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To verify whether a low-frequency electromagnetic field (LFE field) can help reduce structural damage during the freeze–thaw process and maintain shelf life, Mongolian cheese was frozen at −10, −20, and −30 °C, then thawed at microwave or room temperature. Results showed that LFE field-assisted frozen treatment could reduce ice crystal size and protect the protein matrix structure of cheese. Frozen–thawed cheese retained 96.5% of its hardness and showed no significant difference from the fresh one in elasticity, cohesion, and chewiness. Frozen cheese showed similar but slower ripening behavior during storage, suggesting a potential application of the LFE field in the frozen storage of high-protein foods.

ObjectiveBrain tissue changes dynamically during aging. The purpose of this study was to use synthetic magnetic resonance imaging (syMRI) to evaluate the changes in relaxation values in different brain regions during brain aging and to construct a brain age prediction model.Materials and methodsQuantitative MRI was performed on 1,000 healthy people (≥ 18 years old) from September 2020 to October 2021. T1, T2 and proton density (PD) values were simultaneously measured in 17 regions of interest (the cerebellar hemispheric cortex, pons, amygdala, hippocampal head, hippocampal tail, temporal lobe, occipital lobe, frontal lobe, caudate nucleus, lentiform nucleus, dorsal thalamus, centrum semiovale, parietal lobe, precentral gyrus, postcentral gyrus, substantia nigra, and red nucleus). The relationship between the relaxation values and age was investigated. In addition, we analyzed the relationship between brain tissue values and sex. Finally, the participants were divided into two age groups: < 60 years old and ≥ 60 years old. Logistic regression analysis was carried out on the two groups of data. According to the weight of related factors, a brain age prediction model was established and verified.ResultsWe obtained the specific reference value range of different brain regions of individuals in different age groups and found that there were differences in relaxation values in brain tissue between different sexes in the same age group. Moreover, the relaxation values of most brain regions in males were slightly higher than those in females. In the study of age and brain relaxation, it was found that brain relaxation values were correlated with age. The T1 values of the centrum semiovale increased with age, the PD values of the centrum semiovale increased with age, while the T2 values of the caudate nucleus and lentiform nucleus decreased with age. Seven brain age prediction models were constructed with high sensitivity and specificity, among which the combined T1, T2 and PD values showed the best prediction efficiency. In the training set, the area under the curve (AUC), specificity and sensitivity were 0.959 [95% confidence interval (CI): 0.945–0.974], 91.51% and 89.36%, respectively. In the test cohort, the above indicators were 0.916 (95% CI: 0.882–0.951), 89.24% and 80.33%, respectively.ConclusionOur study provides specific reference ranges of T1, T2, and PD values in different brain regions from healthy adults of different ages. In addition, there are differences in brain relaxation values in some brain regions between different sexes, which help to provide new ideas for brain diseases that differ according to sex. The brain age model based on synthetic MRI is helpful to determine brain age.

Abstract Purpose The aim of this study was to characterize changes in hippocampal inflammasomes, pyroptosis and apoptosis in juvenile rats after brain irradiation and to assess whether manganese-enhanced magnetic resonance imaging (MEMRI) reflected those changes. Materials and methods Four-week-old male Sprague-Dawley rats received a whole-brain radiation dose of 15 Gy or 25 Gy. Hippocampal inflammasomes and apoptosis were measured using Western blot analysis at 4 days and 8 weeks after irradiation. MEMRI and magnetic resonance spectroscopy (MRS) were performed at the same time points. Results Neither the 15 Gy nor 25 Gy group showed changes in the expression of inflammasome proteins absent in melanoma 2 (AIM2), gasdermin-D (GSDMD), nucleotide oligomerization domain-like receptor protein 1 (NLRP1) and NLRP3 at 4 days or 8 weeks after radiation injury (P > 0.05). Furthermore, the expression levels of the inflammatory cytokines interleukin-1β (IL-1β) and IL-18 were not significantly different among the groups (P > 0.05). The expression levels of cleaved caspase-1 and -3, indicators of apoptosis, were higher in the irradiation groups than in the control group at 4 days post irradiation, especially for caspase-3 (P 0.05), but the NAA/Cr ratio in the 25 Gy group remained significantly lower than that in the control group (P