One-fourth of colorectal neoplasias are missed during screening colonoscopies; these can develop into colorectal cancer (CRC). Deep learning systems allow for real-time computer-aided detection ...(CADe) of polyps with high accuracy. We performed a multicenter, randomized trial to assess the safety and efficacy of a CADe system in detection of colorectal neoplasias during real-time colonoscopy.
We analyzed data from 685 subjects (61.32 ± 10.2 years old; 337 men) undergoing screening colonoscopies for CRC, post-polypectomy surveillance, or workup due to positive results from a fecal immunochemical test or signs or symptoms of CRC, at 3 centers in Italy from September through November 2019. Patients were randomly assigned (1:1) to groups who underwent high-definition colonoscopies with the CADe system or without (controls). The CADe system included an artificial intelligence–based medical device (GI-Genius, Medtronic) trained to process colonoscopy images and superimpose them, in real time, on the endoscopy display a green box over suspected lesions. A minimum withdrawal time of 6 minutes was required. Lesions were collected and histopathology findings were used as the reference standard. The primary outcome was adenoma detection rate (ADR, the percentage of patients with at least 1 histologically proven adenoma or carcinoma). Secondary outcomes were adenomas detected per colonoscopy, non-neoplastic resection rate, and withdrawal time.
The ADR was significantly higher in the CADe group (54.8%) than in the control group (40.4%) (relative risk RR, 1.30; 95% confidence interval CI, 1.14–1.45). Adenomas detected per colonoscopy were significantly higher in the CADe group (mean, 1.07 ±1.54) than in the control group (mean 0.71 ± 1.20) (incidence rate ratio, 1.46; 95% CI, 1.15–1.86). Adenomas 5 mm or smaller were detected in a significantly higher proportion of subjects in the CADe group (33.7%) than in the control group (26.5%; RR, 1.26; 95% CI, 1.01–1.52), as were adenomas of 6 to 9 mm (detected in 10.6% of subjects in the CADe group vs 5.8% in the control group; RR, 1.78; 95% CI, 1.09–2.86), regardless of morphology or location. There was no significant difference between groups in withdrawal time (417 ± 101 seconds for the CADe group vs 435 ± 149 for controls; P = .1) or proportion of subjects with resection of non-neoplastic lesions (26.0% in the CADe group vs 28.7% of controls; RR, 1.00; 95% CI, 0.90–1.12).
In a multicenter, randomized trial, we found that including CADe in real-time colonoscopy significantly increases ADR and adenomas detected per colonoscopy without increasing withdrawal time. ClinicalTrials.gov no: 04079478
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Background & Aims Although the adenoma detection rate is used as a measure of colonoscopy quality, there are limited data on the quality of endoscopic resection of detected adenomas. We determined ...the rate of incompletely resected neoplastic polyps in clinical practice. Methods We performed a prospective study on 1427 patients who underwent colonoscopy at 2 medical centers and had at least 1 nonpedunculated polyp (5–20 mm). After polyp removal was considered complete macroscopically, biopsies were obtained from the resection margin. The main outcome was the percentage of incompletely resected neoplastic polyps (incomplete resection rate IRR) determined by the presence of neoplastic tissue in post-polypectomy biopsies. Associations between IRR and polyp size, morphology, histology, and endoscopist were assessed by regression analysis. Results Of 346 neoplastic polyps (269 patients; 84.0% men; mean age, 63.4 years) removed by 11 gastroenterologists, 10.1% were incompletely resected. IRR increased with polyp size and was significantly higher for large (10–20 mm) than small (5–9 mm) neoplastic polyps (17.3% vs 6.8%; relative risk = 2.1), and for sessile serrated adenomas/polyps than for conventional adenomas (31.0% vs 7.2%; relative risk = 3.7). The IRR for endoscopists with at least 20 polypectomies ranged from 6.5% to 22.7%; there was a 3.4-fold difference between the highest and lowest IRR after adjusting for size and sessile serrated histology. Conclusions Neoplastic polyps are often incompletely resected, and the rate of incomplete resection varies broadly among endoscopists. Incomplete resection might contribute to the development of colon cancers after colonoscopy (interval cancers). Efforts are needed to ensure complete resection, especially of larger lesions. ClinicalTrials.gov Number: NCT01224444.
The Double Asteroid Redirection Test (DART) is a NASA-sponsored mission that will be the first direct test of the kinetic impactor technique for planetary defense. The DART spacecraft will impact ...into Didymos-B, the moon of the binary system 65803 Didymos, and the resulting period change will be measured from Earth. Impact simulations will be used to predict the crater size and momentum enhancement expected from the DART impact. Because the specific material properties (strength, porosity, internal structure) of the Didymos-B target are unknown, a wide variety of numerical simulations must be performed to better understand possible impact outcomes. This simulation campaign will involve a large parameter space being simulated using multiple different shock physics hydrocodes. In order to understand better the behaviors and properties of numerical simulation codes applicable to the DART impact, a benchmarking and validation program using different numerical codes to solve a set of standard problems was designed and implemented. The problems were designed to test the effects of material strength, porosity, damage models, and target geometry on the ejecta following an impact and thus the momentum transfer efficiency. Several important results were identified from comparing simulations across codes, including the effects of model resolution and porosity and strength model choice: 1) momentum transfer predictions almost uniformly exhibit a larger variation than predictions of crater size; 2) the choice of strength model, and the values used for material strength, are significantly more important in the prediction of crater size and momentum enhancement than variation between codes; 3) predictions for crater size and momentum enhancement tend to be similar (within 15‐20%) when similar strength models are used in different codes. These results will be used to better design a modeling plan for the DART mission as well as to better understand the potential results that may be expected due to unknown target properties. The DART impact simulation team will determine a specific desired material parameter set appropriate for the Didymos system that will be standardized (to the extent possible) across the different codes when making predictions for the DART mission. Some variation in predictions will still be expected, but that variation can be bracketed by the results shown in this study.
•DART is the first space-based test of a kinetic impactor for momentum enhancement.•Porosity has large effects on crater size and significantly affects β predictions.•Predictions of momentum enhancement strongly depend on resolution.•Momentum enhancement predictions show larger variation than crater size predictions.•Strength model choice is more important than inherent inter-code variation.
Acceptance rules for reaction ensemble Monte Carlo (RxMC) simulations containing classically modeled atomistic degrees of freedom are derived for complex molecular systems where insertions and ...deletions are achieved gradually by utilizing the continuous fractional component (CFC) method. A self-consistent manner in which to utilize statistical mechanical data contained in ideal gas free energy parameters during RxMC moves is presented. The method is tested by applying it to two previously studied systems containing intramolecular degrees of freedom: the propene metathesis reaction and methyl-tert-butyl-ether (MTBE) synthesis. Quantitative agreement is found between the current results and those of Keil et al. (J. Chem. Phys. 2005, 122, 164705) for the propene metathesis reaction. Differences are observed between the equilibrium concentrations of the present study and those of Lísal et al. (AIChE J. 2000, 46, 866−875) for the MTBE reaction. It is shown that most of this difference can be attributed to an incorrect formulation of the Monte Carlo acceptance rule. Efficiency gains using CFC MC as opposed to single stage molecule insertions are presented.
New global models provide the opportunity to generate quantitative information about the world water situation. Here the WaterGAP 2 model is used to compute globally comprehensive estimates about ...water availability, water withdrawals, and other indicators on the river-basin scale. In applying the model to the current global water situation, it was found that about 24% of world river basin area has a withdrawal to availability ratio greater than 0.4, which some experts consider to be a rough indication of "severe water stress"; the impacts of this stress are expected to be stronger in developing countries than in industrialized ones. Under a "business-as-usual" scenario of continuing demographic, economic and technological trends up to 2025, water withdrawals are expected to stabilize or decrease in 41% of world river basin areas because of the saturation of water needs and improvement in water-use efficiency. Withdrawals grow elsewhere because population and economic growth will lead to rising demand for water, and this outweighs the assumed improvements in water-use efficiency. An uncertainty analysis showed that the uncertainty of these estimates is likely to have a strong geographic variability.
Results of molecular dynamics simulations are reported in which the structure and dynamics of the reacted and unreacted forms of the task-specific ionic liquid (TSIL) tetrabutylphosphonium ...2-cyanopyrrolide were computed. This particular ionic liquid is one of several newly discovered TSILs containing aprotic heterocyclic anions designed specifically for CO2 capture. The physical properties, liquid structure, and dynamics of the ionic liquid were computed as a function of extent of reaction with CO2. Translational and rotational dynamics showed little change upon reaction with CO2, in sharp contrast to traditional TSILs and consistent with experimental viscosity measurements. It is shown that this is due to the failure of a hydrogen-bond network to form upon reaction with CO2. The Henry’s law constants for the physical solubility of CO2, N2, O2, and H2O were computed for the unreacted TSIL and found to be comparable to values observed with other ionic liquids. In the reacted state, the solubility of CO2, N2, and O2 remained essentially unchanged, whereas the solubility of H2O increased by over a factor of 10 because of favorable hydrogen-bonding interactions with the carbamate.
A randomized trial compared peroral endoscopic myotomy with laparoscopic Heller’s myotomy plus Dor’s fundoplication in patients with symptomatic idiopathic achalasia. POEM was noninferior to LHM in ...controlling symptoms of achalasia at 2 years. Symptoms of gastroesophageal reflux were more common in the POEM group.
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