Walking the Ancient Tea Horse Road: The Rise of the Outdoors and China’s First Long Distance Branded Hiking Trail

Having made the transition from a life-time acquired skill to something acquired by the casual tourist through a professional operator, outdoor ‘adventure’ tourism is now one of the fastest growing sectors. After having experienced the initial stages of the development of mass tourism, the tourism market in China is undergoing a period of significant diversification in which outdoor adventure tourism in the form of hiking is also a key growth area. In China the hikers, known as ‘donkey friends’, are growing in numbers and exploring new destinations to engage in short and long distance treks. As a result, whilst outdoor adventure tourism presents itself as a valuable opportunity, its development is constrained by the lack of adequate planning, management and infrastructure, and by the potential negative impacts of overcapacity on fragile ecosystems. In this paper we argue that the Ancient Tea Horse Road (ATHR) – a series of ancient trade and administrative networks criss-crossing Southwest China – could prove to be an excellent foundation for creating a world class hiking infrastructure and a hiking trail that as a brand could attract many domestic and international hikers. It is also a tool for ‘thinking out loud’ the challenges and opportunities that such a proposal presents in the Chinese context thereby giving insights into broader trends in outdoor tourism

Recycled PETg embedded with graphene, multi-walled carbon nanotubes and carbon black for high-performance conductive additive manufacturing feedstock

The first report of conductive recycled polyethylene terephthalate glycol (rPETg) for additive manufacturing and electrochemical applications is reported herein. Graphene nanoplatelets (GNP), multi-walled carbon nanotubes (MWCNT) and carbon black (CB) were embedded within a recycled feedstock to produce a filament with lower resistance than commercially available conductive polylactic acid (PLA). In addition to electrical conductivity, the rPETg was able to hold >10 wt% more conductive filler without the use of a plasticiser, showed enhanced temperature stability, had a higher modulus, improved chemical resistance, lowered levels of solution ingress, and could be sterilised in ethanol. Using a mix of carbon materials CB/MWCNT/GNP (25/2.5/2.5 wt%) the electrochemical performance of the rPETg filament was significantly enhanced, providing a heterogenous electrochemical rate constant, k0, equating to 0.88 (±0.01) × 10−3 cm s−1 compared to 0.46 (±0.02) × 10−3 cm s−1 for commercial conductive PLA. This work presents a paradigm shift within the use of additive manufacturing and electrochemistry, allowing the production of electrodes with enhanced electrical, chemical and mechanical properties, whilst improving the sustainability of the production through the use of recycled feedstock

Mitigating Gender Bias in Machine Learning Data Sets

Artificial Intelligence has the capacity to amplify and perpetuate societal biases and presents profound ethical implications for society. Gender bias has been identified in the context of employment advertising and recruitment tools, due to their reliance on underlying language processing and recommendation algorithms. Attempts to address such issues have involved testing learned associations, integrating concepts of fairness to machine learning and performing more rigorous analysis of training data. Mitigating bias when algorithms are trained on textual data is particularly challenging given the complex way gender ideology is embedded in language. This paper proposes a framework for the identification of gender bias in training data for machine learning.The work draws upon gender theory and sociolinguistics to systematically indicate levels of bias in textual training data and associated neural word embedding models, thus highlighting pathways for both removing bias from training data and critically assessing its impact.Comment: 10 pages, 5 figures, 5 Tables, Presented as Bias2020 workshop (as part of the ECIR Conference) - http://bias.disim.univaq.i

Electroanalytical point-of-care detection of gold standard and emerging cardiac biomarkers for stratification and monitoring in intensive care medicine - a review

Determination of specific cardiac biomarkers (CBs) during the diagnosis and management of adverse cardiovascular events such as acute myocardial infarction (AMI) has become commonplace in emergency department (ED), cardiology and many other ward settings. Cardiac troponins (cTnT and cTnI) and natriuretic peptides (BNP and NT-pro-BNP) are the preferred biomarkers in clinical practice for the diagnostic workup of AMI, acute coronary syndrome (ACS) and other types of myocardial ischaemia and heart failure (HF), while the roles and possible clinical applications of several other potential biomarkers continue to be evaluated and are the subject of several comprehensive reviews. The requirement for rapid, repeated testing of a small number of CBs in ED and cardiology patients has led to the development of point-of-care (PoC) technology to circumvent the need for remote and lengthy testing procedures in the hospital pathology laboratories. Electroanalytical sensing platforms have the potential to meet these requirements. This review aims firstly to reflect on the potential benefits of rapid CB testing in critically ill patients, a very distinct cohort of patients with deranged baseline levels of CBs. We summarise their source and clinical relevance and are the first to report the required analytical ranges for such technology to be of value in this patient cohort. Secondly, we review the current electrochemical approaches, including its sub-variants such as photoelectrochemical and electrochemiluminescence, for the determination of important CBs highlighting the various strategies used, namely the use of micro- and nanomaterials, to maximise the sensitivities and selectivities of such approaches. Finally, we consider the challenges that must be overcome to allow for the commercialisation of this technology and transition into intensive care medicine. Graphical abstract: [Figure not available: see fulltext.

Adjusting the connection length of additively manufactured electrodes changes the electrochemical and electroanalytical performance

Changing the connection length of an additively manufactured electrode (AME) has a significant impact on the electrochemical and electroanalytical response of the system. In the literature, many electrochemical platforms have been produced using additive manufacturing with great variations in how the AME itself is described. It is seen that when measuring the near-ideal outer-sphere redox probe hexaamineruthenium (III) chloride (RuHex), decreasing the AME connection length enhances the heterogeneous electrochemical transfer (HET) rate constant ((Formula presented.)) for the system. At slow scan rates, there is a clear change in the peak-to-peak separation (ΔEp) observed in the RuHex voltammograms, with the ΔEp shifting from 118 ± 5 mV to 291 ± 27 mV for the 10 and 100 mm electrodes, respectively. For the electroanalytical determination of dopamine, no significant difference is noticed at low concentrations between 10- and 100-mm connection length AMEs. However, at concentrations of 1 mM dopamine, the peak oxidation is shifted to significantly higher potentials as the AME connection length is increased, with a shift of 150 mV measured. It is recommended that in future work, all AME dimensions, not just the working electrode head size, is reported along with the resistance measured through electrochemical impedance spectroscopy to allow for appropriate comparisons with other reports in the literature. To produce the best additively manufactured electrochemical systems in the future, researchers should endeavor to use the shortest AME connection lengths that are viable for their designs

Utilising bio-based plasticiser castor oil and recycled PLA for the production of conductive additive manufacturing feedstock and detection of bisphenol A

The production of electrically conductive additive manufacturing feedstocks from recycled poly(lactic acid) (rPLA), carbon black (CB), and bio-based plasticiser castor oil is reported herein. The filament was used to print additively manufactured electrodes (AMEs), which were electrochemically benchmarked against geometrically identical AMEs printed from a commercially available conductive filament. The castor oil/rPLA AMEs produced an enhanced heterogeneous electrochemical rate constant of (1.71 ± 0.22) × 10−3 cm s−1 compared to (0.30 ± 0.03) × 10−3 cm s−1 for the commercial AME, highlighting the improved performance of this filament for the production of working electrodes. A bespoke electroanalytical cell was designed and utilised to detect bisphenol A (BPA). The AMEs made from the castor oil/rPLA gave an enhanced electroanalytical performance compared to the commercial filament, producing a sensitivity of 0.59 μA μM−1, a LOD of 0.10 μM and LOQ of 0.34 μM. This system was then successfully applied to detect BPA in spiked bottled and tap water samples, producing recoveries between 89-104%. This work shows how the production of conductive filaments may be done more sustainably while improving performance

Additive manufacturing of a portable electrochemical sensor with a recycled conductive filament for the detection of atropine in spiked drink samples

Additive manufacturing (three-dimensional (3D) printing) has promising features for fast prototyping electrochemical systems, from cells to sensors. Conductive filaments containing carbon black and poly(lactic acid) (CB/PLA) for electrode fabrication are commercially available but usually rely on low carbon content, resulting in poor electrochemical properties. Filament fabrication can be done within the laboratory by exploring different materials according to the desired applications. In this work, recycled PLA was used as the thermoplastic base polymer, alongside CB as the conductive filler, and tris (2-ethylhexyl) trimellitate was introduced into the filament matrix as a plasticizer (CB/PLA/TTM) to fabricate additively manufactured electrodes (AMEs). This enhanced the electrochemical properties toward different redox probes and the forensic target atropine. Thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize the filament and AMEs before and after activation. Additive manufacturing has also been used to develop different cell configurations, which is equally important for good electroanalytical performance. Flow analytical techniques, such as batch-injection analysis (BIA), can be used as an alternative to stationary measurements to enhancing sensitivity and detection limits (LOD) via increasing the mass transport of analytes to the electrochemical platform surface, providing automation and high sample throughput. In this context, we developed a compact (∼5 mL capacity) and versatile additively manufactured BIA cell that can either perform static or hydrodynamic analyses by simply placing a lid on the device with a hole for the BIA pipette tip. Moreover, knowing that forensic chemistry necessitates portable analytical tools to help police investigation at the crime scene, the AM-BIA cell and the bespoke AMEs were coupled to a portable electrochemical apparatus for on-site atropine analysis in adulterated beverage samples. Atropine determination was performed by differential pulse voltammetry (DPV) and amperometry (BIA-AMP) in the same cell, presenting good repeatability for both methods (6% RSD). As expected, the BIA-AMP method showed higher sensitivity (0.0783 μA μM–1) and lower LOD (0.51 μM) compared to the stationary DPV method (sensitivity: 0.0148 μA μmol–1 L; LOD: 2.60 μM); they both presented good recovery values, varying from 102 to 109% for two spiked samples of gin and whisky. Thus, the versatility and portability of the developed AM-BIA cell coupled with the bespoke filament CB/PLA/TTM allow for rapid and accurate screening and quantification of atropine in real forensic scenarios

Recycled additive manufacturing feedstocks for fabricating high voltage, low-cost aqueous supercapacitors

The first recycled conductive poly(lactic acid) (PLA) filament derived from post-industrial waste sources for additive manufacturing (AM) is reported herein, presenting a paradigm shift in plastic waste recycling, AM filament production, and AM energy storage architectures. Filaments utilizing a base of recycled PLA, carbon black (CB) as a conductive filler, and polyethylene glycol (PEG) as a plasticizer are used to produce aqueous AM symmetric supercapacitor platforms that can reach capacitance values 75 times higher than commercially available conductive PLA filaments. Furthermore, through the rapid prototyping capabilities of AM and GCode modification, it is seen that changing the electrode architecture from solid to a mesh with additional inter-layer spacing is able to further enhance electrode performance by 3.5 times due to improvements in the surface area, ion accommodating capabilities and faster ion diffusion. The symmetric full cell device is capable of delivering 7.82 mF cm−2, 4.82 µWh cm−2, and 433.32 µW cm−2 of capacitance, energy, and power density, respectively. Moreover, the material cost is £0.15 per electrode. This work represents a new direction for plastic waste recycling, in which low-value recycled base products can be manufactured into high-value end products in their second cycles

Circular economy electrochemistry: recycling old mixed material additively manufactured sensors into new electroanalytical sensing platforms

Recycling used mixed material additively manufactured electroanalytical sensors into new 3D-printing filaments (both conductive and non-conductive) for the production of new sensors is reported herein. Additively manufactured (3D-printed) sensing platforms were transformed into a non-conductive filament for fused filament fabrication through four different methodologies (granulation, ball-milling, solvent mixing, and thermal mixing) with thermal mixing producing the best quality filament, as evidenced by the improved dispersion of fillers throughout the composite. Utilizing this thermal mixing methodology, and without supplementation with the virgin polymer, the filament was able to be cycled twice before failure. This was then used to process old sensors into an electrically conductive filament through the addition of carbon black into the thermal mixing process. Both recycled filaments (conductive and non-conductive) were utilized to produce a new electroanalytical sensing platform, which was tested for the cell's original application of acetaminophen determination. The fully recycled cell matched the electrochemical and electroanalytical performance of the original sensing platform, achieving a sensitivity of 22.4 ± 0.2 μA μM-1, a limit of detection of 3.2 ± 0.8 μM, and a recovery value of 95 ± 5% when tested using a real pharmaceutical sample. This study represents a paradigm shift in how sustainability and recycling can be utilized within additively manufactured electrochemistry toward promoting circular economy electrochemistry

Circular economy electrochemistry: creating additive manufacturing feedstocks for caffeine detection from post-industrial coffee pod waste

The recycling of post-industrial waste poly(lactic acid) (PI-PLA) from coffee machine pods into electroanalytical sensors for the detection of caffeine in real tea and coffee samples is reported herein. The PI-PLA is transformed into both nonconductive and conductive filaments to produce full electroanalytical cells, including additively manufactured electrodes (AMEs). The electroanalytical cell was designed utilizing separate prints for the cell body and electrodes to increase the recyclability of the system. The cell body made from nonconductive filament was able to be recycled three times before the feedstock-induced print failure. Three bespoke formulations of conductive filament were produced, with the PI-PLA (61.62 wt %), carbon black (CB, 29.60 wt %), and poly(ethylene succinate) (PES, 8.78 wt %) chosen as the most suitable for use due to its equivalent electrochemical performance, lower material cost, and improved thermal stability compared to the filaments with higher PES loading and ability to be printable. It was shown that this system could detect caffeine with a sensitivity of 0.055 ± 0.001 μA μM–1, a limit of detection of 0.23 μM, a limit of quantification of 0.76 μM, and a relative standard deviation of 3.14% after activation. Interestingly, the nonactivated 8.78% PES electrodes produced significantly better results in this regard than the activated commercial filament toward the detection of caffeine. The activated 8.78% PES electrode was shown to be able to detect the caffeine content in real and spiked Earl Grey tea and Arabica coffee samples with excellent recoveries (96.7–102%). This work reports a paradigm shift in the way AM, electrochemical research, and sustainability can synergize and feed into part of a circular economy, akin to a circular economy electrochemistry