Introduction Serotonin (5-HT) is a key signalling molecule within the mucosal epithelium of the intestinal wall and has been shown to be an important modulator of motility. At present, no single approach has been established for simultaneous dual measurement of 5-HT overflow and circular muscle contraction. Methods We developed a 3D-printed carbon black/polylactic acid (PLA) electrochemical sensor, which had a geometry suitable for ex vivo measurement in the guinea pig anorectum. Phasic changes in the current were used to track contractility, whilst basal changes were used to track changes in mucosal 5-HT signalling. Using amperometric detection, the sensitivity and stability of the device for 5-HT measurements was assessed. The device was compared with an isometric force transducer for tracking of anorectal contractions. Results The 3D-printed electrochemical sensor had a linear range in physiological concentrations of 5-HT (1−10 μM) present within the intestinal tract and a limit of detection of 540 nM. There was a significant correlation in the amplitude and duration of individual contractions when comparing the measurements using an isometric force transducer and 3D-printed electrochemical sensor (p<0.001, n=7). Finally, in the presence of 1 μM fluoxetine, the sensor was able to monitor a reduction in contractility (p<0.001, n=7) as well as an increase in 5-HT overflow (p<0.001, n=7). The sensor was stable for 5-HT measurement following ex vivo tissue measurements. Conclusions The 3D-printed sensor can simultaneously measure 5-HT overflow and contractility in the anorectum. This single device will have significant potential for clinical measurements of anorectum function and signalling that can direct therapeutic management of patients with lower bowel disorders.

A road bicycle’s dynamic comfort relates to its capacity to filter vibration generated by the road surface. Typically, four quantities have been used to assess a road bicycle’s dynamic comfort, acceleration, force, power, and energy; however, little has been done to compare the effectiveness of these in distinguishing between impact events. The aim of this study was to assess the ability of these four quantities when measured at a cyclist’s hands, to discriminate between small changes in the level of an impact load applied at the front wheel of a road bicycle. With a rider seated on a bicycle, acceleration and force time signals were recorded at the left and right hands using instrumented brake hoods during a series of impacts at the front wheel on a bicycle treadmill. Six derived parameters of the acceleration, force, and power time signals were considered: discrete values: maximum, peak; mean values: root-mean-square, root-mean-quad; ratio values: crest factor, shock content quotient. Integral values were used for the energy. Various criteria were developed to assess the performance of these parameters and whether they should be recommended as road bicycle dynamic comfort metrics for impact events. The criteria were related to three characteristics: the consistency of the measurements, the parameter’s statistical discrimination power, and how well changes in the parameter matched corresponding changes in impact level. The energy and root-mean-square value of power were found to be the top performers and are recommended as road bicycle dynamic comfort metrics for impact events. All acceleration-based parameters are not recommended. The remaining parameters demonstrated mixed results.

Wheelchair racing gloves are typically solid 3D structures held in a clenched fist which help to propel the chair by pushing the glove against a rotating rail which is attached to the wheel to drive the wheelchair forward. There has been a recent movement towards developing customisable gloves using 3D scanning technique, however, currently there are no commercial offerings which allow for product customisation without being prohibitively expensive. The aim of this project, therefore, was to develop a scalable method for producing customised wheelchair racing gloves in a cost-effective way. The generated 3D forms were 3D printed in a variety of infill densities and finished with a grip liner. These 3D printed gloves were compared in terms of fit and perception of performance, and for their mass, cost and energy/power cost. The 3D printed gloves provided a substantially reduced mass with only a minimal reduction in overall strength at a comparable cost to the solid equivalent.

In this study, we outline and critically evaluate an approach to setting and assessing group design projects that has been used with relative success on an undergraduate product design degree for approximately 10 years. Firstly, we carried out a comprehen

Steel, being the most commonly used bicycle frame material, has a major role to play in future developments within the bicycle industry, and there is scope to enhance the role of engineering in the development of steel bicycles. This paper introduces The Steel Bicycle Project (TSBP), an open-ended project which aims to raise awareness of engineering principles that relate to steel bicycle frames and aims to support frame builders in designing and fabricating better and safer products. In this paper, we give details of the main project themes (Design and simulation, Materials and fabrication, Testing and measurements, Knowledge and education) and outcomes. We also present some initial activities from the early stages of the project and will discuss general models to bring together key partners under the umbrella of the sports engineering community.

The practice of road cycling is often associated with low levels of comfort for the cyclist and can be a physically painful experience on bad roads. Apart from cushioning in the saddle, applying handlebar tape, or reducing tyre pressure, a road bicycle offers in itself few options for comfort improvement, as it is primarily designed for performance, with emphasis on low mass and high stiffness. However, a range of components exist (e.g., suspension stems and seatposts) that can be fitted to a road bicycle, which can potentially improve comfort. In this context, the aim of this study was to assess the effectiveness of suspension stems in reducing the vibration transmitted to a cyclist’s hands in the case of impact loading. The results showed an important reduction in the vibrational energy transmitted to a cyclist’s hands with two commercially available suspension stems compared to a regular stem.

In this study, we aim to critically evaluate the process, comparability and benefits of self, peer and tutor marking in a first year design project. Students were required to undertake a series of week-long design projects culminating in a range of separa

3D-printing of conductive carbon materials in sensing applications and energy storage devices has significant potential, however high resistivity of 3D-printed filaments poses a challenge. Strategies to enhance sensors post printing are time consuming and can reduce structural integrity. In this work, we investigated the effects different printing layer thickness and orientation can have on the electron transfer kinetics and resistivity of conductive materials. The response of these electrodes was investigated by cyclic voltammetry, electrochemical impedance spectroscopy and imaging. Electrodes printed with the lowest layer thickness of 0.1 mm in a vertical orientation had the greatest conductivity. With increasing print layer thickness and printing in a horizontal orientation, the electrode was more resistive. This work is the first to demonstrate the significant impact 3D-printing parameters can have on the electron transfer kinetics of carbon conductive electrodes. The implications of this study are important in defining the manufacturing process of electrodes for all applications. (C) 2020 Elsevier Ltd. All rights reserved.

Objective: In previous research the use of hydrostatic pressure (HP) has been applied to enhance the formation of engineered cartilage, through the up-regulation of proteoglycan synthesis by mechanotransduction. However, the HP stimulation approach has been shown to vary between studies with a wide disparity in results, including anabolic, catabolic and non-responsive outcomes. To this end, a meta-analysis of HP publications using 3D cultured chondrocytes was performed to elucidate the key experiment factors involved in achieving a mechanotransducive response. Design: The effects of different HP regimes on proteoglycan production were investigated based on the following factors: static vs dynamic application, pressure magnitude, and experiment duration. Meta-analysis was performed on raw data taken from 11 publications which employed either aggrecan gene expression analysis or dimethyl methylene blue colorimetric assay. The measure of effect was calculated based on mean difference using a random effects model. Results: Analysis revealed that a significant anabolic response was most likely achieved when the following factors were employed; a static HP application, a magnitude within the mid-high physiological range of cartilage (<= 5-10 MPa) and a study duration of >= 2 weeks. Conclusions: Thus, we propose that the selection of HP experiment factors can have a significant influence on engineered cartilage development, and that the results of this meta-analysis can be used as a basis for the planning of future HP experiments. (c) 2020 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

For both the incorporation of cells and future therapeutic applications the sterility of a biomaterial must be ensured. However, common sterilisation techniques are intense and often negatively impact on material physicochemical attributes, which can affect its suitability for tissue engineering and 3D printing. In the present study four sterilisation methods, autoclave, supercritical CO2 (scCO2) treatment, UV- and gamma (γ) irradiation were evaluated regarding their impact on material properties and cellular responses. The investigations were performed on methyl cellulose (MC) as a component of an alginate/methyl cellulose (alg/MC) bioink, used for bioprinting embedded bovine primary chondrocytes (BPCs). In contrast to the autoclave, scCO2 and UV-treatments, the γ-irradiated MC resulted in a strong reduction in alg/MC viscosity and stability after extrusion which made this method unsuitable for precise bioprinting. Gel permeation chromatography analysis revealed a significant reduction in MC molecular mass only after γ-irradiation, which influenced MC chain mobility in the Ca2+-crosslinked alginate network as well as gel composition and microstructure. With regard to cell survival and proteoglycan matrix production, the results determined UV-irradiation and autoclaving as the best candidates for sterilisation. The scCO2-treatment of MC resulted in an unfavourable cell response indicating that this method needs careful optimisation prior to application for cell encapsulation. As proven by consistent FT-IR spectra, chemical alterations could be excluded as a cause for the differences seen between MC treatments on alg/MC behaviour. This investigation provides knowledge for the development of a clinically appropriate 3D-printing-based fabrication process to produce bioengineered tissue for cartilage regeneration.

Serotonin (5-HT) is a key signalling molecule within the mucosal epithelium of the intestinal wall and has been shown to be an important modulator of motility. At present no single approach has been established for simultaneous dual measurement of 5-HT overflow and circular muscle contraction. We have developed a 3D printed carbon black / polylactic acid (PLA) electrochemical sensor, which had a geometry suitable for ex vivo measurement in the anorectum. The device was characterised for sensitivity and stability for 5-HT measurements as well as suitability for accurate tracking of anorectal contractions. The 3D printed electrochemical sensor had a linear range in physiological concentrations of 5-HT (1 - 10 µM) present within the intestinal tract and a limit of detection of 540 nM. The sensor was stable for 5-HT measurement following ex vivo tissue measurements. There was a signficant correlation in the amplitude and duration of individual contractions when comparing the measurements using an isometric force transducer and 3D printed electrochemical sensor. Finally, in the presence of 1 µM fluoxetine, the sensor was able to monitor a reduction in contractility as well as an increase in 5-HT overflow as predicted. Overall the 3D printed sensor has the ability to conduct dual simultaneous measurements of 5-HT overflow and contractility. This single device will have significant potential for clinical measurements of anorectum function and signalling, that can direct therapeutic management of patients with bowel disorders.

The objective of this work was to assess the effectiveness of cycling gloves and handlebar tape in reducing the vibration transmitted to the cyclist’s hands in the classic “hoods” position for shock-type excitation at the front wheel on a bicycle treadmill. Three pairs of conditions were tested on a single participant: (1) With gloves vs. no gloves, no bar tape; (2) With bar tape vs. no bar tape, no gloves; (3) With gloves and bar tape vs. no gloves and no bar tape. We have shown that a rider can expect a small but significant drop in the level of transmitted power and energy through the handlebars when wearing a standard pair of road cycling gloves. If bar tape is used however (both with and without gloves), there is a significantly larger drop in the level of transmitted power and energy through the handlebars.

Additive manufacturing also known as 3D printing is being utilised in electrochemistry to reproducibly develop complex geometries with conductive properties. In this study, we explored if the electrochemical behavior of 3D printed acrylonitrile butadiene styrene (ABS)/carbon black electrodes was influenced by printing direction. The electrodes were printed in both horizontal and vertical directions. The horizsontal direction resulted in a smooth surface (HPSS electrode) and a comparatively rougher surface (HPRS electrode) surface. Electrodes were characterized using cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry. For various redox couples, the vertical printed (VP) electrode showed enhanced current response when compared the two electrode surfaces generated by horizontal print direction. No differences in the capacitive response was observed, indicating that the conductive surface area of all types of electrodes were identical. The VP electrode had reduced charge transfer resistance and uncompensated solution resistance when compared to the HPSS and HPRS electrodes. Overall, electrodes printed in a vertical direction provide enhanced electrochemical performance and our study indicates that print orientation is a key factor that can be used to enhance sensor performance.

Previous studies have shown how finite element analysis (FEA) can be used to support designers and frame builders in the selection of butted tubes to tune the stiffness and strength behaviour of steel bicycles. The aim of this paper was therefore to analyse the effects of tube butting on the stiffness, stress distribution and energy absorption behaviour of bicycle frames using numerical simulations. Butted tubes were shown to provide a highly effective means to decrease mass whilst producing a disproportionately small change in stress compared with a straight gauge tubeset with a maximum material condition although there was no added benefit in terms of stiffness or strain energy. Conversely, decreasing the wall thickness produced an increase in stress at the tube ends that was disproportionate to the change in mass. This work can now be extended to analyse a fuller set of butted profiles for a range of tube types.

The activity of the colon is regulated by chemical signaling, of which serotonin (5-HT) is a key transmitter. Monitoring of mucosal 5-HT overflow has been achieved to date using microelectrodes on a small segment of colonic tissue; however, little is known if such measurements are reflective with regards to 5-HT signaling from the entire colon. This study focused on developing an electrochemical array device that could be utilized to conduct multisite measurements of 5-HT overflow from the entire colon. A 3D printed mold was fabricated that could house 6 multiwall carbon nanotube composite electrodes and provide a fixed distance between the electrodes and the tissue along the entire length of the colon. The electrodes were assessed for sensitivity, stability, and crosstalk before conducting in vitro measurements using colons obtained from 6- and 24-month old mice. As composite electrodes can have a high degree of variability, normalization factors were required between electrodes for a given array. The device had the sensitivity and stability required for 5-HT measurements from intestinal tissue. Regio-specific changes in 5-HT overflow were observed with age, where increases in 5-HT overflow were observed in the distal colon due to an impairment/loss in the serotonin transporter (SERT). Our strategy can be utilized to develop arrays of varying sizes and geometries, which can offer practical solutions for large-scale tissue measurements.

MRI-informed Biomimetic Design of Artificial Intervertebral Disc Scaffolds using 3D Bioplotting

Understanding the three‐dimensional (3D) nature of the human form is imperative for effective medical practice and the emergence of 3D printing creates numerous opportunities to enhance aspects of medical and healthcare training. A recently deceased, un‐embalmed donor was scanned through high‐resolution computed tomography. The scan data underwent segmentation and post‐processing and a range of 3D‐printed anatomical models were produced. A four‐stage mixed‐methods study was conducted to evaluate the educational value of the models in a medical program. (1) A quantitative pre/post‐test to assess change in learner knowledge following 3D‐printed model usage in a small group tutorial; (2) student focus group (3) a qualitative student questionnaire regarding personal student model usage (4) teaching faculty evaluation. The use of 3D‐printed models in small‐group anatomy teaching session resulted in a significant increase in knowledge (P = 0.0001) when compared to didactic 2D‐image based teaching methods. Student focus groups yielded six key themes regarding the use of 3D‐printed anatomical models: model properties, teaching integration, resource integration, assessment, clinical imaging, and pathology and anatomical variation. Questionnaires detailed how students used the models in the home environment and integrated them with anatomical learning resources such as textbooks and anatomy lectures. In conclusion, 3D‐printed anatomical models can be successfully produced from the CT data set of a recently deceased donor. These models can be used in anatomy education as a teaching tool in their own right, as well as a method for augmenting the curriculum and complementing established learning modalities, such as dissection‐based teaching. Anat Sci Educ 11: 44–53. © 2017 American Association of Anatomists.

This paper outlines the use of a finite element model to simulate the behaviour for a standard steel bicycle frames under a range of measured load cases. These load cases include those measured both in the laboratory setting and also in the field, and include loads transmitted at key areas such as the dropouts and hub, the bottom bracket and drive, the headset and handlebars, and the seat post and saddle. The load cases analysed include static representations of dynamic bump situations which occur sporadically and also those which occur constantly or regularly such as those generated at the drive and handlebars during climbing or cruising. The resulting stresses within the bicycle are analysed in the context of frame performance relating to static and fatigue strengths and are also compared to similar load cases presented in the literature. Further research is required to understand the influence of tube profiles on frame strength, and to analyse the modes of failure for various bicycle designs and materials used under typical and extreme usage in order to understand the implications of design on safety.

This study presents a theoretical contribution on mid-air interface design. With the technological development of devices able to interpret gestures made by hands and arms as Kinect and Leap Motion, designers and developers might think beyond the traditional mouse and keyboard input. However, these interfaces that supposedly aim to be more natural and intuitive have found barriers to its acceptance by users and researchers, partly due to a lack of understanding of the variables involved in the project, as well as the lack of existing standards. This article aims to bring insight into the translation and understanding of these interfaces as language, establishing a communication process based on the following principles: (1) an understanding of Mid-air interfaces and its concept, (2) an analysis of the different ways to interact, (3) an understanding of native and intuitiveness of gestures and (4) generating insights for mid-air interface standards.