318 research outputs found

    Prospects for Nuclear Microreactors: A Review of the Technology, Economics, and Regulatory Considerations

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    The nuclear energy sector is actively developing a new class of very small advanced reactors, called microreactors. This technology has disruptive potential as an alternative to carbon-intensive energy technologies based on its mobility and transportability, resilience, and independence from the grid, as well as its capacity for long refueling intervals and low-carbon emissions. Microreactors may extend nuclear energy to a new set of international customers, many of which are located where energy is at a price premium and/or limited to fossil sources. Developers are creating designs geared toward factory production where quality and costs may be optimized. This paper reviews the existing literature on the technology, potential markets, economic viability, and regulatory and institutional challenges of nuclear microreactors. The technological characteristics are reviewed to describe the wide range of microreactor designs and to distinguish them from large nuclear power plants and small modular reactor (SMR) designs. The expanding literature on the cost competitiveness of SMRs relative to other nuclear and nonnuclear technologies is also reviewed, with an emphasis on understanding the challenges of making microreactors economically viable. A major part of this study focuses on the deployment potential of microreactors across global markets. Previous work on SMR market assessment is reviewed, and the adaptation of these studies to the deployment of microreactors is more fully examined. Characteristics that differentiate microreactors from SMRs and other energy technologies may make microreactors suitable for unique and localized applications if they can be economically competitive with other energy technologies, as well as meet regulatory and other societal requirements. Recent research on global markets for microreactors is evaluated and extended in this paper to a previously unevaluated use case in which microreactors can play a role in grid resiliency and integration with renewables. Further challenges associated with the commercialization of microreactors, in addition to cost competitiveness, are explored by examining the regulatory and safety challenges of microreactor deployment

    Practice variation and outcomes of minimally invasive minor liver resections in patients with colorectal liver metastases:a population-based study

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    Introduction: In 2017, the Southampton guideline stated that minimally invasive liver resections (MILR) should considered standard practice for minor liver resections. This study aimed to assess recent implementation rates of minor MILR, factors associated with performing MILR, hospital variation, and outcomes in patients with colorectal liver metastases (CRLM). Methods: This population-based study included all patients who underwent minor liver resection for CRLM in the Netherlands between 2014 and 2021. Factors associated with MILR and nationwide hospital variation were assessed using multilevel multivariable logistic regression. Propensity-score matching (PSM) was applied to compare outcomes between minor MILR and minor open liver resections. Overall survival (OS) was assessed with Kaplan–Meier analysis on patients operated until 2018. Results: Of 4,488 patients included, 1,695 (37.8%) underwent MILR. PSM resulted in 1,338 patients in each group. Implementation of MILR increased to 51.2% in 2021. Factors associated with not performing MILR included treatment with preoperative chemotherapy (aOR 0.61 CI:0.50–0.75, p &lt; 0.001), treatment in a tertiary referral hospital (aOR 0.57 CI:0.50–0.67, p &lt; 0.001), and larger diameter and number of CRLM. Significant hospital variation was observed in use of MILR (7.5% to 93.0%). After case-mix correction, six hospitals performed fewer, and six hospitals performed more MILRs than expected. In the PSM cohort, MILR was associated with a decrease in blood loss (aOR 0.99 CI:0.99–0.99, p &lt; 0.01), cardiac complications (aOR 0.29, CI:0.10–0.70, p = 0.009), IC admissions (aOR 0.66, CI:0.50–0.89, p = 0.005), and shorter hospital stay (aOR CI:0.94–0.99, p &lt; 0.01). Five-year OS rates for MILR and OLR were 53.7% versus 48.6%, p = 0.21. Conclusion: Although uptake of MILR is increasing in the Netherlands, significant hospital variation remains. MILR benefits short-term outcomes, while overall survival is comparable to open liver surgery. Graphical abstract: [Figure not available: see fulltext.].</p

    Outcomes of liver surgery:A decade of mandatory nationwide auditing in the Netherlands

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    Background: In 2013, the nationwide Dutch Hepato Biliary Audit (DHBA) was initiated. The aim of this study was to evaluate changes in indications for and outcomes of liver surgery in the last decade. Methods: This nationwide study included all patients who underwent liver surgery for four indications, including colorectal liver metastases (CRLM), hepatocellular carcinoma (HCC), and intrahepatic– and perihilar cholangiocarcinoma (iCCA – pCCA) between 2014 and 2022. Trends in postoperative outcomes were evaluated separately for each indication using multilevel multivariable logistic regression analyses. Results: This study included 8057 procedures for CRLM, 838 for HCC, 290 for iCCA, and 300 for pCCA. Over time, these patients had higher risk profiles (more ASA-III patients and more comorbidities). Adjusted mortality decreased over time for CRLM, HCC and iCCA, respectively aOR 0.83, 95%CI 0.75–0.92, P &lt; 0.001; aOR 0.86, 95%CI 0.75–0.99, P = 0.045; aOR 0.40, 95%CI 0.20–0.73, P &lt; 0.001. Failure to rescue (FTR) also decreased for these groups, respectively aOR 0.84, 95%CI 0.76–0.93, P = 0.001; aOR 0.81, 95%CI 0.68–0.97, P = 0.024; aOR 0.29, 95%CI 0.08–0.84, P = 0.021). For iCCA severe complications (aOR 0.65 95%CI 0.43–0.99, P = 0.043) also decreased. No significant outcome differences were observed in pCCA. The number of centres performing liver resections decreased from 26 to 22 between 2014 and 2022, while median annual volumes did not change (40–49, P = 0.66). Conclusion: Over time, postoperative mortality and FTR decreased after liver surgery, despite treating higher-risk patients. The DHBA continues its focus on providing feedback and benchmark results to further enhance outcomes.</p

    Case-mix adjustment to compare nationwide hospital performances after resection of colorectal liver metastases

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    Background: Differences in patient demographics and disease burden can influence comparison of hospital performances. This study aimed to provide a case-mix model to compare short-term postoperative outcomes for patients undergoing liver resection for colorectal liver metastases (CRLM). Methods: This retrospective, population-based study included all patients who underwent liver resection for CRLM between 2014 and 2018 in the Netherlands. Variation in case-mix variables between hospitals and influence on postoperative outcomes was assessed using multivariable logistic regression. Primary outcomes were 30-day major morbidity and 30-day mortality. Validation of results was performed on the data from 2019. Results: In total, 4639 patients were included in 28 hospitals. Major morbidity was 6.2% and mortality was 1.4%. Uncorrected major morbidity ranged from 3.3% to 13.7% and mortality ranged from 0.0% to 5.0%. between hospitals. Significant differences between hospitals were observed for age higher than 80 (0.0%-17.1%, p <0.001), ASA 3 or higher (3.3%-36.3%, p <0.001), histopathological parenchymal liver disease (0.0%-47.1%, p <0.001), history of liver resection (8.1%-36.3%, p <0.001), major liver resection (6.7%-38.0%, p <0.001) and synchronous metastases (35.5%-62.1%, p <0.001). Expected 30-day major morbidity between hospitals ranged from 6.4% to 11.9% and expected 30-day mortality ranged from 0.6% to 2.9%. After case-mix correction no significant outliers concerning major morbidity and mortality remained. Validation on patients who underwent liver resection for CRLM in 2019 affirmed these outcomes. Conclusion: Case-mix adjustment is a prerequisite to allow for institutional comparison of short-term postoperative outcomes after liver resection for CRLM. (C) 2020 University Medical Center Groningen. Published by Elsevier Ltd

    Nationwide oncological networks for resection of colorectal liver metastases in the Netherlands:Differences and postoperative outcomes

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    INTRODUCTION: Widespread differences in patient demographics and disease burden between hospitals for resection of colorectal liver metastases (CRLM) have been described. In the Netherlands, networks consisting of at least one tertiary referral centre and several regional hospitals have been established to optimize treatment and outcomes. The aim of this study was to assess variation in case-mix, and outcomes between these networks. METHODS: This was a population-based study including all patients who underwent CRLM resection in the Netherlands between 2014 and 2019. Variation in case-mix and outcomes between seven networks covering the whole country was evaluated. Differences in case-mix, expected 30-day major morbidity (Clavien-Dindo ≥3a) and 30-day mortality between networks were assessed. RESULTS: In total 5383 patients were included. Thirty-day major morbidity was 5.7% and 30-day mortality was 1.5%. Significant differences between networks were observed for Charlson Comorbidity Index, ASA 3+, previous liver resection, liver disease, preoperative MRI, preoperative chemotherapy, ≥3 CRLM, diameter of largest CRLM ≥55 mm, major resection, combined resection and ablation, rectal primary tumour, bilobar and extrahepatic disease. Uncorrected 30-day major morbidity ranged between 3.3% and 13.1% for hospitals, 30-day mortality ranged between 0.0% and 4.5%. Uncorrected 30-day major morbidity ranged between 4.4% and 6.0% for networks, 30-day mortality ranged between 0.0% and 2.5%. No negative outliers were observed after case-mix correction. CONCLUSION: Variation in case-mix and outcomes are considerably smaller on a network level as compared to a hospital level. Therefore, auditing is more meaningful at a network level and collaboration of hospitals within networks should be pursued

    A nationwide assessment of hepatocellular adenoma resection:Indications and pathological discordance

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    Hepatocellular adenomas (HCAs) are benign liver tumors associated with bleeding or malignant transformation. Data on the indication for surgery are scarce. We analyzed indications and outcome of patients operated for HCAs 50 mm (52%), suspicion of (pre)malignancy (28%), and (previous) bleeding (5.1%). No difference was observed in HCA-subtype distribution between small and large tumors. Ninety-six (43%) patients had a postoperative change in diagnosis. Independent risk factors for change in diagnosis were tumor size <50 mm (adjusted odds ratio [aOR], 3.4; p < 0.01), male sex (aOR, 3.7; p = 0.03), and lack of hepatobiliary contrast-enhanced magnetic resonance imaging (CE-MRI) (aOR, 1.8; p = 0.04). Resection for small (suspected) HCAs was mainly indicated by suspicion of (pre)malignancy, whereas for large (suspected) HCAs, tumor size was the most prevalent indication. Male sex, tumor size <50 mm, and lack of hepatobiliary CE-MRI were independent risk factors for postoperative change in tumor diagnosis

    ApoCIII-Enriched LDL in Type 2 Diabetes Displays Altered Lipid Composition, Increased Susceptibility for Sphingomyelinase, and Increased Binding to Biglycan

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    Objective- Apolipoprotein CIII (apoCIII) is an independent risk factor for cardiovascular disease, but the molecular mechanisms involved are poorly understood. Here, we investigated potential proatherogenic properties of apoCIII-containing LDL from hypertriglyceridemic patients with type 2 diabetes. Research design and methods - LDL was isolated from controls and subjects with type 2 diabetes, and from apoB transgenic mice. LDL-biglycan binding was analyzed with a solid-phase assay using immunoplates coated with biglycan. Lipid composition was analyzed with mass spectrometry. Hydrolysis of LDL by sphingomyelinase was analyzed after labeling plasma LDL with [(3)H]sphingomyelin. ApoCIII isoforms were quantified after isoelectric focusing. Human aortic endothelial cells were incubated with desialylated apoCIII or with LDL enriched with specific apoCIII isoforms. Results- We showed that enriching LDL with apoCIII only induced a small increase in LDL-proteoglycan binding, and this effect was dependent on a functional Site A in apoB100. Our findings indicated that intrinsic characteristics of the diabetic LDL other than apoCIII per se are responsible for further increased proteoglycan binding of diabetic LDL with high endogenous apoCIII, and we showed alterations in the lipid composition of diabetic LDL with high apoCIII. We also demonstrated that high apoCIII increased susceptibility of LDL to hydrolysis and aggregation by SMase. In addition, we demonstrated that sialylation of apoCIII increased with increasing apoCIII content, and that sialylation of apoCIII was essential for its proinflammatory properties. Conclusions- We have demonstrated a number of features of apoCIII-containing LDL from hypertriglyceridemic patients with type 2 diabetes that could explain the proatherogenic role of apoCIII

    Trends and overall survival after combined liver resection and thermal ablation of colorectal liver metastases:a nationwide population-based propensity score-matched study

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    Background: In colorectal liver metastases (CRLM) patients, combination of liver resection and ablation permit a more parenchymal-sparing approach. This study assessed trends in use of combined resection and ablation, outcomes, and overall survival (OS). Methods: This population-based study included all CRLM patients who underwent liver resection between 2014 and 2022. To assess OS, data was linked to two databases containing date of death for patients treated between 2014 and 2018. Hospital variation in the use of combined minor liver resection and ablation versus major liver resection alone in patients with 2–3 CRLM and ≤3 cm was assessed. Propensity score matching (PSM) was applied to evaluate outcomes. Results: This study included 3593 patients, of whom 1336 (37.2%) underwent combined resection and ablation. Combined resection increased from 31.7% in 2014 to 47.9% in 2022. Significant hospital variation (range 5.9–53.8%) was observed in the use of combined minor liver resection and ablation. PSM resulted in 1005 patients in each group. Major morbidity was not different (11.6% vs. 5%, P = 1.00). Liver failure occurred less often after combined resection and ablation (1.9% vs. 0.6%, P = 0.017). Five-year OS rates were not different (39.3% vs. 33.9%, P = 0.145). Conclusion: Combined resection and ablation should be available and considered as an alternative to resection alone in any patient with multiple metastases.</p
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