Belousov-Zhabotinsky liquid marbles in robot control

© 2019 Elsevier B.V. We show how to control the movement of a wheeled robot using on-board liquid marbles made of Belousov-Zhabotinsky solution droplets coated with polyethylene powder. Two stainless steel, iridium coated electrodes were inserted in a marble and the electrical potential recorded was used to control the robot's motor. We stimulated the marble with a laser beam. It responded to the stimulation by pronounced changes in the electrical potential output. The electrical output was detected by the robot. The robot changed its trajectory in response to the stimulation. The results open new horizons for applications using oscillatory chemical reactions in robotics

Evaporation, lifetime, and robustness studies of liquid marbles for collision-based computing

© 2018 American Chemical Society. Liquid marbles (LMs) have recently attracted interest for use as cargo carriers in digital microfluidics and have successfully been implemented as signal carriers in collision-based unconventional computing circuits. Both application domains require LMs to roll over substantial distances and to survive a certain number of collisions without degrading. To evaluate the lifetime of LMs being subjected to movement and impact stresses, we have selected four types of coating to investigate: polytetrafluoroethylene (PTFE), ultrahigh density polyethylene (PE), Ni, and a mixture of Ni with PE (Ni-PE). Hierarchies of robustness have been constructed which showed that pure PE LMs survived the longest when stationary and in motion. Pure PTFE LMs were shown to be the least resilient to multiple impacts. The PTFE coating provided minimal protection against evaporative losses for small LM volumes (2 and 5 μL) however, larger LMs (10 μL) were shown to have good evaporative stabilities when stationary. Conversely, PE LMs showed a remarkable ability to withstand multiple impacts and were also stable when considering just passive evaporation. Hybrid Ni-PE LMs exhibited more resilience to multiple impacts compared to Ni LMs. Thus, when designing LM devices, it is paramount to determine impact pathways and select appropriate coating materials

Neuromorphic liquid marbles with aqueous carbon nanotube cores

Neuromorphic computing devices attempt to emulate features of biological nervous systems through mimicking the properties of synapses, towards implementing the emergent properties of their counterparts, such as learning. Inspired by recent advances in the utilisation of liquid marbles (microlitre quantities of fluid coated in hydrophobic powder) for the creation of unconventional computing devices, we describe the development of liquid marbles with neuromorphic properties through the use of copper coatings and l.0mgml-1 carbon nanotube-containing fluid cores. Experimentation was performed through sandwiching the marbles between two cup-style electrodes and stimulating them with repeated DC pulses at 3.0 V. Our results demonstrate that 'entrainment∗ of a carbon nanotube filled-copper liquid marble via periodic pulses can cause their electrical resistance to rapidly switch between high to low resistance profiles, upon inverting the polarity of stimulation: The reduction in resistance between high and low profiles was approximately 88% after two rounds of entrainment. This effect was found to be reversible through reversion to the original stimulus polarity and was strengthened by repeated experimentation, as evidenced by a mean reduction in time to switching onset of 43%. These effects were not replicated in nanotube solutions not bound inside liquid marbles. Our electrical characterisation also reveals that nanotube-filled liquid marbles exhibit pinched loop hysteresis IV profiles consistent with the description of memristors. We conclude by discussing the applications of this technology to the development of unconventional computing devices and the study of emergent characteristics in biological neural tissue

Mapping outcomes of liquid marble collisions

© 2019 The Royal Society of Chemistry. Liquid marbles (LMs) have many promising roles in the ongoing development of microfluidics, microreactors, bioreactors, and unconventional computing. In many of these applications, the coalescence of two LMs is either required or actively discouraged, therefore it is important to study liquid marble collisions and establish parameters which enable the desired collision outcome. Recent reports on LM coalescence have focused on either two mobile LMs colliding, or an accelerating LM hitting a sessile LM with a backstop. A further possible scenario is the impact of a mobile LM against a non-supported static LM. This paper investigates such a collision, using high-speed videography for single-frame analysis. Multiple collisions were undertaken whilst varying the modified Weber number (We∗) and offset ratios (X∗). Parameter ranges of 1.0 0.25, and We∗ 1.55 resulted in 100% non-coalescence. Additionally, observations of LMs moving above a threshold velocity of 0.6 m s -1 have revealed a new and unusual deformation. Comparisons of the outcome of collisions whilst varying both the LM volume and the powder grain size have also been made, revealing a strong link. The results of this work provide a deeper understanding of LM coalescence, allowing improved control when designing future collision experiments

A study of human resource competencies required to implement community rehabilitation in less resourced settings.

BACKGROUND: It is estimated that over one billion persons worldwide have some form of disability. However, there is lack of knowledge and prioritisation of how to serve the needs and provide opportunities for people with disabilities. The community-based rehabilitation (CBR) guidelines, with sufficient and sustained support, can assist in providing access to rehabilitation services, especially in less resourced settings with low resources for rehabilitation. In line with strengthening the implementation of the health-related CBR guidelines, this study aimed to determine what workforce characteristics at the community level enable quality rehabilitation services, with a focus primarily on less resourced settings. METHODOLOGY: This was a two-phase review study using (1) a relevant literature review informed by realist synthesis methodology and (2) Delphi survey of the opinions of relevant stakeholders regarding the findings of the review. It focused on individuals (health professionals, lay health workers, community rehabilitation workers) providing services for persons with disabilities in less resourced settings. RESULTS: Thirty-three articles were included in this review. Three Delphi iterations with 19 participants were completed. Taken together, these produced 33 recommendations for developing health-related rehabilitation services. Several general principles for configuring the community rehabilitation workforce emerged: community-based initiatives can allow services to reach more vulnerable populations; the need for supportive and structured supervision at the facility level; core skills likely include case management, social protection, monitoring and record keeping, counselling skills and mechanisms for referral; community ownership; training in CBR matrix and advocacy; a tiered/teamwork system of service delivery; and training should take a rights-based approach, include practical components, and involve persons with disabilities in the delivery and planning. CONCLUSION: This research can contribute to implementing the WHO guidelines on the interaction between the health sector and CBR, particularly in the context of the Framework for Action for Strengthening Health Systems, in which human resources is one of six components. Realist syntheses can provide policy makers with detailed and practical information regarding complex health interventions, which may be valuable when planning and implementing programmes

Crisis resolution and home treatment: stakeholders\u27 views on critical ingredients and implementation in England

BACKGROUND: Crisis resolution teams (CRTs) can provide effective home-based treatment for acute mental health crises, although critical ingredients of the model have not been clearly identified, and implementation has been inconsistent. In order to inform development of a more highly specified CRT model that meets service users\u27 needs, this study used qualitative methods to investigate stakeholders\u27 experiences and views of CRTs, and what is important in good quality home-based crisis care. METHOD: Semi-structured interviews and focus groups were conducted with service users (n = 41), carers (n = 20) and practitioners (CRT staff, managers and referrers; n = 147, 26 focus groups, 9 interviews) in 10 mental health catchment areas in England, and with international CRT developers (n = 11). Data were analysed using thematic analysis. RESULTS: Three domains salient to views about optimal care were identified. 1. The organisation of CRT care: Providing a rapid initial responses, and frequent home visits from the same staff were seen as central to good care, particularly by service users and carers. Being accessible, reliable, and having some flexibility were also valued. Negative experiences of some referral pathways, and particularly lack of staff continuity were identified as problematic. 2. The content of CRT work: Emotional support was at the centre of service users\u27 experiences. All stakeholder groups thought CRTs should involve the whole family, and offer a range of interventions. However, carers often feel excluded, and medication is often prioritised over other forms of support. 3. The role of CRTs within the care system: Gate-keeping admissions is seen as a key role for CRTs within the acute care system. Service users and carers report that recovery is quicker compared to in-patient care. Lack of knowledge and misunderstandings about CRTs among referrers are common. Overall, levels of stakeholder agreement about the critical ingredients of good crisis care were high, although aspects of this were not always seen as achievable. CONCLUSIONS: Stakeholders\u27 views about optimal CRT care suggest that staff continuity, carer involvement, and emotional and practical support should be prioritised in service improvements and more clearly specified CRT models

Liquid marble interaction gate for collision-based computing

© 2017 Elsevier Ltd Liquid marbles are microliter droplets of liquid, encapsulated by self-organized hydrophobic particles at the liquid/air interface. They offer an efficient approach for manipulating liquid droplets and compartmentalizing reactions in droplets. Digital fluidic devices employing liquid marbles might benefit from having embedded computing circuits without electronics and moving mechanical parts (apart from the marbles). We present an experimental implementation of a collision gate with liquid marbles. Mechanics of the gate follows principles of Margolus’ soft-sphere collision gate. Boolean values of the inputs are given by the absence (FALSE) or presence (TRUE) of a liquid marble. There are three outputs: two outputs are trajectories of undisturbed marbles (they only report TRUE when just one marble is present at one of the inputs), one output is represented by trajectories of colliding marbles (when two marbles collide they lose their horizontal momentum and fall), this output reports TRUE only when two marbles are present at inputs. Thus the gate implements AND and AND-NOT logical functions. We speculate that by merging trajectories representing AND-NOT output into a single channel one can produce a one-bit half-adder. Potential design of a one-bit full-adder is discussed, and the synthesis of both a pure nickel metal and a hybrid nickel/polymer liquid marble is reported

The CORE Service Improvement Programme for mental health Crisis Resolution Teams: results from a cluster-randomised trial

Background: Crisis Resolution Teams (CRTs) offer brief, intensive home treatment for people experiencing mental health crisis. CRT implementation is highly variable; positive trial outcomes have not been reproduced in scaled up CRT care. Aims: To evaluate a one-year programme to improve CRTs’ model fidelity in a non-blind, cluster randomised trial. Methods: Fifteen CRTs in England received an intervention, informed by the US Implementing Evidence Based Practice project, involving support from a CRT Facilitator, online implementation resources and regular team fidelity reviews. Ten control CRTs received no additional support. The primary outcome was service user satisfaction, measured by the Client Satisfaction Questionnaire (CSQ-8), completed by fifteen service users per team at CRT discharge (N=375). Secondary outcomes: CRT model fidelity, continuity of care, staff wellbeing, inpatient admissions and bed use and CRT readmissions were also evaluated. Results: All CRTs were retained in the trial. Median follow-up CSQ-8 score was 28 in each group: the adjusted average in the intervention group was higher than in the control group by 0.97 (CI -1.02, 2.97) but this was not significant (p=0.34). There were fewer inpatient admissions, lower inpatient bed use and better staff psychological health in intervention teams. Model fidelity rose in most intervention teams and was significantly higher than in control teams at follow up. There were no significant effects for other outcomes. Conclusions: The CRT Service Improvement Programme did not achieve its primary aim of improving service user satisfaction. It showed some promise in improving CRT model fidelity and reducing acute inpatient admissions

Development of a measure of model fidelity for mental health Crisis Resolution Teams

Background Crisis Resolution Teams (CRTs) provide short-term intensive home treatment to people experiencing mental health crisis. Trial evidence suggests CRTs can be effective at reducing hospital admissions and increasing satisfaction with acute care. When scaled up to national level however, CRT implementation and outcomes have been variable. We aimed to develop and test a fidelity scale to assess adherence to a model of best practice for CRTs, based on best available evidence. Methods A concept mapping process was used to develop a CRT fidelity scale. Participants (n = 68) from a range of stakeholder groups prioritised and grouped statements (n = 72) about important components of the CRT model, generated from a literature review, national survey and qualitative interviews. These data were analysed using Ariadne software and the resultant cluster solution informed item selection for a CRT fidelity scale. Operational criteria and scoring anchor points were developed for each item. The CORE CRT fidelity scale was then piloted in 75 CRTs in the UK to assess the range of scores achieved and feasibility for use in a 1-day fidelity review process. Trained reviewers (n = 16) rated CRT service fidelity in a vignette exercise to test the scale’s inter-rater reliability. Results There were high levels of agreement within and between stakeholder groups regarding the most important components of the CRT model. A 39-item measure of CRT model fidelity was developed. Piloting indicated that the scale was feasible for use to assess CRT model fidelity and had good face validity. The wide range of item scores and total scores across CRT services in the pilot demonstrate the measure can distinguish lower and higher fidelity services. Moderately good inter-rater reliability was found, with an estimated correlation between individual ratings of 0.65 (95% CI: 0.54 to 0.76). Conclusions The CORE CRT Fidelity Scale has been developed through a rigorous and systematic process. Promising initial testing indicates its value in assessing adherence to a model of CRT best practice and to support service improvement monitoring and planning. Further research is required to establish its psychometric properties and international applicability

Randomized factorial trial of esomeprazole and aspirin in Barrett’s oesophagus: the Aspirin and Esomeprazole Chemoprevention in Barrett’s metaplasia Trial (AspECT)

Background: Oesophageal adenocarcinoma (OA) is the sixth commonest cause of cancer death worldwide and Barrett’s oesophagus (BO) is the most significant risk factor. We evaluated the efficacy of high-dose esomeprazole proton pump inhibitor acid suppression (PPI) and aspirin in improving outcome for BO patients in the largest such randomized controlled trial. Methods: Patients with ≥1cm BO in UK and Canadian hospitals were randomized 1:1:1:1 using a computer-generated schedule held in a central trials unit in a 2X2 factorial design to high-dose (40mg twice-daily) or low-dose (20mg once-daily) PPI, alone or with aspirin (UK: 300mg/day, Canada: 325mg/day), unblinded (reporting pathologists blinded). The primary composite endpoint was time to all-cause mortality, OA, or high-grade dysplasia, analysed using accelerated failure time modelling adjusted for minimization factors (age, BO length, intestinal metaplasia). Findings: Recruited patients (N=2557) were followed for 8·9 years (median; interquartile range 8·2–9·8), collecting 20,095 follow-up years and 99·9% of planned data. There were 313 primary events. High-dose PPI was superior to low-dose PPI (p=0·037, N=1265 (low dose), N=1270 (high dose), time ratio (TR)=1·27, 95%CI=1·01–1·58). Aspirin was not significantly better than no aspirin (p=0·068, N=1142 (no aspirin), N = 1138 (aspirin), TR=1·24, 95%CI=0·98–1·57). If patients using NSAIDs were censored at time of first use,aspirin was significantly better than no Aspirin (p=0·043, N=2,236, TR=1·29 95%CI=1·01– 1·66). Combining high-dose PPI with aspirin had the strongest effect compared with low dose PPI without aspirin (p=0·0068, TR=1·59, 95%CI=1·14–2·23). NNT for PPI and aspirin benefit is 34 and 43, respectively. Only 1·0% (28) of participants reported study-treatment related serious adverse events. Interpretation: High-dose PPI and aspirin chemoprevention therapy, especially in combination, significantly and safely improve outcome in BO patients