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Radio frequency cavities are among the most challenging and costly components of an accelerator facility. They are usually manufactured in individual parts, which are then joined by complex processes, e.g., several brazing steps. 3D printing has become an alternative to these conventional manufacturing methods due to higher cost efficiency, freedom in design, and recent achievement of high print quality for pure copper. A fully functional 3 GHz drift tube linac (DTL) prototype was 3D printed in one piece, made from pure copper by selective laser melting (SLM). To achieve a higher surface quality, the DTL geometry was optimized for the SLM process. The DTL design is related to the design of the DTL part of the side-coupled DTL modules used in linac-based proton therapy facilities. The quality factor (8750) and the shunt impedance per unit length (102 m Ω m ) of the printed prototype are already comparable to traditionally manufactured DTL structures and can be further enhanced by surface treatments. [ABSTRACT FROM AUTHOR]

Dermatofibrosarcoma protuberans ( DFSP) is a low-grade, mesenchymal, spindle cell tumor. In addition to the classical form characterized by a storiform pattern of tumor cells, pigmented (Bednar's tumor) and myxoid variants can be observed. Classical DFSP and Bednar's tumor are easily diagnosed. The myxoid variant represents a diagnostic challenge. Pigmented and myxoid variants are rare and thus far have never been reported in association in congenital DFSP. We came across a unique DFSP that was, at the same time, congenital, pigmented, and myxoid. The tumor was surgically excised with broad free margins and no recurrence. The differential diagnosis with other entities such as giant cell fibroblastoma, CD34-positive plaque-like dermal fibroma, superficial plaque-like CD34 DFSP, and neurocristic hamartoma is discussed. The recognition of this hybrid variant of congenital DFSP is important to avoid under- or overtreatment. [ABSTRACT FROM AUTHOR]

Objective: Our objective was to assess how often "outlet obstruction" was the cause of constipation in a tertiary referral population. Methods: We retrospectively audited the ease records of 70 consecutive patients referred to a single gastroenterologist in a tertiary referral motility clinic. Patients were classified by physiological tests of colonic transit, as well as tests of anorectal and pelvic floor function. A subset of 28 patients also under-went a battery of tests to assess the autonomic nervous system supply. Results: Thirty-six patients had symptoms suggestive of a rectal outlet obstruction syndrome. Thirty seven percent of patients had pelvic floor dysfunction, 27% had slow transit constipation, and 8% bad anismus. Fully 55% of those with pelvic floor dysfunction had slow transit in addition. The remaining patients (23%) had at least two of Manning's criteria suggestive of the irritable bowel syndrome. Only four patients had documented abnormalities of autonomic function. Conclusions: Pelvic floor dysfunction is the most common cause of severe constipation in a tertiary referral motility clinic; slow transit constipation and irritable bowel syndrome occur equally. An algorithmic approach to evaluating patients using clinical features, anorectal functions tests, and assessment of colonic transit facilitates selection of management strategies. Autonomic dysfunction occurs rarely. [ABSTRACT FROM AUTHOR]