Ease Of Handling Research Articles

A WIRELESS POWER TRANSFER SYSTEM DESIGN FOR CHARGING OF INTRA-BODY IMPLANT DEVICES

Wireless power transfer (WPT) presents numerous possibilities for recharging electronic devices in challenging environments. Charging of biomedical devices within the body is among the available opportunities. Inductively coupled WPT is a dependable and effective solution for powering these devices. Energy is transferred from the transmitter to the receiver in the inductively coupled WPT system through the use of coils and magnetic coupling. A WPT system was designed for this study, with dimensions of 4 cm by 4 cm, power output of 1 mW, and a frequency of 13.56 MHz. Series-Series (SS) topology was selected for its ease of handling and simple architecture. A square coil was selected as the receiver and transmitter coil structure due to its higher coupling factor than circular coils. ANSYS® Maxwell 3D was used to design the coils and perform magnetic analysis. In the ANSYS® HFSS program, the WPT system was placed inside the male human model and the electromagnetic exposure of the WPT on humans was examined. The magnetic scattering of the WPT system was within the safe values specified by IEEE and ICNIRP standards.

Analyzing the potency of Viscosity Modifying Agents on the Characteristics and Static Segregation of Fresh and Hardened Fluid Concrete

Self-compacting concrete (SCC) represents a recent advancement in the field of concrete technology due to its ease of handling and placement. In order to regulate the internal integrity of the concrete, a supplementary mixture component is employed. The term used to refer to this particular component is a viscosity-modifying agent (VMA). Different quantities of VMA were incorporated into the concrete mixture in order to evaluate its performance in both the fresh and hardened states. This study focused on the impact of VMA (Viscosity Modifying Agent) on various characteristics of concrete mixes. Specifically, the features under examination included flowing time, slump flow, flow time into a 500-mm diameter, and resistance to vertical segregation. In contrast, a measurement was conducted on the compressive strength of the cured concrete. The utilization of the column of segregation test allows for the identification and assessment of static segregation in SCC mixtures. This test offers a direct quantitative determination of the stability of segregation in fresh concrete. The purpose of this experiment is to determine the precise quantity of coarse aggregate with a diameter above 8 mm present within a specimen of 300 mm in height. This can be achieved by conducting sedimentation tests at a specific time interval of 30 minutes after the pouring of concrete. The research results indicate that the addition of VMA had a substantial impact on the rheological characteristics of the concrete mixture. It effectively stabilized the mixture, minimized static segregation, and improved the compressive strength when compared to the reference mixture without VMA. Furthermore, a comprehensive illustration of the segregation phenomenon is provided by the column of static segregation tests.

Advances in liquid organic hydrogen carriers: developing efficient dehydrogenation strategies.

In pursuit of global carbon neutrality, countries are intensifying their efforts to harness clean energy sources. Hydrogen emerges as a superior alternative to traditional fossil fuels and plays a crucial role in the global energy shift. Liquid Organic Hydrogen Carrier (LOHC) systems are lauded for their high hydrogen storage capacity, ease of handling, and safe and efficient transportation, positioning them as effective solutions for extensive hydrogen storage and international distribution. Nevertheless, the dehydrogenation of hydrogen-rich LOHCs is slow, requiring high temperatures and substantial energy inputs. Addressing these challenges by reducing energy demands and improving dehydrogenation rates is essential for advancing LOHC technology. This paper comprehensively examines various LOHC systems, focusing on the selection of carriers and dehydrogenation catalysts, and their dehydrogenation efficacy. It also highlights our recent contributions in photocatalytic LOHC and outlines future research directions to enhance LOHC technology.

Fabricating mesoscale polymer ribbons with tunable mechanical properties via evaporative deposition and dewetting.

Synthetic replication of the precise mesoscale control found in natural systems poses substantial experimental challenges due to the need for manipulation across multiple length scales (from nano- to millimeter). We address this challenge by using a 'flow coating' method to fabricate polymer ribbons with precisely tunable dimensions and mechanical properties. Overcoming barriers that previously limited the achievable range of properties with this method, we eliminate the need for substrate patterning and post-processing etching to facilitate the production of high aspect ratio, filament-like ribbons across a range of polymers-from glassy polystyrene to elastomeric poly(butadiene), as well as poly(butadiene-block-styrene). Our method uniquely enables the preservation of chemical fidelity, composition, and dimensions of these ribbons, leveraging polymers with elastic moduli from GPa to tens of MPa to achieve multi-scale features. We demonstrate the role of the elastocapillary length (γ/E) in determining morphological outcomes, revealing the increase in curvature with lower elastic modulus. This finding underscores the intricate relationship among surface tension, elastic modulus, and resultant structural form, enabling control over the morphology of mesoscale ribbons. The soft (MPa) polybutadiene-based ribbons exemplify our method's utility, offering structures with significant extensibility, resilience, and ease of handling, thus expanding the potential for future applications. This work advances our understanding of the fundamental principles governing mesoscale structure formation and unlocks new possibilities for designing soft materials with tailored properties, mirroring the complexity and functionality observed in nature.

Microglial involvement in ocular hypertension

Glaucoma, a chronic and multifactorial neurodegenerative disease, is the leading cause of irreversible blindness. It is characterized by the degeneration of retinal ganglion cells (RGCs), loss of their axons, and damage to the lamina cribrosa. To study glaucomatous optic neuropathy, experimental rodent models are commonly used due to their low cost, ease of handling, and similarities to the human retina. The ideal model must reproduce tissue changes observed in human glaucoma, such as alterations of the optic nerve head, thinning of the retinal nerve fibre layer, activation of glial cells, and progressive degeneration of RGCs.The DBA/2J transgenic mouse model is the most commonly used genetic model, characterized by a gradual increase in intraocular pressure (IOP) with age, leading to rapid and progressive loss of RGCs and optic nerve degeneration. However, limitations such as iris atrophy and peripheral anterior synechiae can alter the anterior segment and influence IOP measurement. Induced models of ocular hypertension (OHT) have a predictable IOP increase following experimental procedures, but this increase is usually rapid and sustained for a relatively short time, which may not represent the slow and sustained IOP elevation observed in primary open‐angle glaucoma. Nonetheless, induced models produce similar pathophysiological mechanisms to genetic models. Other models include the injection of hypertonic saline into episcleral veins to cause scarring of the trabecular meshwork and elevate IOP, and the intracameral injection of polystyrene or magnetic microbeads to obstruct normal drainage flow of aqueous humour, resulting in an IOP increase. A new model employs an intracameral injection of a cross‐linking polymer that produces a viscosity increase, impeding normal drainage of the aqueous humour and resulting in an IOP increase and loss of RGCs.In this SIS, we review the different glaucoma models, their methods, and the retinal tissue changes, with a focus on microglial cell changes.

Skeletal phenotypes and molecular mechanisms in aging mice.

Aging is an inevitable physiological process, often accompanied by age-related bone loss and subsequent bone-related diseases that pose serious health risks. Research on skeletal diseases caused by aging in humans is challenging due to lengthy study durations, difficulties in sampling, regional variability, and substantial investment. Consequently, mice are preferred for such studies due to their similar motor system structure and function to humans, ease of handling and care, low cost, and short generation time. In this review, we present a comprehensive overview of the characteristics, limitations, applicability, bone phenotypes, and treatment methods in naturally aging mice and prematurely aging mouse models (including SAMP6, POLG mutant, LMNA, SIRT6, ZMPSTE24, TFAM, ERCC1, WERNER, and KL/KL-deficient mice). We also summarize the molecular mechanisms of these aging mouse models, including cellular DNA damage response, senescence-related secretory phenotype, telomere shortening, oxidative stress, bone marrow mesenchymal stem cell (BMSC) abnormalities, and mitochondrial dysfunction. Overall, this review aims to enhance our understanding of the pathogenesis of aging-related bone diseases.

A simple and low-cost environmental enrichment program improves the welfare of Calomys callosus, a species that adapts to animal facilities.

An environmental enrichment protocol is essential for testing experimental models because it upholds animal welfare, aligns with ethical principles in animal experimentation, and reduces the number of animals needed. Calomys callosus, a South American rodent from the Cricetidae family, is bred in rodent animal facilities for its ease of handling, longevity, prolificacy, and effectively mimicking diseases like Toxoplasmosis, Leishmaniasis, Chagas, and Schistosomiasis. There are no reports on environmental enrichments for this species or their impact on reproductive parameters. This study aimed to analyze the influence of the Environmental Enrichment Program (EEP) on the reproductive and zootechnical performance of C. callosus kept in the Rodents Animal Facilities Complex of Universidade Federal de Uberlândia (UFU). Two experimental groups were established: with environmental enrichment EE+ and without environmental enrichment EE-. The materials used in the experimental design were changed weekly and alternated between dietary, occupational, physical/cognitive, and non-enrichment items. After the inclusion of the EEP, an improvement in the reproductive indices of C. callosus was identified in the EE+ group. These improvements included increased female precocity, a decreased interbirth interval, and a higher number of pairs producing more offspring. The postpartum zootechnical indices were also better, such as the number of animals born alive, improved weaning rates, and a reduced average number of deaths from birth to weaning. After the inclusion of the EEP, the general health status of C. callosus improved, reducing cases of non-infectious lumbar alopecia. Therefore, EEP allows C. callosus to express natural reproductive behaviors and improves parental care.

Transformative solidification techniques for self-emulsifying drug delivery and its foresight in modern-day drug delivery

Self-emulsifying drug delivery systems (SEDDSs) represent a significant breakthrough in addressing bioavailability challenges by enhancing the solubilization of poorly water-soluble drugs, ensuring consistent formulation properties, and facilitating easy industrial scale-up. Despite their liquid form posing some limitations, these challenges can be effectively addressed by solidifying SEDDSs, offering numerous advantages. The solidification of SEDDS has opened avenues for overcoming limitations associated with liquid formulations. Different approaches to solidification of SEDDS have been investigated to overcome the practical limitations of liquid formulations. Each method offers a plethora of benefits such as improved physiochemical stability, extended gastric residence time, controlled release of the drug, enhanced bioavailability, ease of handling, dose accuracy, and so on. While limitations persist, ongoing research is paving the path for the commercialization of solid SEDDS formulations with enhanced therapeutic effects. In light of previous publications, the current review paper makes an effort to give a comprehensive account of the most recent advancements in solid SEDDSs technology, with a focus on the formulation aspects of various types of novel solid self-emulsifying dosage forms for oral and nonoral drug delivery.

INFLUENCE OF CONFINING MATERIALS ON DETONATION PARAMETERS OF ANFO EXPLOSIVE

Due to the low manufacturing cost and ease of handling, ammonium nitrate-fuel oil (ANFO) is one of the most popular mining explosives. ANFO explosive is a typical representative of non-ideal explosives, which means that its detonation properties are strongly dependent on the charge diameter and the existence and properties of the confinement. In this work, the effect of different confining materials on the detonation properties of ANFO explosive is studied experimentally, and by hydrocode simulation by varying charge diameter, and the type and thickness of the confining materials. The results show that, along with the diameter of the charge, density and thickness of the confining material have a key impact on the detonation properties. An empirical confinement model, applicable in the range 0.3 < mC/mE < 15, is proposed. The model enables the estimation of detonation velocity of confined ANFO charges with a mean absolute percentage error (MAPE) of 14.25%.

Roadmap to mercury free dentistry: Toxic past to a healthier future

Ever since its introduction, mercury has been widely used in dental practice because of its durability, ease of handling and placement, low cost, lower technical sensitivity compared to other restorative materials, antibacterial effect, etc. When esthetics are not an issue, it can be used in people of all ages, in stressed areas and with poor oral hygiene. However, concerns have been raised that amalgam causes mercury toxicity. At present, there is much controversy about the safety of dental amalgam and it has been shown to pose an occupational risk to patients, dentists, and their assistants. This review has attempted to summarize the past controversies and the current status of this restorative material in routine dental practice. It also discusses various alternatives to its use in terms of safety and esthetics.

Battery Production Solvent Alternative to NMP - Jeffsol® MEOX

Solvents are commonly used in in battery manufacturing to dissolve binders, aid in slurry dispersion, stability, and the coating process [1]. For the cathode, N-Methylpyrrolidone (NMP) is the commonly used solvent for working with PVDF binder. However, it has been classified as Reprotoxic, and labeled as a CMR substance. Due to the classification, there are existing strict emission regulations and increasing regulations on the handling and use of the solvent [1,2]. As a result of these regulations with NMP, there has been increased interest for replacements that can improve the safety without significantly affecting the existing processes. Huntsman has developed JEFFSOL® MEOX, a solvent which may be less hazardous to handle while having similar performance capability to NMP.JEFFSOL® MEOX and NMP are both clear, colorless, and odorless aprotic solvents. They also share similar dipole moments and dispersion energy parameters. Therefore, JEFFSOL®MEOX may have an advantage in solubility performance in some applications when compared with other NMP alternatives (Table 1). Due to these comparable characteristics and the ease of handling, JEFFSOL® MEOX can be used in a wide variety of applications. In addition to use as a solvent for PVDF or PAN binders in batteries, JEFFSOL® MEOX can be applied in chemical reactions and polymerization applications [3]. Due to its usefulness in multiple markets, there are multiple grades of MEOX available, including E-Grade® MEOX which contains ultra-low metals and can be used in semiconductor production without contaminating the wafer.As an example of the comparable solubility performance, Figure 1 shows results of NMP and JEFFSOL® MEOX with multiple PVDF samples that are commonly used in battery production, including mono- and co-polymers of low and high molecular weights. With both solvents, heat and agitation decreased the time needed to fully dissolve the PVDF.In addition to MEOX, Huntsman offers other experimental solvents which could be used as NMP replacements as well. In addition to the range of solvents currently offered, Huntsman has the capability to synthesize new solvents based on user feedback. This Huntsman technology gives users greater flexibility and capabilities in selecting the ideal solvent for their unique processes while shifting away from NMP.This presentation shows the latest results with JEFFSOL®MEOX benchmarked against industry standard NMP.[1] Y. Liu, R. Zhang, J. Wang, Y. Wang: Current and future lithium-ion battery manufacturing (iScience, Volume 24, Issue 4, 2021)[2] REACH COMMISSION REGULATION (EU) 2018/588 (2018)[3] V. White. H. Zhou, K. Zhang, J. Gazda: Advanced Battery Materials as reported at the International Battery Seminar (2023) Figure 1

Flow Simulation Study on Bed Bath for Bedridden Patient

Easy tasks such as showering or bathing independently are impossible for a bedridden individual. This paper presents a comprehensive study on designing an easy shower specifically tailored for bedridden patients. The challenges bedridden individuals face in maintaining personal hygiene are highlighted, emphasizing the importance of a suitable bathing system to enhance their quality of life. The proposed design aims to address these challenges and improve caregiving efficiency. The chosen methodology involves a weighted decision matrix to select the optimal design, followed by flow simulation using SolidWorks Flow Simulation software to evaluate its performance. The paper's objectives include designing an efficient easy shower model, assessing its performance via simulation, and analyzing the impact of various velocity settings on its functionality. Three design concepts were proposed, with Design A selected as the optimal choice due to its lightweight, high water capacity, ease of handling, and low production cost. Modifications were made to enhance its water pressure efficiency. The simulation encompassed different velocity settings, with flow trajectories analyzed within the tank and at the water outlet. These boundary conditions included analysis type (internal), fluids (water), default wall thermal condition (adiabatic wall), pressure (101325 Pa), temperature (293.2 K), and velocity in the Y direction (5 m/s for water inlet and 0.5 m/s for water outlet). In the first simulation, all the results obtained were within the specified velocity range of 0.5 m/s, 2 m/s, and 5 m/s. The analysis of flow trajectories revealed distinct flow patterns and velocities for different velocity values, indicating stable and controlled environments within the tank and efficient water discharge through the outlet in Design A. However, errors were observed in the water outlet simulation due to the presence of vortices, which impacted the results. Recommendations were made to address these challenges, such as modifying the design to eliminate or minimize vortex effects. In conclusion, this study contributes to the well-being of bedridden patients by proposing an improved bathing mechanism, enhancing caregiving efficiency, and offering insights into design optimization and simulation challenges. The proposed design could have a significant positive impact on the lives of bedridden patients and caregivers.

Stabilized municipal solid waste as an alternative to natural sand in paver block construction

A large amount of stabilized municipal solid waste (SMSW) obtained in landfill mining operations constitutes about 60–70% of total mining waste. In this study, attempts were made to use SMSW in paver block construction, a unique solution for unpaved urban surfaces considering its ease of handling and low cost. The mechanical and durability properties of the paver block, along with microstructure and mineralogical analysis, were investigated in which various dosages of SMSW vary from 10–50% by the weight of natural sand. The results of various tests, i.e., compressive, flexural strength, abrasion resistance, water absorption, and analysis of microstructure and mineralogical, revealed that SMSW as a partial replacement of natural sand up to 30% replacement could be satisfactorily used in the paver block construction, especially in the low volume roads. Also, the replacements, 40% and 50%, can be used for footpaths, cycle paths, garden parks, domestic drives, and embankment slopes. The geometrical properties and visual aspects were checked to confirm the production standardization of the paver blocks. All the samples have shown promising results in respect of all dimensions. The statistical analysis exhibited that the SMSW had a significant effect on the compressive and flexural strength of the paver block. Therefore, incorporating SMSW as a natural sand replacement will be a sustainable and economical construction solution for light-traffic roads. It also promotes a ‘Circular economy’ as it recycles the stabilized municipal solid waste.

The Application of Bamboo in the Railway Industry: A Sustainable Solution for Track Construction

The railway industry has shown a strong interest in utilizing sustainable materials, including recycled materials and composites, in construction. Bamboo, as a highly renewable natural resource, has been proposed as a construction material for the railway industry. This material offers several advantages, such as high strength and durability, sustainability, low embodied energy, and ease of handling. It has been used in various construction materials like plywood, scrimber, laminates, and fibers. This paper aims to review the application of bamboo as a material in the railway industry and provide suggestions for its future use as railway sleepers. The mechanical properties of bamboo and its desirable features for sleeper construction, such as versatility, durability, low embodied energy and carbon footprint, lightweight, and ease of handling, are discussed. Bamboo-based products like plywood and scrimber can offer higher mechanical properties compared to traditional timber sleepers. Moreover, due to its rapid growth rate, bamboo is considered an environmentally friendly material. However, there are certain factors that limit the widespread deployment of bamboo in the railway industry. For instance, the lightweight nature of bamboo can reduce the lateral resistance of sleepers. Additionally, long-term performance studies and its performance in regions with varying weather conditions need to be further investigated. This review paper aims to promote the increased utilization of bamboo in the railway industry, contributing to the development of sustainable railway tracks. By considering the mechanical properties and advantageous characteristics of bamboo, it is possible to explore its potential as a viable and eco-friendly material for railway sleepers.

Effectiveness of F3 feline facial pheromone analogue for acute stress reduction within clinical veterinary practice

PICO Question In cats within a clinical veterinary context, does the application of the F3 feline facial pheromone (Feliway™), when compared to placebo, reduce signs of acute stress? Clinical bottom line Category of research Treatment. Number and type of study designs reviewed Five papers were critically reviewed. There were three prospective, double-blinded, randomised controlled trials, one prospective, single-blinded, randomised controlled trial and one prospective, single-blinded, non-randomised controlled trial. Strength of evidence Moderate. Outcomes reported Four studies found improvement in select indicators of acute stress following F3 feline facial pheromone analogue (FFPA) exposure. One study showed FFPA reduced patient stress during routine physical examination, and improved caregiver impression of patient relaxation and ease of handling. One study revealed FFPA decreased vocalisations but had no effect upon systolic blood pressure during physical examination. One study determined that FFPA calmed but did not reduce struggling during venous catheterisation. One study demonstrated reduced time to sedation and propofol induction dose for routine surgical procedures when a transport protocol incorporating FFPA was applied. Finally, one study found no significant effect of FFPA upon behavioural and physiologic measures of acute stress during physical examination. No studies reported outward negative effects associated with FFPA exposure. Conclusion It can be concluded that FFPA may reduce signs of acute stress within a clinical veterinary context. Additionally, exposure to FFPA is unlikely to cause patient harm. To optimise patient welfare, FFPA is not recommended as a sole agent for stress mitigation and should instead be incorporated holistically with patient friendly handling, clinic design, and pharmacotherapy where indicated. How to apply this evidence in practice The application of evidence into practice should take into account multiple factors, not limited to: individual clinical expertise, patient’s circumstances and owners’ values, country, location or clinic where you work, the individual case in front of you, the availability of therapies and resources. Knowledge Summaries are a resource to help reinforce or inform decision making. They do not override the responsibility or judgement of the practitioner to do what is best for the animal in their care.

Effects of Extended-Release Buprenorphine on Mouse Models of Influenza.

Mice are widely used as small animal models for influenza infection and immunization studies because of their susceptibility to many strains of influenza, obvious clinical signs of infection, and ease of handling. Analgesia is rarely used in such studies even if nonstudy effects such as fight wounds, tail injuries, or severe dermatitis would otherwise justify it because of concerns that treatment might have confounding effects on primary study parameters such as the course of infection and/or the serological response to infection. However, analgesia for study-related or -unrelated effects may be desirable for animal welfare purposes. Opioids, such as extended-release buprenorphine, are well-characterized analgesics in mice and may have fewer immune-modulatory effects than other drug classes. In this study, BALB/c and DBA/2 mice were inoculated with influenza virus, and treatment groups received either no analgesics or 2 doses of extended-release buprenorphine 72 h apart. Clinical signs, mortality, and influenza-specific antibody responses were comparable in mice that did or did not receive buprenorphine. We therefore conclude that extended-release buprenorphine can be used to alleviate incidental pain during studies of influenza infection without altering the course of infection or the immune response.

From the Glovebox to the Benchtop: Air-Stable High Performance Molybdenum Alkylidyne Catalysts for Alkyne Metathesis.

Molybdenum alkylidynes endowed with tripodal silanolate ligands belong to the most active and selective catalysts for alkyne metathesis known to date. This paper describes a new generation that is distinguished by an unprecedented level of stability and practicality without sacrificing the chemical virtues of their predecessors. Specifically, pyridine adducts of type 16 are easy to make on gram scale, can be routinely weighed and handled in air, and stay intact for many months outside the glovebox. When dissolved in toluene, however, spontaneous dissociation of the stabilizing pyridine ligand releases an active species of excellent performance and functional group tolerance. Specifically, a host of polar and apolar groups, various protic sites, and numerous basic functionalities proved compatible. The catalysts are characterized by crystallographic and spectroscopic means, including 95Mo NMR; their activity and stability are benchmarked in detail, and the enabling properties are illustrated by advanced applications to natural product synthesis. For the favorable overall application profile and ease of handling, complexes of this new series are expected to replace earlier catalyst generations and help encourage a more regular use of alkyne metathesis in general.

Synergistic co-combustion of carbon-rich fraction from coal gasification fine slag and corncob char: Performance, mechanism, kinetics, and thermodynamics

Coal gasification fine slag (FS) is a coal-based solid waste with high carbon content, and landfill-based disposal causes water-soil-gas composite pollution. Co-combustion is a common method of solid waste thermal disposal, and corn cob is used as an auxiliary fuel for co-combustion because of its energy density and ease of handling and processing. In this paper, the thermal degradation characteristics, interaction mechanism, kinetics, and thermodynamics of co-combustion RC (carbon-rich fraction obtained by flotation) and CC (corncob char) were studied. The results showed that physicochemical properties suggested that RC and CC will complement and promote each other in the combustion process. The addition of CC reduced the RC ignition temperature and improved the overall combustion performance. The interaction effect was mainly due to metal catalysis, the effect of the porous carbon structure, the thermal effect, and the hindering effect of ash. The activation energy was reduced due to the blending of RC-CC, and the activation energy was lowest (132.19 kJ/mol) when the RC adding ratio was 60%. The co-combustion process was controlled by the F3 model (chemical third-order reaction kinetics), and it was a typical gas-solid phase reaction with a progressive process from the outsides toward the insides. Thermodynamic analysis showed that the co-firing process was an extremely complex multi-stage reaction. The results of this study provide a theoretical reference for the synergistic resource utilization of coal gasification fine slag and waste biomass.

THE USE OF AN ULTRASONIC TOOL TO CUT HUMAN BONE: CUTTING SPEED AND FORCES OF ORTHOPAEDIC SURGEONS

AbstractBackgroundUltrasonic cutting of bone boasts many advantages over alternatively powered surgical instruments, including but not limited to: elimination of swarf, reduced reaction forces, increased precision in cutting and reduced adjacent soft tissue damage, reduced post-operative complications such as bleeding and bone fracture, reduced healing time, reduced intra-operative noise and ease of handling. Despite ultrasonic cutting devices being well established in oral and maxillofacial surgery, applications in orthopaedic surgery are more niche and are not as well understood. The aim of this study was to investigate the cutting speed (mm/s) and cutting forces (N) of orthopaedic surgeons using a custom-designed state of the art ultrasonic cutting tool to cut fresh human bone samples.MethodsA setup based on the Robot Operating System (ROS) and AprilTag was designed to track and to record the real time position of the ultrasonic cutting tool in space. Synchronised load cell axial force readings of three separate orthopaedic surgeons during ultrasonic cutting were recorded. Each surgeon was asked to find a comfortable position that reflects as close as possible their clinical handling of a cutting instrument used in surgery, and to perform two cuts in each of three samples of human cortical bone. Bone samples were obtained following ethical approval from an institutional review board (ethics approval number: SR1342) and prior informed consent was obtained from all patients. Bone samples were extracted from the femoral neck region of three hip osteoarthritis patients. During cutting, surgeons were allowed a total cutting time of one minute and cutting was conducted using an ultrasonic tool with frequency of a 35kHz (35.7 µm peak to peak displacement amplitude) under constant irrigation using a MINIPULS® 3 Peristaltic pump (38 revolutions per minute) using Phosphate-Buffered Saline (PBS) at 25°C. From the recorded data, the average instantaneous cutting velocity was calculated and the maximum cutting force was identified.ResultsAll surgeons assumed a back-and-forth cutting motion, variation in the applied cutting force was observed. The average vertical cutting speed, axial cutting force and cutting depth across all surgeons and all samples was 1.64 mm/s, 1.91 N and 0.73 mm, respectively. While increasing the axial cutting force resulted in a deeper cut, overloading of the ultrasound transducer occurred when the tool advanced too quickly into the bone tissue during cutting. The exact force threshold, or the optimal speed at which the surgeon can maintain a constant force during cutting, requires further investigation.ConclusionsIn this study, all surgeons cut using a back-and-forth cutting motion, with variation in the applied cutting force which may ultimately inform which clinical applications in orthopaedic engineering are most suitable for this technology. Applying too much force caused overloading of the ultrasound transducer, which is a limitation with the current cutting tool. The results from this study may facilitate the eventual uptake of ultrasonic cutting tools for application in orthopaedic surgery.Declaration of Interest(b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Acoustically Actuated Flow in Microrobots Powered by Axisymmetric Resonant Bubbles

Bubble‐driven microsystems inspired by the therapeutic use of microbubbles under clinical ultrasound actuation offer innovative remote manipulation in biological settings. Ultrasound‐powered microrobots, benefiting from a distribution of vibrating microbubbles (1–100 μm in diameters), exhibit localized fluid flow for self‐propulsion. Microbubbles also contribute to the design of acoustic metamaterials, where distributed actuation of bubbles enables exotic material properties (e.g., negative refractive index). Herein, a metamaterial‐inspired microrobot design, which exploits the streaming induced by the collective oscillation of microbubble arrays (> 10), is reported. Such a large distribution of bubbles offers twofold advantages: a mesoscale microrobot allowing ease of handling and motion at a considerably low acoustic driving pressure of 50 kPa. In this work, the oscillatory amplitude of a single bubble that acts as a unit cell of the metamaterial‐based microrobot is first characterized. Thereon, this amplitude is related to the flow generated by the collective vibration of all the bubbles close to the theoretically predicted resonant frequency of the bubbles. Finally, the hovering motion of the microrobot induced by the streaming and flow‐assisted debris clearance is demonstrated. Such auxiliary functionalities of the microrobot can be useful for applications like contactless sample extraction in inaccessible biological environments.