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1.
J Med Virol ; 96(7): e29774, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38953434

RESUMEN

Factor VIII and IX clotting factor concentrates manufactured from pooled plasma have been identified as potent sources of virus infection in persons with hemophilia (PWHs) in the 1970s and 1980s. To investigate the range and diversity of viruses over this period, we analysed 24 clotting factor concentrates for several blood-borne viruses. Nucleic acid was extracted from 14 commercially produced clotting factors and 10 from nonremunerated donors, preserved in lyophilized form (expiry dates: 1974-1992). Clotting factors were tested by commercial and in-house quantitative PCRs for blood-borne viruses hepatitis A, B, C and E viruses (HAV, HBV, HCV, HEV), HIV- types 1/2, parvoviruses B19V and PARV4, and human pegiviruses types 1 and 2 (HPgV-1,-2). HCV and HPgV-1 were the most frequently detected viruses (both 14/24 tested) primarily in commercial clotting factors, with frequently extremely high viral loads in the late 1970s-1985 and a diverse range of HCV genotypes. Detection frequencies sharply declined following introduction of virus inactivation. HIV-1, HBV, and HAV were less frequently detected (3/24, 1/24, and 1/24 respectively); none were positive for HEV. Contrastingly, B19V and PARV4 were detected throughout the study period, even after introduction of dry heat treatment, consistent with ongoing documented transmission to PWHs into the early 1990s. While hemophilia treatment is now largely based on recombinant factor VIII/IX in the UK and elsewhere, the comprehensive screen of historical plasma-derived clotting factors reveals extensive exposure of PWHs to blood-borne viruses throughout 1970s-early 1990s, and the epidemiological and manufacturing parameters that influenced clotting factor contamination.


Asunto(s)
Factores de Coagulación Sanguínea , Patógenos Transmitidos por la Sangre , Humanos , Patógenos Transmitidos por la Sangre/aislamiento & purificación , Infecciones de Transmisión Sanguínea/epidemiología , Infecciones de Transmisión Sanguínea/virología , Contaminación de Medicamentos , Historia del Siglo XX , Hemofilia A , Virus/clasificación , Virus/aislamiento & purificación , Virus/genética , Reacción en Cadena de la Polimerasa , Factor VIII , Factores de Tiempo
2.
BMC Prim Care ; 25(1): 60, 2024 02 16.
Artículo en Inglés | MEDLINE | ID: mdl-38365606

RESUMEN

BACKGROUND: Physical inactivity is associated with feelings of burnout and fatigue, which in turn are associated with reduced performance among healthcare practitioners. This study explored movement behaviours of general practitioners (GPs) and the association between these behaviours with burnout and fatigue. METHODS: GPs in Northern Ireland were asked to wear a thigh-worn accelerometer for seven days and complete validated questionnaires to assess the association between daily number of steps, time spent sitting and standing with feelings of burnout and fatigue. RESULTS: Valid accelerometer data were obtained from 47 (77.0%) participants. Average workday sitting time, standing time and number of steps were 10.6 h (SD 1.5), 3.8 h (SD 1.3), and 7796 steps (SD 3116) respectively. Participants were less sedentary (8.0 h (SD 1.6)) and more active (4.7 h (SD 1.4) standing time and 12,408 steps (SD 4496)) on non-workdays. Fourteen (30.4%) participants reported burnout and sixteen (34.8%) reported severe fatigue. There were no significant associations between sitting, standing and step counts with burnout or fatigue (p > 0.05). CONCLUSION: GPs were less active on workdays compared to non-workdays and exhibited high levels of sitting. Feelings of burnout and fatigue were highly prevalent, however movement behaviours were not found to be associated with burnout and fatigue. Given the increased sedentariness among GPs on workdays compared to non-workdays, GPs should consider how they can improve their movement behaviours on workdays to help optimise their wellbeing.


Asunto(s)
Médicos Generales , Humanos , Ejercicio Físico , Conducta Sedentaria , Encuestas y Cuestionarios , Agotamiento Psicológico
3.
Biosystems ; 229: 104933, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37257553

RESUMEN

Living fungal mycelium networks are proven to have properties of memristors, capacitors and various sensors. To further progress our designs in fungal electronics we need to evaluate how electrical signals can be propagated through mycelium networks. We investigate the ability of mycelium-bound composites to convey electrical signals, thereby enabling the transmission of frequency-modulated information. Mycelium networks were found to reliably transfer signals with a recoverable frequency comparable to the input, in the 100Hz to 10 000Hz frequency range. Mycelial adaptive responses, such as tissue repair, may result in fragile connections, however. While the mean amplitude of output signals was not reproducible among replicate experiments exposed to the same input frequency, the variance across groups was highly consistent. Our work is supported by NARX modelling through which an approximate transfer function was derived. These findings advance the state of the art of using mycelium-bound composites in analogue electronics and unconventional computing.


Asunto(s)
Hongos , Micelio , Hongos/fisiología
4.
BJGP Open ; 6(3)2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35273006

RESUMEN

BACKGROUND: General practice is a highly sedentary occupation, with many GPs spending more than 10.5 hours sitting each workday. This excessive sedentary behaviour and lack of physical activity (PA) is potentially detrimental to the health of GPs, as well as their ability to counsel patients regarding sedentary behaviour and PA. There is a lack of prior research examining the perspectives of GPs regarding their sedentary behaviour and PA. AIM: To explore GPs' perspectives regarding their sedentary behaviour and PA. DESIGN & SETTING: A qualitative interview study of GPs in Northern Ireland. METHOD: Semi-structured interviews were conducted with a purposive sample of 13 GPs who had previously taken part in a study to objectively measure their levels of sedentary behaviour and PA. Interview transcripts were analysed using deductive thematic analysis. The Theoretical Domains Framework (TDF) was used to facilitate identification of barriers and enablers affecting the ability of GPs to increase their PA. RESULTS: Key themes were categorised within six theoretical domains (environmental context and resources, social professional role and identity, goals, social influences, knowledge, and intentions) with sub-themes within each domain. CONCLUSION: Most GPs are unhappy with their current levels of sedentary behaviour and PA, and are concerned with how this is affecting their health. Numerous barriers and facilitators were identified affecting the ability of GPs to increase their PA, including working environment, and personal and professional responsibilities, among others. Addressing these could improve the health of GPs and their ability to counsel patients regarding sedentary behaviour and PA.

5.
Biosystems ; 212: 104588, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34979157

RESUMEN

Fungal electronics is a family of living electronic devices made of mycelium bound composites or pure mycelium. Fungal electronic devices are capable of changing their impedance and generating spikes of electrical potential in response to external control parameters. Fungal electronics can be embedded into fungal materials and wearables or used as stand alone sensing and computing devices.


Asunto(s)
Electrónica , Hongos , Hongos/fisiología , Micelio
6.
J Biol Eng ; 16(1): 3, 2022 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-34986856

RESUMEN

BACKGROUND: The potential to directly harness photosynthesis to make actuators, biosensors and bioprocessors has been previously demonstrated in the literature. Herein, this capability has been expanded to more advanced systems - Marimo Actuated Rover Systems (MARS) - which are capable of autonomous, solar powered, movement. RESULTS: We demonstrate this ability is both a practical and viable alternative to conventional mobile platforms for exploration and dynamic environmental monitoring. Prototypes have been successfully tested to measure their speed of travel and ability to automatically bypass obstacles. Further, MARS is electromagnetically silent, thus avoiding the background noise generated by conventional electro/mechanical platforms which reduces instrument sensitivity. The cost of MARS is significantly lower than platforms based on conventional technology. CONCLUSIONS: An autonomous, low-cost, lightweight, compact size, photosynthetically powered rover is reported. The potential for further system enhancements are identified and under development.

7.
BJGP Open ; 6(2)2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-34880031

RESUMEN

BACKGROUND: Sedentary behaviour, which may have increased among GPs due to increasing use of telemedicine, is associated with many illnesses and increased all-cause mortality. AIM: To explore levels of sedentary behaviour among GPs and General Practice Specialty Trainees (GPSTs). DESIGN & SETTING: Sequential, cross-sectional design (initial online sedentary behaviour questionnaire and subsequent thigh-worn accelerometer substudy) of GPs and GPSTs in Northern Ireland. METHOD: Self-reported questionnaire data were aggregated and compared with device-measured accelerometry data. RESULTS: Data from 353 participants (17.7% of GPs and GPSTs in Northern Ireland) revealed doctors in general practice self-reported higher workday sedentary time (10.33 hours, SD 2.97) than those in secondary care (7.9 hours, SD 3.43 [mean difference {MD} 2.43 hours; P<0.001]). An active workstation (for example, sit-stand desk), was used by 5.6% of participants in general practice, while 86.0% of those without one would consider using one in future. Active workstation users self-reported lower workday sedentary time (7.88 hours, SD 3.2) than non-users (10.47 hours, SD 2.88 [MD -2.58 hours, P = 0.001]). Accelerometer substudy participants underestimated their workday sedentary time by 0.17 hours (95% confidence interval [CI] = -1.86 to 2.20; P = 0.865), and non-workday sedentary time by 2.67 hours (95% CI = 0.99 to 4.35; P = 0.003). Most GPs (80.7%) reported increased workday sitting time compared to prior to the COVID-19 pandemic, while 87.0% would prefer less workday sitting time. CONCLUSION: GPs have high levels of workday sedentary time, which may be detrimental to their health. It is imperative to develop methods to address sedentary behaviour among GPs on workdays, both for their own health and the health of their patients.

8.
BMC Sports Sci Med Rehabil ; 13(1): 116, 2021 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-34583747

RESUMEN

BACKGROUND: Monitoring technology is increasingly accessible to recreational runners. Our aim was to examine patterns of technology use in recreational runners, and its potential association with injury. METHODS: We conducted a cross-sectional questionnaire study in a sample of adult runners. Recruitment took place at three different 5 km parkrun event across Northern Ireland. Demographics, technology use, running behaviour and running-related injury (RRI) history were examined. Regression analyses were performed to determine relationships between variables. RESULTS: Responses were obtained from 192 of 483 eligible finishers (39.8% response rate). Average age was 45.9 years (SD 10.3), with males (47.1 years SD 9.7) slightly older than females (44.8 years SD 10.8). On average, participants ran 3.0 days per week (SD 1.3), with an average weekly distance of 22.6 km (SD 19.7). Males typically ran further (MD 6.2 km/week; 95% CI 0.4 to 12.0) than females. Monitoring technology was used by 87.4% (153/175); with GPS watches the most common device (87.6% (134/153)). Runners using monitoring technology ran further (MD 14.4 km/week; 95% CI 10.3 to 18.5) and more frequently (MD 1.3 days/week; 95% CI 0.7 to 1.9) than those who did not use monitoring technology. There was no significant difference in average age between runners who used monitoring technology and those who did not (MD 4.0 years; 95% CI -0.7 to 8.7). RRI was reported by 40.6% (71/175) of participants in the previous 12 months. In a univariate analysis, none of the selected predictors (age, number of days run per week, distance run per week, or usage of technology to modify training pattern) (p > 0.1) were associated with RRI. CONCLUSIONS: This study found a high prevalence of monitoring technology usage among recreational runners. While the incidence of RRI remains high, it is not associated with the usage of monitoring technology. Further prospective research should examine if monitoring technology can reduce RRI incidence among recreational runners in future.

9.
ACS Biomater Sci Eng ; 7(8): 3718-3726, 2021 08 09.
Artículo en Inglés | MEDLINE | ID: mdl-34309374

RESUMEN

Fungi cells can sense extracellular signals via reception, transduction, and response mechanisms, allowing them to communicate with their host and adapt to their environment. They feature effective regulatory protein expressions that enhance and regulate their response and adaptation to various triggers such as stress, hormones, physical stimuli such as light, and host factors. In our recent studies, we have shown that Pleurotus oyster fungi generate electrical potential impulses in the form of spike events in response to their exposure to environmental, mechanical, and chemical triggers, suggesting that the nature of stimuli may be deduced from the fungal electrical responses. In this study, we explored the communication protocols of fungi as reporters of human chemical secretions such as hormones, addressing whether fungi can sense human signals. We exposed Pleurotus oyster fungi to hydrocortisone, which was directly applied to the surface of a fungal-colonized hemp shavings substrate, and recorded the electrical activity of the fungi. Hydrocortisone is a medicinal hormone replacement that is similar to the natural stress hormone cortisol. Changes in cortisol levels released by the body indicate the presence of disease and can have a detrimental effect on physiological process regulation. The response of fungi to hydrocortisone was also explored further using X-rays to reveal changes in the fungi tissue, where receiving hydrocortisone by the substrate can inhibit the flow of calcium and, as a result, reduce its physiological changes. This research could open the way for future studies on adaptive fungal wearables capable of detecting human physiological states and biosensors built of living fungi.


Asunto(s)
Pleurotus , Humanos , Hidrocortisona/farmacología
10.
BMC Fam Pract ; 22(1): 6, 2021 01 04.
Artículo en Inglés | MEDLINE | ID: mdl-33397302

RESUMEN

BACKGROUND: Sedentary behaviour is when someone is awake, in a sitting, lying or reclining posture and is an independent risk factor for multiple causes of morbidity and mortality. A dose-response relationship has been demonstrated, whereby increasing sedentary time corresponds with increasing mortality rate. This study aimed to identify current levels of sedentary behaviour among General Practitioners (GPs), by examining and synthesising how sedentary behaviour has been measured in the primary care literature. METHODS: A systematic review was conducted to identify studies relating to levels of sedentary behaviour among GPs. Searches were performed using Medline®, Embase®, PscycINFO, Web of Science and the Cochrane Library, from inception of databases until January 2020, with a subsequent search of grey literature. Articles were assessed for quality and bias, with extraction of relevant data. RESULTS: The search criteria returned 1707 studies. Thirty four full texts were reviewed and 2 studies included in the final review. Both were cross-sectional surveys using self-reported estimation of sedentary time within the International Physical Activity Questionnaire (IPAQ). Keohane et al. examined GP trainees and GP trainers in Ireland. 60% reported spending in excess of 7 h sitting each day, 24% between 4 and 7 h, and 16% less than or equal to 4 h. Suija et al. examined female GPs in Estonia. The mean reported daily sitting time was 6 h and 36 min, with 56% sitting for over 6 h per day. Both studies were of satisfactory methodological quality but had a high risk of bias. CONCLUSION: There is a paucity of research examining current levels of sedentary behaviour among GPs. Objective data is needed to determine GPs' current levels of sedentary behaviour, particularly in light of the increase in remote consulting as a result of the COVID-19 pandemic.


Asunto(s)
COVID-19/psicología , Médicos Generales/psicología , Promoción de la Salud , Pandemias , Conducta Sedentaria , Autoinforme , COVID-19/epidemiología , Humanos , Factores de Riesgo , SARS-CoV-2
11.
Sci Justice ; 60(5): 466-472, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32873386

RESUMEN

Simulated crime scene investigation is an essential component of forensic science education, but its implementation is costly and poses challenges to accessibility; offering personal investigations in higher education scenarios is often impossible. Virtual reality (VR) is an emerging technology which offers exciting prospects for teaching and learning, especially for imparting practical skills. We document here a multidisciplinary experimental study in which a bespoke VR crime scene app was designed and implemented, after which it was tested by both undergraduate student and staff/postgraduate student cohorts. Through both qualitative and quantitative analyses, we demonstrate that VR applications support learning of practical crime scene processing skills. VR-based practical sessions have the potential to add value to forensic science courses, through offering cost-effective practical experience, the ability to work in isolation and in a variety of different scenarios. Both user groups reported high levels of satisfaction with using the app and reports of adverse effects (motion sickness) were minimal. With reference to user feedback, we proceed to evaluate the scalability and development challenges associated with large-scale implementation of VR as an adjunct to forensic science education.


Asunto(s)
Realidad Virtual , Crimen , Ciencias Forenses , Humanos
12.
Biosystems ; 193-194: 104138, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32259561

RESUMEN

A fungal colony maintains its integrity via flow of cytoplasm along mycelium network. This flow, together with possible coordination of mycelium tips propagation, is controlled by calcium waves and associated waves of electrical potential changes. We propose that these excitation waves can be employed to implement a computation in the mycelium networks. We use FitzHugh-Nagumo model to imitate propagation of excitation in a single colony of Aspergillus niger. Boolean values are encoded by spikes of extracellular potential. We represent binary inputs by electrical impulses on a pair of selected electrodes and we record responses of the colony from sixteen electrodes. We derive sets of two-inputs-on-output logical gates implementable the fungal colony and analyse distributions of the gates.


Asunto(s)
Aspergillus niger/genética , Recuento de Colonia Microbiana/métodos , Simulación por Computador , Redes Reguladoras de Genes , Micelio/genética , Citoplasma/genética
13.
Lab Chip ; 20(1): 136-146, 2020 01 07.
Artículo en Inglés | MEDLINE | ID: mdl-31777892

RESUMEN

Liquid marbles (LMs) are of growing interest in many fields, including microfluidics, microreactors, sensors, and signal carriers. The generation of LMs is generally performed manually, although there has recently been a burst of publications involving 'automatic marble makers'. The characteristics of a LM is dependent on many things, including how it is generated, it is therefore important to be able to characterise LMs once made. Here is presented a novel contactless LM sensor, constructed on a PCB board with a comb-like structure of 36 interlacing electrical traces, 100 µm wide and 100 µm apart. This cheap, scalable, and easy to use sensor exploits the inherent impedance (comprised of the electrical resistance, capacitive reactance and inductive reactance) of different LMs. With it, parameters of a LM can be easily determined, without interfering with the LM. These parameters are (1) particle size of the LM coating, (2) the concentration of a NaCl solution used as the LM core, and (3) the volume of the LM. Additionally, due to the comb-like nature of the sensor, the accurate positioning (down to the inter-trace spacing) of the LM can be ascertained. The new sensor has been shown to work under both static and dynamic (mobile) conditions. The capacitance of a LM was recorded to be 0.10 pF, which compares well with the calculated value of 0.12 pF.

14.
J Colloid Interface Sci ; 560: 589-595, 2020 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-31679777

RESUMEN

HYPOTHESIS: Tubulin is a key protein of the cytoskeleton, forming networks of microtubules (MTs). These networks are vital for many aspects of a cell, including intra-cellular transport. It has been suggested by others that this network could be responsible for sub-cellular information processing, which naturally raises the question of whether such a system could be exploited for more artificial constructs. In this endeavour, this paper studies the electrical properties of Taxol-stabilised MT ensembles. EXPERIMENTS: Electrical experiments were conducted on samples containing MTs. Measurements were made using iridium-coated needle electrodes on a droplet. Cyclic voltammetry was performed, by sweeping through a DC voltage range of [-1.2,+1.2] V. AC measurements were also taken, between 1 kHZ and 10 MHz, and with a DC bias. Separately, pulse train stimulation were conducted, with an amplitude of 0.5 V and duration of 1 ms. FINDINGS: Cyclic voltammetry experiments reveal that the MT droplets act as electrical switches, under the experimental conditions. This is partly revealed in a substantial hysteresis. The stimulation of a MT droplet with a positive fast-impulse resulted in oscillation of the droplet's resistance, not observed in control experiments. Taxol-stabilised MT samples proved to be mem-resistive/mem-inductive, therefore the history of their electrical characterisation is able to change their response and behaviour. If the history of electrical stimuli is the same, so is the response. These findings pave a way towards future designs of MT-based sensing and computing devices, including data storage featuring liquid states.


Asunto(s)
Conductividad Eléctrica , Impedancia Eléctrica , Microtúbulos/química , Paclitaxel/química , Tubulina (Proteína)/química , Animales , Electroquímica
15.
Chemphyschem ; 21(1): 90-98, 2020 01 03.
Artículo en Inglés | MEDLINE | ID: mdl-31696651

RESUMEN

A liquid marble is a liquid droplet coated by a hydrophobic powder. The liquid marble does not wet adjacent surfaces and therefore can be manipulated as a dry soft body. A Belousov-Zhabotinsky (BZ) reaction is an oscillatory chemical reaction exhibiting waves of oxidation. We demonstrate how to make a photo-sensor from BZ medium liquid marbles. We insert electrodes into a liquid marble, prepared from BZ solution and coated with polyethylene powder. The electrodes record a potential difference which oscillates due to oxidation wave-fronts crossing the electrodes. When the BZ marble is illuminated by a light source, the oxidation wave-fronts are hindered and, thus, the electrical potential recorded ceases to oscillate. We characterise several types of responses of BZ marble photosensors to various stimuli, and provide explanations of the recorded activity. BZ liquid marble photosensors may find applications in the fields of liquid electronics, soft robotics and unconventional computing.

16.
J Biol Eng ; 13: 72, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31508146

RESUMEN

BACKGROUND: The green algae balls (Aegagropila linnaei), known as Marimo, are large spherical colonies of live photosynthetic filaments, formed by rolling water currents in freshwater lakes. Photosynthesis therein produces gas bubbles that can attach to the Marimo, consequently changing its buoyancy. This property allows them to float in the presence of light and sink in its absence. RESULTS: We demonstrate that this ability can be harnessed to make actuators, biosensors and bioprocessors (oscillator, logic gates). Factors affecting Marimo movement have been studied to enable the design, construction and testing of working prototypes. CONCLUSIONS: A novel actuator design is reported, incorporating an enhanced bubble retention system and the design and optimisation of a bio-oscillator is demonstrated. A range of logic gates (or, and, nor, nand, xor) implementable with Marimo have been proposed.

17.
Langmuir ; 35(40): 13182-13188, 2019 10 08.
Artículo en Inglés | MEDLINE | ID: mdl-31525934

RESUMEN

Neuromorphic computing devices attempt to emulate features of biological nervous systems through mimicking the properties of synapses toward implementing the emergent properties of their counterparts, such as learning. Inspired by recent advances in the utilization of liquid marbles (LMs, microliter quantities of fluid coated in hydrophobic powder) for the creation of unconventional computing devices, we describe the development of LMs with neuromorphic properties through the use of copper coatings and 1.0 mg mL-1 carbon nanotube (CNT)-containing fluid cores. Experimentation was performed through sandwiching the LMs between two cup-style electrodes and stimulating them with repeated dc pulses at 3.0 V. Our results demonstrate that "entrainment" of CNT-filled copper LMs 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 LMs. Our electrical characterization also reveals that nanotube-filled LMs 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.

18.
Sci Rep ; 9(1): 8957, 2019 06 20.
Artículo en Inglés | MEDLINE | ID: mdl-31222047

RESUMEN

As the extent to which aquatic environments are polluted with nano-scale objects is becoming known, we are presented with an urgent need to study their effects on various forms of life and to clear and/or detoxify them. A range of methods exist to these ends, but a lack of inter-study comparability arising from an absence of experimental standardisation impedes progress. Here we present experiments that demonstrate measurement of orchestrated uptake and clearance of two environmentally-relevant nano- and micromaterials by a model aquatic microoraganism, Paramecium caudatum. Experiments were based on a simple, modular, multi-chamber platform that permits standardised control of organism behaviour and measurement of variables relevant to the study of nanotoxicology, including nanomaterial chemotaxis assays, bioaccumulation and deleterious effects on cell motility systems. Uptake of internalised materials may be estimated through the addition of a low-cost fluorescence spectrometer. P. caudatum cells can clear an estimated 0.7 fg of contaminant materials (or 161 of the particles used) per cell over a 5 mm distance per 6 hour experiment, whilst suffering few short-term adverse effects, suggesting that the organism and the platform used to investigate their properties are well-suited to a range of laboratory and field-based nanotoxicological studies.


Asunto(s)
Nanopartículas/toxicidad , Paramecium caudatum/metabolismo , Espectrometría de Fluorescencia
19.
Soft Matter ; 15(17): 3541-3551, 2019 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-30945723

RESUMEN

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 < We* < 1.4 and 0.0 < X* < 0.1, resulted in a coalescence rate of approximately 50%. Whereas, parameter ranges X* > 0.25, and We* < 0.95 or 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.

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