Anaesthetic challenges in carotid body tumour resection: a case report and review of literature

Carotid body tumour (CBT) is an extremely rare, non-chromaffin  paraganglioma arising from chemoreceptor cells at the carotid bifurcation. Reported incidence is 1-2 per 100,000. Surgical excision of the tumour, the definitive treatment, poses several anaesthetic challenges and a high incidence of perioperative morbidity and mortality (20-40%). Very few cases have been reported so far. We report the anaesthetic management of a case of CBT excision with a review of recent literature on the same

Construction of an Interface Terminology on SNOMED CT Generic Approach and Its Application in Intensive...

Objective: To provide a generic approach for developing a domain-specific interface terminology on SNOMED CT and to apply this approach to the domain of intensive care. Methods:The process of developing an interface terminology on SNOMED CT can be regarded as six sequential phases: domain analysis, mapping from the domain con - cepts to SNOMED CT concepts, creating the SNOMED CT subset guided by the mapping, extending the subset with non-covered concepts, constraining the subset by removing irrelevant content, and deploying the subset in a terminology server. Results:The APACHE IV classification, a standard in the intensive care with 445 diagnostic categories, served as the starting point for designing the interface terminology. The majority (89.2%) of the diagnostic categories from APACHE IV could be mapped to SNOMED CT concepts and for the remaining concepts a partial match was identified. The resulting initial set of mapped concepts consisted of 404 SNOMED CT concepts. This set could be extended to 83,125 concepts if all taxonomic children of these concepts were included. Also including all concepts that are referred to in the definition of other concepts lead to a subset of 233,782 concepts. An evaluation of the interface terminology should reveal what level of detail in the subset is suitable for the intensive care domain and whether parts need further constraining. In the final phase, the interface terminology is implemented in the intensive care in a locally developed terminology server to collect the reasons for intensive care admission. Conclusions: We provide a structure for the process of identifying a domain-specific interface terminology on SNOMED CT. We use this approach to design an interface terminology on SNOMED CT for the intensive care domain. This work is of value for other researchers who intend to build a domain-specific interface terminology on SNOMED CT

Experimental and analytical study of the high-strain rate flexural behavior of SFRC

Steel fiber-reinforced concrete (SFRC) with hooked-end steel fibers was created for use in urban furniture to protect against blast and impact loads. Due to the variety of impact loads that these structures may experience, it is necessary to assess the impact of high strain rates on the flexural behavior of SFRC. This study involved testing SFRC beams with 1% volume content of hooked-end fibers, which were 30 mm long and had an aspect ratio of 80. The beams were tested at different strain rates and in a three-point loading configuration. Four strain rates were tested, ranging from 10−6 to 10−2 s−1, and impact tests were conducted using a drop weight impact test machine and varying drop heights, corresponding to strain rates ranging from 1 to 20 s−1. Two load cells were used to measure the total impact force and one reaction force, which were then used to assess the inertial force. Two accelerometers measured the maximum acceleration at the midspan of the beams. The results included quasi-static and dynamic load-deflection relationships, dynamic flexural tensile strength, and failure mode of SFRC specimens, as well as the relationship between the inertial force and strain rate. The study revealed that deflection capacity and flexural tensile strength increased with loading rate. The study also provides dynamic to static property ratios, such as flexural tensile strength and fracture energy, which are compared with those recommended by the CEB-FIP Model Code and other researchers.(undefined

Experimental and analytical study of the high-strain-rate compressive behavior of SFRC

The compressive behavior of steel-fiber-reinforced-concrete (SFRC) is dependent on the loading rate. This research investigates, experimentally and analytically, the effect of loading rate on the compressive behavior of SFRC designed to be used in prefabricated urban protective furniture. For this purpose, cylinder SFRC specimens were subjected to modified instrumented-drop-weightimpact tests at four dropping heights and quasi-static tests with four different strain rates. The inertia force was analytically obtained and also experimentally measured. The results demonstrate that by increasing the strain rate, elastic modulus, compressive strength, and energy dissipation capacity have increased. Three different models were proposed for predicting each mechanical characteristic, one in the range of quasi-static and the others in the range of impact corresponding to the split Hopkinson pressure bar and drop-weight-impact tests. The experimental dynamic to static ratios obtained for SFRC properties were discussed and compared with those proposed by present study and from other researchers. Three proposed models significantly improve the prediction the dynamic increase factor values in terms of compressive strength, modulus of elasticity and toughness.This paper is a part of the project “PufProtec – Prefabricated Urban Furniture Made by Advanced Materials for Protecting Public Built” with the reference of (POCI-01-0145-FEDER-028256) supported by FEDER and FCT funds. The first author appreciatively acknowledges the financial support of FCT-Fundação para a Ciência e Tecnologia for the Ph.D. Grant SFRH/BD/149246/2019

Experimental investigation of the effect of high strain rate loading on the compressive behaviour of the steel fibre-reinforced concrete

This research investigates the effect of loading rate on the compressive behaviour of steel fibre reinforced concrete (SFRC) designed to be used in prefabricated urban protective furniture. Although SFRC is known as a rate sensitive material and its dynamic and static compressive behaviour can be significantly different, the experimental studies on the loading rate sensitivity of SFRC in the range of impact have been rarely done compared to quasi-static. In the present study, the inertia effect in the range of impact as an important parameter for dynamic analysis of SFRC is considered. For this purpose, the SFRC mixture developed includes 1% hooked end steel fibres with length of 30 mm and aspect ratio of 80. The drop-weight impact tests were performed with three different drop heights, corresponding to maximum strain rates that range from 1 to 50 s-1. Using a servo-hydraulic testing machine, the quasi-static tests with four different loading rates were also performed with strain rates ranging from 10-6 to 10-2 s-1. The impact forces on top (impact force) and bottom (reaction force) of specimens were recorded in order to evaluate the inertia force and the stress wave propagation in the direction of the applied load. The strain and the strain rates were directly measured by three strain gauges installed on the specimens’ mid height and also indirectly measured using a high-speed video camera during the impact loading. The results show that, by increasing the strain rates, compressive strength, modulus of elasticity and energy absorption capacity of SFRC were increased. The dynamic to static ratios established for SFRC main properties are discussed and compared with those proposed by other researchers and recommended by CEB-FIP 2010. The models proposed by CEB-FIP describe quite well the dynamic increasing factor for the compressive strength of SFRC, at the measured strain rate range. The CEB-FIP models seemed to underestimate the increase in the modulus of elasticity experimentally measured for SFRC under impact loading.The study reported in this paper is part of the project “PufProtec - Prefabricated Urban Furniture Made by Advanced Materials for Protecting Public Built” with the reference of (POCI-01-0145-FEDER-028256) supported by FEDER and FCT funds. The first author gratefully acknowledges the financial support of FCT Fundação para a Ciência e Tecnologia for the Ph.D. Grant SFRH/BD/149246/2019