Testing and Analysis Method of Low Remanence Materials for Magnetic Shielding Device.

Magnetic shielding devices with a grid structure of multiple layers of highly magnetically permeable materials (such as permalloy) can achieve remanent magnetic fields at the nanotesla (nT) level or even lower. The remanence of the material inside the magnetic shield, such as the building materials used in the support structure, can cause serious damage to the internal remanence of the magnetic shield. Therefore, it is of great significance to detect the remanence of the materials used inside the magnetic shielding device. The existing test methods do not limit the test environment, the test process is vulnerable to additional magnetic field interference and did not consider the real results of the material in the weak magnetic environment. In this paper, a novel method of measuring the remanence of materials in a magnetic shielding cylinder is proposed, which prevents the interference of the earth's magnetic field and reduces the measurement error. This method is used to test concrete components, composite materials and metal materials commonly applicated in magnetic shielding devices and determine the materials that can be used for magnetic shielding devices with 1 nT, 10 nT and 100 nT as residual magnetic field targets.

Multi-Drug-Resistant Bacterial Infection after Pancreatoduodenectomy: Risk Factors and Clinical Impact.

Background: Infection by multi-drug-resistant (MDR) bacteria is a high-risk factor for poor clinical results. Pancreatoduodenectomy (PD) has been associated with a high rate of complications, including intra-abdominal infections. However, there are few data available regarding MDR infection in patients undergoing PD. This study evaluated the present situation of risk factors for and clinical impact of MDR infection on patients who received PD. Methods: A total of 357 consecutive patients who underwent PD in our department from January 2016 to June 2018 were analyzed retrospectively. They were grouped into those with MDR infection (observation group) and those without MDR infection (control group). Univariable and multivariable analyses were used to identify risk factors for MDR infection in the two groups and the relations between MDR infection and clinical outcome. Results: Infections by MDR bacteria occurred in 38 patients (10.6%), and a total of 49 MDR bacterial strains were detected. Carbapenem-resistant Acinetobacter baumannii and MDR Pseudomonas aeruginosa were the most common strains. Multivariable analysis suggested that pancreatic fistula (p = 0.001) and post-operative use of quinolones (p = 0.000) were risk factors for MDR infection. At the same time, MDR infection was an independent risk factor for an increase in the 30-day in-hospital mortality rate (p = 0.005). Conclusions: Intensive intra-operative management to reduce the incidence of pancreatic fistula as well as curtailing empirical use of antibiotics, especially quinolones, may help to reduce the incidence of MDR infection and thus in-hospital deaths.