteen common clinical standard strains and 14 clinical samples of GAS were used to detect the selectivity of this method. The detection limit of this method was detected by using tenfold gradient dilution of GAS genome as template. One hundred fifty-six clinical samples were collected and compared with qPCR method and culture method. Kappa index and clinical application evaluation of the RPA-LFS were carried out. Results: The enhanced RPA-LFS method demonstrates the ability to complete the amplification process within 6 min at 33 °C. This method exhibits a high analytic sensitivity, with the lowest detection limit of 0.908 ng, and does not exhibit cross-reaction with other pathogenic bacteria. Conclusions: The utilization of RPA and LFS allows for efficient and rapid testing of GAS, thereby serving as a valuable method for point-of-care testing. [ABSTRACT FROM AUTHOR]