Duration of androgen deprivation therapy with postoperative radiotherapy for prostate cancer: a comparison of long-course versus short-course androgen deprivation therapy in the RADICALS-HD randomised trial

Background Previous evidence supports androgen deprivation therapy (ADT) with primary radiotherapy as initial treatment for intermediate-risk and high-risk localised prostate cancer. However, the use and optimal duration of ADT with postoperative radiotherapy after radical prostatectomy remains uncertain. Methods RADICALS-HD was a randomised controlled trial of ADT duration within the RADICALS protocol. Here, we report on the comparison of short-course versus long-course ADT. Key eligibility criteria were indication for radiotherapy after previous radical prostatectomy for prostate cancer, prostate-specific antigen less than 5 ng/mL, absence of metastatic disease, and written consent. Participants were randomly assigned (1:1) to add 6 months of ADT (short-course ADT) or 24 months of ADT (long-course ADT) to radiotherapy, using subcutaneous gonadotrophin-releasing hormone analogue (monthly in the short-course ADT group and 3-monthly in the long-course ADT group), daily oral bicalutamide monotherapy 150 mg, or monthly subcutaneous degarelix. Randomisation was done centrally through minimisation with a random element, stratified by Gleason score, positive margins, radiotherapy timing, planned radiotherapy schedule, and planned type of ADT, in a computerised system. The allocated treatment was not masked. The primary outcome measure was metastasis-free survival, defined as metastasis arising from prostate cancer or death from any cause. The comparison had more than 80% power with two-sided α of 5% to detect an absolute increase in 10-year metastasis-free survival from 75% to 81% (hazard ratio [HR] 0·72). Standard time-to-event analyses were used. Analyses followed intention-to-treat principle. The trial is registered with the ISRCTN registry, ISRCTN40814031, and ClinicalTrials.gov , NCT00541047 . Findings Between Jan 30, 2008, and July 7, 2015, 1523 patients (median age 65 years, IQR 60–69) were randomly assigned to receive short-course ADT (n=761) or long-course ADT (n=762) in addition to postoperative radiotherapy at 138 centres in Canada, Denmark, Ireland, and the UK. With a median follow-up of 8·9 years (7·0–10·0), 313 metastasis-free survival events were reported overall (174 in the short-course ADT group and 139 in the long-course ADT group; HR 0·773 [95% CI 0·612–0·975]; p=0·029). 10-year metastasis-free survival was 71·9% (95% CI 67·6–75·7) in the short-course ADT group and 78·1% (74·2–81·5) in the long-course ADT group. Toxicity of grade 3 or higher was reported for 105 (14%) of 753 participants in the short-course ADT group and 142 (19%) of 757 participants in the long-course ADT group (p=0·025), with no treatment-related deaths. Interpretation Compared with adding 6 months of ADT, adding 24 months of ADT improved metastasis-free survival in people receiving postoperative radiotherapy. For individuals who can accept the additional duration of adverse effects, long-course ADT should be offered with postoperative radiotherapy. Funding Cancer Research UK, UK Research and Innovation (formerly Medical Research Council), and Canadian Cancer Society

INVESTIGATION OF IONIC LIQUIDS AS TERMODYNAMIC AND KINETIC METHANE HYDRATE INHIBITORS

The formation of gas hydrates in gas; production and transmission pipelines leads to severe safety problems and huge economic loss, which has been the subject of long-standing problems. As exploration and production moves to deeper seas, temperature and pressure conditions in the field favors hydrate formation. In this dissertation, the performance of nine ionic liquids (ILs) was investigated as thermodynamic and kinetic gas hydrate inhibitors. The hydrate dissociation temperature and induction time were determined for methane gas hydrates using a high pressure micro deferential scanning calorimeter. All the ionic liquids weretested at a concentration 10 wt% for thermodynamic study. Two best screened ionic liquids as thermodynamic inhibitors were further investigated at various concentrations and their performance was compared with commercially available inhibitors

Techno-Economic Feasibility of Large-Scale, Concentrated Solar Power and Desalination (CSP-D) Cogeneration Plants: A Case Study in Abu Dhabi

Climate change and the increasing scarcity of energy and freshwater sources are some of the most pressing challenges of the 21st century. Solar polygeneration of electricity and water desalination presents a potential solution to address these challenges. In this study, a techno- economic analysis is carried out on a multi-effect distillation (MED) and reverse osmosis (RO) desalination processes, integrated with a large-scale 50 MWe concentrated solar power (CSP) plant with a supplementary heater. As a central question, this study investigates whether coupling a desalination (D) plant with a CSP plant can improve its economic feasibility, as compared to either technology alone, under Abu Dhabi weather conditions. System Advisor Model (SAM) was coupled with Matlab to model the transient performance of the CSP desalination plant. The results show that using the waste heat from the CSP plant to run a MED process reduces the net thermal efficiency of the CSP plant by ~5%, whereas coupling CSP with RO reduces the efficiency by ~15% due to its high electricity consumption. Moreover, a sensitivity analysis was carried out on the electricity and water selling prices. The results show that there are no near-term deviations in price that will result in the CSP-D having a shorter payback period when compared with the independent production plants. Overall, CSP-D can offer a sustainable solution for energy and water production; however, techno-economically it might be not representing the best option without subsidies

Proceedings of the 11th Australasian Heat and Mass Transfer Conference, AHMTC11

Energy and clean water demand is on rise due to population and economic growth. Since solar energy resources are ubiquitous around the world, hybrid energy-water technologies driven by low-grade thermal energy represent a potential way to meet this demand while minimizing environmental impacts. Membrane distillation (MD) technology is particularly well-suited to remote/off-grid applications due to its modularity and ability to treat high salinity water with low fouling potential. Compared to other MD configurations, when high permeate flux and gain output ratio are required, a Vacuum Membrane Distillation (VMD) can be employed. However, unlike multi-effect distillation and multi-stage flash, VMD systems have not yet been fully optimized for specific heat consumption (SHC) or water recovery rate (RR). In this study, a techno-economic assessment, using the Chemical Engineering Plant Cost Index (CEPCI) method, of single versus multi-stage VMD configurations with respect to these aspects was carried out. Single stage VMD was considered as the baseline configuration. The effect of brine recirculation on the SHC is examined for the proposed multi-stage configurations. It was found that for a VMD process, brine recirculation is the most effective method to reuse the brine heat, which resulted in reducing the SHC by 60%. Moreover, single stage VMD with brine recirculation was found to be superior than multi-stage configurations achieving the lowest SHC and LCOW. As an understanding of the VMD technology, this work represents the first step in critically evaluating the performance of alternative VMD multi-stage configurations to aid in module design, scale-up and process optimization

Physical-chemical Properties of Aqueous TBAOH Solution for Gas Hydrates Promotion

AbstractGas hydrates attract the attention of many industries for various potential applications such as gas separation and storage. To industrialize the gas hydrate technology, rapid hydrate formation at mild conditions is crucial. Chemical additives such as ionic liquids were investigated for hydrate promotion. The knowledge of physical-chemical properties of ionic liquids is crucial in development of gas hydrate technology in industry as these fundamental properties determined the hydrate formation rate. This work measures the density, pH, electrical conductivity, and surface tension of aqueous tetrabutylammonium hydroxide solutions. The concentrations were chosen to cover the common hydrate promotion range of 0.001-10 wt%. The results showed high dependence of the studied properties on the concentration. pH and electrical conductivity were increased with increase of TBAOH concentration conversely to density and surface tension. The amount of CO2 consumed to form the hydrate was measured at a pressure of 35bar and a temperature 274.15. Significant increase of CO2 consumption in the presence of TBAOH solutions was observed. However, as the concentration increased, more CO2 was consumed

Experimental and numerical evaluation of the energy requirement of multi-stage vacuum membrane distillation designs

Although vacuum membrane distillation (VMD) has a high distillate flux, its potential is limited by its high specific heat consumption (SHC). Flat sheet VMD systems recover the brine energy by employing a cascade system to improve the SHC. Hollow fiber VMD systems, however, have not yet been optimized for energy recovery. To overcome this knowledge gap, four multi-stage configurations (with and without brine energy recovery) were investigated via experimentation and through numerical simulations. The results show that having permeate flux promoting conditions, such as high feed temperature or lower vacuum pressure, improves the SHC for VMD configurations without brine recirculation, but have little impact for configurations with brine energy recovery. A Pareto multi-objective optimization showed that the optimized first-stage heating MS-VMD without brine recirculation has the highest SHC (908 kWh/m3) but one of the lowest LCOW (2.37 USD/m3). In contrast, the configuration with the first-stage heating with brine recirculation provided the lowest SHC (585–629 kWh/m3) and an acceptable LCOW (2.27–8.30 USD/m3). This study reveals that the development of MS-VMD represents a promising direction for thermal desalination technologies, particularly for high saline water applications