Shipyard facility layout optimization through the implementation of a sequential structure of algorithms.

The objective of this work is to optimize a shipyard facility layout through required departments' closeness conditions to minimize total material handling cost. In order to resolve this type facility layout problem, departments' closeness conditions must be respected when the manufacturing and material handling processes require it according to the supply and movement requirements throughout production flow, especially when the activity requires material handling equipment of common use between departments. As a result of this work the optimization is achieved through the implementation of a stochastic sequential algorithm, comprising the following steps: 1) Topological Optimization from a Genetic Algorithm, 2) Transferring the centroid coordinates of each department from the topological grid to the geometrical grid from a computational procedure, and 3) Geometrical Optimization from a Stochastic Growth Algorithm, with a fine-tuning of the solution achieved using the Electre Method and a Local Search Method. Computational experiments were performed to prove the effectiveness of the system and evaluate the performance of each algorithm listed in the scope of the proposed solution. We have proved that the proposed Sequential Structure of Algorithms can successfully solve the problem. Computational experiments results are also presented in the supplementary material of this work.

Endoscopic submucosal tunnel dissection vs conventional endoscopic submucosal dissection for large colorectal neoplasms: a single-centre retrospective study.

BACKGROUND: Colorectal endoscopic submucosal dissection (ESD) is still not widely used due to its technical difficulty and the risk of complications. Several techniques, such as traction techniques, pocket techniques and others, have been proposed to facilitate it. One modified pocket technique especially suitable for large lesions is endoscopic submucosal tunnel dissection (ESTD). The aim of this study was to evaluate the safety and efficacy of ESTD and compare ESTD to the conventional ESD (CESD) for treating large colorectal lesions. METHODS: The charts of consecutive patients referred to the Arcispedale Santa Maria Nuova (Reggio Emilia, Italy) for colorectal ESD between January 2014 and February 2021 for colorectal neoplasms > 40 mm were retrospectively analysed. The primary outcome of the study was the en bloc resection rate. Secondary outcomes were complete and curative resection rates, procedure speed, the adverse events rate and the recurrence rate. RESULTS: There were 59 patients (M:F ratio 29:30, median age 70 years [range 50-93 years]). Of 59 colorectal lesions > 40 mm, 25 were removed by ESTD and 34 by CESD. The en bloc resection rate was 100% in both groups and the complete resection rate was similar (ESTD 92% vs CESD 97.1%, p = 0.569), while the curative resection rate was higher in the CESD group, but not significantly (94.1% vs 76%, p = 0.061). Procedure speed was significantly faster with ESTD (22 vs 17 mm2/min, p = 0.045), and the overall incidence of adverse events was low (6.8%). Eight patients were referred to surgery due to non-curative resection. During follow-up, no recurrence was observed in either treatment group. CONCLUSION: ESTD achieves a very high en bloc resection rate and is faster than CESD.

Endoscopic submucosal dissection of scar-embedded rectal polyps: a prospective study (Esd in scar-embedded rectal polyps).

BACKGROUND & AIMS: Endoscopic submucosal dissection (ESD) was developed for en bloc resection of superficial neoplasm of the digestive tract. We evaluated feasibility and safety of ESD, as a salvage therapy of large refractory rectal polyps, in a tertiary care setting. METHODS: We prospectively enrolled in the present study and treated by ESD 11 consecutive patients with rectal polyps (median diameter 3.5 cm; range 2-5 cm), who had previously undergone several attempts of endoscopic resection and not suitable for further standard endoscopic treatment. The ESD was carried out with a standard needle knife. Follow up examinations were scheduled at 3, 6, 12 and 24 months. RESULTS: We achieved apparently complete resection of polyps in 10/11 patients. In one patient ESD was interrupted and the pathology of the resected fragment showed deep submucosal infiltration; this patient underwent surgery. Deep and lateral margins were shown to be free of neoplasm (radical resection) in six out of 11 patients. However all the 10 patients with apparently complete resection were free of recurrence after a mean follow up of 19.2 months (12-24). A T1 adenocarcinoma was radically resected by ESD, with no recurrence. We recorded 2 cases of subcutaneous emphysema, both treated conservatively. CONCLUSIONS: Radical resection is difficult to be achieved by ESD in patients with rectal scar-embedded polyps. Nevertheless ESD may be proposed as a definitive treatment of selected patients with refractory polyps, avoiding surgery in the majority of them.

A randomized clinical trial comparing 22G and 25G needles in endoscopic ultrasound-guided fine-needle aspiration of solid lesions.

BACKGROUND AND STUDY AIMS: The study aimed to investigate whether the 25G needle is superior to the 22G needle when used in endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) of solid lesions. PATIENTS AND METHODS: The study was a single-center randomized clinical trial. The setting was a tertiary referral hospital, where EUS-FNA of solid lesions was assisted by an on-site cytopathologist, who was blinded to the needle size. The main end point was the number of passes performed to obtain adequate samples. Crossover to the other type of needle was allowed after five passes, or when the gastroenterologist experienced difficulties in puncturing the lesions. RESULTS: A total of 129 solid lesions were randomized and data regarding 127 lesions were analyzed. The mean number of passes was 3.7 (± 1.9) in the 22G needle group and 3.8 (± 2) in the 25G needle groups (difference of means: 0.1; 95% CI: -0.59 to 0.79). Fifty-eight of 63 (92.1%) and 60/64 samples (93.7%) in the 22G and 25G needle groups respectively were adequate (difference: -1.6%; 95%CI: -12.1% to 8.9%). Crossover to the other type of needle was performed in 11/63 (17.5%) and in 12/64 (18.7%) lesions in the two groups respectively (difference: -1.2%; 95%CI: -16.2% to 13.8%). A crossover to the 25G needle was successfully performed in four masses in the uncinate process; these lesions were difficult to puncture using the 22G needle. CONCLUSIONS: Our study failed to demonstrate that the 25G is more effective than the 22G needle in EUS-FNA of solid lesions. However, targeting of lesions in the distal duodenum may be simplified by using the 25G needle.

Comparison of three different risk scoring systems in non-variceal upper gastrointestinal bleeding.

BACKGROUND AND AIMS: To prospectively validate in patients with non-variceal upper gastrointestinal bleeding three risk scoring systems (the Baylor College scoring system, the Rockall's risk scoring system and the Cedars-Sinai Medical Centre predictive index) previously proposed to be predictive of rebleeding/death after upper gastrointestinal bleeding. PATIENTS AND METHODS: We calculated values of the scores for 343 patients, who underwent endoscopy after non-variceal upper gastrointestinal haemorrhage during the years 1997-1999. We compared the observed outcomes with the ones expected upon the original series contributed by the authors. Discriminative ability was evaluated by calculating the area under the receiver operating characteristic curve. RESULTS AND CONCLUSIONS: Rockall's score accurately predicted rebleeding in low- and intermediate-risk categories (< 6), but not in high-risk patients. The rates of rebleeding were significantly higher than the ones predicted by the low-risk categories of either Cedars-Sinai index (< or = 2) or Baylor score (< or = 6). The predicted and the observed mortality was not significantly different throughout all the categories of Rockall's score, except for patients with a score of 4. All the scores had better discriminative ability for mortality than for rebleeding. The Rockall's score identifies a low-risk group of patients (Rockall's score < or = 2) for rebleeding and mortality.

What is the utility of selected clinical and endoscopic parameters in predicting the risk of death after caustic ingestion?

BACKGROUND AND STUDY AIMS: Despite the increasing use of early esophagogastroduodenoscopy, the prognostic evaluation and triage of patients who have ingested caustic material is challenging. We evaluated the usefulness of selected clinical and endoscopic parameters in predicting the risk of death after ingestion of caustic substances. PATIENTS AND METHODS: Clinical and endoscopic parameters were obtained from the records of all the patients admitted to our endoscopy unit because of ingestion of caustic material between 1 March 1982 and 30 June 1999. Parameters significantly associated with the risk of death by univariate analysis were entered into a multivariate logistic model. The independent predictors of death by multivariate analysis were used to build a risk score system. RESULTS: Out of 210 patients, 13 underwent emergency surgery (6.2 %) and 25 died (11.9 %). Multivariate analysis identified the following as independent predictors of death: age (10-year intervals; odds ratio [OR] 2.4; 95 % confidence interval 1.4 - 4.1), ingestion of strong acids (OR 7.9; 1.8 - 35.3), white blood cell count at admission > or = 20 000 units/mm3 (OR 6.0; 1.3-28), deep gastric ulcers (OR 9.7; 1.4 - 66.8), and gastric necrosis (OR 20.9; 4.7 - 91.8). The values of the risk score system devised from the results of the multivariate analysis ranged from 1 to 16. No patient scoring < 10 points died and just one of the patients scoring > 14 points survived. CONCLUSION: Age, ingestion of a strong acid, leucocytosis, deep gastric ulcers, and gastric necrosis are predictive of death after caustic ingestion. A risk score system including these predictors may be useful in prognostic evaluation.