Detection Of Low Levels Research Articles

Electrocatalytic evaluation of β-SnWO4/rGO nanostructure for low-level urea detection

Electrocatalytic evaluation of β-SnWO4/rGO nanostructure for low-level urea detection

V2CTX MXene-based hybrid sensor with high selectivity and ppb-level detection for acetone at room temperature

High-performance, room temperature-based novel sensing materials are one of the frontier research topics in the gas sensing field, and MXenes, a family of emerging 2D layered materials, has gained widespread attention due to their distinctive properties. In this work, we propose a chemiresistive gas sensor made from V2CTx MXene-derived, urchin-like V2O5 hybrid materials (V2C/V2O5 MXene) for gas sensing applications at room temperature. The as-prepared sensor exhibited high performance when used as the sensing material for acetone detection at room temperature. Furthermore, the V2C/V2O5 MXene-based sensor exhibited a higher response (S% = 11.9%) toward 15 ppm acetone than pristine multilayer V2CTx MXenes (S% = 4.6%). Additionally, the composite sensor demonstrated a low detection level at ppb levels (250 ppb) at room temperature, as well as high selectivity among different interfering gases, fast response-recovery time, good repeatability with minimal amplitude fluctuation, and excellent long-term stability. These improved sensing properties can be attributed to the possible formation of H-bonds in multilayer V2C MXenes, the synergistic effect of the newly formed composite of urchin-like V2C/V2O5 MXene sensor, and high charge carrier transport at the interface of V2O5 and V2C MXene.

Method for Orientation Determining of the Detail for the Automated Soldering Technological Process

Purpose of reseach. Development of a technique for determining the orientation of parts during automatic soldering of a contact group based on the assembly of a combined image recognition systems.Methods. Analysis of the technological process of assembling a part and evaluating the possibility of using various technologies for orienting workpieces. Development of a consistent technique for orienting a part, including the stage of recognizing a rounded edge using a vision system. Development of an algorithm for recognizing the orientation of the workpiece directly from the image of the part and along the contour of the shadow of the part. Setting up full-scale experiments on a test bench, obtaining numerical values for the accuracy of recognizing the orientation of a part for various algorithms.Methodology. To solve the problem of transportation and positioning of the studied parts, methods of movement are used, due to controlled vibration inside the developed system of guides and cutters. To determine the rounded edge, image processing and recognition methods are used: the k-means method for clustering the original image, the Hough transform for contour search, etc.Results. In the course of the study, two algorithms for extracting details from the original image and the image of the shadows cast by the detail were developed. In the detection of an increased risk, more than 96%, however, when detecting sensitivity along the contour of the shadow, more than 99% were detected.Conclusion. The technique for determining details developed within the framework of the work, including the stages of preliminary sorting according to the task of vibrotransportation, the stage of searching for a round face using a technical perspective system, including the contour of shadow details, makes it possible to obtain high accuracy even when assembling video equipment with a low level of detection.

DLMFCOS: Efficient Dual-Path Lightweight Module for Fully Convolutional Object Detection

Recent advances in convolutional neural network (CNN)-based object detection have a trade-off between accuracy and computational cost in various industrial tasks and essential consideration. However, the fully convolutional one-stage detector (FCOS) demonstrates low accuracy compared with its computational costs owing to the loss of low-level information. Therefore, we propose a module called a dual-path lightweight module (DLM) that efficiently utilizes low-level information. In addition, we propose a DLMFCOS based on DLM to achieve an optimal trade-off between computational cost and detection accuracy. Our network minimizes feature loss by extracting spatial and channel information in parallel and implementing a bottom-up feature pyramid network that improves low-level information detection. Additionally, the structure of the detection head is improved to minimize the computational cost. The proposed method was trained and evaluated by fine-tuning parameters through experiments and using public datasets PASCAL VOC 07 and MS COCO 2017 datasets. The average precision (AP) metric is used for our quantitative evaluation matrix for detection performance, and our model achieves an average 1.5% accuracy improvement at about 33.85% lower computational cost on each dataset than the conventional method. Finally, the efficiency of the proposed method is verified by comparing the proposed method with the conventional method through an ablation study.

Extraction and concentration of nanoplastic particles from aqueous suspensions using functionalized magnetic nanoparticles and a magnetic flow cell

Although a considerable knowledge base exists for environmental contamination from nanoscale and colloidal particles, significant knowledge gaps exist regarding the sources, transport, distribution, and effects of microplastic pollution (plastic particles < 5 mm) in the environment. Even less is known regarding nanoplastic pollution (generally considered to be plastic particles < 1 μm). Due to their small size, nanoplastics pose unique challenges and potential risks. We herein report a technique focused on the concentration and measurement of nanoplastics in aqueous systems. Hydrophobically functionalized magnetic nanoparticles (HDTMS-FeNPs) were used as part of a method to separate and concentrate nanoplastics from environmentally relevant matrices, here using metal-doped polystyrene nanoplastics (PAN-Pd@NPs) to enable low-level detection and validation of the separation technique. Using a magnetic separation flow cell, PAN-Pd@NPs were removed from suspensions and captured on regenerated cellulose membranes. Depending on the complexity of solution chemistry, variable extraction rates were possible. PAN-Pd@NPs were recovered from ultrapure water, synthetic freshwater, synthetic freshwater with a model natural organic matter isolate (NOM; Suwannee River Humic Acid), and from synthetic marine water, with recoveries for PAN-Pd@NPs of 84.9%, 78.9%, 70.4%, and 56.1%, respectively. During the initial method testing, it was found that the addition of NaCl was needed in the ultrapure water, synthetic freshwater and synthetic fresh water with NOM to induce particle aggregation and attachment. These results indicate that magnetic nanoparticles in combination with a flow-through system is a promising technique to extract nanoplastics from aqueous suspensions with various compositions.

Reproducibility of low-level residual myeloma immunoglobulin detection using ultra-deep sequencing

Multiple myeloma, a mature B-cell neoplasm, is the second most common hematologic malignancy. Despite advancements in treatment, the disease remains incurable, with more than 100,000 annual deaths worldwide. As recommended by the International Myeloma Working Group, measurable residual disease (MRD) should be addressed at a 10-5 sensitivity level or beyond for practical purposes. Next-generation sequencing (NGS) has provided new opportunities with deep sequencing of clonal rearrangements of the immunoglobulin heavy chain (IGH) locus in B-cell malignancies. Although the ability to resolve one cancerous cell in a million other B cells is becoming attractive as a prognostic indicator in sustained patients who are MRD-negative, reaching consistent sensitivity levels is challenging because of sample stochasticity and the substantial amount of deoxyribonucleic acid (DNA) required for library preparation. Thus, in the presented study, we implemented ultra-deep sequencing of rearranged IGH to investigate the reproducibility and consistency aimed at the 10-5 sensitivity level. In this controlled setup, our data provided stable MRD detection of 1.2 clonal cells per 100,000 analyzed cells and longitudinal reproducibility. We also demonstrated a low false-negative rate using 4-5 replicates and 700-800 ng DNA per sequencing replicate. In conclusion, adding an internal control to the replicates enabled clonal cell normalization for MRD evaluation as a stable reference. These findings may guide MRD-level reporting and comparisons between laboratories.

Bacteriophages playing nice: Lysogenic bacteriophage replication stable in the human gut microbiota

Bacteriophages, viruses specific to bacteria, coexist with their bacterial hosts with limited diversity fluctuations in the guts of healthy individuals where they replicate mostly via lysogenic replication. This favors 'piggy-back-the-winner' over 'kill-the-winner' dynamics which are driven by lytic bacteriophage replication. Revisiting the deep-viral sequencing data of a healthy individual sampled over 2.4 years, we explore how these dynamics occur. Prophages found in assembled bacterial metagenomes were also found extra-cellularly, as induced phage particles (iPPs), likely derived from prophage activation. These iPPs were diverse and continually present in low abundance, relative to the highly abundant but less diverse lytic phage population. The continuous detection of low levels of iPPs suggests that spontaneous induction regularly occurs in this healthy individual, possibly allowing prophages to maintain their ability to replicate and avoiding degradation and loss from the gut microbiota.

Microspherical Titanium-Phosphorus Double Oxide: Hierarchical Structure Development for Sensing Applications.

Stable, water-soluble titanium complexed with mandelic acid was used as a precursor for titanium phosphorus double oxide obtained in hydrothermal conditions in the presence of phosphoric acid. Surprisingly, hydrolysis of organic complexes provided a microstructured sphere with narrow size distribution, low aggregation and a small fraction of morphological irregularities. Obtained microspheres had a complex structure comprised of flakes, whose size could be manipulated with temperature conditions. Samples were found to be electrochemically active against sulcotrione, a well-recognized herbicide. Electrochemical sensors based on the synthesized microspheres were successfully adapted for natural water reservoir analysis and exhibited low levels of detection of 0.61 µM, limit of quantification of 1.86 µM, wide dynamic linear range from 2 to 200 µM, good selectivity, excellent reproducibility and in-time stability.

An Acoustic Camera for Use on UAVs.

Airborne acoustic surveillance would enable and ease several applications, including security surveillance, urban and industrial noise monitoring, rescue missions, and wildlife monitoring. Airborne surveillance with an acoustic camera mounted on an airship would provide the deployment flexibility and utility required by these applications. Nevertheless, and problematically for these applications, there is not a single acoustic camera mounted on an airship yet. We make significant advances towards solving this problem by designing and constructing an acoustic camera for direct mounting on the hull of a UAV airship. The camera consists of 64 microphones, a central processing unit, and software for data acquisition and processing dedicatedly developed for far-field low-level acoustic signal detection. We demonstrate a large-aperture mock-up camera operation on the ground, although all preparations have been made to integrate the camera onto an airship. The camera has an aperture of 2 m and has been designed for surveillance from a height up to 300 m, with a spatial resolution of 12 m.

Fluorescent sensor based on solid-phase extraction with negligible depletion: A proof-of-concept study with amines as analytes

This paper describes the development and proof-of-concept testing of an easy-to-use trace analysis technique, namely F-SPE, by coupling fluorescent sensor with solid phase extraction (SPE). F-SPE is a two-step methodology that concentrates an analyte from a liquid sample onto a fluorophore-modified membrane and measures the amount of analyte from the extent the extracted analyte quenches the emission of the fluorophore. By applying the principle of negligible depletion (ND) intrinsic to SPE, the procedure of F-SPE for analyzing a sample can be markedly simplified while maintaining the ability to detect analytes at low limits of detection (LOD). The merits of this approach are demonstrated by impregnating a SPE membrane with a perylene diimide (PDI) fluorophore, N,N′-di(nonyldecyl)-perylene-3,4,9,10-tetracarboxylic diimide (C9/9-PDI), for the low-level detection of organic amines (e.g., aniline) and amine-containing drugs (e.g., Kanamycin). The sensing mechanism is based on the donor-acceptor quenching of PDI by amines, which, when coupled with the concentrative nature of SPE, yields LODs for aniline and Kanamycin of 67 nM (∼6 ppb) and 32 nM (∼16 ppb), respectively.

Carbon quantum dots@metal–organic framework based catalytic nucleic acid fluorescent system for highly sensitive and selective detection of Pb2+ in aqueous solutions

Accumulation of heavy metal ions in the ecosystem has become a major concern due to their adverse impacts on animals, humans, and aquatic habitats. The development of a rapid and portable sensing system is important for the prompt detection and proper management of such pollutants. Herein, we have designed a fluorescence-based biosensor for the selective and sensitive detection of Pb2+ ions using a DNAzyme system that is active only in the presence of lead (II) ions (Pb2+). The developed nanoprobe relies on two major components: (i) boron and nitrogen carbon dots (BNCDs)-doped carboxyl functionalized-terbium metal-organic framework (COOH-Tb MOF) as a fluorescent tag and (ii) quencher-modified catalytic NH3-GR5 DNAzyme as a bioreceptor molecule. The fluorescent tag (BNCDs/MOF) exhibits dual fluorescence with emission peaks located in the regions of blue and green. In the absence of Pb2+ ions, this hybridization undergoes reduced emission intensity because of the overlap in fluorescence emission between BNCDs@Tb-MOF and quenchers. However, as the catalytic core of the DNAzyme strand is activated in the presence of Pb2+ ions, the fluorescent emission of BNCDs/Tb-MOF resumes with the cleavage of quencher-tagged substrate strand. Here, the release of a shorter oligo sequence effectively increases the intensity of the proposed novel biosensor to realize low level detection of Pb2+ (e.g., to 0.96 ppb in a wide detection range from 2 to 1000 nM). The establishment of this novel biosensing approach is expected to offer new insights into rapid, selective, and sensitive detection of major pollutants for food and environmental safety.

Highly selective acetone detection displayed by a surface engineered fiber-like ZnFe2O4 based-sensor following heat-treatment ramping rate variation

• Combustion method derived surface engineered fibrous ZnFe 2 O 4 . • Mesoporous fibrous structured ZnFe 2 O 4 products as a platform for Acetone detection at low detection levels. • Highly Acetone responsive and selective sensing layer based on mesoporous fibrous structured ZnFe 2 O 4 . • Improved sensing capabilities owing to optimization of heat-treatment ramping rate. Herein, mesoporous fibrous structured ZnFe 2 O 4 products were used as a platform to explore the relationship between the sensing performance and microstructural behavior induced by the optimization of the heat-treatment ramping rate. The optimized mesoporous fibrous ZnFe 2 O 4 sensor produced by combustion method at a heat-treatment ramping rate of 10°C/min revealed a remarkable selectivity and response of 192 towards 90ppm acetone at a lower working temperature of 120°C. Such excellent sensing capabilities could be due to the large surface area which exposes the surface reaction sites and offer sufficient gas-diffusion across the mesoporous fiber-like assembled sensing-layer based on ZnFe 2 O 4 .

Inflammatory Endotypes of Chronic Rhinosinusitis in the Korean Population: Distinct Expression of Type 3 Inflammation.

Cluster analyses on inflammatory markers of chronic rhinosinusitis (CRS) in Asians from multicenter data are lacking. This multicenter study aimed to identify the endotypes of CRS in Koreans and to evaluate the relationship between the endotypes and clinical parameters. Nasal tissues were obtained from patients with CRS and controls who underwent surgery. The endotypes of CRS were investigated by measuring interleukin (IL)-5, interferon (IFN)-γ, IL-17A, IL-22, IL-1β, IL-6, IL-8, matrix metalloproteinase-9, eotaxin-3, eosinophil cationic protein, myeloperoxidase (MPO), human neutrophil elastase (HNE), periostin, transforming growth factor-β1, total immunoglobulin E (IgE), and staphylococcal enterotoxin (SE)-specific IgE. We performed hierarchical cluster analysis and evaluated the phenotype, comorbidities, and Lund-Mackay computed tomography (LM CT) score in each cluster. Five clusters and 3 endotypes were extracted from 244 CRS patients: cluster 1 had no upregulated mediators compared to the other clusters (mild mixed inflammatory CRS); clusters 2, 3, and 4 had higher concentrations of neutrophil-associated mediators including HNE, IL-8, IL-17A, and MPO (T3 CRS); and cluster 5 had higher levels of eosinophil-associated mediators (T2 CRS). SE-specific IgE was undetectable in T3 CRS and had low detectable levels (6.2%) even in T2 CRS. The CRS with nasal polyps (CRSwNP) phenotype and LM CT scores showed no significant differences between T2 and T3 CRS, while the incidence of comorbid asthma was higher in T2 CRS than T3 CRS. In T3 clusters, higher levels of neutrophilic markers were associated with disease severity and CRSwNP phenotype. In Koreans, there is a distinct T3 CRS endotype showing a high proportion of CRSwNP and severe disease extent, along with T2 CRS.

Exploring the performance of the GPSC method under several levels of outliers

The aim of this study is to evaluate the performance of the Groupwise Principal Sensitivity Components method which is a robust iterative procedure for fitting linear regression models with fixed group effects. A simulation study is carried out to assess its ability to detect multiple outliers located in the response variable (vertical outliers) or in the explanatory and response variable (high leverage outliers). Several levels of outliers are considered ranging from 5% to 45% within selected groups. The results suggest that the GPSC method is able to avoid the masking effect under low or moderate level of outliers -approximately below to 30%. Additionally, in almost all cases the GPSC method reports lower levels of false outlier detection under high leverage outliers.

RBNet: An Ultrafast Rendering-Based Architecture for Railway Defect Segmentation

Inspection of railway defects is crucial for the safe and efficient operation of trains. Recent advancements in convolutional neural networks have led to the development of many effective detection and segmentation algorithms, however, these algorithms often struggle to balance efficiency and precision. In this paper, we present a rendering-based fully convolutional network that generates segmentation results through a coarse-to-fine approach. This allows our framework to make full use of low-level features while minimizing the number of parameters. Additionally, our network generates segmentation results from multiple scales of the feature map and uses residual connections to improve low-level feature detection. To improve training, we propose a novel method that augments the dataset by cutting and pasting images and corresponding ground truth labels horizontally. To better understand the patterns learned by our model, we also generate importance and uncertainty maps to make our model explainable. Our results show that the proposed method outperforms other state-of-the-art image segmentation methods with a higher frame rate and better performance.

ОБОСНОВАНИЕ АНТИБАКТЕРИАЛЬНОЙ ХИМИОТЕРАПИИ В ПАРОДОНТОЛОГИИ НА ОСНОВАНИИ ОЦЕНКИ АНТИБИОТИКОРЕЗИСТЕНТНОСТИ ПО ДАННЫМ РАЗНЫХ МЕТОДОВ ИССЛЕДОВАНИЯ

The aim of the study was to establish the prevalence of strains of microorganisms resistant to antibacterial drugs isolated from subgingival dental plaques of periodontitis patients in the acute and remission stages. Materials and methods of research։ For the study, were recruited 90 patients who were diagnosed with chronic periodontitis (K05.3) because of clinical examination and subsequent treatment. The research methods included culture (disco-diffusion method) and molecular biological technologies (PCR), which allows identifying resistant strains of bacteria isolated from subgingival biofilm. Results։ Our results confirm that periodontopathogenic anaerobic bacteria, in contrast to sanitary-significant microbes of the ESCAPE pathogen group, were not found to be resistant to doxycycline and ciprofloxacin in the phenotypic test (disk method). The data obtained regarding the detection of genetic markers of resistance to betalactam antibiotics are generally consistent with the results of studies obtained in Western Europe (Spain, Italy, Greece). At the same time, in relation to genetic markers of resistance to tetracyclines and fluoroquinolones, significantly lower levels of detection of resistant strains were established than in studies by foreign authors. Perhaps this is due to the widespread use of these drugs in these years. On the other hand, closer results for tetracycline and fluoroquinolone resistance markers are from researchers in the People's Republic of China. Conclusion։ The results obtained allow us to justify the return to treatment regimens using doxycycline, as one of the most adequate domestic tetracycline drugs.

Gaucher Disease Diagnosed During Adolescence

Gaucher's disease (GD) is an autosomal recessive lysosomal lipid storage disorder caused due to insufficient activity of the enzyme beta-glucocerebrosidase. Type 1 GD may present at any age but manifests in childhood in more than half of patients. In this case report, an adolescent who applied to our gastroenterology outpatient clinic with dyspeptic complaints and was diagnosed with type 1 GD is presented to draw attention to rare metabolic diseases. A 14-year-old girl complaining of abdominal and bone pain was admitted to the hospital. Erlenmeyer flask deformity was detected on the direct knee radiograph of the patient, as well as thrombocytopenia, ferritin elevation and hepatosplenomegaly. A preliminary diagnosis of Gaucher disease was considered upon detection of low levels of beta glucocerebrosidase enzyme for our patient. The homozygous variant was detected in the GBA gene NM_000157.4:c.1226A&gt;G (p.Asn409Ser) and diagnosed as Type 1 GD. When evaluating patients, it is important to remember that some rare metabolic diseases can be observed in older children. Our patient was diagnosed with Type 1 GD at an adolescent age, and treatment was started. Currently, improvements in clinical manifestations can be achieved with existing treatments. Therefore, it is crucial to diagnose the disease at an early stage and begin the necessary treatment.

A review on Schiff base as colorimetric and fluorescence sensors for d-metal ions

Most of the d-metals are familiar with their distinctive properties and their applications have been extended in vast industry fields. Though they are doing outstanding work in industries and help to boost the economy of dependence. The excess uptake of d-metals explores significant health issues, and detrimental effects on the environment, and corrodes the biological species. Fluorescent probes based on Schiff base chemical compounds give more accuracy, and low-level detection for metal ions in water, chemicals, and in biological cells through commendable and quick fluorescence signals. So, it empowers the successful detection of d-metals in terms of dissimilar fluorescence responses by probes in light of metals. Based on the recent research in the field of Schiff base-based fluorescent probes and interpretation on effects for binding like ON-OFF PET, ICT, CHEF, and CHEQ this imperative review is framed.

Estimation of the Detection Limit of Fecal Coliforms and &lt;i&gt;Staphylococcus aureus&lt;/i&gt; Qualitative Methods

ISO/IEC 17025 : 2017 requires laboratories to verify the performance of methods before introducing them. ISO 16140-3 : 2021 employs LOD50 (the level of detection for which 50% of tests give a positive result) as an index for evaluating the performance of microbial qualitative methods. While fecal coliforms and Staphylococcus aureus qualitative methods are widely implemented in Japan, their LOD50 values have not been established, making performance evaluation of these methods impossible at the time of introduction. As a result, we looked into estimating the LOD50 values of fecal coliforms and S. aureus qualitative methods to evaluate the index of method performance. The fecal coliforms method had an LOD50 value of 19–31 CFU/mL and the S. aureus method had an LOD50 value of 29–49 CFU/mL by laboratory personnels using samples without food matrix. We estimated LOD50 of six food samples using each method in a single laboratory. The LOD50 values of all foods calculated using the fecal coliforms method were in the range of 14–27 CFU/g and those calculated using the S. aureus method were in the range of 25–48 CFU/g, indicating that these methods did not have low levels of sensitivity detection compared with skill variation. LOD50 values for food samples with the highest or lowest LOD50 in each method were compared among five laboratories. Because the estimated LOD50 values of both the methods were within four times of each laboratory result, which is the acceptable limit specified in ISO 16140-3 : 2021, they were assumed to be suitable values. This study is expected to be utilized as a benchmark in the verification of method performance in each laboratory.

Selective Low-Level Detection of a Perilous Nitroaromatic Compound Using Tailor-Made Cd(II)-Based Coordination Polymers: Study of Photophysical Properties and Effect of Functional Groups.

Three coordination polymers (CPs 1-3) are prepared based on diverse electron-donating properties and coordination arrangements of conjugated ligands. Interestingly, this is also reflected in their photophysical properties. The distinguishable high emissive nature of the luminescent coordination polymer shows its potentiality toward the detection of the perilous substance 2,4,6-trinitrophenol (TNP) or picric acid (PA). TNP has a higher propensity among explosive nitroaromatic compounds (epNACs) due to its significant π···π interaction with the free benzene moieties present in the CPs. Among CPs 1-3, 2 exhibits the highest sensitivity and selectivity toward TNP because of the most favorable π-π stacking with the conjugated organic linker. The calculated limit of detection (LOD) and corresponding quenching constant (KSV) from the Stern-Volmer (SV) plot for 1, 2, and 3 are found to be 0.68 μM and 7.49 × 104 M-1, 0.41 μM and 8.01 × 104 M-1, and 1.18 μM and 8.1 × 104 M-1, respectively. The fluorescence quenching mechanism is also highly influenced by their structure and coordination arrangement.