Constraint logic programming for fault-tolerant distributed systems

This paper presents key notions of Constraint Logic Programming (CLP), which is a young programming paradigm oriented toward solving difficult discrete highly combinatorial problems by making active use of constraints on the basis of mechanisms of Logic Programming. Being the subject of intensive research all over the world, CLP has already been used successfully in a large variety of application areas. As one of the important applications where CLP demonstrates its potential, we propose CLP-based procedures of solving the problems of optimal resource and task allocation at the stages of design and operation of Fault-Tolerant Distributed Technical Systems.Peer Reviewe

Exact interval propagation for the efficient solution of position analysis problems on planar linkages

This paper presents an interval propagation algorithm for variables in planar single-loop linkages. Given intervals of allowed values for all variables, the algorithm provides, for every variable, the whole set of values, with out over-estimation, for which the linkage can actually be assembled. We show further how this algorithm can be integrated in a branch-and-prune search scheme, in order to solve the position analysis of general planar multi-loop linkages. Experimental results are included, comparing the method’s perfor mance with that of previous techniques given for the same task.Peer ReviewedPostprint (author's final draft

Exact interval propagation for the efficient solution of planar linkages

This paper presents an interval propagation algorithm for variables in single-loop linkages. Given allowed intervals of values for all variables, the algorithm provides, for every variable, the exact interval of values for which the linkage can actually be assembled. We show further how this algorithm can be integrated in a branch-and bound search scheme, in order to solve the position analysis of general multi-loop linkages. Experimental results are included, comparing the method’s performance with that of previous techniques given for the same task.Peer Reviewe

Improving the yield of sonochemical precipitated aragonite synthesis by scaling up intensified conditions

Precipitated aragonite can be synthesized at relatively low temperatures by combining the application of low-frequency sonication with the use of magnesium chloride additive, as demonstrated by our prior study. In the present study, new process conditions were found that promote aragonite formation while accelerating and increasing the reaction yield. It was found that Mg-to-Ca molar ratio of 3:1, together with higher slurry concentration (74 g/L Ca(OH)2) and higher power-to-volume ratio (800 W/L gross, achieved by reducing slurry volume), promoted the aragonite formation while working at a higher CO2 flow rate (2.0 NL/min), and consequently higher precipitated calcium carbonate production rate (1 g/(L · min) CaCO3). The yield was thus improved while conserving the desired product properties as follows: high polymorph purity (95.7 wt%), small and narrow particle size distribution (D[3,2] = 0.74 µm), and unique shape (hubbard squash-like)

Effect of neoadjuvant chemoradiotherapy on health-Related quality of life in esophageal or junctional cancer: Results from the randomized CROSS trial

Purpose To compare pre-agreed health-related quality of life (HRQOL) domains in patients with esophageal or junctional cancer who received neoadjuvant chemoradiotherapy (nCRT) followed by surgery or surgery alone. Secondary aims were to examine the effect of nCRT on HRQOL before surgery and the effect of surgery on HRQOL. Patients and Methods Patients were randomly assigned to nCRT (carboplatin plus paclitaxel with concurrent 41.4-Gy radiotherapy) followed by surgery or surgery alone. HRQOL was measured using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire–Core 30 (QLQ-C30) and –Oesophageal Cancer Module (QLQ-OES24) questionnaires pretreatment and at 3, 6, 9, and 12 months postoperatively. The nCRT group also received preoperative questionnaires. Physical functioning (PF; QLQ-C30) and eating problems (EA; QLQ-OES24) were chosen as predefined primary end points. Predefined secondary end points were global QOL (GQOL; QLQ-C30), fatigue (FA; QLQ-C30), and emotional problems (EM; QLQ-OES24). Results A total of 363 patients were analyzed. No statistically significant differences in postoperative HRQOL were found between treatment groups. In the nCRT group, PF, EA, GQOL, FA, and EM scores deteriorated 1 week after nCRT (Cohen’s d: 20.93, P, .001; 0.47, P, .001; 20.84, P, .001; 1.45, P, .001; and 0.32, P = .001, respectively). In both treatment groups, all end points declined 3 months postoperatively compared with baseline (Cohen’s d: 21.00, 0.33, 20.47, 20.34, and 0.33, respectively; all P, .001), followed by a continuous gradual improvement. EA, GQOL, and EM were restored to baseline levels during follow-up, whereas PF and FA remained impaired 1 year postoperatively (Cohen’s d: 0.52 and 20.53, respectively; both P, .001). Conclusion Although HRQOL declined during nCRT, no effect of nCRT was apparent on postoperative HRQOL compared with surgery alone. In addition to the improvement in survival, these findings support the view that nCRT according to the Chemoradiotherapy for Esophageal Cancer Followed by Surgery Study–regimen can be regarded as a standard of care

The GATA-factor elt-2 is essential for formation of the Caenorhabditis elegans intestine

AbstractThe Caenorhabditis elegans elt-2 gene encodes a single-finger GATA factor, previously cloned by virtue of its binding to a tandem pair of GATA sites that control the gut-specific ges-1 esterase gene. In the present paper, we show that elt-2 expression is completely gut specific, beginning when the embryonic gut has only two cells (one cell cycle prior to ges-1 expression) and continuing in every cell of the gut throughout the life of the worm. When elt-2 is expressed ectopically using a transgenic heat-shock construct, the endogenous ges-1 gene is now expressed in most if not all cells of the embryo; several other gut markers (including a transgenic elt-2-promoter: lacZ reporter construct designed to test for elt-2 autoregulation) are also expressed ectopically in the same experiment. These effects are specific in that two other C. elegans GATA factors (elt-1 and elt-3) do not cause ectopic gut gene expression. An imprecise transposon excision was identified that removes the entire elt-2 coding region. Homozygous elt-2 null mutants die at the L1 larval stage with an apparent malformation or degeneration of gut cells. Although the loss of elt-2 function has major consequences for later gut morphogenesis and function, mutant embryos still express ges-1. We suggest that elt-2 is part of a redundant network of genes that controls embryonic gut development; other factors may be able to compensate for elt-2 loss in the earlier stages of gut development but not in later stages. We discuss whether elements of this regulatory network may be conserved in all metazoa

Ten-Year Outcome of Neoadjuvant Chemoradiotherapy Plus Surgery for Esophageal Cancer:The Randomized Controlled CROSS Trial

PURPOSE: Preoperative chemoradiotherapy according to the chemoradiotherapy for esophageal cancer followed by surgery study (CROSS) has become a standard of care for patients with locally advanced resectable esophageal or junctional cancer. We aimed to assess long-term outcome of this regimen. METHODS: From 2004 through 2008, we randomly assigned 366 patients to either five weekly cycles of carboplatin and paclitaxel with concurrent radiotherapy (41.4 Gy in 23 fractions, 5 days per week) followed by surgery, or surgery alone. Follow-up data were collected through 2018. Cox regression analyses were performed to compare overall survival, cause-specific survival, and risks of locoregional and distant relapse. The effect of neoadjuvant chemoradiotherapy beyond 5 years of follow-up was tested with time-dependent Cox regression and landmark analyses. RESULTS: The median follow-up was 147 months (interquartile range, 134-157). Patients receiving neoadjuvant chemoradiotherapy had better overall survival (hazard ratio [HR], 0.70; 95% CI, 0.55 to 0.89). The effect of neoadjuvant chemoradiotherapy on overall survival was not time-dependent (P value for interaction, P = .73), and landmark analyses suggested a stable effect on overall survival up to 10 years of follow-up. The absolute 10-year overall survival benefit was 13% (38% v 25%). Neoadjuvant chemoradiotherapy reduced risk of death from esophageal cancer (HR, 0.60; 95% CI, 0.46 to 0.80). Death from other causes was similar between study arms (HR, 1.17; 95% CI, 0.68 to 1.99). Although a clear effect on isolated locoregional (HR, 0.40; 95% CI, 0.21 to 0.72) and synchronous locoregional plus distant relapse (HR, 0.43; 95% CI, 0.26 to 0.72) persisted, isolated distant relapse was comparable (HR, 0.76; 95% CI, 0.52 to 1.13). CONCLUSION: The overall survival benefit of patients with locally advanced resectable esophageal or junctional cancer who receive preoperative chemoradiotherapy according to CROSS persists for at least 10 years

Neoadjuvant chemoradiotherapy plus surgery versus active surveillance for oesophageal cancer: A stepped-wedge cluster randomised trial

Background: Neoadjuvant chemoradiotherapy (nCRT) plus surgery is a standard treatment for locally advanced oesophageal cancer. With this treatment, 29% of patients have a pathologically complete response in the resection specimen. This provides the rationale for investigating an active surveillance approach. The aim of this study is to assess the (cost-)effectiveness of active surveillance vs. standard oesophagectomy after nCRT for oesophageal cancer. Methods: This is a phase-III multi-centre, stepped-wedge cluster randomised controlled trial. A total of 300 patients with clinically complete response (cCR, i.e. no local or disseminated disease proven by histology) after nCRT will be randomised to show non-inferiority of active surveillance to standard oesophagectomy (non-inferiority margin 15%, intra-correlation coefficient 0.02, power 80%, 2-sided α 0.05, 12% drop-out). Patients will undergo a first clinical response evaluation (CRE-I) 4-6 weeks after nCRT, consisting of endoscopy with bite-on-bite biopsies of the primary tumour site and other suspected lesions. Clinically complete responders will undergo a second CRE (CRE-II), 6-8 weeks after CRE-I. CRE-II will include 18F-FDG-PET-CT, followed by endoscopy with bite-on-bite biopsies and ultra-endosonography plus fine needle aspiration of suspected lymph nodes and/or PET- positive lesions. Patients with cCR at CRE-II will be assigned to oesophagectomy (first phase) or active surveillance (second phase of the study). The duration of the first phase is determined randomly over the 12 centres, i.e., stepped-wedge cluster design. Patients in the active surveillance arm will undergo diagnostic evaluations similar to CRE-II at 6/9/12/16/20/24/30/36/48 and 60 months after nCRT. In this arm, oesophagectomy will be offered only to patients in whom locoregional regrowth is highly suspected or proven, without distant dissemination. The main study parameter is overall survival; secondary endpoints include percentage of patients who do not undergo surgery, quality of life, clinical irresectability (cT4b) rate, radical resection rate, postoperative complications, progression-free survival, distant dissemination rate, and cost-effectiveness. We hypothesise that active surveillance leads to non-inferior survival, improved quality of life and a reduction in costs, compared to standard oesophagectomy. Discussion: If active surveillance and surgery as needed after nCRT leads to non-inferior survival compared to standard oesophagectomy, this organ-sparing approach can be implemented as a standard of care

Impact of nationwide enhanced implementation of best practices in pancreatic cancer care (PACAP-1): A multicenter stepped-wedge cluster randomized controlled trial

Background: Pancreatic cancer has a very poor prognosis. Best practices for the use of chemotherapy, enzyme replacement therapy, and biliary drainage have been identified but their implementation in daily clinical practice is often suboptimal. We hypothesized that a nationwide program to enhance implementation of these best practices in pancreatic cancer care would improve survival and quality of life. Methods/design: PACAP-1 is a nationwide multicenter stepped-wedge cluster randomized controlled superiority trial. In a per-center stepwise and randomized manner, best practices in pancreatic cancer care regarding the use of (neo)adjuvant and palliative chemotherapy, pancreatic enzyme replacement therapy, and metal biliary stents are implemented in all 17 Dutch pancreatic centers and their regional referral networks during a 6-week initiation period. Per pancreatic center, one multidisciplinary team functions as reference for the other centers in the network. Key best practices were identified from the literature, 3 years of data from existing nationwide registries within the Dutch Pancreatic Cancer Project (PACAP), and national expert meetings. The best practices follow the Dutch guideline on pancreatic cancer and the current state of the literature, and can be executed within daily clinical practice. The implementation process includes monitoring, return visits, and provider feedback in combination with education and reminders. Patient outcomes and compliance are monitored within the PACAP registries. Primary outcome is 1-year overall survival (for all disease stages). Secondary outcomes include quality of life, 3- and 5-year overall survival, and guideline compliance. An improvement of 10% in 1-year overall survival is considered clinically relevant. A 25-month study duration was chosen, which provides 80% statistical power for a mortality reduction of 10.0% in the 17 pancreatic cancer centers, with a required sample size of 2142 patients, corresponding to a 6.6% mortality reduction and 4769 patients nationwide. Discussion: The PACAP-1 trial is designed to evaluate whether a nationwide program for enhanced implementation of best practices in pancreatic cancer care can improve 1-year overall survival and quality of life. Trial registration: ClinicalTrials.gov, NCT03513705. Trial opened for accrual on 22th May 2018

Exact interval propagation for the efficient solution of position analysis problems on planar linkages

This paper presents an interval propagation algorithm for variables in planar single-loop linkages. Given intervals of allowed values for all variables, the algorithm provides, for every variable, the whole set of values, without overestimation, for which the linkage can actually be assembled. We show further how this algorithm can be integrated in a branch-and-prune search scheme, in order to solve the position analysis of general planar multi-loop linkages. Experimental results are included, comparing the method's performance with that of previous techniques given for the same task. © 2012 Elsevier Ltd. All rights reserved.This work has been partially supported by the Spanish Ministry of Education and Science through the I+D project DPI2010-18449.Peer Reviewe