scholarly journals Regional tongue deformations during chewing and drinking in the pig

Author(s):  
Rachel A Olson ◽  
Stéphane J Montuelle ◽  
Hannah Curtis ◽  
Susan H Williams

Abstract As a muscular hydrostat, the tongue undergoes complex deformations during most oral behaviors, including chewing and drinking. During these behaviors, deformations occur in concert with tongue and jaw movements to position and transport the bolus. Moreover, the various parts of the tongue may move and deform at similar timepoints relative to the gape cycle or they may occur at different timepoints, indicating regional biomechanical and functional variation. The goal of this study is to quantify tongue biomechanics during chewing and drinking in pigs by characterizing intrinsic deformations of the tongue across multiple regions simultaneously. Tongue deformations are generally larger during chewing cycles compared to drinking cycles. Chewing and drinking also differ in the timing of regional length and width, but not total length, deformations. This demonstrates functional differences in the temporal dynamics of localized shape changes whereas the global properties of jaw-tongue coordination are maintained. Finally, differences in the trade-off between length and width deformations demonstrate that the properties of a muscular hydrostat are observed at the whole tongue level, but biomechanical variation (e.g., changes in movements and deformations) at the regional level exists. This study provides new critical insights into the regional contributions to tongue deformations as a basis for future work on multidimensional shape changes in soft tissues.

2016 ◽  
Vol 01 (02) ◽  
pp. 1650001 ◽  
Author(s):  
Elisa Beretta ◽  
Giancarlo Ferrigno ◽  
Elena De Momi

Surgeons can benefit from the cooperation with a robotic assistant during the repetitive execution of precise targeting tasks on soft tissues, such as brain cortex stimulation procedures in open-skull neurosurgery. Position-based force-to-motion control schemes may not be satisfactory solution to provide the manipulator with the high compliance desirable during guidance along wide trajectories. A new torque controller with nonlinear force feedback enhancement (FFE) is presented to provide augmented haptic perception to the operator from instrument-tissue interaction. Simulation tests were performed to evaluate the system stability according to different nonlinear force modulation functions (power, sigmoidal and arc tangent). The FFE controller with power modulation was experimentally validated with a pool of nonexpert users using brain-mimicking gelatin phantoms (8–16% concentration). Besides providing hand tremor rejection for a stable holding of the tool, the FFE controller was proven to allow for a safer tissue contact with respect to both robotic assistance without force feedback and freehand executions (50% and 75% reduction of the indentation depth, respectively). Future work will address the evaluation of the safety features of the FFE controller with expert surgeons on a realistic brain phantom, also accounting for unpredictable tissue motions as during seizures due to cortex stimulation.


2010 ◽  
Vol 15 (3) ◽  
pp. 119-132
Author(s):  
Elizabeth Quinlan ◽  
Susan Robertson

The introduction of knowledge teams, as a new form of work organisation, is one of many institutional transformations associated with the knowledge economy. The research on the effects of this new form of work organisation on the social processes by which knowledge workers exchange, create, and apply knowledge is limited. The research that does exist uses various communication theories to explain the social interactions within knowledge teams. We offer an alternative theoretical framework, based on Habermas’ theory of communicative action. In this paper, we operationalise the theory using dynamic agent-based modelling to perform a series of ‘virtual experiments’ on the temporal dynamics of knowledge exchange within teams. The modelling results are used to critically reflect on the theory and draw conclusions regarding the lifeworld rationalisation within knowledge teams. The paper closes by specifying areas of future work and suggesting that a practical outcome of the completed research agenda will be an evaluation tool to be used by knowledge teams to assess how effective they are at communicating and producing knowledge.


2021 ◽  
Vol 8 ◽  
pp. 205435812110037
Author(s):  
Robert R. Quinn ◽  
Farah Mohamed ◽  
Robert Pauly ◽  
Tracy Schwartz ◽  
Nairne Scott-Douglas ◽  
...  

Background: Most of the patients with end-stage kidney failure are treated with dialysis. Jurisdictions around the world are actively promoting peritoneal dialysis (PD) because it is equivalent to hemodialysis in terms of clinical outcomes, but is less costly. Unfortunately, PD penetration remains low. Objectives: The Starting dialysis on Time, At Home, on the Right Therapy (START) Project had 2 overarching goals: (1) to provide information that would help programs increase the safe and effective use of PD, and (2) to reduce inappropriate, early initiation of dialysis in patients with kidney failure. In this article, we focus on the first objective and describe the rationale for START and the methods employed. Design: The START Project was a comprehensive, province-wide quality improvement intervention. Setting: The START project was implemented in both Alberta Kidney Care (AKC)-South and AKC-North, including all 7 renal programs in the province. Patients: The project included all patients who commenced maintenance dialysis between October 1, 2015, and March 31, 2018, in Alberta, Canada who met our inclusion criteria. Measurements: We reported baseline characteristics of incident dialysis patients overall, and by site. Our key performance indicator was the proportion of patients who received PD for any period of time within 180 days of the first dialysis treatment. Reports also included detailed metrics pertaining to the 6 steps in the process of modality selection and we had the capacity to provide more granular data on an as-needed basis. To understand loss of PD patients, we reported the numbers of incident patients who recovered kidney function, experienced technique failure, received a transplant, were lost to follow-up, transferred to another program, or died. Methods: START provided dialysis programs with a conceptual framework for understanding the drivers of PD utilization. High-quality, detailed data were collected using a tool that was custom-built for this purpose, and were mapped to steps in the process of care that drove the outcomes of interest. This allowed sites to identify gaps in care, develop action plans, and implement local interventions to address them. The process was supported by an Innovation Learning Collaborative consisting of 3 learning sessions that brought frontline staff together from across the province to share strategies and learnings. Ongoing data collection allowed teams to determine whether their interventions were effective at each subsequent learning session, and to revisit their interventions if required (the “Plan-Do-Study-Act Cycle”). Results: Future work will report on the impact of the START project on incident PD utilization at a provincial and regional level. Limitations: The time required to design and implement interventions in practice, as well as the need for multiple PDSA (Plan-Do-Study-Act) cycles to see results, meant that the true potential may not be realized during a relatively short intervention period. Change required buy-in and support from local and provincial leadership and frontline staff. In the absence of accountability for local performance, we relied on the goodwill of participating programs to use the information and resources provided to effect change. Finally, the burden of documentation and data collection for frontline staff was high at baseline. We anticipated that adding supplemental data collection would be difficult. Conclusions: The START project was a comprehensive, province-wide initiative to maximize the safe and effective use of PD in Alberta, Canada. It standardized the management of incident dialysis patients, leveraged high-quality data to facilitate the reporting of metrics mapped to steps in the process of care that drove incident PD utilization, and helped programs to identify gaps in care and target them for improvement. Future work will report on the impact of the program on incident utilization at the provincial and regional level.


Author(s):  
A. Sarretta ◽  
M. Minghini

Abstract. Digital transformation is at core of Europe’s future and the importance of data is well highlighted by the recently published European strategy for data, which envisions the establishment of so-called European data spaces enabling seamless data flows across actors and sectors to ultimately boost the economy and generate innovation. Integrating datasets produced by multiple actors, including citizen-generated data, is a key objective of the strategy. This study focuses on OpenStreetMap (OSM), the most popular crowdsourced geographic information project, and is the first step towards an exploration of pros and cons of integrating its open-licensed data with authoritative geospatial datasets from European National Mapping Agencies. In contrast to previous work, which has only tested data integration at the local or regional level, an experiment was presented to integrate the national address dataset published by the National Land Survey (NLS) of Finland with the corresponding dataset from OSM. The process included the analysis of the two datasets, a mapping between their data models and a set of processing steps – performed using the open source QGIS software – to transform and finally combine their content. The resulting dataset confirms that, while addresses from the NLS are in general more complete across Finland, in some areas OSM addresses provide a higher detail and more up-to-date information to usefully complement the authoritative one. Whilst the analysis confirms that an integration between OSM and authoritative geospatial datasets is technically and semantically feasible, future work is needed to evaluate enablers and barriers that also exist at the legal and organisational level.


Author(s):  
Srinivas Vasista ◽  
Johannes Riemenschneider ◽  
Torsten Mendrock ◽  
Hans Peter Monner

Early research on a new concept for a morphing system based on unit structures or cells containing pressurized fluid is presented in this article. The motivation stems from the desire to achieve 3D smooth variations with multiple degrees of freedom and variations in surface area. Such a cell is composed of a hybrid between elastomeric material and stiffening material, creating an orthotropic system. When connected in a network of cells, the morphing system is highly integrated in terms of the components of the skin, substructure and actuation means. Numerical predictions of small simple prismatic cells show a force and axial strain capability of above 200 N and 14% respectively for typical elastomeric and stiffening materials at 8 bar pressure. PolyJet™ additively-manufactured models of wings show how such actuators can be integrated into aircraft structures, including when 3D geometry is highly challenging. These additively-manufactured models were operated at low pressures in the order of 0.5 bar, and a number of open questions on the design, manufacture and operation of such structures are discussed along with intended future work towards higher grade materials and working pressures.


Author(s):  
David Oliveira Ramin ◽  
Gleyce Kelly Dantas Araujo Figueiredo

The temporal dynamics of pasture areas is strongly associated with the change in economic activity in the area. The impact of this transition, impacts the environmental, economic and social parameters. The evaluation of the temporal dynamics of pasture areas is extremely important for the generation of information to support decisions whether at the local or regional level, public or private. The use of satellite images and geographic information systems is completely indispensable for the evaluation of the dynamics of pasture areas over time, and this is the fact that motivates this research to identify areas of pasture in different years from official maps of land use classification and to evaluate, by NDVI series, which is associated strongly to the biomass of vegetation, the areas of retraction or increase of pasturelan areas, thus identifying the dynamics of land use transition.


2021 ◽  
Author(s):  
◽  
L. M. González Torres

The standing finite element models allow the study of their biomechanical-structural behavior. Research of this type provides podiatrists with knowledge in improving surgical techniques, thus allowing the exploration of new alternatives in the correction of biomechanical alterations in the lower extremities. Thus, reporting models in the literature with different types of contact in the joints, insertion of soft tissues such as the skin, as well as variation in the properties of the tissues. This research presents two numerical finite element models, healthy foot and claw toe pathology in the second radius. Based on the model of Mancera et al. (2020). The modifications include changes in load and contour conditions to simulate the "midstance" phase with 700 N load. The pathology model presents rotations and adjustments in the main soft tissues involved in the second radius of the foot. The two models were meshed and solved under the same conditions. The results of the simulation of the models are validated with the Costa Bartani and Kite angle. This was performed in the unloaded and loaded foot cases to verify that the model is within the parameters of the healthy foot. The Costa Bartani angle presented the greatest variation, while the Kite angle remained within the range value for a healthy foot. The models proposed during their evaluation show that pathologies that only involve the second radius of the foot affect the aforementioned angles, therefore, the biomechanical-structural behavior of the foot, allowing the study of other pathologies in future work.


2018 ◽  
Vol 24 (3) ◽  
pp. 284-291 ◽  
Author(s):  
Brandon P. Hedrick ◽  
Laurel Yohe ◽  
Abby Vander Linden ◽  
Liliana M. Dávalos ◽  
Karen Sears ◽  
...  

AbstractThe increased accessibility of soft-tissue data through diffusible iodine-based contrast-enhanced computed tomography (diceCT) enables comparative biologists to increase the taxonomic breadth of their studies with museum specimens. However, it is still unclear how soft-tissue measurements from preserved specimens reflect values from freshly collected specimens and whether diceCT preparation may affect these measurements. Here, we document and evaluate the accuracy of diceCT in museum specimens based on the soft-tissue reconstructions of brains and eyes of five bats. Based on proxies, both brains and eyes were roughly 60% of the estimated original sizes when first imaged. However, these structures did not further shrink significantly over a 4-week staining interval, and 1 week in 2.5% iodine-based solution yielded sufficient contrast for differentiating among soft-tissues. Compared to six “fresh” bat specimens imaged shortly after field collection (not fixed in ethanol), the museum specimens had significantly lower relative volumes of the eyes and brains. Variation in field preparation techniques and conditions, and long-term storage in ethanol may be the primary causes of shrinkage in museum specimens rather than diceCT staining methodology. Identifying reliable tissue-specific correction factors to adjust for the shrinkage now documented in museum specimens requires future work with larger samples.


eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Luke Hayden ◽  
Katerina Lochovska ◽  
Marie Sémon ◽  
Sabrina Renaud ◽  
Marie-Laure Delignette-Muller ◽  
...  

Do developmental systems preferentially produce certain types of variation that orient phenotypic evolution along preferred directions? At different scales, from the intra-population to the interspecific, the murine first upper molar shows repeated anterior elongation. Using a novel quantitative approach to compare the development of two mouse strains with short or long molars, we identified temporal, spatial and functional differences in tooth signaling center activity, that arise from differential tuning of the activation-inhibition mechanisms underlying tooth patterning. By tracing their fate, we could explain why only the upper first molar reacts via elongation of its anterior part. Despite a lack of genetic variation, individuals of the elongated strain varied in tooth length and the temporal dynamics of their signaling centers, highlighting the intrinsic instability of the upper molar developmental system. Collectively, these results reveal the variational properties of murine molar development that drive morphological evolution along a line of least resistance.


1978 ◽  
Vol 48 ◽  
pp. 175-178 ◽  
Author(s):  
K. J. Johnston
Keyword(s):  

A summary of results for radio astrometry with baselines ≤ 35 km and priorities for future work are given.


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