Conformations of surface atoms in various stages of nanogold-based genechip testing were scanned by the atomic force microscope based on the scanning tunneling microscope. The findings were: First, the surface atoms of genechip slide (formylphenyl glass) were in a regular porous-arrangement; Second, after combination with probe, the regular porous arrangement changed to be irregular; Third, after hybridization with the target nucleic acid, the surface atoms were once again in a cable-like arrangement which was relatively structured and intensively cross-parallel. However, after the silver staining, the surface atoms showed a larger block structure with serious unevenness. From these results we can intuitively know the process and differences in probe combination, nucleic acid hybridization, and silver staining. Moreover, the relevant experiment was verified at the micro-level.
Gold ; Metal Nanoparticles ; chemistry ; Microscopy, Atomic Force ; methods ; Microscopy, Scanning Tunneling ; methods ; Molecular Conformation ; Nanotechnology ; methods ; Oligonucleotide Array Sequence Analysis ; instrumentation ; methods ; Particle Size ; Surface Properties

The surface plasmon resonance (SPR)-based gene chip was prepared according to the following processes: First, a film of nanogold, which was synthesized by using Frens' method, was plated on chip by Chlorauric acid/hydroxylamine method. Then probes were fixed on nanogold film by Self-assembled monolayer (SAM) technology. Subsequently, the fixing time and concentration of probes, the sensitivity and the specificity of the chip were optimized. Our results suggested that the chip plated with 2.5 nm nanogold film has a better SPR reflection, and when fixed by probes for 4.5 h at the concentration of 1 500 nmol/L, the gene chip also shows a fine performance of detection and can identify accurately the mismatch between bases in SPR detection system. The gene chip constructed in the research can be used for SPR sensor detection.
Gold ; chemistry ; Nanoparticles ; chemistry ; Neisseria gonorrhoeae ; genetics ; Oligonucleotide Array Sequence Analysis ; Sensitivity and Specificity ; Surface Plasmon Resonance ; methods

Objective:To construct a spatial radiomics model based on the spatial distribution characteristics of supratentorial pilocytic astrocytoma (PA) and ganglioglioma (GG) and to evaluate its differential diagnosis efficiency.Methods:The study was a cross-sectional study. A retrospective collection of 244 patients with episodic PA and GG who attended Beijing Tiantan Hospital of Capital Medical University (Center 1) from June 2016 to June 2022 and 116 patients with episodic PA and GG who attended General Hospital of Eastern Theater Command (Center 2) from March 2019 to October 2022 was performed. The patients in Center 1 were divided into a training set (171 patients) and a validation set (73 patients) in a 7∶3 ratio according to the random number table method, and the patients in Center 2 as a whole were regarded as test sets. All patients underwent MRI. Segmentation of tumor based on enhanced T 1WI and T 2WI images, alignment to standard space to generate a statistical parametric mapping of tumor locations and intergroup comparison was conducted. The Johns Hopkins University template was used to extract 189 tumor location features to construct a spatial model of tumor location; PyRadiomic 3.0.1 software was used to extract tumor radiomics features to construct a radiomics model; and the two models were fused to construct a spatial radiomics model. The efficacy of spatial radiomics model, spatial model, and radiomics model to discriminate PA from GG was analyzed using receiver operating characteristic curves and area under the curve (AUC). The generalization ability of the model was assessed by the difference in accuracy between the test sets and the validation sets (ΔACC). The clinical utility of the model was compared using clinical decision curves and calibration curves. Results:The statistical parametric mapping of lesions showed that supratentorial PA was vulnerable to medial structure areas such as suprasellar region, thalamus, basal ganglia and frontal lobe, temporal lobe, parietal lobe. GG was mainly distributed in bilateral temporal lobes, as well as frontal lobe, occipital lobe and parietal lobe. The AUCs of spatial radiomics model, radiomics model and spatial model to identify PA and GG in the test set were 0.876, 0.785, and 0.819, with accuracies of 77.59%, 72.41%, and 77.14%, respectively, and ΔACCs in the test set and validation set were 11.6%, 15.43%, and 6.94%, respectively. The clinical decision curves showed an overall greater clinical benefit of the spatial radiomics model compared with the conventional radiomics model and spatial model.Conclusion:Spatial radiomics model containing spatial information on lesion location can improve the diagnostic efficacy of supratentorial PA and GG, and enhance the generalization of the prediction model.

AIM: To investigate the population pharmacokinetic characteristics of capecitabine and its possible influencing factors in Chinese patients of breast cancer. METHODS: 78 cases of Chinese patients with breast cancer were chosen as the objects in this study. Following treatment with capecitabine (0.6 g, 0.15 g/piece, 4 pieces, orally), blood samples were collected and concentrations of capecitabine in plasma were analyzed by high performance liquid chromatography-mass spectrometry (HPLC-MS/MS) method. The nonlinear mixed-effects software (NONMEM) was used to analyze the data and the population pharmacokinetic model was constructed accordingly. RESULTS: The final established model of absorption and elimination is one-compartment model. The clearance (CL/F) in pharmacokinetic formula of the model is as follows: CL/F=291×e