Selective vignetting of Type 1 X-ray telescopes

Selective vignetting technique optimizes the performance of a Type 1 X-ray telescope. The image quality of the telescope system is improved by matching the detector to the optimum focal surface and by vignetting rays which formerly contributed to the flare in comatic images

Glancing incidence telescopes for space astronomy

Design optimization is reported for glancing telescopes of increased collecting areas. Considered are nested geometries for X-ray and extreme ultraviolet telescopes, each of which generates only one singular principal surface. In the case of the X-ray telescope, the field curvature of the outer telescope serves as a standard and the focus of each of the inner telescopes is made coplanar by a slight descrease in the collecting area of each of the inner telescopes. In the case of the EUV telescope, a slight change in the maximum slope angle of the inner telescope makes the field curvatures coincide. Five concentric X-ray telescopes form a collecting area of approximately 900 sq cm, and a nested EUV telescope consisting of two concentric telescopes produces a collecting area of about 45 sq cm

De novo head and neck cancer after liver transplant with antibody-based immunosuppression induction

Background Powerful antibody-based immunosuppression induction is now used routinely during organ transplantation, and may place patients at even higher risk of post-transplant cancer. Materials and Methods Incidence of de-novo head and neck cancer was extracted from the records of 1685 consecutive adult, deceased donor liver transplant recipients with a minimum 1-year follow-up from 2001 to 2015. There were 121 patients positively identified as having developed de-novo head and neck cancer post-liver transplant. Records of these patients were analyzed to determine demographics, history of cancer pre-liver transplant, de-novo cancer type and location, treatment modalities, and alcohol and tobacco exposure. Results Of the 121 patients who developed cancer of the head and neck (7%), there were 103 cutaneous (6%) and 25 non-cutaneous (1%). For non-cutaneous cancers, factors associated with increased risk of cancer included alcohol abuse (p<0.001), any smoking history (p=0.05), and increasing exposure to tobacco (p<0.01). Ten-year Cox regression patient survival demonstrates a survival disadvantage for patients who develop non-cutaneous cancer (p=0.06), but a survival advantage for patients who develop cutaneous cancer (p<0.01). Conclusions The incidence and pattern of head and neck cancer in this population of liver transplant patients was similar to those published previously, suggesting that induction immunosuppression does not increase risk of these types of cancers. Long term survival was worse for patients with non-cutaneous cancers, but better for those with cutaneous cancers, though the reason is unclear