Objective: To investigate the situation of quality control of 3.0T magnetic resonance imaging (MRI) system. Methods: A series of indicators, including signal noise ratio(SNR), image uniformity, resolution of long-scale contrast, resolution of space, linearity and quality control of slice thickness, of 3.0T MRI system were measured by using Magphan SMR170 phantom (made by the phantom laboratory in American) on the Discovery MR 750 w system which made by GE company of American. And a series of formula, including SNR=(Sinside-Soutside)÷SDinside, U∑=(1-Smax-Smin/Smax+Smin ×100%, linearity=LR-LM/LR×100%、thickness=half of height and width ×0.25, were used to calculate SNR, image uniformity, linearity and quality control of slice thickness, and all of these results were used to evaluate the situation of quality control of 3.0T MRI system. Results:The results revealed that SNR of 3.0T MRI was 105, the imaging uniformity achieved to 99.13%, the resolution of long-scale contrast was 5mm/0.5mm, the resolution of space was 6 LP/cm, linearity achieved to 0.89% and the deviation of slice thickness was 0.6mm. All of these indicators has achieved the standards of detection. Conclusion: Through detecting the SNR, imaging uniformity, resolution, linearity and the deviation of slice thickness of 3.0T MRI system, the performance of the MRI can be accurately obtained, and these contribute to ensure the equipment operating in ideal situation.

Background: Biofilms, such as those from Staphylococcus epidermidis, are generally insensitive to traditional antimicrobial agents, making it difficult to inhibit their formation. Although quercetin has excellent antibiofilm effects, its clinical applications are limited by the lack of sustained and targeted release at the site of S. epidermidis infection. Objectives: Polyethylene glycol-quercetin nanoparticles (PQ-NPs)-loaded gelatin-N,Ocarboxymethyl chitosan (N,O-CMCS) composite nanogels were prepared and assessed for the on-demand release potential for reducing S. epidermidis biofilm formation. Methods: The formation mechanism, physicochemical characterization, and antibiofilm activity of PQ-nanogels against S. epidermidis were studied. Results: Physicochemical characterization confirmed that PQ-nanogels had been prepared by the electrostatic interactions between gelatin and N,O-CMCS with sodium tripolyphosphate. The PQ-nanogels exhibited obvious pH and gelatinase-responsive to achieve on-demand release in the micro-environment (pH 5.5 and gelatinase) of S. epidermidis.In addition, PQ-nanogels had excellent antibiofilm activity, and the potential antibiofilm mechanism may enhance its antibiofilm activity by reducing its relative biofilm formation, surface hydrophobicity, exopolysaccharides production, and eDNA production. Conclusions This study will guide the development of the dual responsiveness (pH and gelatinase) of nanogels to achieve on-demand release for reducing S. epidermidis biofilm formation.

Mastitis is one of the most widespread infectious diseases that adversely affects the profitability of the dairy industry worldwide. Accurate diagnosis and identification of pathogens early to cull infected animals and minimize the spread of infection in herds is critical for improving treatment effects and dairy farm welfare. The major pathogens causing mastitis and pathogenesis are assessed first. The most recent and advanced strategies for detecting mastitis, including genomics and proteomics approaches, are then evaluated .Finally, the advantages and disadvantages of each technique, potential research directions, and future perspectives are reported. This review provides a theoretical basis to help veterinarians select the most sensitive, specific, and cost-effective approach for detecting bovine mastitis early.