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Purpose: We provide a comparison of X-ray fluorescence emission tomography (XFET) and computed tomography (CT) for detecting low concentrations of gold nanoparticles (GNPs) in soft tissue and characterize the conditions under which XFET outperforms energy-integrating CT (EICT) and photon-counting CT (PCCT)., Approach: We compared dose-matched Monte Carlo XFET simulations and analytical fan-beam EICT and PCCT simulations. Each modality was used to image a numerical mouse phantom and contrast-depth phantom containing GNPs ranging from 0.05% to 4% by weight in soft tissue. Contrast-to-noise ratios (CNRs) of gold regions were compared among the three modalities, and XFET's detection limit was quantified based on the Rose criterion. A partial field-of-view (FOV) image was acquired for the phantom region containing 0.05% GNPs., Results: For the mouse phantom, XFET produced superior CNR values ( CNRs = 24.5 , 21.6, and 3.4) compared with CT images obtained with both energy-integrating ( CNR = 4.4 , 4.6, and 1.5) and photon-counting ( CNR = 6.5 , 7.7, and 2.0) detection systems. More generally, XFET outperformed CT for superficial imaging depths ( < 28.75    mm ) for gold concentrations at and above 0.5%. XFET's surface detection limit was quantified as 0.44% for an average phantom dose of 16 mGy compatible with in vivo imaging. XFET's ability to image partial FOVs was demonstrated, and 0.05% gold was easily detected with an estimated dose of ∼ 81.6    cGy to a localized region of interest., Conclusions: We demonstrate a proof of XFET's benefit for imaging low concentrations of gold at superficial depths and the feasibility of XFET for in vivo metal mapping in preclinical imaging tasks., (© 2024 The Authors.)

This paper studies the problem of constructing confidence intervals (CIs) for the difference between coefficients of variation (CV) of two censored zero-inflated gamma distributions. Firstly, we propose a Fiducial inference based method that extends the traditional CI construction method of gamma distribution to the scenario of zero-inflated gamma distributions with censored data. Secondly, we propose a Box-Cox transformation based method, in which not only the sample data needs to be transformed, but also the detection limit of gamma distribution with censored data accordingly. Thirdly, we investigate the Method of Variance Estimate Recovery (MOVER), to combine the previous two gamma distribution CI estimates with three binomial distribution CI estimates, and obtain six combination methods. Furthermore, we conduct Monte Carlo simulations to evaluate the performances of the proposed methods, the results indicate that all CI construction methods achieve satisfactory performances in terms of coverage probability, average length and tail error rates. Finally, we perform real data analysis using 11 years of precipitation data from Zhengzhou and Lhasa., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

The latest pandemic resulting from the novel SARS-CoV-2 coronavirus has significantly affected public health, the worldwide economy, and social life. Metal organic frameworks (MOFs) are currently being implemented in biosensors for rapid and accurate detection of viruses thanks to their exceptional properties. This research aims to develop a Zeolitic Imidazolate Framework-8 (ZIF-8) based fluorescent biosensor for facile and rapid COVID-19 RNA sequence detection. ZIF-8 was characterized using several tests, such as FT-IR, TGA, and PXRD, to examine the MOF's crystalline structure and thermal stability. The results demonstrated high crystallinity and thermal stability up to a temperature of 550 °C. The experimental study showed that ZIF-8 is an excellent fluorescence quencher, with 78.39% quenching efficiency. Analyzing the adsorption mechanism of probe DNA into ZIF-8 revealed that they can form electrostatic and π-π stacking interactions, forming a P-DNA@ZIF-8 complex and that PET is more dominant than FRET in the quenching mechanism. This ZIF-8 biosensing platform showed high sensitivity towards COVID-19 RNA with an ultra-low limit of detection of 6.24 pM, a rapid detection time of 8 min, and high selectivity to COVID-19 RNA. Indeed, ZIF-8 experienced much lower fluorescence recovery when tested on two mismatched RNAs. The experimental results show the potential use of ZIF-8 as a novel biosensor for a rapid and sensitive COVID-19 diagnosis., (© 2024. The Author(s).)

Molybdenum nitride is a promising candidate for surface-enhanced Raman scattering (SERS) substrates due to its high conductivity, surface plasmon resonance, and chemical stability. Core-shell structures possess unique physical and chemical properties, such as high-volume ratio, low density, short diffusion length, and high load-bearing capacity, making them favorable for SERS applications. In this research, core-shell MoO 3 is first synthesized as a precursor oxide using a sacrificial template method, and core-shell MoN microspheres are successfully prepared via subsequent nitriding. As a representative transition metal nitride, the obtained core-shell MoN nanospheres show strong localized surface plasmon resonance and SERS effects. Using these MoN microspheres as Raman substrates allows a range of highly targeted compounds to be accurately detected, and the detection limits for this non-precious-metal substrate morphology are exceptionally high, reaching 10 -10 M. In addition, MoN nanospheres exhibit excellent resistance to acid-base corrosion, oxidation, and radiation, thus rendering them suitable for use as substrates in harsh environments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

An easily synthesized reaction-based probe for the fluorescence detection of Hg 2+ ions using was reported. The designed probe exhibited "turn-on" fluorescence response towards Hg 2+ ions via deprotection of the thiocarbonate-protecting group to alcohol in the HEPES/EtOH=8:2 (v/v, 5 mM, pH 7.4). The investigation results of probe Bzp-1 properties for Hg 2+ detection indicated that probe Bzp-1 has satisfactory high selectivity and sensitivity. The detection limit of Bzp-1 for Hg 2+ was found to be 4.2 nM. The recognition mechanism of Bzp-1 for Hg 2+ was confirmed by ESI-MS. Moreover, the probe Bzp-1 has been successfully used to rapidly detect trace amounts of hazardous Hg 2+ ions in real samples such as tap water, seafood and soil with good recoveries and less the relative standard deviations. Moreover, the Bzp-1 can also be used for fluorescence imagining of Hg 2+ in living cells., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

In this study, a new Schiff base, (E)-2-(2-aminophenylthio)-N-(thiophen-2-yl-methylene) benzenamine was synthesized for selective detection of Hg 2+ . This Schiff base was characterized by proton nuclear magnetic resonance ( 1 HNMR), carbon-13 nuclear magnetic resonance ( 13 CNMR), and Fourier-transform infrared (FTIR) spectroscopy. Binding interaction between (E)-2-(2-aminophenylthio)-N-(thiophen-2-yl-methylene)benzenamine and various metal ions has been studied by UV-Vis spectroscopic measurements and shows promising coordination towards Hg 2+ and almost no interference from other metal ions (Ag + , Mn 2+ , Fe 3+ , Al 3+ , Co 2+ , Ni 2+ , Cu 2+ , Zn 2+ , Cd 2+ , Fe 2+ and Cr 3+ ).This Schiff base exhibiting detection limit of 3.8 × 10 - 8  M. The Schiff base newly synthesized in this study was successfully applied to the determination of Hg 2+ in water samples. In addition to the experimental study, a theoretical study was conducted using Gaussian 09 program to support the experimental findings. FTIR, NMR, bond angle, bond length, torsional angles, and structural approximation were studied using theoretical consideration., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Hydrogen heralded as a promising renewable and environmentally friendly energy carrier, carries inherent risks owing to its highly flammable nature. A mere 4 % concentration of hydrogen in the air can trigger an explosion. To counteract this peril, a composite material comprising PbO X -ZnO (2 : 1) was synthesized, characterized, and subsequently employed to fabricate a hydrogen sensing device. Various analytical tools were used to characterize as-deposited materials, including X-ray diffraction, Scanning electron microscopy /Energy Dispersive X-ray Spectroscopy, Transmission electron microscopy UV-Vis Reflectance Spectroscopy and Fourier-transform infrared spectroscopy. The device exhibited favorable properties, such as good selectivity, stability, and a low detection limit for hydrogen. At ambient room temperature, the device demonstrated a sensing signal reaching 468.7, with a response time (T90) of 155 seconds and a recovery time (Tr90) of 69 seconds when exposed to a hydrogen concentration of 5 ppm. This performance underscores the device's rapid and effective response to hydrogen exposure. Moreover, the PbOX-ZnO (2 : 1) composite-based device exhibited a detection limit of 2.4 ppm, functioning accurately within a linear range spanning from 5 ppm to 50 ppm. This capability confirms its precision in accurately detecting hydrogen concentrations within this designated range., (© 2023 Wiley-VCH GmbH.)

Herein we have reported a fluorescent probe (MB-M) based on MB derivative for Cu 2+ ions detection. The probe was well characterized by 1 H NMR, 13 C NMR and HR-MS spectrum. Probe MB-M showed naked-eyes recognition to Cu 2+ as color change from colorless to indigo. The probe exhibited promising features such as high fluorescence and UV-vis selectivity, fast response (5 mint), workable at pH 2-7, and low limit of detection (LOD = 0.33 µM). Probe MB-M was also used for Cu 2+ ions imaging in HepG-2 cells and detection in daily life (Test Strip and lake water). Moreover, non-covalent interaction (NCI) and quantum theory of atoms in molecules (QTAIM) analysis were used to study the interaction between MB-M and Cu 2+ ions. By examining the electronic characteristics of the complex using natural bond orbital (NBO), electron density difference (EDD), and frontier molecular orbital (FMO) analysis, the sensitivity of MB-M towards Cu 2+ ions were investigated. The results illustrated that the interactions between MB-M and Cu 2+ ions involved chemisorption., (© 2024. The Author(s).)

Due to the toxicity of mercury and its harmful effects on human health, it is essential to establish a low-cost, highly sensitive and highly specific monitoring method with a wide detection range, ideally with a simple visual readout. In this study, a whole-cell biosensor with adjustable detection limits was developed for the detection of mercury ions in water samples, allowing controllable threshold detection with an expanded detection range. Gene circuits were constructed by combining the toehold switch system with lactose operon, mercury-ion-specific operon, and inducible red fluorescent protein gene. Using MATLAB for design and selection, a total of eleven dual-input single-output sensing logic circuits were obtained based on the basic logic of gene circuit construction. Then, biosensor DTS-3 was selected based on its fluorescence response at different isopropyl β-D-Thiogalactoside (IPTG) concentrations, exhibiting the controllable detection threshold. At 5-20 μM IPTG, DTS-3 can achieve variable threshold detection in the range of 0.005-0.0075, 0.06-0.08, 1-2, and 4-6 μM mercury ion concentrations, respectively. Specificity experiments demonstrated that DTS-3 exhibits good specificity, not showing fluorescence response changes compared with other metal ions. Furthermore spiked sample experiments demonstrated its good resistance to interference, allowing it to distinguish mercury ion concentrations as low as 7.5 nM by the naked eye and 5 nM using a microplate reader. This study confirms the feasibility and performance of biosensor with controllable detection threshold, providing a new detection method and new ideas for expanding the detection range of biosensors while ensuring rapid and convenient measurements without compromising sensitivity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This review provides a thorough examination of small molecule-based fluorescence chemosensors tailored for bioimaging applications, showcasing their unique ability to visualize biological processes with exceptional sensitivity and selectivity. It explores recent advancements, methodologies, and applications in this domain, focusing on various designs rooted in anthracene, benzothiazole, naphthalene, quinoline, and Schiff base. Structural modifications and molecular engineering strategies are emphasized for enhancing sensor performance, including heightened sensitivity, selectivity, and biocompatibility. Additionally, the review offers valuable insights into the ongoing development and utilization of these chemosensors, addressing current challenges and charting future directions in this rapidly evolving field., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The recent regulatory spotlight on continuous monitoring (CM) solutions and the rapid development of CM solutions have demanded the characterization of solution performance through regular, rigorous testing using consensus test protocols. This study is the second known implementation of such a protocol involving single-blind controlled testing of 9 CM solutions. Controlled releases of rates (6-7100 g) CH 4 /h over durations (0.4-10.2 h) under a wind speed range of (0.7-9.9 m/s) were conducted for 11 weeks. Results showed that 4 solutions achieved method detection limits (DL90s) within the tested emission rate range, with all 4 solutions having both the lowest DL90s (3.9 [3.0, 5.5] kg CH 4 /h to 6.2 [3.7, 16.7] kg CH 4 /h) and false positive rates (6.9-13.2%), indicating efforts at balancing low sensitivity with a low false positive rate. These results are likely best-case scenario estimates since the test center represents a near-ideal upstream field natural gas operation condition. Quantification results showed wide individual estimate uncertainties, with emissions underestimation and overestimation by factors up to >14 and 42, respectively. Three solutions had >80% of their estimates within a quantification factor of 3 for controlled releases in the ranges of [0.1-1] kg CH 4 /h and > 1 kg CH 4 /h. Relative to the study by Bell et al., current solutions performance, as a group, generally improved, primarily due to solutions from the study by Bell et al. that were retested. This result highlights the importance of regular quality testing to the advancement of CM solutions for effective emissions mitigation.

Glucaric acid (GA) is a value-added chemical and can be used to manufacture food additives, anticancer drugs, and polymers. The non-genetic cell-to-cell variations in GA biosynthesis are naturally inherent, indicating the presence of both high- and low-performance cells in culture. Low-performance cells can lead to nutrient waste and inefficient production. Furthermore, myo -inositol oxygenase (MIOX) is a key rate-limiting enzyme with the problem of low stability and activity in GA production. Therefore, eliminating cell-to-cell variations and increasing MIOX stability can select high-performance cells and improve GA production. In this study, an in vivo GA bioselector was constructed based on GA biosensor and tetracycline efflux pump protein TetA to continuously select GA-efficient production strains. Additionally, the upper limit of the GA biosensor was improved to 40 g/L based on ribosome-binding site optimization, achieving efficient enrichment of GA high-performance cells. A small ubiquitin-like modifier (SUMO) enhanced MIOX stability and activity. Overall, we used the GA bioselector and SUMO-MIOX fusion in fed-batch GA production and achieved a 5.52-g/L titer in Escherichia coli , which was 17-fold higher than that of the original strain.IMPORTANCEGlucaric acid is a non-toxic valuable product that was mainly synthesized by chemical methods. Due to the problems of non-selectivity, inefficiency, and environmental pollution, GA biosynthesis has attracted significant attention. The non-genetic cell-to-cell variations and MIOX stability were both critical factors for GA production. In addition, the high detection limit of the GA biosensor was a key condition for performing high-throughput screening of GA-efficient production strains. To increase GA titer, this work eliminated the cell-to-cell variations by GA bioselector constructed based on GA biosensor and TetA, and improved the stability and activity of MIOX in the GA biosynthetic pathway through fusing the SUMO to MIOX. Finally, these approaches improved the GA production by 17-fold to 5.52 g/L at 65 h. This study represents a significant step toward the industrial application of GA biosynthetic pathways in E. coli ., Competing Interests: The authors declare no conflict of interest.

Synchronous fluorescence spectroscopy (SFS) is a technique that involves the simultaneous detection of fluorescence excitation and emission at a constant wavelength difference. The spectrum yields bands that are narrower and less complex than the original excitation and emission bands. The SFS bands correspond uniquely to the fluorescing molecule. Our investigation focuses on evaluating the sensitivity of the SFS technique for the detection and quantitation of PAHs relevant to astrochemistry. Results are presented for naphthalene, anthracene, and pyrene in three different solvents: n-hexane, water, and ethanol. SF bands are obtained with a constant wavelength difference between the peak excitation and emission wavelength (Δλ = λ ex - λ em ) at a concentration ranging from 10 -4 to 10 -10 M. Limit of detection (LOD) and limit of quantitation (LOQ) calculations are based on integrated SF band areas at different concentrations. Spectra of 23 pg/g of anthracene, 16 pg/g, and 2.6 pg/g of pyrene are recorded using ethanol as the solvent. The PAHs exhibit detection limits in the fractions of parts-per-billion (ng/g) range. Through comparison with similar prior studies employing fluorescence emission, our findings reveal a better detectability limit, demonstrating the effectiveness and applicability of the SFS technique.

CA125 (carbohydrate antigen 125) is an important biomarker of ovarian cancer, so developing effective method for its detection is of great significance. In the present work, a novel sandwich-like electrochemical immunosensor (STEM) of CA125 was constructed by preparing nanoribbon-like Ti 3 C 2 T x MXenes (Ti 3 C 2 T x NR) to immobilize primary antibody (PAb) of CA125 and UIO-66-NH 2 MOFs structure to immobilize second antibody (SAb) and electroactive toluidine blue (Tb) probe. In this designed STEM assay, the as-prepared Ti 3 C 2 T x NR nanohybrid offers the advantages in large surface area and conductivity as carrier, and UIO-66-NH 2 provided an ideal platform to accommodate SAb and a large number of Tb molecules as signal amplifier. In the presence of CA125, the peak currents of Tb from the formed STEM structure increase with the increase of CA125 level. After optimizing the related control conditions, a wide linear range (0.2-150.0 U mL -1 ) and a very low detection limit (0.05 U mL -1 ) of CA125 were achieved. It's thus expected the developed STEM strategy has important applications for the detection of CA125., (© 2024. The Author(s), under exclusive licence to The Japan Society for Analytical Chemistry.)

The Flinders Technology Associates (FTA) card, a cotton-based cellulose membrane impregnated with a chaotropic agent, effectively inactivates infectious microorganisms, lyses cellular material, and fixes nucleic acid. The aim of this study is to assess the stability and detection limit of various RNA viruses, especially the avian influenza virus (AIV), Newcastle disease virus (NDV), and African horse sickness virus (AHSV), on the FTA card, which could significantly impact virus storage and transport practices. To achieve this, each virus dilution was inoculated onto an FTA card and stored at room temperature in plastic bags for durations ranging from 1 week to 6 months. Following storage, the target genome was detected using conventional reverse transcription polymerase chain reaction. The present study demonstrated that the detection limit of AIV ranged from 1.17 to 6.17 EID 50 values over durations ranging from 1 week to 5 months, while for NDV, it ranged from 2.83 to 5.83 ELD 50 over the same duration. Additionally, the detection limit of AHSV was determined as 4.01 PFU for both 1 and 2 weeks, respectively. Based on the demonstrated effectiveness, stability, and safety implications observed in the study, FTA cards are recommended for virus storage and transport, thus facilitating the molecular detection and identification of RNA viral pathogens.

Introduction: Difenoconazole (DIFE) is a common pesticide used in citrus cultivation; excessive intake can cause neurological damage to the organism, and the existing colloidal gold immunochromatographic test strips cannot meet the requirements for the detection of citrus samples., Methods: Difenoconazole test strip was prepared based on the colloidal gold immunochromatographic technique (GICT), and its application in citrus samples was investigated; with colloidal gold (CG) as the probe, the optimization of GICT parameters, and the determination of reaction method, the immunochromatographic test strips for the detection of DIFE in citrus was developed, and the limit of detection (LOD), specificity, accuracy, and stability of the test strips were verified., Results: The results showed that the visual detection limit of the prepared colloidal gold immunochromatographic test strips was 0.2 mg/kg and the quantitative range was 0.06-0.6 mg/kg, and the test strips could specifically identify DIFE and have no cross-reaction with other common triazole pesticides. The detection method established in this study was verified by the GC-MS method, and the detection results achieved good consistency ( R 2  > 0.98)., Conclusion: The test strips developed in this study have good performance and can be used for highly sensitive detection of citrus samples., Competing Interests: YW was employed by Beijing Kwinbon Technology Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Wang, Gong, Liu, Zhu, Zhang, Zhao, Yin, Liu, Wang and Wan.)

In this study, a novel fluorescent chemosensor 1 based on chromone-3-carboxaldehyde Schiff base was synthesized and featured through nuclear magnetic resonance (NMR) and mass spectra. Spectroscopic investigation indicated that the fluorescent sensor showed high selectivity toward Zn 2+ over other metal ions and that the detection limit of 1 could reach 10 -7  M. These indicated that 1 acted as a highly selective and sensitive fluorescence chemosensor for Zn 2+ ., (© 2024 John Wiley & Sons Ltd.)

In this work, we designed and synthesized a novel, simple, low-cost, and effective chromone-based Schiff base ligand ( HL ) and its application as a chemosensor for Fe 3+ detection. The structure of the synthesized sensor bears carboxylic, azomethine, and carbonyl groups which act as chelating sites for the detection of Fe 3+ ions. The chemosensor HL exhibited highly selective detection of Fe 3+ via a significant colour change from yellow to brown. The colour change is due to the ligand-to-metal charge-transfer (LMCT) mechanism. The sensor ( HL ) was characterized using UV-Vis, FTIR, NMR ( 1 H- and 13 C), and mass spectroscopy. The ligand solubility, detection condition, and sensitivity assessment suggested optimal use of DMF-water (9:1 v/v) as a working solvent at pH 7.0. Among a list of 15 metal ions screened, HL was highly selective, with instant response, towards Fe 3+ ions without significant interferences with the other metal ions. The complexation ratio and association constants of HL to Fe 3+ was determined by Job's plot and Benesi-Hildebrand methods, and were 2:1 and 2.24 × 10 3 , respectively, with a detection limit of 2.86 μM. The -1 , respectively, with a detection limit of 2.86 μM. The HL probe was also applied to detect Fe 3+ ions with a detection limit of 68 µM. The DFT was used to examine the best interaction mode of 3+ ions with a detection limit of 68 µM. The DFT was used to examine the best interaction mode of HL with Fe metal to be Fe(III)-L or Fe(III)-2L. The chemical-reactivity and molecular electrostatic optional were figured to predict the interaction behaviour of the tested compounds.

Purpose: Human Papillomavirus (HPV) in semen represents a controversial topic. Recent evidence suggests a correlation with poor semen quality, but its detection is still unstandardized in this biological fluid. Thus, the aims of this study were to verify the ability of nested PCR to reveal HPV-DNA in semen; to evaluate association of seminal HPV with sperm parameters and risk factors for infection; to investigate the rate of HPV-DNA positivity in patients with and without risk factors; to assess HPV transcriptional activity., Methods: We enrolled sexually active men and collected clinical and anamnestic data during andrological and sexually transmitted infections (STIs) evaluation. For each patient, we performed semen analysis and nested PCR to detect HPV-DNA in semen. In positive semen samples, we proceeded with genotyping and RNA quantification to detect HPV transcriptional activity., Results: We enrolled 185 men (36.0 ± 8.3 years), of which 85 with (Group A) and 100 without HPV risk factors (Group B). Nested PCR was able to reveal HPV-DNA in semen, discovering a prevalence of 8.6% (11.8% in Group A and 6% in Group B, respectively). We observed no correlation between sperm quality and seminal HPV. Genital warts and previous anogenital infection were significantly associated with the risk of HPV positivity in semen. Moreover, no viral transcriptional activity was detected in positive semen samples., Conclusions: Our study suggests that searching for seminal HPV could be important in patients both with and without risk factors, especially in assisted reproduction where the risk of injecting sperm carrying HPV-DNA is possible., (© 2023. The Author(s).)

Introduction: Acute haemorrhagic diarrhoea syndrome (AHDS) in dogs is a condition of unknown aetiology. Providencia alcalifaciens is suspected to play a role in the disease as it was commonly found in dogs suffering from AHDS during a Norwegian outbreak in 2019. The role of this bacterium as a constituent of the canine gut microbiota is unknown, hence this study set out to investigate its occurrence in healthy dogs using metagenomics., Materials and Methods: To decrease the likelihood of false detection, we established a metagenomic threshold for P. alcalifaciens by spiking culture-negative stool samples with a range of bacterial dilutions and analysing these by qPCR and shotgun metagenomics. The detection limit for P. alcalifaciens was determined and used to establish a metagenomic threshold. The threshold was validated on naturally contaminated faecal samples with known cultivation status for P. alcalifaciens . Finally, the metagenomic threshold was used to determine the occurrence of P. alcalifaciens in shotgun metagenomic datasets from canine faecal samples (n=362) collected in the HUNT One Health project., Results: The metagenomic assay and qPCR had a detection limit of 1.1x10 3 CFU P. alcalifaciens per faecal sample, which corresponded to a Cq value of 31.4 and 569 unique k- mer counts by shotgun metagenomics. Applying this metagenomic threshold to 362 faecal metagenomic datasets from healthy dogs, P. alcalifaciens was found in only 1.1% (95% CI [0.0, 6.8]) of the samples, and then in low relative abundances (median: 0.04%; range: 0.00 to 0.81%). The sensitivity of the qPCR and shotgun metagenomics assay was low, as only 40% of culture-positive samples were also positive by qPCR and metagenomics., Discussion: Using our detection limit, the occurrence of P. alcalifaciens in faecal samples from healthy dogs was low. Given the low sensitivity of the metagenomic assay, these results do not rule out a significantly higher occurrence of this bacterium at a lower abundance., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Aardal, Soltvedt, Nørstebø, Haverkamp, Rodriguez-Campos, Skancke and Llarena.)

Halide perovskites have emerged as highly promising materials for ionizing radiation detection due to their exceptional characteristics, including a large mobility-lifetime product, strong stopping power, tunable band gap, and cost-effective crystal growth via solution processes. Semiconductor-type X-ray detectors employing various micro/nano perovskite materials have shown impressive progress in achieving heightened sensitivity and lower detection limits. Here, we present a comprehensive review of the applications of micro/nano perovskite materials for direct type X-ray detection, with a focus on the requirements for micro/nano crystal assembly and device properties in advanced X-ray detectors. We explore diverse processing techniques and optoelectronic considerations applied to perovskite X-ray detectors. Additionally, this review highlights the challenges and promising opportunities for perovskite X-ray detector arrays in real-world applications, potentially necessitating further research efforts.

Measures of substance concentration in urine, serum or other biological matrices often have an assay limit of detection. When concentration levels fall below the limit, exact measures cannot be obtained, and thus are left censored. The problem becomes more challenging when the censored data come from heterogeneous populations consisting of exposed and non-exposed subjects. If the censored data come from non-exposed subjects, their measures are always zero and hence censored, forming a latent class governed by a distinct censoring mechanism compared with the exposed subjects. The exposed group's censored measurements are always greater than zero, but less than the detection limit. It is very often that the exposed and non-exposed subjects may have different disease traits or different relationships with outcomes of interest, so we need to disentangle the two different populations for valid inference. In this article, we aim to fill the methodological gaps in the literature by developing a novel joint modeling approach to not only address the censoring issue in predictors, but also untangle different relationships of exposed and non-exposed subjects with the outcome. Simulation studies are performed to assess the numerical performance of our proposed approach when the sample size is small to moderate. The joint modeling approach is also applied to examine associations between plasma metabolites and blood pressure in Bogalusa Heart Study, and identify new metabolites that are highly associated with blood pressure., (© 2023 John Wiley & Sons Ltd.)

Nanostructures have played a key role in the development of different techniques to attack severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Some applications include masks, vaccines, and biosensors. The latter are of great interest for detecting diseases since some of their features allowed us to find specific markers in secretion samples such as saliva, blood, and even tears. Herein, we highlight how hierarchical nanoparticles integrated into two or more low-dimensional materials present outstanding advantages that are attractive for photonic biosensing using their nanoscale functions. The potential of nanohybrids with their superlative mechanical characteristics together with their optical and optoelectronic properties is discussed. The progress in the scientific research focused on using nanoparticles for biosensing a variety of viruses has become a medical milestone in recent years, and has laid the groundwork for future disease treatments. This perspective analyzes the crucial information about the use of hierarchical nanostructures in biosensing for the prevention, treatment, and mitigation of SARS-CoV-2 effects.

This study presents a dipyrromethene-based sensitive and selective probe for Zn 2+ ions detection in aqueous and water-organic media. The probe demonstrates absorbance-ratiometric and "off-on" fluorescent sensing for Zn 2+ in a DMSO/H 2 O (9:1, v/v) mixture. The 3,3',4,4',5,5'-hexamethyl-2,2'-dipyrromethene (HL), similar to its analogs, exhibits weak fluorescence (with a quantum yield of less than 0.001). However, upon the presence of Zn 2+ ions in the sensor HL solution, there is a remarkable increase (up to 200-fold) in fluorescence intensity due to the formation of a stable intramolecular chelate complex [ZnL 2 ]. This complex formation induces a significant hyperchromic effect and a red shift (57 nm) in the characteristic absorption bands. The sensing mechanism of the probe towards Zn 2+ ions was thoroughly investigated through absorbance and fluorescent titrations, molar ratio plots, 1 H NMR, and DFT/TDDFT studies. The fluorescence response exhibited a strong linear relationship with Zn 2+ concentration within the range of 0 to 5.7 × 10 -6 mol/L. The detection limit (LOD) and limit of quantitation (LoQ) for Zn 2+ were determined as 2 × 10 -8 mol/L and 6.6 × 10 -8 mol/L, respectively. Moreover, the probe demonstrated high selectivity for Zn 2+ ions over other metal ions (Na + , Mg 2+ , Al 3+ , Cr 3+ , Mn 2+ , Fe 3+ , Co 2+ , Ni 2+ , Cu 2+ , Pd 2+ , Cd 2+ , Hg 2+ , Pb 2+ ). Test systems in the form of test-strips and cotton-pads were developed based on the dipyrromethene sensor for rapid "naked-eye" detection of zinc ions in water. The sensor was successfully applied for detecting Zn 2+ ions in real water samples., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Alexander A. Ksenofontov reports financial support was provided by Ministry of Science and Higher Education of the Russian Federation., (Copyright © 2023. Published by Elsevier B.V.)

Accurate and efficient bacterial typing methods are crucial to microbiology. Fourier transform infrared (FT-IR) spectroscopy enables highly distinguishable fingerprint identification of closely related bacterial strains by producing highly specific fingerprints of bacteria, which is increasingly being considered as an alternative to genotypic methods, such as pulsed field gel electrophoresis (PFGE) and whole genome sequencing (WGS), for bacterial typing. Compared with genotypic methods, FT-IR has significant advantages of convenient operation, fast speed, and low cost. Fundamental research into the detection limit based on optimized analytical conditions for FT-IR bacterial typing, which can avoid excessive bacterial culture time or sampling volume, is particularly important, especially in clinical practice. However, the corresponding parameters have not been fully investigated. In this study, we developed a simplified and reliable procedure for sample preparation, optimized the data analysis procedure, and evaluated the FT-IR detection limit based on the above conditions. In particular, we combined the film mold and calcium fluoride plate for sample preparation. We evaluated the detection limit (about 10 8 CFU/mL) after parameter optimization using hierarchical cluster analysis (HCA) and artificial neural network (ANN). The optimization and evaluation of these key fundamentals will better promote future application of FT-IR-based bacterial typing., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Background: Babesia is a unique apicomplexan parasite that specifically invades and proliferates in red blood cells and can be transmitted via blood transfusion, resulting in transfusion-transmitted babesiosis. However, detecting Babesia in blood before transfusion has not received enough attention, and the risk of transfusing blood containing a low density of Babesia microti ( B. microti ) is unclear, possibly threatening public health and wellness., Purpose: This study aimed to determine the lower detection limit of B. microti in blood and to evaluate the transmission risk of blood transfusion containing low-density B. microti ., Methods: Infected BALB/c mouse models were established by transfusing infected whole blood with different infection rates and densities of B. microti . Microscopic examination, nested Polymerase Chain Reaction (nested PCR), and an enzyme-linked immunosorbent assay (ELISA) were used to evaluate the infection status of the mouse models. Meanwhile, the nested PCR detection limit of B. microti was obtained using pure B. microti DNA samples with serial concentrations and whole blood samples with different densities of B. microti -infected red blood cells. Thereafter, whole mouse blood with a B. microti density lower than that of the nested PCR detection limit and human blood samples infected with B. microti were transfused into healthy mice to assess the transmission risk in mouse models. The infection status of these mice was evaluated through microscopic examination, nested PCR tests, and ELISA., Results: The mice inoculated with different densities of B. microti reached the peak infection rate on different days. Overall, the higher the blood B. microti density was, the earlier the peak infection rate was reached. The levels of specific antibodies against B. microti in the blood of the infected mice increased sharply during the first 30 days of infection, reaching a peak level at 60 days post-infection, and maintaining a high level thereafter. The nested PCR detection limits of B. microti DNA and parasite density were 3 fg and 5.48 parasites/μL, respectively. The whole blood containing an extremely low density of B. microti and human blood samples infected with B. microti could infect mice, confirming the transmission risk of transfusing blood with low-density B. microti ., Conclusion: Whole blood containing extremely low density of B. microti poses a high transmission risk when transfused between mice and mice or human and mice, suggesting that Babesia detection should be considered by governments, hospitals, and disease prevention and control centers as a mandatory test before blood donation or transfusion., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Cai, Xu, Liu, Yang, Mo, Zheng, Chen and Hu.)

Fluorescent and colorimetric chemosensors for selective detection of various biologically important analytes have been widely applied in different areas such as biology, physiology, pharmacology, and environmental sciences. The research area based on fluorescent chemosensors has been in existence for about 150 years with the development of large number of fluorescent chemosensors for selective detection of cations as metal ions, anions, reactive species, neutral molecules and different gases etc. Despite the progress made in this field, several problems and challenges still exist. The most important part of sensing is limit of detection (LOD) which is the lowest concentration that can be measured (detected) with statistical significance by means of a given analytical procedure. Although there are so many reports available for detection of millimolar to micromolar range but the development of chemosensors for the detection of analytes in nanomolar range is still a challenging task. Therefore, in our current review we have focused the history and a general overview of the development in the research of fluorescent sensors for selective detection of various analytes at nanomolar level only. The basic principles involved in the design of chemosensors for specific analytes, binding mode, photophysical properties and various directions are also covered here. Summary of physiochemical properties, mechanistic view and type of different chemosensors has been demonstrated concisely in the tabular forms., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The work described is focused on a newly developed colorimetric Schiff base fluorescent sensor that exhibits a "turn-off" response when detecting fluoride ions (F - ) in an aqueous environment. The confirmation of the recognition event is accomplished through fluorescence titration, absorbance titration, and Density Functional Theory (DFT) calculation study. From the results, it is determined that the detection limit of F - is 2.35 × 10 -8 M which is much lower than the World Health Organization (WHO) permissible limit for drinking water while the binding constant was obtained to be 0.1 × 10 6 M -1 indicating a moderate affinity for the fluoride ions. Furthermore, the binding stoichiometry between the Probe L and F - was found to be 1:1 which is evidenced by the Job's plot and DFT calculation study. Overall, the novel sensor's impressive sensitivity and selectivity make it a promising candidate for the detection of fluoride ions in aqueous media, particularly for monitoring drinking water quality to ensure compliance with WHO guidelines., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Thiazole and its derivatives play an important role in biological and non-biological fields due to several structural and electronic behaviors associated with it. Thiazole derivatives act as chemosensors because they formed metal complexes upon interacting with various heavy metal ions like Cd 2+ , Co 2+ , Cr 3+ , Fe 3+ , Ag + , Al 3+ , Cu 2+ , Pd 2+ , Hg 2+ , Ni 2+ , Ga 3+ , In 3+ , Sn 4+ , Pb 2+ , Zn 2+ as well as other cations. These metal ions are of prime importance from the environmental point of view with high. This review article focuses on the thiazole-based colorimetric as well as fluorometric sensor for the recognition of different heavy metal cations in various specimens like agricultural, biological, and environmental. It also summarizes the binding stoichiometry, detection limit, pH, structure, and practical application of the reported thiazole-based chemosensors. Further, the sensing performances, have been discussed and compared with some reported organic sensors.

In this study, a simple Schiff base sensor 1-(((4-nitrophenyl)imino)methyl)naphthalen-2-ol(NNM) has been used for chemosensing of metal ions. The metal sensing properties of sensor NNM have been investigated using UV-visible and fluorescence spectroscopic approaches. The spectral investigations revealed a red shift in absorption spectra and quenching in the emission band of the ligand molecule in the presence of Cu 2+ and Ni 2+ ions. The binding stoichiometry of sensor NNM for the analyte (Cu 2+ and Ni 2+ ions) has been investigated by the Job's plot analysis and found to be 1:1 (NNM:Analyte). The data of the Benesi-Hildebrand plot demonstrated that NNM detected Cu 2+ and Ni 2+ ions in nanomolar quantity. The binding insights among NNM and analytes (Cu 2+ and Ni 2+ ions) have been confirmed by shifted IR signals. Moreover, the reusabilty of the sensor has been investigated using an EDTA solution. In addition, the sensor NNM also successfully applied to real water samples for the identification and measurement of Cu 2+ and Ni 2+ ions. Hence, this system could be highly applicable in environmental and biological applications., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

In situ and on-site analysis of trace components, such as methanol and ethyl acetate, in distilled spirits poses significant challenges. In this study, we have proposed a simple, yet effective and rapid approach that combines Raman spectroscopy with Raman integrating sphere technology to accurately detect trace constituents in distilled spirits. An external standard method to effectively separate overlapping Raman peaks from different substances are developed. Experimental results demonstrate that with an exposure time of 180 s under normal temperature and pressure, the detection limits for methanol, acetic acid, and ethyl acetate in proportioned distilled spirits are below 0.1 g/L. Importantly, the detection limit of methanol and acetic acid remains unaffected by the concentration of distilled spirits and the types of trace substances. Notably, the concentration of trace solute exhibits a highly linear relationship with its corresponding Raman intensity, offering a reliable probe for identifying unknown components in distilled spirits., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Here, we developed a novel isoniazid based fluorescent probe (E)-N'-(thiophen-2-ylmethylene)isonicotinohydrazide (TINH) through simple condensation reaction and employed for selective detection of Pd 2+ ions with a low detection limit of 4.102 × 10 -11  M. Among the many existing cations, TINH bound Pd 2+ ions with an association affinity of 9.794 × 10 5  M -1 . Adding Pd 2+ ions to ligand solution increased the absorption intensity in UV-Visible and quenched the emission intensity in fluorescence spectroscopic experiments. More importantly, this TINH complexed to Pd 2+ ions in 1:1 stoichiometric ratio. To evaluate the stability of complexed system, pH experiments has been performed. The binding insights among the ligand and Pd 2+ ions has been confirmed by IR spectroscopic and MASS spectrometric methods. Additionally, TINH also applied to real water samples for the identification and measurement of Pd 2+ ions. Hence, this system could be highly applicable for detection of Pd 2+ ions in environmental and industrial samples with in low detection range., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

A Cu@Pani/MoS 2 nanocomposite was successfully synthesized via combined in-situ oxidative polymerization and hydrothermal reaction and applied to an electrochemical nonenzymatic glucose sensor. The morphology of the prepared Cu@Pani/MoS 2 nanocomposite was characterized using FE-SEM and Cs-STEM, and electrochemical analysis was performed using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry techniques. Electrostatic interaction between Cu@Pani and MoS 2 greatly enhanced the charge dispersion, electrical conductivity, and stability, resulting in excellent electrochemical performance. The Cu@Pani/MoS 2 was used as an electrocatalyst to detect glucose in an alkaline medium. The proposed glucose sensor exhibited a sensitivity, detection limit, and wide linear range of 69.82 μAmM -1 cm -2 , 1.78 μM, and 0.1-11 mM, respectively. The stability and selectivity of the Cu@Pani/MoS 2 composite for glucose compared to that of the potential interfering species, as well as its ability to determine the glucose concentration in diluted human serum samples at a high recovery percentage, demonstrated its viability as a nonenzymatic glucose sensor., Competing Interests: There is no conflict of interest to disclose for this research paper. The human serum samples were not taken form human patients. We have used commercially available human serum (H4522, Sigma- Aldrich) for the real sample analysis., (© 2023 The Authors.)

The sensor coverage problem aims to maximize the coverage of a target area with a fixed or minimum number of sensors. However, the sampling point coverage for radiation mapping has yet to be specified or adequately established. When dealing with unknown radiation fields, it is critical that the placements of sampling points will ensure that all hotspots are detected and accurately identified. Therefore, the concept of coverage and detection limit for a sampling point in radiation mapping is proposed in this paper. The proposed concept relates the angular dependency of the radiation measurement instruments with the detector detection limit or minimum detectable amount (MDA). To demonstrate the implementation, the concept is used to compute the sensitivity of the radiation map for coverage radiation mapping with mobile robot. Simulation results showed that hotspots with intensity equal to or above the sampling point detection limit were successfully detected regardless of their position within the coverage circle. Moreover, the experimental results of coverage radiation mapping showed that the concept can be used to compute the resolution of the radiation map. This will help the user to efficiently configure the appropriate grid size that suit their mapping situation and requirements., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Nur Aira Abd Rahman and Khairul Salleh Mohamed Sahari reports financial support was provided by Ministry of Higher Education (MoHE) Malaysia., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Whether a nuclear installation has radiological impact and, in that case, its extension, are the questions behind any environmental analysis of the installation along its operational life. This analysis is based on the detailed establishment of the radiological background of the area. Accordingly, the dismantling and decommissioning process (D&D) of a nuclear power plant starts with a radiological monitoring plan, which includes the radiological characterization of the area and of its surroundings. At the completion of the D&D, unrestricted use for the site will be permitted strictly in accordance with results of the radiological survey within the limits established by the local authorities. Groundwater quality is typically included in any radiological analysis since, among other reasons, a significant part of it is highly likely to end up being extracted for domestic use and hence, human consumption. While there is no regulation containing maximum activity concentration or radionuclide guidance values for water that may be destined for uses other than public consumption, if groundwater is considered a "part" of the land, dose criteria for site release can be applied. Therefore, together with the guidance levels to be established for the different radionuclides expected in the groundwater, the detection limits to be employed when performing routine radio analytical characterization procedures in the laboratory should also be provided. In this paper, we first propose a relation of the potential radionuclides to be analyzed in groundwater, together with their detection limits to be achieved when the determinations are performed in a laboratory, and subsequently, we discuss the most suitable analytical methodologies and resources that would be necessary to undertake radiological characterization plans from a practical point of view., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors. Published by Elsevier Ltd.)

With the increasing population, food toxicity has become a prevalent concern due to the growing contaminants of food products. Therefore, the need for new materials for toxicant detection and food quality monitoring will always be in demand. Metal-organic frameworks (MOFs) based on luminescence and electrochemical sensors with tunable porosity and active surface area are promising materials for food contaminants monitoring. This review summarizes and studies the most recent progress on MOF sensors for detecting food contaminants such as pesticides, antibiotics, toxins, biomolecules, and ionic species. First, with the introduction of MOFs, food contaminants and materials for toxicants detection are discussed. Then the insights into the MOFs as emerging materials for sensing applications with luminescent and electrochemical properties, signal changes, and sensing mechanisms are discussed. Next, recent advances in luminescent and electrochemical MOFs food sensors and their sensitivity, selectivity, and capacities for common food toxicants are summarized. Further, the challenges and outlooks are discussed for providing a new pathway for MOF food contaminant detection tools. Overall, a timely source of information on advanced MOF materials provides materials for next-generation food sensors., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Metal cations such as Zn 2+ , Al 3+ , Hg 2+ , Cd 2+ , Sn 2+ , Fe 2+ , Fe 3+ and Cu 2+ play important roles in biology, medicine, and the environment. However, when these are not maintained in proper concentration, they can be lethal to life. Therefore, selective sensing of metal cations is of great importance in understanding various metabolic processes, disease diagnosis, checking the purity of environmental samples, and detecting toxic analytes. Schiff base probes have been largely used in designing fluorescent sensors for sensing metal ions because of their easy processing, availability, fast response time, and low detection limit. Herein, an in-depth report on metal ions recognition by some Schiff base fluorescent sensors, their sensing mechanism, their practical applicability in cell imaging, building logic gates, and analysis of real-life samples has been presented. The metal ions having biological, industrial, and environmental significance are targeted. The compiled information is expected to prove beneficial in designing and synthesis of the related Schiff base fluorescent sensors., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

In the current research work "4-{[1-(2,5-dihydroxyphenyl)ethylidene]amino}-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one" chemosensor (C1) synthesized by condensation reaction using "4-amino-1,2-dihydro-1,5-dimethyl-2-phenylpyrazol-3-one" and "2,5-dihydroxy actophenone" was used as the effective sensor of metal ion. The C1 shows absorption peak at 326 nm due to the C = C bond (π-π* transition), while the absorption peak at 364 nm is caused by the C = O bond (n-π* transition). In the presence of copper, C1 only demonstrated a redshift in absorption peak from 364 to 425 nm. Even in the presence of other competing metal ions, the hypsochromic shift of the absorption band and the quenching of the fluorescence emission intensity were different for detecting Cu 2+ , in CH 3 OH-H 2 O (v/v = 6:4). The capacity of the C1 to bind with Cu 2+ was further proved using DFT simulations. The complex C1 + Cu 2+ has a HOMO-LUMO energy gap of 2.8002 eV, which is lesser than C1 (2.9991 eV) showing improvement in the stability of the C1 + Cu 2+ complex. Using the Benesi-Hildebrand and Scatchard plots, calculated Kb values were to be 47,340 and 48369 M -1 respectively, showing the creation of stable complexation between Cu 2+ and C1 with 1:1 stoichiometry. The limit of detection (LOD) for Cu 2+ ion was 649 nM. Strip sheets were also built and tested to detect varying amounts of Cu 2+ in aqueous solution, and their color change suggested that they might be used for on-site Cu 2+ detection in polluted water., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Silicon nanowire (SiNW) biosensors have attracted a lot of attention due to their superior sensitivity. Recently, the dependence of biomolecule detection sensitivity on the nanowire (NW) width, number, and doping density has been partially investigated. However, the primary reason for achieving ultrahigh sensitivity has not been elucidated thus far. In this study, we designed and fabricated SiNW biosensors with different widths (10.8-155 nm) by integrating a complementary metal-oxide-semiconductor process and electron beam lithography. We aimed to investigate the detection limit of SiNW biosensors and reveal the critical effect of the 10-nm-scaled SiNW width on the detection sensitivity. The sensing performance was evaluated by detecting antiovalbumin immunoglobulin G (IgG) with various concentrations (from 6 aM to 600 nM). The initial thickness of the depletion region of the SiNW and the changes in the depletion region due to biomolecule binding were calculated. The basis of this calculation are the resistance change ratios as functions of IgG concentrations using SiNWs with different widths. The calculation results reveal that the proportion of the depletion region over the entire SiNW channel is the essential reason for high-sensitivity detection. Therefore, this study is crucial for an indepth understanding on how to maximize the sensitivity of SiNW biosensors.

Continuous emission monitoring (CM) solutions promise to detect large fugitive methane emissions in natural gas infrastructure sooner than traditional leak surveys, and quantification by CM solutions has been proposed as the foundation of measurement-based inventories. This study performed single-blind testing at a controlled release facility (release from 0.4 to 6400 g CH 4 /h) replicating conditions that were challenging, but less complex than typical field conditions. Eleven solutions were tested, including point sensor networks and scanning/imaging solutions. Results indicated a 90% probability of detection (POD) of 3-30 kg CH 4 /h; 6 of 11 solutions achieved a POD < 6 kg CH 4 /h, although uncertainty was high. Four had true positive rates > 50%. False positive rates ranged from 0 to 79%. Six solutions estimated emission rates. For a release rate of 0.1-1 kg/h, the solutions' mean relative errors ranged from -44% to +586% with single estimates between -97% and +2077%, and 4 solutions' upper uncertainty exceeding +900%. Above 1 kg/h, mean relative error was -40% to +93%, with two solutions within ±20%, and single-estimate relative errors were from -82% to +448%. The large variability in performance between CM solutions, coupled with highly uncertain detection, detection limit, and quantification results, indicates that the performance of individual CM solutions should be well understood before relying on results for internal emissions mitigation programs or regulatory reporting.

In this study, systematic development of a portable sensor for the rapid detection of Escherichia coli (E. coli) and Exiguobacterium aurantiacum (E. aurantiacum) was reported. A conductive glass was utilized as a substrate and developed the electrode patterns on it. Trisodium citrate (TSC) and chitosan-stabilized gold nanoparticles (AuNPs) (CHI-AuNP-TSC) and chitosan-stabilized AuNPs (CHI-AuNP) were synthesized and utilized as a sensing interface. The morphology, crystallinity, optical properties, chemical structures, and surface properties of immobilized AuNPs on the sensing electrodes were investigated. The sensing performance of the fabricated sensor was evaluated by using an electrochemical method to observe the current changes in cyclic voltammetric responses. The CHI-AuNP-TSC electrode has higher sensitivity toward E. coli than CHI-AuNP with a limit of detection (LOD) of 1.07 CFU/mL. TSC in the AuNPs synthesis process played a vital role in the particle size, the interparticle spacing, the sensor's effective surface area, and the presence of CHI around AuNPs, thus enhancing the sensing performance. Moreover, post-analysis of the fabricated sensor surface exhibited the sensor stability and the interaction between bacteria and the sensor surface. The sensing results showed a promising potential for rapid detection using a portable sensor for various water and food-borne pathogenic diseases., (© 2023. The Author(s).)

Qualitative and quantitative analysis of mercury at concentration levels as low as parts per billion (ppb) is a basic and practical concern. The vast majority of research in this field has centered on the development of potent chemosensor to monitor mercuric (Hg 2+ ) ions. Mercury exists in three oxidation states, + 2, + 1 and 0, all of which are highly poisonous. In this study, (N 1 E,N 2 E)-N 1 ,N 2 -bis(pyrene-1-ylmethylene)benzene-1,2-diamine (PAPM), a novel photoluminescent sensor based on pyrene platform was synthesized. Over the tested metal ions (Cd 2+ , Co 2+ , Cu 2+ , Mg 2+ , Mn 2+ , Ni 2+ , K + , Na + , Zn 2+ , Sr 2+ , Pb 2+ , Al 3+ , Cr 3+ and Fe 3+ ) the sensor responds only to Hg 2+ by showing high selectivity and sensitivity. After treatment with mercuric ions at room temperature, the luminescence intensity of probe was quenched at 456 nm. The quenching of fluorescence intensity of probe upon addition of mercury is due to the effect of "turn-off" chelation enhanced quenching (CHEQ) by the formation of 1:1 complex. The ESI-MS spectrum and the Job's experimental results confirm the formation of 1:1 complex between PAPM and Hg 2+ . The detection limit and association constant of sensor for mercury is computed using fluorescence titration data and were found to be 9.0 × 10 -8  M and 1.29 × 10 5  M -1 respectively. The practical application of sensor towards recognition of mercury(II) ions was explored through economically viable test strips and also using cell imaging studies., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

This study reports a liquid phase microextraction method based on binary extraction solvents, which were used to preconcentrate chlorbenside and fenobucarb from aqueous samples for determination by gas chromatography mass spectrometry. Parameters including the type, ratio, and volume of binary solvents, disperser solvent type and volume, and vortex period were optimized systematically to achieve high enrichment for the analytes. The optimum conditions obtained were used to validate the method, and the detection limits calculated for chlorbenside (0.71 ng/mL) and fenobucarb (0.33 ng/mL) correlated to enrichment factors of 399- and 912-folds, respectively. The optimum method was applied to lake water and wastewater samples in spike recovery experiments, and the results obtained (96-104%) verified the method as accurate and applicable to the aqueous sample matrices. Matrix matching calibration method was used to boost the accuracy of quantifying the two analytes in the wastewater sample, which presented interference effects. Assessment of the method's green profile based on penalty points confirmed the method's compliance with green analytical chemistry., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Nuclear medicine therapies using [ 177 Lu]Lu-labeled radiopharmaceuticals have increased significantly in recent years. Some of these radiopharmaceuticals contain long-lived impurities of [ 177m Lu]Lu. Identification of this specific contamination and its quantification is important in different scenarios., Purpose: In this study, standard measurement hardware used for handling radioisotopes was evaluated for the measurement of [ 177m Lu]Lu and [ 177 Lu]Lu at equilibrium. Device-specific detection limits (LODs) for [ 177m Lu]Lu were determined according to international standards and then validated., Methods: The LODs were determined according to the international standard ISO 11929-1 for [ 177m Lu]Lu for five identical portable contamination monitors (PCMs), a wastewater counter (WWC), and a release counter system (RCS) at different measuring times. Subsequent activity measurements of the defined samples were used to validate the linearity of the measurement instruments down to the LOD for each system., Results: The average LOD across all PCMs was 0.249 ± 0.009 and 0.129 ± 0.005 Bq/cm 2 for 10 and 30 s measurements, respectively. The LODs of WWC varied between 3.3 and 4.7 Bq/L for measurement times of 300 s and 0.8-1.3 Bq/L for 3600 s depending on the energy window studied. The LOD of the RCS depended on the container volume and was 0.08 Bq/g for the 50 L container at 60 s measurement. The measurements for all examined devices were linear down to the LOD (correlation coefficient R ≥ 0.96; coefficient of determination R 2  ≥ 0.92)., Conclusions: All investigated measuring instruments (PCM, WWC, RCS) were suitable for the determination of [ 177m Lu]Lu at equilibrium, and their specific LODs were determined. Based on the measurements performed, activity is overestimated; however, this is tolerable because assumptions and measurements in the context of radiation protection should be conservative., (© 2022 The Authors. Medical Physics published by Wiley Periodicals LLC on behalf of American Association of Physicists in Medicine.)

In this study, a resonance Rayleigh scattering technique-based sensing method for detecting Bentazone residual in water samples has been developed. This technique was carried out using chitosan-capped gold nanoparticles with a spectrofluorimetric method. Experimental results revealed that the developed method could allow the detection of Bentazone residual as low as a concentration of 0.02 ng mL -1 within 50-sec time. Overall results confirmed the very low detection limit for measuring the Bentazone. The chitosan-capped gold nanoparticles as an excellent sensor were applied to measure and analyze Bentazone in water samples.

Three-dimensional (3D) lead-halide perovskites with outstanding mobility-lifetime products and large attenuation coefficients for X-ray photons have demonstrated highly sensitive X-ray detection. However, there exists severe ion migration, especially under electrical bias, that results in dark-current drift and poorer device stability. Theoretical analyses suggest that 3D perovskites with two-dimensional (2D) perovskites may mitigate ion migration and reduce the dark current to achieve a drastically lower detection limit, which is badly needed for X-ray diagnostics. A bulk 2D/3D perovskite heterostructure is therefore designed and prepared by hot-pressing a mixture of BA 2 PbI 4 and MAPbI 3 particles. Compared with the pure MAPbI 3 pellet, the bulk 2D/3D heterostructure pellet shows much higher resistivity, hence, significantly reduced ion migration and a much smaller dark-current drift of 4.84 × 10 -5 nA cm -1 s -1 V -1 , which is much lower than that of the pristine MAPbI 3 pellet, thus demonstrating its effectiveness for the suppression of ion migration. The bulk 2D/3D heterostructure pellet attains an X-ray sensitivity of 2.0 × 10 3 μC Gy air -1 as well as a lower detection limit of 111.76 nGy s -2 as well as a lower detection limit of 111.76 nGy s -1 under 10 V bias. This work provides a successful strategy to prepare X-ray detectors with suppressed ion migration and negligible dark current drift, which will further benefit the development of lead-halide perovskite X-ray detectors.

A rapid surge in world population leads to an increase in worldwide demand for agricultural products. Nanotechnology and its applications in agriculture have appeared as a boon to civilization with enormous potential in transforming conventional farming practices into redefined farming activities. Low-cost portable nanobiosensors are the most effective diagnostic tool for the rapid on-site assessment of plant and soil health including plant biotic and abiotic stress level, nutritional status, presence of hazardous chemicals in soil, etc. to maintain proper farming and crop productivity. Nanobiosensors detect physiological signals and convert them into standardized detectable signals. In order to achieve a reliable sensing analysis, nanoparticles can aid in signal amplification and sensor sensitivity by lowering the detection limit. The high selectivity and sensitivity of nanobiosensors enable early detection and management of targeted abnormalities. This study identifies the types of nanobiosensors according to the target application in agriculture sector., Competing Interests: The authors declare no conflict of interest., (© 2022 The Author(s).)

Extracellular vesicles (EVs) are an upcoming biomarker for disease. However, the measured concentrations of EVs by flow cytometry are incomparable due to analytical variables. This study aimed to investigate how the choice of fluorophore, and thereby brightness, affects the measured concentration of EVs. Four commonly used fluorophores allophycocyanin, Brilliant Violet-421, fluorescein isothiocyanate, and phycoerythrin, all conjugated to CD61 antibodies, were used to label platelet-derived extracellular vesicles (PEVs) in human plasma. PEVs were measured by flow cytometry. The concentration of EVs was obtained by manually set fluorescence gates, automatically determined fluorescence gates, and automatically determined fluorescence gates combined with specific size gates. Manually set fluorescence gates by five independent experts resulted in a variation coefficient (CV) of 41% between the measured PEV concentrations labeled with the four different fluorophores. A new algorithm for automatic determination of fluorescence gates was applied to reduce inter-operator variability. Applying this algorithm resulted in a CV of 58%. However, when the algorithm was combined with a size gate to correct for differences in brightness between fluorophores, the CV reduced to 25%. In this study, we showed that different fluorophores can detect similar concentrations of EVs by (1) determining fluorescence gates automatically, and (2) by adding a size gate to correct for differences in brightness between fluorophores. Therefore, our research contributes to further standardization of EV concentration measurements by flow cytometry., (© 2022 The Authors. Cytometry Part A published by Wiley Periodicals LLC on behalf of International Society for Advancement of Cytometry.)

The present study involves detecting and determining CIP by a new electrochemical sensor based on graphene (Gr) in the presence of sodium dodecyl sulfate (SDS) employing voltammetric techniques. Surface morphology studies of the sensing material were analyzed using a scanning electron microscope (SEM) and atomic force microscope (AFM). In the electroanalysis of CIP at the developed electrode, an enhanced anodic peak response was recorded, suggesting the electro-oxidation of CIP at the electrode surface. Furthermore, we evaluated the impact of the electrolytic solution, scan rate, accumulation time, and concentration variation on the electrochemical behavior of CIP. The possible electrode mechanism was proposed based on the acquired experimental information. A concentration variation study was performed using differential pulse voltammetry (DPV) in the lower concentration range, and the fabricated electrode achieved a detection limit of 2.9 × 10 -8 M. The proposed sensor detected CIP in pharmaceutical and biological samples. The findings displayed good recovery, with 93.8% for tablet analysis and 93.3% to 98.7% for urine analysis. The stability of a developed electrode was tested by inter- and intraday analysis.

Metal cations are present in domestic and industrial wastewater and have adverse effects on human and aqueous life. The present study describes the development of the molecular probe 9-anthracen-9-ylmethylene)hydrazineylidene)methyl)-2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]quinolin-8-ol (AMHMPQ) to detect Cr 3+ , Cu 2+ , Fe 3+ , and Gd 3+ ions by using UV-visible, fluorescence, colorimetric and excitation-emission matrix (EEM) spectroscopy techniques. The interaction of Cr 3+ , Cu 2+ , Fe 3+ , and Gd 3+ can be observed by the absorption maxima shift, turn-off, colour changes, and EEM shifts. In addition, fluorescence limits of detection 17.66 × 10 -6 M, 6.44 × 10 -9 M, 28.87 × 10 -8 M, and 12.49 × 10 -6 M in wide linear ranges, low limits of quantifications, high values of Stern-Volmer constant, Job's plot and Benesi-Hildebrand plot justify the 1:1 association affinity with association constants of 1.46 × 10 4 M -1 , 1.86 × 10 7 M -1 , 2.69 × 10 5 M -1 , 2.13 × 10 4 M -1 for AMHMPQ-metal ions (Cr 3+ , Cu 2+ , Fe 3+ , and Gd 3+ ions), respectively. Paper- and mask-based kits are developed to explore the utility of the designed chemosensor. Additionally, AMHMPQ acts as a reusable sensor for two, seven, two, and zero cycles for Cr 3+ , Cu 2+ , Fe 3+ , and Gd 3+ ions, respectively, when checked with EDTA., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.)