Global wealth disparities drive adherence to COVID-safe pathways in head and neck cancer surgery

Peer reviewe

The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study

AIM: The SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery. METHODS: This was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin. RESULTS: Overall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P < 0.001). After adjustment, delay was not associated with a lower rate of complete resection (OR 1.18, 95% CI 0.90-1.55, P = 0.224), which was consistent in elective patients only (OR 0.94, 95% CI 0.69-1.27, P = 0.672). Longer delays were not associated with poorer outcomes. CONCLUSION: One in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease

Size Effects in Testing of Carbon Fiber Vinyl Ester Laminate For Marine Application and Damage Evolution.

This study reports a series of mechanical tests on carbon fiber reinforced vinyl ester composites CF VE , consisting of fiber dominated samples of [0 90]2S and matrix dominated samples of [ 45]2S orientation, while employing variable specimen sizes. In order to extend the observations from coupon based mechanical tests of fiber reinforced polymer composites, towards the design and application of large ship structures, it is important to consider the effect of the physical specimen size. Previous studies indicate that the strength of fiber reinforced composites which are subjected to tensile loading, decreases as the specimen size increases, strongly depending on manufacturing parameters. Three sizes of CF VE composite specimens were made 12.5 mm wide by 100 mm long, 25 mm by 200 mm, and 25 mm by 300 mm , all with an average uniform thickness of 2.8 mm. The composite laminates were prepared using Vacuum Assisted Resin Transfer Molding VARTM process. The mechanical strengths of the samples were experimentally evaluated and are compared, The present study also reports different CF VE failure mechanisms of matrix crack interactions, such as matrix dominated transverse tension, tension along fibers, and fiber delamination. Digital Image Correlation DIC technique was implemented to track the evolution of surface damage showing the existence of localized damage for both fiber and matrix dominated CF VE composites. Additionally, high resolution x ray and neutron tomography under in situ mechanical loading was used for the investigation of damage evolution at different stress levels. Specimen of 12.5 mm by 100 mm were incrementally loaded under tension and torsion, while in situ tomography using x ray and neutron radiation was performed, which also enables a comparison between interior specimen damage and surface damage readily observable using DIC

Accepted for the Council:

The purpose of this work is to further develop experimental methodologies using flat punch nanoindentation to measure the constitutive behavior of viscoelastic solids in the frequency and time domain. The reference material used in this investigation is highly plasticized polyvinylchloride (PVC) with a glass transition temperature of-17 degrees Celsius. The nanoindentation experiments were conducted using 103 and 983 micron diameter flat punches. For comparative purposes, the storage and loss modulus obtained by dynamic mechanical analysis are also presented. Over the frequency range of 0.01 to 50 Hz, the storage and loss modulus measured using nanoindentation and uniaxial compression are shown to be in excellent agreement. The creep compliance function predicted from nanoindentation data acquired in the frequency domain is also found to be in excellent agreement over two decades in time with the creep compliance function measured using a constant stress test performed in uniaxial compression. A constraint factor of 1.55 is found to overlay the creep compliance function measured by nanoindentation in the time domain with th

Evolutionary intelligence in asphalt pavement modeling and quality-of-information

he analysis and development of a novel approach to asphalt pavement modeling, able to attend the need to predict failure according to technical and non- technical criteria in a highway, is a hard task, namely in terms of the huge amount of possible scenarios. Indeed, the current state-of-the-art for service-life prediction is at empiric and empiric-mechanistic levels, and do not provide any suitable answer even for one single failure criteria. Consequently, it is imperative to achieve qualified models and qualitative reasoning methods, in particular due to the need to have first-class environments at our disposal where defective information is at hand. In order to fulfill this goal, this paper presents a dynamic and formal model oriented to fulfill the task of making predictions for multi-failure criteria, in particular in scenarios with incomplete information; it is an intelligence tool that advances according to the Quality-of- Information of the extensions of the predicates that model the universe of discourse. On the other hand, it is also considered the Degree-of-Confidence factor, a parameter that measures one`s confidence on the list of characteristics presented by an asphalt pavement, set in terms of the attributes or variables that make the argument of the predicates referred to above.The authors would like to thank the Foundation of Science and Technology (FCT), Portugal, for financial support received under the contract UTAustin/CA/0012/2008