The fate of retained gallstones following laparoscopic cholecystectomy in a prairie dog model

By extrapolation to zero time, the initial and final slopes of data sets which probably demonstrate the existence of accelerated repopulation during radiotherapy can be used to estimate the lower limits of the initial tumour hypoxic fraction. The slow repopulation phase (initial slope) is assumed to reflect treatment in mixed oxic and hypoxic conditions and the later fast repopulation (final slope) phase that of a well-oxygenated cell population. The method assumes that accelerated repopulation in tumours results from an improvement in oxygen status during radiotherapy, but quantitative knowledge of repopulation factors is not required in the calculations. Using the data of (a) Withers et al. (for head and neck squamous cell cancer) and (b) Maciejewski & Majewski (for bladder cancer), the lower limits of initial hypoxic fraction appear to be between 10 and 52%, the exact values depending on the value assumed for the oxygen-enhancement ratio (OER) of the hypoxic compartment. The analysis also suggests that the half-life of effective tumour reoxygenation is probably less than 5 days.     

横向微堆积大功率半导体激光器线阵的制备

提出了一种横向微堆积大功率半导体激光器线阵的新结构,在相同的注入电流下提高了器件的输出光功率,有效缓解了大电流下的器件热烧毁和光学灾变性毁坏(COD)。制备了横向微堆积三有源区半导体激光器线阵列,在50A的工作电流下,其输出光功率可达到79.3W,斜率效率可达1.81W/A,是传统单有源区bar条的两倍多。     

Submillimeter-resolution MR of the endolymphatic sac in healthy subjects and patients with Menière disease

PURPOSE: To evaluate the utility of submillimeter resolution MR imaging for direct depiction of functional soft-tissue components of the intraosseous endolymphatic duct and sac in healthy subjects and in patients with Menière disease. METHODS: Axial MR images were acquired of 14 patients with Menière disease and 14 healthy volunteers at 1.5 T with a short-echo-time steady-state 3-D gradient-echo sequence. Seven volunteers and eight patients were also studied with a T1-weighted 3-D spoiled gradient-echo sequence. T1/T2 relaxation times were estimated from studies with multiple flip angles. RESULTS: Independent of the acquisition method, intraosseous endolymphatic ducts and sacs were seen unambiguously in the ears of 20 of 21 healthy subjects but in only four of 12 asymptomatic and two of 10 symptomatic ears of patients with Menière disease. Other labyrinthine structures were well depicted in all subjects. Furthermore, shorter relaxation times were measured for the contents of the vestibular aqueduct than for other labyrinthine structures. CONCLUSION: In our high-resolution study, the intraosseous portions of the endolymphatic ducts and sacs were depicted in most of the healthy subjects. They were frequently not seen in either ear of patients with unilateral Menière disease, presumably because of their small size.