In order to explore the application of the dielectric properties of white matter and grey matter in β, δ and γ dispersion transition zones used in clinical medicine and microwave imaging technology, we calculated the dielectric constant and its increment by using Cole-Cole equation. Based on the mutation of the increment of dielectric constant, the frequency range of three dispersions were evaluated. The dominate dispersion and the corresponding polarization mechanism were analyzed by using Cole-Cole circle. The results showed that there are 3 transition zones in brain white matter, which occur between β and δ dispersion, δ and γ dispersion and β and γ dispersion respectively. In grey matter, there are only 2 transition zones, which are between β and δ dispersion and δ and γ dispersion respectively. By comparing the frequency range of white matter and grey matter, the frequency range in white matter is broader than that in grey matter for the transition zone of β and δ dispersion with the β dispersion occupying dominate position in both tissues, and the corresponding polarization mechanism is interfacial polarization. For the transition zone of δ and γ dispersion, the frequency range in white matter is also broader than that in grey matter with the δ dispersion occupying dominate position in both tissues, and the corresponding polarization mechanism is orientation polarization. This study can provide basic theory and reference for diagnosis of brain diseases and microwave imaging technology.
Objective To analyze the trends in the burden of intracerebral hemorrhage (ICH) and its related risk factors in China from 1990 to 2021, providing evidence for targeted prevention and control. Methods Based on public data from the Global Burden of Disease Study 2021, four epidemiological indicators, including incidence, prevalence, deaths, and disability-adjusted life-years (DALYs) were selected to describe the burden of ICH in China in 2021. Change rates and estimated annual percentage changes (EAPC) were calculated to evaluate the trends in disease burden from 1990 to 2021. The Das Gupta method was used to decompose the effects of population growth, population aging and epidemiological changes on the burden during this period. Finally, the attributable burden of risk factors related to ICH was analyzed. Results In 2021, the age-standardized incidence, prevalence, mortality, and DALY rates of ICH in China were 61.2/100000, 222.1/100000, 68.8/100000, and 1351.6/100000, respectively, all higher than global estimates. From 1990 to 2021, although these rates showed a declining trend (EAPC: −2.24, −1.26, −2.38, and −2.47, respectively), the absolute disease burden, including the absolute number of prevalence cases, incidence cases, deaths, and DALYs, continued to rise, with an increase ranging from 20.57% to 51.59%. In addition, the burden of ICH in China varied by age and sex, with older adults and males experiencing a higher burden. Decomposition analysis indicated that population aging and growth were the primary drivers of the increasing ICH burden in China, while epidemiological changes mitigated this trend. Metabolic factors were the predominant attributable risk factors for ICH. High systolic blood pressure, ambient particulate matter pollution, and diet high in sodium were important risk factors common to both genders. The DALY burden attributable to smoking and alcohol use was higher in men, whereas impaired kidney function and secondhand smoke had a greater impact on women. Conclusions The burden of ICH in China has continued to increase from 1990 to 2021, and it may further escalate in the context of population aging. Risk factor control remains a key priority for prevention. Future strategies should incorporate age- and sex-specific interventions to reduce the ICH burden in China.
ObjectiveTo develop and validate a nomogram for predicting the cancer-specific survival in patients with intrahepatic cholangiocarcinoma (ICC) after hepatectomy. MethodsSuitable patient cases were selected from the Surveillance, Epidemiology, and End Results (SEER) database. Nomograms were established based on the independent prognostic factors identified by COX and Lasso regression models. The performance of the nomograms was validated internally and externally by using the concordance index (c-index), calibration plot, and decision curve analysis. ResultsThe multi factor COX regression results showed that: age, gender, T stage, tumor grade, tumour diameter and number of positive lymph nodes were independent prognostic predictors for cancer-specific survival (CSS) in ICC patients. Nomogram predicting CSS had a c-index of 0.66 (95%CI 0.64 to 0.69) in the training cohort and 0.67 (95%CI 0.63 to 0.72) in the internal validation cohort. The 1-, 3- and 5-year areas under the curve (AUC) of nomogram were 0.68, 0.74 and 0.75 in the training cohort respectively. In the validation cohort, the 1-, 3- and 5-year AUC of nomogram were 0.69, 0.68 and 0.71, respectively. ConclusionThe prediction model constructed based on six factors, including age, gender, pathological stage, T-stage, tumour diameter and number of positive lymph nodes, shows good prediction accuracy.