Giant cell collagenomas associated with Cowden syndrome: A case report.

Storiform collagenoma, also known as sclerotic fibroma, is a relatively rare benign cutaneous tumor consisting of a proliferation of fibroblasts that shows increased production of type I collagen. It may appear as a solitary, sporadic lesion, or, especially when multiple, associated with Cowden syndrome. Giant cell collagenoma has a histopathologic appearance similar to that of storiform collagenoma with the addition of floret-type giant cells. Herein, we report the finding of multiple giant cell collagenomas arising in an individual with Cowden syndrome. In a review of the published literature, this histopathologic variant appears to be rarely observed in association with Cowden syndrome.

First High power test results for 2.1 GHz superconducting photonic band gap accelerator cavities.

We report the results of the recent high power testing of superconducting radio frequency photonic band gap (PBG) accelerator cells. Tests of the two single-cell 2.1 GHz cavities were performed at both 4 and 2 K. An accelerating gradient of 15 MV/m and an unloaded quality factor Q(0) of 4×10(9) were achieved. It has been long realized that PBG structures have great potential in reducing long-range wakefields in accelerators. A PBG structure confines the fundamental TM(01)-like accelerating mode, but does not support higher order modes. Employing PBG cavities to filter out higher order modes in superconducting particle accelerators will allow suppression of dangerous beam instabilities caused by wakefields and thus operation at higher frequencies and significantly higher beam luminosities. This may lead towards a completely new generation of colliders for high energy physics and energy recovery linacs for the free-electron lasers.