Cooperative Radio Navigation for Robotic Exploration: Evaluation of a Space-Analogue Mission

Autonomous robotic systems will play an important role in future planetary exploration missions. To allow autonomous operation of robots, reliable navigation is vital. Such a navigation solution is provided by cooperative radio navigation, where radio signals are exchanged among the robots. Based on the signal round-trip time (RTT) and direction-of-arrival (DoA), the robots' positions and orientations are estimated. Cooperative navigation has been well studied theoretically, but experiments mainly focused on indoor scenarios and other applications. For the first time, we have demonstrated cooperative radio navigation within a space-analogue exploration mission with two robotic rovers. The mission took place on the volcano Mt Etna, Sicily, Italy. During the first part of the mission, simultaneous localization and calibration (SLAC) is performed to improve the accuracy of RTT and DoA estimates by reducing the bias. Then, the rovers travel to a distant area of interest. Ultimately, one rover travels so far that it is connected to the network only via another rover. We find that even in this challenging single-link scenario, robust cooperative navigation is achieved. When the rovers are not further than 60 m away from the lander, their position root-mean-square errors (RMSEs) are 0.3m to 0.9m. Even for the most challenging mission phase, when the rovers are 100 m to 160 m away from the lander with single-link localization, the position RMSEs are 1.7m to 2.6m. The orientation RMSEs of the rovers lie between 2.4° to 6.1°. Thus, with this space-analogue mission, we show that cooperative radio navigation for planetary exploration is robust and accurate

Urinary Diversion for Severe Urinary Adverse Events of Prostate Radiation: Results from a Multi-Institutional Study

PurposeWe evaluated the short and long-term surgical outcomes of urinary diversion done for urinary adverse events arising from prostate radiation therapy. We hypothesized that patient characteristics are associated with complications after urinary diversion.Materials and methodsWe performed a retrospective cohort study of 100 men who underwent urinary diversion (urinary conduit or continent catheterizable pouch) due to urinary adverse events after prostate radiotherapy from 2007 to 2016 from 9 academic centers in the United States. Outcome measurements included predictors of short and long-term complications, and readmission after urinary diversion of patients who had prostate cancer treated with radiotherapy. The data were summarized using descriptive statistics and univariate associations with complications were identified with logistic regression controlling for center.ResultsMean patient age was 71 years and median time from radiotherapy to urinary diversion was 8 years. Overall 81 (81%) patients had combined modality therapy (radical prostatectomy plus radiotherapy or various combinations of radiotherapy). Grade 3a or greater Clavien-Dindo complications occurred in 31 (35%) men, including 4 deaths (4.5%). Normal weight men had more short-term complications compared to overweight (OR 4.9, 95% CI 1.3-23.1, p=0.02) and obese men (OR 6.3, 95% CI 1.6-31.1, p=0.009). Hospital readmission within 6 weeks of surgery occurred for 35 (38%) men. Surgery was needed to treat long-term complications after urinary diversion in 19 (22%) patients with a median followup of 16.3 months.ConclusionsUrinary diversion after prostate radiotherapy has a considerable short and long-term surgical complication rate. Urinary diversion most often cannot be avoided in these patients but appreciation of the risks allows for informed shared decision making between surgeons and patients

Distance Estimation from a Diffusive Process: Theoretical Limits and Experimental Results

Estimating the distance between the source of a diffusive process and a receiver has a variety of applications, ranging from gas source localization at the macro-scale to molecular communication at the micro-scale. Distance information can be extracted from features of the observed particle concentration, e.g. its peak. This paper derives the Cramér-Rao lower bound (CRB) for distance estimation given the advection-diffusion model for absorbing receivers, which is the fundamental limit of any distance estimator. Furthermore, CRBs are obtained for estimators using only information about the observed peak. A maximum-likelihood estimator using the entire signal and two estimators based on peak detection are deduced. The derived CRBs are used to study the effect of channel parameters on the estimation performance. Finally, the performance of the proposed estimators is verified by comparing the root mean squared errors with their theoretical bounds in a simulation, and preliminary experimental results are presented

Transrectal Ultrasound Guided Needle Aspiration of a Prostatic Abscess: Salvage Treatment After Failed Transurethral Resection

The treatment for prostate abscesses includes a combination of antimicrobial therapy and surgical drainage of the abscess cavity. There is a lack of published cases involving treatment options for a prostate abscess after a failed transurethral resection of the prostate. This is a case report describing a successful salvage treatment after a failed attempt at abscess drainage by a transurethral resection of the prostate. The patient was successfully managed with a needle drainage of his prostate abscess utilizing a transrectal ultrasound guided needle decompression his prostate abscess

Patient Risk Factors Associated with Reported Urinary Quality of Life Following Artificial Urinary Sphincter Placement: A Paired Pre and Postoperative Analysis.

ObjectiveTo evaluate potential associations between patient risk factors and incontinence related patient-reported outcome measures (PROMs) preandpost artificial urinary sphincter (AUS) implantation. We hypothesize patient risk factors, including prior radiation and diabetes will have a negative association with post AUS PROMs.MethodsA review of prospectively collected preandpostoperative Incontinence Symptom Index [ISI] and Incontinence Impact Questionnaire-7 (IIQ-7)s from multiple institutions in the Trauma and Urologic Reconstruction Network of Surgeons was performed. Changes in preandpost AUS ISI and IIQ-7 scores were compared for the entire cohort then stratified by patients with prior AUS, obesity, diabetes, prior radiation, and mixed urinary incontinence.ResultsA total of 145 patients, 67.2 (SD 10.9) years had complete preandpost AUS questionnaires (median follow up 186 days, IQR 136-362). Post AUS ISI and IIQ-7 scores improved significantly for the group at large. Prior radiation was associated with less improvement in total IIQ-7 scores, -25.5 (31.9) vs -39 (33.0), P = .03. Obesity was associated with a greater reduction in incontinence severity -13.6 (SD 9.1) vs -9.2 (SD 8.9), P<0.01, urge -5.2(SD 4.2) vs -2.5(SD 4.5), P <.01, and total ISI score -29.7(SD19.7) vs -21.2 (SD 19.9), P = .02. Prior AUS, diabetes, and mixed incontinence were not associated with post AUS PROMs outcome.ConclusionOverall, patients reported a significant reduction in incontinence severity, bother, impact, and distress following AUS placement. Prior radiation was associated with less improvement in total IIQ-7 scores. In contrast, obesity demonstrated a greater reduction in ISI severity and urge scores compared to non-obese patients