The single strand template shortening strategy improves the sensitivity and specificity of solid-state nanopore detection.

Through controlling the ssDNA product length of rolling circle amplification with AcyNTP, here we develop a nanopore signal enhancement strategy (STSS), which can successfully transfer the short oligonucleotide targets into long ssDNAs with appropriate lengths that can generate significant translocation currents. By labelling the RCA product with tags such as tetrahedral structures and isothermal amplicons, the resolution, signal specificity, and target range of the STSS can be further extended.

Iso-E-Codelock: A Rebuilding-free Electrochemical Chip with a Customizable Decoding Probe for Real-Time and Portable Pathogen Diagnostics.

In order to realize portable pathogen diagnostics with easier quantitation, digitization and integration, we develop a ready-to-use electrochemical sensing strategy (Iso-E-Codelock) for real-time detection of isothermal nucleic acid amplification. Bridged by a branched DNA as codelock, the isothermal amplicon is transduced into increased current of an electrochemical probe, holding multiple advantages of high sensitivity, high selectivity, signal-on response, "zero" background and one-pot operation. Through a self-designed portable instrument (BioAlex PHE-T), the detection can be implemented on a multichannel microchip and output real-time amplification curves just like an expensive commercial PCR machine. The microchip is a rebuilding-free and disposable component. The branch codelock probe can be customized for different targets and designs. Such high performance and flexibility have been demonstrated utilizing four virus (SARS-CoV-2, African swine fever, FluA and FluB) genes as targets, and two branch (3-way and 4-way) DNAs as codelock probes.

Multiplex detection of clinical pathogen nucleic acids via a three-way junction structure-based nucleic acid circuit.

Nucleic acid testing technology has made considerable progress in the last few years. However, there are still many challenges in the clinical application of multiple nucleic acid assays, such as how to ensure accurate results, increase speed and decrease cost. Herein, a three-way junction structure has been introduced to specifically translate analytes of loop-mediated isothermal amplification to a catalytic hairpin assembly. For different analyses, a well-optimized nucleic acid circuit can be directly applied to detection, through only one-component replacement, which only not avoids duplicate sequence design but also saves detection cost. Thanks to this design, multiple and logical analysis can be easily realized in a single reaction with ultra-high sensitivity and selectivity. In this paper, Mycoplasma pneumoniae and Streptococcus pneumoniae can be clearly distinguished from the clinical mixed sample with negative control or one analyte in one tube single fluorescence channel. The fair experimental results of actual clinical samples provide a strong support for the possibility of clinical application of this methodology.

Coupling nucleic acid circuitry with the CRISPR-Cas12a system for universal and signal-on detection.

We report a universal and signal-on HCR based detection platform via innovatively coupling the CRISPR-Cas12a system with HCR. By using this CRISPR-HCR pathway, we can detect different targets by only changing the crRNA. The CRISPR-HCR platform coupling with an upstream amplifier can achieve a practical sensitivity as low as ∼aM of ASFV gene in serum.

Potential feature exploration and model development based on 18F-FDG PET/CT images for differentiating benign and malignant lung lesions.

PURPOSE: The study is to explore potential features and develop classification models for distinguishing benign and malignant lung lesions based on CT-radiomics features and PET metabolic parameters extracted from PET/CT images. MATERIALS AND METHODS: A retrospective study was conducted in baseline 18 F-flurodeoxyglucose positron emission tomography/ computed tomography (18 F-FDG PET/CT) images of 135 patients. The dataset was utilized for feature extraction of CT-radiomics features and PET metabolic parameters based on volume of interest, then went through feature selection and model development with strategy of five-fold cross-validation. Specifically, model development used support vector machine, PET metabolic parameters selection used Akaike's information criterion, and CT-radiomics were reduced by the least absolute shrinkage and selection operator method then forward selection approach. The diagnostic performances of CT-radiomics, PET metabolic parameters and combination of both were illustrated by receiver operating characteristic (ROC) curves, and compared by Delong test. Five groups of selected PET metabolic parameters and CT-radiomics were counted, and potential features were found and analyzed with Mann-Whitney U test. RESULTS: The CT-radiomics, PET metabolic parameters, and combination of both among five subsets showed mean area under the curve (AUC) of 0.820 ±â€¯0.053, 0.874 ±â€¯0.081, and 0.887 ±â€¯0.046, respectively. No significant differences in ROC among models were observed through pairwise comparison in each fold (P-value from 0.09 to 0.81, Delong test). The potential features were found to be SurfaceVolumeRatio and SUVpeak (P < 0.001 of both, U test). CONCLUSION: The classification models developed by CT-radiomics features and PET metabolic parameters based on PET/CT images have substantial diagnostic capacity on lung lesions.

Validation of source biasing method for its use in CSNS beamline shielding calculation.

The Chinese spallation neutron source (CSNS) is a high-performance pulsed neutron source, having 20 neutron beamlines for neutron scattering instruments. The shielding design of these beamlines is usually needed for Monte Carlo (MC) calculation, and the use of variance reduction methods is critical to carrying out an efficient, reliable MC shielding calculation. This paper discusses the source biasing method based on actual source term and geometry model of a CSNS neutron beamline. Dose distribution throughout the geometry model was calculated with the FLUKA MC code. Full analogue calculation and biased calculation were compared, and it was validated that the source biasing method can effectively promote the calculation efficiency.