454 research outputs found
Concept definition study for recovery of tumbling satellites. Volume 1: Executive summary, study results
The first assessment is made of the design requirements and conceptual definition of a front end kit to be transported on the currently defined Orbital Maneuvering Vehicle (OMV) and the Space Transportation System Shuttle Orbiter, to conduct remote, teleoperated recovery of disabled and noncontrollable, tumbling satellites. Previous studies did not quantify the dynamic characteristics of a tumbling satellite, nor did they appear to address the full spectrum of Tumbling Satellite Recovery systems requirements. Both of these aspects are investigated with useful results
Concept definition study for recovery of tumbling satellites. Volume 2: Supporting research and technology report
A number of areas of research and laboratory experiments were identified which could lead to development of a cost efficient remote, disable satellite recovery system. Estimates were planned of disabled satellite motion. A concept is defined as a Tumbling Satellite Recovery kit which includes a modular system, composed of a number of subsystem mechanisms that can be readily integrated into varying combinations. This would enable the user to quickly configure a tailored remote, disabled satellite recovery kit to meet a broad spectrum of potential scenarios. The capability was determined of U.S. Earth based satellite tracking facilities to adequately determine the orientation and motion rates of disabled satellites
Patient-Reported Functional Outcomes After Hypofractionated or Conventionally Fractionated Radiation for Prostate Cancer: A National Cohort Study in England.
PURPOSE: The aim of the current study was to determine patient-reported functional outcomes in men with prostate cancer (PCa) undergoing moderately hypofractionated (H-RT) or conventionally fractionated radiation therapy (C-RT) in a national cohort study. PATIENDS AND METHODS: All men diagnosed with PCa between April 2014 and September 2016 in the English National Health Service undergoing C-RT or H-RT were identified in the National Prostate Cancer Audit and mailed a questionnaire at least 18 months after diagnosis. We estimated differences in patient-reported urinary, bowel, sexual, and hormonal function-Expanded Prostate Cancer Index Composite short-form 26 domain scores on a 0 to 100 scale-and health-related quality of life-EQ-5D-5L on a 0 to 1 scale-using linear regression with adjustment for patient, tumor, and treatment-related factors in addition to GI and genitourinary baseline function, with higher scores representing better outcomes. RESULTS: Of the 17,058 men in the cohort, 77% responded: 8,432 men received C-RT (64.2%) and 4,699 H-RT (35.8%). Men in the H-RT group were older (age ≥ 70 years: 67.5% v 60.9%), fewer men had locally advanced disease (56.5% v 71.3%), were less likely to receive androgen-deprivation therapy (79.5% v 87.8%), and slightly more men had pretreatment genitourinary procedures (24.2% v 21.2%). H-RT was associated with small increases in adjusted mean Expanded Prostate Cancer Index Composite short-form 26 sexual (3.3 points; 95% CI, 2.1 to 4.5; P < .001) and hormonal function scores (3.2 points; 95% CI, 1.8 to 4.6; P < .001). These differences failed to meet established thresholds for a clinically meaningful change. There were no statistically significant differences in urinary or bowel function and quality of life. CONCLUSION: This is the first national cohort study comparing functional outcomes after H-RT and C-RT reported by patients. These real-world results further support the use of H-RT as the standard for radiation therapy in men with nonmetastatic PCa
Advanced orbit transfer vehicle propulsion system study
A reuseable orbit transfer vehicle concept was defined and subsequent recommendations for the design criteria of an advanced LO2/LH2 engine were presented. The major characteristics of the vehicle preliminary design include a low lift to drag aerocapture capability, main propulsion system failure criteria of fail operational/fail safe, and either two main engines with an attitude control system for backup or three main engines to meet the failure criteria. A maintenance and servicing approach was also established for the advanced vehicle and engine concepts. Design tradeoff study conclusions were based on the consideration of reliability, performance, life cycle costs, and mission flexibility
Containing, embracing and hyper-activating Britishness: British-based foreign-owned firms
There are in the UK ownership forms different to the characteristics of Britishness – British-based foreign-owned firms where dominant owners may have differentiated control interests. These may contain, that is, override, national institutional characteristics embedded in a particular national capitalism. Accordingly, separating the agency of these firms from presumed business system structures may reveal how diverse patterns of firm ownership – those associated with British-based foreign-owned firms – can inform dynamic ownership developments in British capitalism which contain and hyper-activate Britishness. The article theorizes British-based foreign-owned firms and provides empirical detail on how ownership characteristics influence financial commitment and strategic control in 10 of these firms
Treatment-Related Toxicity Using Prostate-Only Versus Prostate and Pelvic Lymph Node Intensity-Modulated Radiation Therapy: A National Population-Based Study.
PURPOSE: There is a debate about the effectiveness and toxicity of pelvic lymph node (PLN) irradiation for the treatment of men with high-risk prostate cancer. This study compared the toxicity of intensity-modulated radiation therapy (IMRT) to the prostate and the pelvic lymph nodes (PPLN-IMRT) with prostate-only IMRT (PO-IMRT). MATERIALS AND METHODS: Patients with high-risk localized or locally advanced prostate cancer treated with IMRT in the English National Health Service between 2010 and 2013 were identified by using data from the Cancer Registry, the National Radiotherapy Dataset, and Hospital Episode Statistics, an administrative database of all hospital admissions. Follow-up was available up to December 31, 2015. Validated indicators were used to identify patients with severe toxicity according to the presence of both a procedure code and diagnostic code in patient Hospital Episode Statistics records. A competing risks regression analysis, with adjustment for patient and tumor characteristics, estimated subdistribution hazard ratios (sHRs) by comparing GI and genitourinary (GU) complications for PPLN-IMRT versus PO-IMRT. RESULTS: Three-year cumulative incidence in the PPLN-IMRT (n = 780) and PO-IMRT (n = 3,065) groups was 14% for both groups for GI toxicity, and 9% and 8% for GU toxicity, respectively. Patients receiving PPLN-IMRT and PO-IMRT had similar levels of severe GI (adjusted sHR, 1.00; 95% CI, 0.80 to 1.24; P = .97) and GU (adjusted sHR, 1.10; 95% CI, 0.83 to 1.46; P = .50) toxicity rates. CONCLUSION: Including PLNs in radiation fields for high-risk or locally advanced prostate cancer is not associated with increased GI or GU toxicity at 3 years. Additional follow-up is required to answer questions about its impact on late GU toxicity. Results from ongoing trials will provide insight into the anticancer effectiveness of PLN irradiation
Impact of cancer service centralisation on the radical treatment of men with high-risk and locally advanced prostate cancer: A national cross-sectional analysis in England.
In many countries, specialist cancer services are centralised to improve outcomes. We explored how centralisation affects the radical treatment of high-risk and locally advanced prostate cancer in the English NHS. 79,085 patients diagnosed with high-risk and locally advanced prostate cancer in England (April 2014 to March 2016) were identified in the National Prostate Cancer Audit database. Poisson models were used to estimate risk ratios (RR) for undergoing radical treatment by whether men were diagnosed at a regional co-ordinating centre ('hub'), for having surgery by the presence of surgical services on-site, and for receiving high dose-rate brachytherapy (HDR-BT) in addition to external beam radiotherapy by its regional availability. Men were equally likely to receive radical treatment, irrespective of whether they were diagnosed in a hub (RR 0.99, 95% CI 0.91-1.08). Men were more likely to have surgery if they were diagnosed at a hospital with surgical services on site (RR 1.24, 1.10-1.40), and more likely to receive additional HDR-BT if they were diagnosed at a hospital with direct regional access to this service (RR 6.16, 2.94-12.92). Centralisation of specialist cancer services does not affect whether men receive radical treatment, but it does affect treatment modality. Centralisation may have a negative impact on access to specific treatment modalities
Identifying skeletal-related events for prostate cancer patients in routinely collected hospital data.
BACKGROUND: Non-osteoporotic skeletal-related events (SREs) are clinically important markers of disease progression in prostate cancer. We developed and validated an approach to identify SREs in men with prostate cancer using routinely-collected data. METHODS: Patients diagnosed with prostate cancer between January 2010 and December 2013 were identified in the National Prostate Cancer Audit, based on English cancer registry data. A coding framework was developed based on diagnostic and procedure codes in linked national administrative hospital and routinely-collected radiotherapy data to identify SREs occurring before December 2015. Two coding definitions of SREs were assessed based on whether the SRE codes were paired with a bone metastasis code ('specific definition') or used in isolation ('sensitive definition'). We explored the validity of both definitions by comparing the cumulative incidence of SREs from time of diagnosis according to prostate cancer stage at diagnosis with death as a competing risk. RESULTS: We identified 40,063, 25,234 and 13,968 patients diagnosed with localised, locally advanced and metastatic disease, respectively. Using the specific definition, we found that the 5-year cumulative incidence of SREs was 1.0 % in patients with localised disease, 6.0 % in patients with locally advanced disease, and 42.3 % in patients with metastatic disease. Using the sensitive definition, the corresponding cumulative incidence figures were 9.0 %, 14.9 %, and 44.4 %, respectively. CONCLUSION: The comparison of the cumulative incidence of SREs identified in routinely collected hospital data, based on a specific coding definition in patients diagnosed with different prostate cancer stage, supports their validity as a clinically important marker of cancer progression
Hospital volume and outcomes after radical prostatectomy: a national population-based study using patient-reported urinary continence and sexual function.
BACKGROUND: Improvements in short-term outcomes have been reported for hospitals with higher radical prostatectomy (RP) volumes. However, the association with longer-term functional outcomes is unknown. METHODS: All patients diagnosed with non-metastatic prostate cancer in the English NHS between 2014 and 2016 who underwent RP (N = 10,089) were mailed a survey ≥18 months after diagnosis. Differences in patient-reported urinary continence and sexual function (EPIC-26 on scale from 0 to 100) by hospital volume group (≤60, 61-100, 101-140, >140 RPs/year) were estimated using multilevel linear regression. RESULTS: Overall, 7702 men (76.3%) responded. There were no statistically significant differences in urinary continence (p = 0.08) or sexual function scores with increasing volume group (p = 0.2). When modelled as a linear function, we found a non-significant increase of 0.70 (95% CI -0.41 to 1.80; p = 0.22) in urinary continence and a significant increase of 1.54 (0.62-2.45; p = 0.001) in sexual function scores for a 100-procedure increase in hospital volume, which did not meet the threshold for a minimal clinically important difference (10-12 points). The results were similar for robotic-assisted RP (5529 men [71.8%]). CONCLUSIONS: These results do not support further centralisation of RP services beyond levels in England where four in five hospitals perform >60 RPs/year
Toxicity of Pelvic Lymph Node Irradiation With Intensity Modulated Radiation Therapy for High-Risk and Locally Advanced Prostate Cancer: A National Population-Based Study Using Patient-Reported Outcomes.
PURPOSE: Little is known about the toxicity of additional pelvic lymph node irradiation in men receiving intensity modulated radiation therapy (IMRT) for prostate cancer. The aim of this study was to compare patient-reported outcomes after IMRT to the prostate only (PO-IMRT) versus the prostate and pelvic lymph nodes (PPLN-IMRT). METHODS AND MATERIALS: Patients who received a diagnosis of high-risk or locally advanced prostate cancer in the English National Health Service between April 2014 and September 2016 who were treated with IMRT were mailed a questionnaire at least 18 months after diagnosis. Patient-reported urinary, sexual, bowel, and hormonal functional domains on a scale from 0 to 100, with higher scores indicating better outcomes, and generic health-related quality of life were collected using the Expanded Prostate Cancer Index Composite 26-item version and EQ-5D-5L. We used linear regression to compare PPLN-IMRT versus PO-IMRT with adjustment for patient, tumor, and treatment characteristics. RESULTS: Of the 7017 men who received a questionnaire, 5468 (77.9%) responded; 4196 (76.7%) had received PO-IMRT and 1272 (23.3%) PPLN-IMRT. Adjusted differences in the Expanded Prostate Cancer Index Composite 26-item version domain scores were smaller than 1 (P always >.2), except for sexual function, with men who had PPNL-IMRT reporting a lower mean score (adjusted difference, 2.3; 95% confidence interval, 0.9-3.7; P = .002). This did not represent a clinically relevant difference. There was no significant difference in health-related quality of life (P = .5). CONCLUSIONS: Additional pelvic lymph node irradiation does not lead to clinically meaningful increases in the toxicity of IMRT for prostate cancer according to patient-reported functional outcomes and health-related quality of life
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