AbstractPurpose The primary aim was to study the in-vitro suction performance of three different Flexible and Navigable Suction Ureteral Access Sheaths (FANS) of two sizes each. The secondary aim was to study the impact of digital occlusion versus thumb sliders on suction performance.Methods We used the 7.5Fr single-use Flexible Ureterorenoscope from Innovex Medical (US27F-12-EU). The six FANS used were: 10/12Fr and 11/13Fr Innovex 40cm FANS, ClearPetra 46cm FANS, and Reborn 40cm FANS. Time taken to suction 100ml saline was measured. To test efficiency of stone suction, 1000mm3 of 1 to 2mm stones were distributed equally between the upper and lower poles of a kidney model.Results All three 11/13Fr FANS had suction rates three times faster than their 10/12Fr counterparts (p = 0.001 for all FANS), when digital occlusion was used. Innovex and Clearpetra FANS had faster suction rates than Reborn FANS when suctioning 100ml saline, for both 10/12Fr and 11/13Fr. For the Innovex FANS, there was no difference in suction rate when using the thumb slider or digital occlusion. However, Reborn FANS had slower suction rates when using the thumb slider compared to digital occlusion for both 10/12Fr and 11/13Fr sizes. Innovex FANS was the fastest in suctioning upper pole calculi, followed by Clearpetra FANS, and Reborn FANS the slowest for 10/12Fr (198s versus 237s versus 537s respectively, p < 0.001) and 11/13Fr (158s versus 174s versus 332s respectively, p < 0.001). 10/12Fr and 11/13Fr Reborn FANS were not able to reach the lower pole calculi. Between Clearpetra and Innovex, there was no significant difference in time taken to suction lower pole calculi.Conclusions Faster suction was achieved with 11/13Fr instead of 10/12Fr FANS. With digital occlusion, the Innovex and Clearpetra FANS both performed similarly better in their suction performance than the Reborn FANS.
Illumination characteristics of flexible ureteroscopes have been evaluated in air, but not in saline, the native operative medium for endourology. The aim was to evaluate light properties of contemporary ureteroscopes in air versus saline, light distribution analysis, and color temperature.
Abstract Purpose To date, no study has evaluated effects of varying brightness settings on image quality from flexible ureteroscopes submerged in saline. The aim was to evaluate blackout and whiteout occurrences in an in-vitro kidney calyx model. Material and methods We evaluated a series of contemporary flexible ureteroscopes including the Storz Flex-Xc and Flex-X2s, Olympus V3 and P7, Pusen 7.5F and 9.2F, as well as OTU WiScope using a 3D-printed enclosed pink in-vitro kidney calyx model submerged in saline. Endoscopic images were captured with ureteroscope tip placed at 5 mm,10 mm and 20 mm distances. The complete range of brightness settings and video capture modes were evaluated for each scope. Distribution of brightness on a grayscale histogram of images was analyzed (scale range 0 to 255). Blackout and whiteout were defined as median histogram ranges from 0 to 35 and 220 to 255, respectively (monitor image too dark or too bright for the human eye, respectively). Results Blackout occurred with the P7, Pusen 7.5F, 9.2F and WiScope at all distances, and V3 at 20 mm - with lowest brightness settings. Whiteout occurred with Flex-X2s, V3 and P7 at 5 mm and 10 mm, as well as with V3 and P7 at 20 mm - mostly with highest brightness settings. The Flex-Xc had neither blackout nor whiteout at all settings and distances. Conclusion Blackout or whiteout of images is an undesirable property that was found for several scopes, possibly impacting diagnostic and therapeutic purposes during ureteroscopy. These observations form a guide to impact a urologist’s choice of instruments and settings.
This paper describes the implementation of two computer programs that predict the motion of artificial satellites. The two programs are developed in a microcomputer environment. The particular microcomputer used is an IBM AT system. The programs can predict the orbital behavior of artificial satellites under the influence of gravity harmonics up to a 21 by 21 field, luni-solar gravity, drag, and solar radiation pressure. One program uses Cowell's method and the other uses variation of parameters with a singly averaging technique. Both programs use commercially available software to post-process trajectory information and to generate graphics display. The programs reside on floppy disks and are available to the general public through NASA's Computer Software Management and Information Center (COSMIC).
Periodic orbits of the asteroidal type in the circular restricted problem are studied by varying the period of the infinitesimal body (asteroid) and the mass ratio of the primaries (Sun-Jupiter mass ratio). The results indicate that asteroidal periodic orbits can exist for the actual Sun-Jupiter mass ratio for resonances of the Hecuba (2:1), Hilda (3:2) and Thule (4:3) groups, but not for resonances of higher consecutive integer ratios. It is also found that an asteroid can be placed in a periodic orbit at a position with mean motion between 2:1 and 3:2 even if Jupiter is about 9 times more massive than its actual value. However, an asteroid cannot be placed in a periodic orbit beyond the 4:3 resonance for the actual Sun-Jupiter mass ratio.
