Erosion and sediment transport have critical implications for aquatic ecology, agriculture, water supply and river navigation. In recent years, with the construction and operation of several reservoirs in Red river basin (China

Internal erosion is a major cause related to nearly half of dam dysfunctions and failures. This phenomenon occurs when loose soil particles are transported outwards the soil mass by seepage through a series of pores and pore constrictions. As loose particles are usually fine and embedded in the pores formed by the soil primary fabric, traditional methods often correlate the representative sizes of fine and coarse particles to indicate the susceptibility to internal erosion of an assessed soil. These methods are not very accurate because soil particle size distribution can vary widely with several identical key sizes. This paper presents a new indicator for internal erosion assessment using the probability to be transported of loose particles: the segregation index. This index is estimated experimentally and analytically for the correlation with internal erosion test results. The index also has a significant role in the estimation of real effective stress of soils.

Objective: To evaluate the result of gamma knife radiosurgery (GKRS) for drug-resistant primary trigeminal neuralgia (TN). Methods: Patients who were diagnosed with drug-resistant primary TN were treated with GKRS at the Nuclear Medicine and Oncology Center, Bach Mai Hospital from January 2015 to June 2020. Using the pain rating scale of the Barrow Neurological Institute (BNI), follow-ups and evaluations were conducted at 1 month, 3 months, 6 months, and 9 month, and 1, 2 years, 3 years, and 5 years after radiosurgery. Comparisons of pain levels was performed before and after radiosurgery according to the BNI scale. Results: From January 2015 to June 2020, 33 patients were treated with GKS. There were 23 female patients and 10 male patients; the average age was 61.9. The average onset time of disease was 4.42 years. Among all patients, 84.8% of patients were relieved from pain and 78.8% were pain-free without medication. The mean time for pain relief was 3 months and was not related to the dose of GKS (<80 Gy and ≥80 Gy). The efficacy of pain relief is not related to blood vessel contact with the trigeminal nerve, the dose of GKS, and the onset of disease. The rate of recurrence after the first pain relief was low (14.3%). Conclusions: Gamma knife is an effective method for the treatment of primary drug-resistant TN, especially in elderly patients with underlying medical conditions. The analgesic effect does not depend on the presence of nerve-vascular conflict.