Detection of Atrazine Residue in Food Samples by a Monoclonal Antibody-based Enzyme-linked Immunosorbent Assay

Atrazine（AT,2-chloro-4-ethylamino-6-isopropyl-amino-s-triazine）has been detected in ground water in several areas of the United States for many years,as well as in China,wherein the growth rate of its gross

Scanning electron microscopy coupled with energydispersive X-ray spectrometry for quick detection of sulfuroxidizing bacteria in environmental water samples

Detection of sulfur-oxidizing bacteria has largely been dependent on targeted gene sequencing technology or traditional cell cultivation, which usually takes from days to months to carry out. This clearly does not meet the requirements of analysis for time-sensitive samples and/or complicated environmental samples. Since energy-dispersive X-ray spectrometry(EDS) can be used to simultaneously detect multiple elements in a sample, including sulfur, with minimal sample treatment, this technology was applied to detect sulfur-oxidizing bacteria using their high sulfur content within the cell. This article describes the application of scanning electron microscopy imaging coupled with EDS mapping for quick detection of sulfur oxidizers in contaminated environmental water samples, with minimal sample handling. Scanning electron microscopy imaging revealed the existence of dense granules within the bacterial cells, while EDS identified large amounts of sulfur within them. EDS mapping localized the sulfur to these granules. Subsequent 16S rRNA gene sequencing showed that the bacteria detected in our samples belonged to the genus Chromatium, which are sulfur oxidizers. Thus, EDS mapping made it possible to identify sulfur oxidizers in environmental samples based on localized sulfur within their cells, within a short time(within 24 h of sampling). This technique has wide ranging applications for detection of sulfur bacteria in environmental water samples.

Combination of Loop-Mediated Isothermal Amplification Assay and Nested PCR for Detection of Borrelia burgdorferi sensu lato in Human Serum Samples

A set of universal loop-mediated isothermal amplification （LAMP） primers targeting the flo gene was designed to detect Borrelia burgdorferi sensu lato （B. burgdorferi s.I.） in human samples. The sensitivity of LAMP was 20 copies/reaction, and the assay did not detect false positives among 11 other related bacteria. A positive LAMP result was obtained for 9 of the 24 confirmed cases and for 12 of 94 suspected cases. The positive rate of LAMP was the same as that of nested PCR. The LAMP is a useful diagnostic method that can be developed for rapid detection of B. burgdorferi s.I. in human sera. Combination of the LAMP and nested PCR was more sensitive for detecting B. burgdorferi s.I. in human serum samples.

B-GQDs@GSH as a Highly Selective and Sensitive Fluorescent Probe for the Detection of Fe^(3+) in Water Samples and Intracellular

Owing to the excellent stability,biocompatibility and photoluminescence property,graphene quantum dots(GQDs)are emerging as a kind of potential materials to be applied in a series of fields ranging from sensor to drug delivery.As the growing concern for human and environmental safety,selective detection of metal ions has been paid more and more attention.GQDs,as nanoparticles with superior optical properties,have been attracting growing attention in the field of metal ions detection.In this work,glutathione(GSH)functionalized boron doped graphene quantum dots(B-GQDs@GSH)were successfully synthesized with stable bright blue fluorescence and has been used for the detection of Fe^(3+).A good linear relationship between 1/(F_(0)-F)and 1/c with the concentration ranging from 0.70 to 53μmol/L was obtained with a detection limit of 5.5 nmol/L.The application of B-GQDs@GSH for Fe^(3+)detection in water samples was demonstrated and the quenching mechanism was further explored.Due to low cytotoxicity and favorable biocompatibility,B-GQDs@GSH were successfully applied for cell fluorescence imaging and intracellular determination of Fe^(3+).

Rapid detection of Mycoplasma Pneumoniae in Clinical Samples by the Polymerase Chain Reaction Technique.

The polymerase chain reaction (PCR) technique was used to detect mycoplasma pneumoniae in clinical samples

Detection of Myobacterium Tuberculosis in the Samples of 122 TB Patients Using Polymerase Chain Reaction Technique

By means of polymerase chain reaction(PCR) technique,direct smear fluorescence microscopy and bacterial culture,the sputa and purulent secretion of 122 TB patients were examined to detect mycobacterium tuberculosis.

False Negative Sample Detection for Graph Contrastive Learning

Recently,self-supervised learning has shown great potential in Graph Neural Networks (GNNs) through contrastive learning,which aims to learn discriminative features for each node without label information. The key to graph contrastive learning is data augmentation. The anchor node regards its augmented samples as positive samples,and the rest of the samples are regarded as negative samples,some of which may be positive samples. We call these mislabeled samples as “false negative” samples,which will seriously affect the final learning effect. Since such semantically similar samples are ubiquitous in the graph,the problem of false negative samples is very significant. To address this issue,the paper proposes a novel model,False negative sample Detection for Graph Contrastive Learning (FD4GCL),which uses attribute and structure-aware to detect false negative samples. Experimental results on seven datasets show that FD4GCL outperforms the state-of-the-art baselines and even exceeds several supervised methods.

Rapid thin-layer WS_(2) detection based on monochromatic illumination photographs

The thickness of two-dimensional(2D)nanomaterials shows a significant effect on their optical and electrical properties.Therefore,a rapid and automatic detection technology of 2D nanomaterials with desired layer-number is required to extend their practical application in optoelectronic devices.In this paper,an image recognition technology was proposed for rapid and reliable identification of thin-layer WS_(2) samples,which combining a layer-thickness identification criterion and a novel image segmentation algorithm.The criterion stemmed from optical contrast study of monochromatic illumination photographs,and the algorithm was based on Canny operator and edge connection iteration.This optical identification method can seek out thin-layer WS_(2) samples on complex surfaces,which provides a promising approach for automatic search of thin-layer nanomaterials.