| 1. |
- Bonjer, H Jaap, et al.
(författare)
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A randomized trial of laparoscopic versus open surgery for rectal cancer.
- 2015
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Ingår i: The New England journal of medicine. - 1533-4406. ; 372:14, s. 1324-32
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Tidskriftsartikel (refereegranskat)abstract
- Laparoscopic resection of colorectal cancer is widely used. However, robust evidence to conclude that laparoscopic surgery and open surgery have similar outcomes in rectal cancer is lacking. A trial was designed to compare 3-year rates of cancer recurrence in the pelvic or perineal area (locoregional recurrence) and survival after laparoscopic and open resection of rectal cancer.
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| 2. |
- Deijen, Charlotte L., et al.
(författare)
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Ten-year outcomes of a randomised trial of laparoscopic versus open surgery for colon cancer
- 2017
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Ingår i: Surgical Endoscopy. - : SPRINGER. - 0930-2794 .- 1432-2218. ; 31:6, s. 2607-2615
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Tidskriftsartikel (refereegranskat)abstract
- Laparoscopic surgery for colon cancer is associated with improved recovery and similar cancer outcomes at 3 and 5 years in comparison with open surgery. However, long-term survival rates have rarely been reported. Here, we present survival and recurrence rates of the Dutch patients included in the COlon cancer Laparoscopic or Open Resection (COLOR) trial at 10-year follow-up. Between March 1997 and March 2003, patients with non-metastatic colon cancer were recruited by 29 hospitals in eight countries and randomised to either laparoscopic or open surgery. Main inclusion criterion for the COLOR trial was solitary adenocarcinoma of the left or right colon. The primary outcome was disease-free survival at 3 years, and secondary outcomes included overall survival and recurrence. The 10-year follow-up data of all Dutch patients were collected. Analysis was by intention-to-treat. The trial was registered at ClinicalTrials.gov (NCT00387842). In total, 1248 patients were randomised, of which 329 were Dutch. Fifty-eight Dutch patients were excluded and 15 were lost to follow-up, leaving 256 patients for 10-year analysis. Median follow-up was 112 months. Disease-free survival rates were 45.2 % in the laparoscopic group and 43.2 % in the open group (difference 2.0 %; 95 % confidence interval (CI) -10.3 to 14.3; p = 0.96). Overall survival rates were 48.4 and 46.7 %, respectively (difference 1.7 %; 95 % CI -10.6 to 14.0; p = 0.83). Stage-specific analysis revealed similar survival rates for both groups. Sixty-two patients were diagnosed with recurrent disease, accounting for 29.4 % in the laparoscopic group and 28.2 % in the open group (difference 1.2 %; 95 % CI -11.1 to 13.5; p = 0.73). Seven patients had port- or wound-site recurrences (laparoscopic n = 3 vs. open n = 4). Laparoscopic surgery for non-metastatic colon cancer is associated with similar rates of disease-free survival, overall survival and recurrences as open surgery at 10-year follow-up.
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| 3. |
- Mondejar, M. E., et al.
(författare)
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A review of the use of organic Rankine cycle power systems for maritime applications
- 2018
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Ingår i: Renewable and Sustainable Energy Reviews. - : Elsevier BV. - 1879-0690 .- 1364-0321. ; 91, s. 126-151
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Forskningsöversikt (refereegranskat)abstract
- Diesel engines are by far the most common means of propulsion aboard ships. It is estimated that around half of their fuel energy consumption is dissipated as low-grade heat. The organic Rankine cycle technology is a well-established solution for the energy conversion of thermal power from biomass combustion, geothermal reservoirs, and waste heat from industrial processes. However, its economic feasibility has not yet been demonstrated for marine applications. This paper aims at evaluating the potential of using organic Rankine cycle systems for waste heat recovery aboard ships. The suitable vessels and engine heat sources are identified by estimating the total recoverable energy. Different cycle architectures, working fluids, components, and control strategies are analyzed. The economic feasibility and integration on board are also evaluated. A number of research and development areas are identified in order to tackle the challenges limiting a widespread use of this technology in currently operating vessels and new-buildings. The results indicate that organic Rankine cycle units recovering heat from the exhaust gases of engines using low-sulfur fuels could yield fuel savings between 10% and 15%.
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| 4. |
- Andreasen, J. G., et al.
(författare)
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Multi-objective optimization of organic Rankine ycle power plants using pure and mixed working fluids
- 2015
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Ingår i: Proceedings of ASME ORC 2015. ; , s. 11-
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Konferensbidrag (refereegranskat)abstract
- For zeotropic mixtures, the temperature varies during phase change, which is opposed to the isothermalphase change of pure fluids. The use of such mixtures as working fluids in organic Rankine cyclepower plants enables a minimization of the mean temperature difference of the heat exchangers whenthe minimum pinch point temperature difference is kept fixed. A low mean temperature differencemeans low heat transfer irreversibilities, which is beneficial for cycle performance, but it also results inlarger heat transfer surface areas. Moreover, the two-phase heat transfer coefficients for zeotropic mixturesare usually degraded compared to an ideal mixture heat transfer coefficient linearly interpolatedbetween the pure fluid values. This entails a need for larger and more expensive heat exchangers. Previousstudies primarily focus on the thermodynamic benefits of zeotropic mixtures by employing firstand second law analyses. In order to assess the feasibility of using zeotropic mixtures, it is, however,important to consider the additional costs of the heat exchangers. In this study, we aim at evaluatingthe economic feasibility of zeotropic mixtures compared to pure fluids. We carry out a multi-objectiveoptimization of the net power output and the component costs for organic Rankine cycle power plantsusing low-temperature heat at 90 ◦C to produce electrical power at around 500 kW. The primary outcomesof the study are Pareto fronts, illustrating the power/cost relations for R32, R134a and R32/R134a(0.65/0.35mole). The results indicate that R32/134a is the best of these fluids, with 3.4 % higher net powerthan R32 at the same total cost of 1200 k$.
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| 5. |
- Balasubramanian, Ishwarya, et al.
(författare)
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Out-Patient Management of Mild or Uncomplicated Diverticulitis: A Systematic Review
- 2017
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Ingår i: Digestive Surgery. - : S. Karger AG. - 0253-4886 .- 1421-9883. ; 34, s. 151-160
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Forskningsöversikt (refereegranskat)abstract
- © 2016 S. Karger AG, Basel. Background: Management of diverticular disease has undergone a paradigm shift, with movement towards a less invasive management strategy. In keeping with this, outpatient management of uncomplicated diverticulitis (UD) has been advocated in several studies, but concerns still remain regarding the safety of this practice. Aim: To assess outcomes of out-patient management of acute UD. Methods: A comprehensive search for published studies using the search terms 'uncomplicated diverticulitis', 'mild diverticulitis' and 'out-patient' was performed. The primary outcomes were failure of medical treatment. Secondary outcomes were recurrence rate at follow up and medical cost savings. Results: The search yielded 192 publications. Of these, 10 studies met the inclusion criteria including 1 randomized controlled trial, 6 clinical controlled trials and 3 case series. There was no difference in failure rates of medical treatment (6.5 vs. 4.6%, p = 0.32) or in recurrence rates (13.0 vs. 12.1%, p = 0.81) between those receiving ambulatory care and in-patient care for UD. Ambulatory treatment is associated with an estimated daily cost savings of between 600 and 1,900 euros per patient treated. Meta-analysis of data was not possible due to heterogeneity in study designs and inclusion criteria. Conclusion: Ambulatory management of acute UD is reasonable in selected patients.
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| 6. |
- Baldasso, Enrico, et al.
(författare)
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Prediction of the annual performance of marine organic Rankine cycle power systems
- 2018
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Ingår i: ECOS 2018 - Proceedings of the 31st International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems.
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Konferensbidrag (refereegranskat)abstract
- The increasing awareness about the environmental impact of shipping and the increasingly stricter regulations introduced by the International Maritime Organization are driving the development of solutions to reduce the pollutant emissions from ships. While some previous studies focused on the implementation of a specific technology, others considered a wider perspective and investigated the feasibility of the integration of various technologies on board vessels. Among the screened technologies, organic Rankine cycle (ORC) power systems represent a viable solution to utilize the waste heat contained in the main engine exhaust gases to produce additional power for on board use. The installation of ORC power systems on board ships could result in a reduction of the CO 2 emissions by 5 – 10 %. Although a number of methods to derive the optimal design of ORC units in marine applications have been proposed, these methods are complex, computationally expensive and require specialist knowledge to be included as part of a general optimization procedure to define the optimal set of technologies to be implemented on board a vessel. This study presents a novel method to predict the performance of ORC units installed on board vessels, based upon the characteristics of the main engine exhaust gases and the ship sailing profile. The method is not computationally intensive, and is therefore suitable to be used in the context of large optimization problems, such as holistic optimization and evaluation of a ship performance given the operational profile, weather and route. The model predicted the annual energy production of two case studies with an accuracy within 4 %.
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| 7. |
- Baldasso, Enrico, et al.
(författare)
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Technical and economic feasibility of organic Rankine cycle-based waste heat recovery systems on feeder ships: Impact of nitrogen oxides emission abatement technologies
- 2019
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904. ; 183, s. 577-589
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Tidskriftsartikel (refereegranskat)abstract
- The International Maritime Organization recently revised the regulations concerning nitrogen and sulphur oxides emissions from commercial ships. In this context, it is important to investigate how emission abatement technologies capable of meeting the updated regulation on nitrogen oxides emissions affect the performance of waste heat recovery units to be installed on board new vessels. The objective of this paper is to assess the potential fuel savings of installing an organic Rankine cycle unit on board a hypothetical liquefied natural gas-fuelled feeder ship operating inside emission control areas. The vessel complies with the updated legislation on sulphur oxides emissions by using a dual fuel engine. Compliance with the nitrogen oxides emission regulation is reached by employing either a high or low-pressure selective catalytic reactor, or an exhaust gas recirculation unit. A multi-objective optimization was carried out where the objective functions were the organic Rankine cycle unit annual electricity production, the volume of the heat exchangers, and the net present value of the investment. The results indicate that the prospects for attaining a cost-effective installation of an organic Rankine unit are larger if the vessel is equipped with a low-pressure selective catalytic reactor or an exhaust gas recirculation unit. Moreover, the results suggest that the cost-effectiveness of the organic Rankine cycle units is highly affected by fuel price and the waste heat recovery boiler design constraints.
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| 8. |
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| 9. |
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| 10. |
- Petersson, Josefin, et al.
(författare)
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Bowel Obstruction and Ventral Hernia After Laparoscopic Versus Open Surgery for Rectal Cancer in A Randomized Trial (COLOR II).
- 2019
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Ingår i: Annals of surgery. - 1528-1140. ; 269:1, s. 53-57
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to evaluate the risk of bowel obstruction, incisional, and parastomal hernia following laparoscopic versus open surgery for rectal cancer.Laparoscopic surgery for rectal cancer has been adopted worldwide, after trials reported similar oncological outcomes compared with open surgery. Little is known about long-term morbidity, including bowel obstruction, incisional, and parastomal hernia following surgery.Patients included in the international, multicenter, noninferior, open-label, randomized COLOR II trial were followed for five years. Primary endpoint was local recurrence at 3-year follow-up. Secondary endpoints included bowel obstruction, incisional and parastomal hernia within 5 years, and the current article reports on these secondary endpoints.All 1044 patients included in the COLOR II trial were analyzed. There was no difference in risk of bowel obstruction, incisional, or parastomal hernia following laparoscopic or open surgery for rectal cancer.Based on long-term morbidity outcomes, laparoscopic surgery for rectal cancer could be considered a routine technique as there are no differences with open surgery.
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