Hygroscopicity research has long been a key focus and hot topic in Chinese materia medica（CMM）. Elucidating hygroscopic mechanisms plays a vital role in formulation design， process optimization， and storage condition selection. Hygroscopic models serve as essential tools for characterizing CMM hygroscopic mechanisms， with various types available. The double exponential model is a kinetic mathematical model constructed based on the law of conservation of energy and Fick's first law of diffusion， tailored to the physical properties of CMM extracts. In recent years， this model has been extensively applied to simulate the dynamic moisture absorption behavior of CMM extracts and solid dosage forms under varying humidity conditions. It has revealed the correlation between moisture absorption kinetic parameters and material properties， offering a new perspective for characterizing the moisture uptake behavior of CMM. This paper systematically reviews the application progress of this model in the field of CMM， analyzes its advantages， disadvantages， and challenges in this domain， and explores its potential application trends in other fields. It aims to provide references for elucidating the moisture absorption mechanisms of CMM and researching moisture-proofing technologies， while also offering insights for its broader application in food and polymer materials.

Objective To investigate the clinic features and risk factors for central nervous system (CNS) infection in patients with systemic lupus erythematosus. Methods Clinical data of 18 cases of hospitalized lupus patients with CNS infection were analyzed retrospectively.Thirty-three lupus patients without CNS infection were selected as control. Results There were significant differences between the CNS infection group and control group in the dosage of corticosteroid used for pulse therapy (22% vs 3%, P<0.05), the aver-age dosage of corticosteroid used within one year (35±18 vs 24±17, P<0.05), peripheral blood leukocyte count (4.4±3.4 vs 6.7±2.9, P<0.05) and lymphocyte count (0.7±0.6 vs 1.5±0.7, P<0.01), and clinical outcome (mortality rate was 22% vs 0, P<0.05). Conclusion The clinical manifestations of CNS infection may be atypical. Large-dosage corticosteroid therapy, higher daily dosage of corticosteroid used, decreased peripheral lymphocytes and leucocytes counts are risk factors of central nervous system infection in lupus patients.