Flexible Silicone Research Articles

Regular heart rhythm restoration after a period of asystole: modeling in experimental cardiology

Abstract Funding Acknowledgements Type of funding sources: None. Regular heart rhythm restoration after a period of asystole: modeling in experimental cardiology Purpose To study the arterial hemodynamics during the regular heart rhythm restoration after a period of asystole using the original device for modeling of intra-arterial circulation. Materials and methods We used the device for modeling of intra-arterial circulation made by us (Document of invention № RU 202780 U1). The main part of the device is rotameter glass tube - a prototype of human arterial vessel. Electric pump with various modes of work was connected into the closed system with rotameter by flexible silicone tubes. Inside the closed system we introduced an aqueous solution of glycerin diluted to have the same viscosity as the human blood. As indicators for studying the intra-arterial hemodynamics we used intravascular piezoelectric crystal pressure sensor connected to an oscilloscope, 5 mm long silk thread alternately installed inside the tube, and a dye - clerical ink. Results With the electric pump work modes, we were able to imitate the regular heart rhythm (RR) restoration after a period of asystole inside the device for modeling of intra-arterial circulation. We observed the speed of fluid increased in comparison with the RR with the pendency: if longer pause of asystole was than more speed increased. We observed the appearance of reflected, stand waves on the walls of rotameter during the spread of the pulse wave after the long asystole pause. We alternatively put the plastic diaphragm inside the rotameter with internal lumen stenosis of 70% with symmetrical and asymmetrical hole. The speed with a RR was 3.24 m/s, after the pause of asystole 1 s speed was 4.08 m/s, after the pause 2 s speed was 7.36 m/s, after the pause 3 s speed was 9.22 m/s. The pressure measured by piezoelectrical probe increased proportionally to the speed. Conclusion Intense mechanical effect of the pressure waves after the long period of asystole can cause the additional trauma of intima of arterial vessels that can lead to non-stability of atherosclerotic plaques, stimulating of endothelial dysfunction and as a result of atherosclerosis progression with further complications. Changes in hemodynamics we characterized by proposed concept of "hydraulic shock".

Planning of Soft-Rigid Hybrid Arms in Contact With Compliant Environment: Application to the Transrectal Biopsy of the Prostate

In this study, a rigid robot is hybridized with a soft part to improve its properties of relative positioning and safe interaction. While the design of the device is quite simple, the kinematics, on the other hand, becomes complex. Pre-operative planning of such a robot is a challenge that is faced in this letter. The clinical context is the automation of transrectal prostate biopsy: a robot is connected to a thin ultrasound (US) probe instrumented with a needle through a flexible silicone part. The procedure consists of: moving the probe near the prostate through the rectum, aligning the probe with identified lesions in the prostate, and shooting the needle to collect tissue samples. In this letter we demonstrate in simulation the feasibility of our methods to solve the planning of the entire procedure. The approach we propose is based on numerical models of both robot and soft tissues, using the Finite Element Method (FEM) to model the soft parts, and a mapping mechanism to propagate the forces and displacements between the soft and rigid models. Finally, we extend the optimization algorithm proposed in previous work for the relative positioning of the hybrid robot on targets in the prostate, as it interacts with the soft tissues. With this formulation we can also set an upper limit to the force the robot is applying on its surroundings, which is particularly critical for the application we study in this letter.

Long-term outcomes of lacrimal canalicular trephination with viscoelastic-assisted monocanalicular stenting for canalicular obstructions.

Purpose: To study the long-term outcomes of lacrimal canalicular trephination (LCT) with viscoelastic-assisted monocanalicular stenting (VAMS) for the treatment of epiphora secondary to lacrimal canalicular obstructions (LCO).Methods: Our study was a retrospective interventional work. All patients diagnosed with LCO, having morbid epiphora (Munk’s scale ≥ 2), were included. The LCO was divided as proximal (< 6mm from punctum) and distal (≥ 6mm from punctum). Sisler’s lacrimal trephine (21 gauge) was used to recanalize the LCO with monocanalicular stent (0.64mm diameter) insertion, which was kept for a minimum of 6 weeks and a post-stent removal follow-up of 12 months was ensured. Fluorescein dye disappearance test and lacrimal irrigation were used as functional and anatomical tests for evaluation, respectively. Results: We included 73 eyes of 52 patients having a mean age of 44.5 years. Of the total, the proximal LCO was seen in 38 eyes (52.1%) and distal in 35 eyes (47.9%). The preoperative Munk’s score of 5 was noted in the majority (n=57 eyes, 78.1%). The majority (n=32 eyes, 43.8%) had chronic blepharitis or meibomian gland disease as etiology. Monocanalicular stent was kept in place for a mean of 13.5 weeks. At a mean follow-up of 14.5 months, complete response was noted in 35.6% cases, while 50.7% had partial and 13.7% had a failure of the procedure.Conclusions: LCT (without DCR) is a minimally invasive, simple, and effective technique for the treatment of LCO in the long term. VAMS is a helpful innovation to facilitate the insertion of the flexible silicone stent.

Investigation into the anti-inflammatory properties of metformin in intervertebral disc cells.

IntroductionIntervertebral disc degeneration (IDD) is closely related to heightened inflammation in the annulus fibrosis (AF) and nucleus pulposus (NP) cells in the intervertebral disc. An imbalanced matrix homeostasis has been shown to contribute to disc degeneration and associated discogenic low back pain. Metformin, a diabetes medication, has been noted to exhibit anti‐inflammatory properties through upregulation of the AMPK pathway, leading to various anti‐inflammatory‐related responses in hepatocytes. However, it is still unclear how metformin influences disc cellular response to inflammatory stress and the corresponding mechanism. Hence, the objective of this study is to elucidate the effects of metformin on expression of key pro‐inflammatory, catabolic, and anabolic factors within rat AF cells in response to inflammatory stimulation and mechanical tensile stress.MethodsFive Fischer 344 rats were sacrificed and their spines isolated. AF cells were cultured and plated in flexible silicone membrane‐based six‐well plates. Wells were split into eight groups and subjected to metformin, IL‐1β, mechanical stretch, and combined treatments. Relative gene expressions of MMP‐13, COX‐2, iNOS, AGC, and Col1 were assessed with quantitative real‐time polymerase chain reaction (qRT‐PCR), and downstream prostaglandin E2 (PGE2) production was quantified with enzyme‐linked immunosorbent assay (ELISA). NF‐kB nuclear translocation was also quantified.ResultsMetformin in the presence of the combined stress treatments (M + IL/S) significantly increased Col1, COX‐2, and MMP‐13 gene expression, decreased PGE2 production compared to IL/S conditions alone. Metformin treatment of cultured rat annulus fibrosus cells significantly reduced the nuclear translocation of NF‐κB after 4 h of IL‐1β treatment from 43.1% in case of IL‐1β treatment down to 26.2% in the case of metformin + IL‐1β treatment.DiscussionThe lack of metformin‐mediated suppression of inflammatory response in the nonstretch groups indicates that metformin may be enacting its effects through a stretch‐dependent manner. These results suggest a foundation for pursuing further research into metformin's potential role as an anti‐inflammatory agent for curtailing intervertebral disc degeneration.

Efecto del ibuprofeno y el ultrasonido pulsado de baja intensidad en la reducción del dolor después de la colocación inicial del arco de ortodoncia: un ensayo clínico aleatorizado doble ciego

Objetivo: Este estudio tuvo como objetivo comparar el efecto del ibuprofeno y el ultrasonido pulsado de baja intensidad (LIPUS) en la reducción del dolor después de la colocación del arco inicial en pacientes de ortodoncia. Material y Métodos: Este estudio de ensayo clínico doble ciego se llevó a cabo en 60 candidatas a tratamiento de ortodoncia fija referidas al Departamento de Ortodoncia de la Facultad de Odontología de la Universidad de Ciencias Médicas de Mashhad, Mashhad, Irán, durante 2015-2016. Los sujetos se dividieron en cuatro grupos: ibuprofeno, LIPUS, placebo y LIPUS simulado. Se entregó un cuestionario y un bloque de silicona cúbica rectangular y flexible a cada paciente para registrar la intensidad del dolor según la escala analógica visual en puntos de tiempo específicos (es decir, 2 h, 6 h, hora de acostarse, 2do, 3er y 7mo día después de la colocación del arco) al morder el bloque de silicona con los dientes anteriores y posteriores, y sin morder en absoluto. Se utilizó el análisis de varianza de medidas repetidas para comparar la intensidad del dolor en diferentes momentos. Resultados: La comparación de la intensidad del dolor en varios puntos de tiempo mostró que las puntuaciones medias de dolor más altas y más bajas se informaron a la hora de acostarse y siete días después de la intervención (p&lt;0,001). En cada una de las tres condiciones (es decir, al morder el bloque de silicona con los dientes anteriores y posteriores, y sin morder) en seis momentos (2 h, 6 h, antes de acostarse 2do, 3er y 7mo día después de la colocación del arco), no se observó diferencia significativa en la severidad del dolor (p&gt;0.05). Conclusion: En conclusión, LIPUS (con una frecuencia de 1 MHz y una intensidad de 100 mW) y el ibuprofeno no tienen efectos significativos en la reducción de la severidad del dolor en diferentes puntos de tiempo y diversas condiciones en pacientes de ortodoncia.

Modeling of intra-arterial hemodynamics in main arteries atherosclerosis

Abstract Funding Acknowledgements Type of funding sources: None. Aim. To study intra-arterial hemodynamics of the main arteries in atherosclerosis using the original device for modeling of intra-arterial circulation. Material and methods. To study hemodynamics inside an arterial vessel, we used an original device developed by us for modeling of intra-arterial circulation (Document of invention № RU 202780 U1). The main part of the device is a prototype of an artery - a glass tube of a rotameter with a length of 365 mm, an inlet end with a diameter of 20 mm, an outlet end - 16.5 mm. Flexible silicone tubes are attached to the rotameter on both sides, with free ends connected to an electric pump, with various modes of work (imitation of pulse waves at the regular rhythm (RR), extrasystole (ES), atrial fibrillation (AF)). An aqueous solution of glycerin was introduced into a closed system diluted with water corresponding to the viscosity of the blood. A 5 mm long silk thread was alternately installed inside the tube, an intravascular piezoelectric crystal pressure sensor connected to an oscilloscope was injected with a dye - clerical ink. Plastic diaphragms 15 mm long with stenosis of the internal lumen of 50%, 70%, and 90% were alternately hermetically installed in the rotameter. Results. When imitating ES in the first post-extrasystolic contraction (1PEC), the speed of fluid flow through the diaphragms increased in the 1PEC in comparison with the RR. So, with a stenosis of 50%, the speed with a RR was 2.09 m/s, with an ES 0.03 m/s, with 1PEC 3.83 m/s; with 70% stenosis, the speed at RR 3.24 m/s, with ES 0.04 m/s, with 1PEC 5.26 m/s; with 90% stenosis, the speed at RR 8.96 m / s, with ES 0.10 m/s, with 1PEC 12.36 m/s. The pressure increased proportionally to the speed. We observed the appearance of reflected, standing waves in the edge zones of the diaphragm and a turbulent flow of liquid behind the diaphragm. Conclusion. These changes in hemodynamics are characterized by the concept of "hydraulic shock". Intense mechanical effect of 1PEC pressure waves in the marginal zones of the diaphragm can contribute to the further growth and progression of atherosclerosis in arterial vessels. Abstract Figure.

Investigation of suitable material and adhesion promoter combinations for fused filament fabrication on flexible silicone build plates

PurposeThe extension of the vacuum-assisted multipoint moulding (VAMM) technology to a broader field of geometries makes it necessary to extend it with attachments to the enhanced vacuum-assisted multipoint moulding with additive attachments (EMMA) technology. Therefore, it is necessary to build additive manufactured attachments on a curved silicone surface by fused filament fabrication (FFF). The main challenge of FFF on a silicone-made build plate is the adhesion of the part on the build plate. Hence, the purpose of this paper is to find suitable and reliably manufacturable material and adhesion promoter combinations for the use of the FFF on silicone build plates.Design/methodology/approachThe combinations of seven different filaments and four adhesion promoters were investigated with an experimental study. Therefore, four different specimen geometries were built with the different combinations and tested in a tensile test, and some of the specimens were analysed with a confocal laser scanning microscope (CLSM).FindingsThis study proves that the FFF on unheated silicone building plates is possible for several material combinations. As a filament material, polylactide can reliably be manufactured with all of the investigated adhesion promoters on the silicone build plate. Thereby, the highest adhesion strengths were achieved with an adhesive foil as an adhesion promoter, whereas the glue stick is the most appropriate solution. The investigations with the CLSM showed that there are large differences in the manifestation of the first layer depending on the adhesion promoter used.Originality/valueTo the best of the authors’ knowledge, this study is the first to demonstrate the manufacturing of FFF-made attachments on silicone build plates for the EMMA process. This paper provides measurement data on the build plate adhesion of the attachments on silicone-made build plates.

Flexible silicone‐hollow glass microballoon syntactic foams for application in fire protective clothing

AbstractThis work deals with the development of flexible syntactic foams based on silicone and hollow glass microballoons (HGMs) for potential application as a lightweight thermal cum vapor barrier in fire‐protective ensembles. HGMs offer excellent thermal insulation and their inclusion into silicone leads to significant weight reduction, while improving the level of protection. Flexible silicone foams containing different types and loadings of HGMs were prepared and it was observed that high‐density microballoons (K46) survived compression molding process, due to their superior crushing strength (6000 psi) as compared to K15 (300 psi). The specific quasi‐static mechanical properties increased proportionally to the extent of loading. The inclusion of HGMs did not alter the curing behavior of silicone resin. Syntactic foams (40% HGMs) were coated onto glass fabric (GF) to prepare composites and thermal protective performance tests were performed to establish their effect on heat transfer. The protection level was higher for syntactic foam containing K46 glass microballoons, as compared to K15. The second‐degree burn time increased from 6.4 s (neat GF) to 10s for syntactic foam‐coated GF. Our studies demonstrate the potential of the developed syntactic foam‐coated GFs as a vapor cum thermal barrier in fire protective clothing.

Preparation and High Temperature Inorganic Transformation of Flexible Silicone Aerogels

Preparation and High Temperature Inorganic Transformation of Flexible Silicone Aerogels

Synchronized and Desynchronized Dynamics Observed from Physical Models of the Vocal and Ventricular Folds

The ventricular folds, located superiorly to the vocal folds, do not usually vibrate during normal phonations. It has been shown, however, that they do vibrate together with the vocal folds under special circumstances such as voice pathology and singing voice. Towards understanding the effect of the ventricular fold oscillations on the vocal fold oscillations, the present study developed a synthetic model that takes into account anatomical features of the human ventricular folds. The synthetic model is made of flexible silicone compounds with material properties comparable to those of human ventricular fold tissues. In our experiment, an air-flow was injected into the vocal and ventricular fold models. As the distance between the left and right ventricular folds was reduced, the ventricular folds started to co-vibrate with the vocal folds. Depending upon the distance, various oscillation patterns of the vocal-ventricular folds were observed, e.g., synchronized dynamics with 1:1 or 1:2 frequency ratio and desynchronized chaotic dynamics. The observed chaotic dynamics might be related to voice pathology induced by the ventricular phonation. A computational model was further presented to elucidate the experimental findings.

Lightweight and flexible silicone rubber foam with dopamine grafted multi-walled carbon nanotubes and silver nanoparticles using supercritical foaming technology: Its preparation and electromagnetic interference shielding performance

Herein, dopamine is grafted onto multi-walled carbon nanotubes (MWCNTs), and then grafted dopamine is used as a chemical activation point to initiate the in-situ synthesis of silver nanoparticles (Ag-NPs). The foam technology with supercritical N2 (Sc-N2) gas was used to prepare a lightweight and flexible silicone rubber foam material with efficient electromagnetic shielding performance. The prepared material has uniform cells and a density of only 0.3 g/cm3. The electrical conductivity can be achieved as high as 5.69 S/m. At the same time, the optimal modified conductive filler MWCNTs conditions are determined: DOPA concentration is 2 g/L, deposition time is 18 h, formaldehyde concentration is 5 g/L and AgNO3 concentration is 16 g/L. From the perspective of electromagnetic interference shielding performance (EMI SE), the value of prepared silicone rubber foam with 15 parts of MWCNT-PDA-Ag (VMPA15) can reach 36 dB, far exceeding the commercial requirement (20 dB). The EMI shielding performance is also improved with the increased thickness of the sample. When the sample thickness is 10 mm, the EMI SE value can be as high as 52 dB; more importantly, this type of VMPA foam has a shielding mechanism based on absorption, which is the most effective for solving the problem of secondary magnetic pollution caused by electromagnetic wave reflection.

Do Flexible Silicone Tubes Immersed in Water Combined With Vocalise Improve the Immediate Effect on Voice?

This study aimed to analyze the immediate effect on a singer's voice of a flexible silicone tube immersed in water combined with ascending and descending vocalise scales compared with ascending and descending vocalise scales alone. A pre- and post-intervention quasi-experimental study was conducted. Thirty adult singers between 18 and 45 years old with no laryngeal disorders performed the two techniques for 3 min each on different days. Acoustic measurements of frequency, jitter, shimmer, glottal-to-noise excitation ratio, noise, smoothed cepstral peak prominence (CPPS), maximum phonation time (MPT), voice range profile, and self-perceived vocal effort (Borg Category Ratio 10-BR Scale adapted for vocal effort) were assessed before and after performing the techniques. The results indicated an increase in singers' CPPS and MPT values and a decrease in shimmer and noise when performing with a flexible silicone tube immersed in water combined with vocalise. The singers reported a perception of decreased vocal effort after both methods. However, the diminished perceived vocal effort became more pronounced with the tube phonation technique combined with vocalise. Phonation in tubes combined with vocalise improved the vocal acoustic parameters (including cepstral measurements), increased MPT, and diminished perceived vocal effort. Although using vocalise alone diminished perceived vocal effort, this decrease was more pronounced in the tube phonation technique combined with vocalise.

A feasible route for the design and manufacture of customised respiratory protection through digital facial capture

The World Health Organisation has called for a 40% increase in personal protective equipment manufacturing worldwide, recognising that frontline workers need effective protection during the COVID-19 pandemic. Current devices suffer from high fit-failure rates leaving significant proportions of users exposed to risk of viral infection. Driven by non-contact, portable, and widely available 3D scanning technologies, a workflow is presented whereby a user’s face is rapidly categorised using relevant facial parameters. Device design is then directed down either a semi-customised or fully-customised route. Semi-customised designs use the extracted eye-to-chin distance to categorise users in to pre-determined size brackets established via a cohort of 200 participants encompassing 87.5% of the cohort. The user’s nasal profile is approximated to a Gaussian curve to further refine the selection in to one of three subsets. Flexible silicone provides the facial interface accommodating minor mismatches between true nasal profile and the approximation, maintaining a good seal in this challenging region. Critically, users with outlying facial parameters are flagged for the fully-customised route whereby the silicone interface is mapped to 3D scan data. These two approaches allow for large scale manufacture of a limited number of design variations, currently nine through the semi-customised approach, whilst ensuring effective device fit. Furthermore, labour-intensive fully-customised designs are targeted as those users who will most greatly benefit. By encompassing both approaches, the presented workflow balances manufacturing scale-up feasibility with the diverse range of users to provide well-fitting devices as widely as possible. Novel flow visualisation on a model face is presented alongside qualitative fit-testing of prototype devices to support the workflow methodology.

A Robust and Wearable Triboelectric Tactile Patch as Intelligent Human-Machine Interface.

The human–machine interface plays an important role in the diversified interactions between humans and machines, especially by swaping information exchange between human and machine operations. Considering the high wearable compatibility and self-powered capability, triboelectric-based interfaces have attracted increasing attention. Herein, this work developed a minimalist and stable interacting patch with the function of sensing and robot controlling based on triboelectric nanogenerator. This robust and wearable patch is composed of several flexible materials, namely polytetrafluoroethylene (PTFE), nylon, hydrogels electrode, and silicone rubber substrate. A signal-processing circuit was used in this patch to convert the sensor signal into a more stable signal (the deviation within 0.1 V), which provides a more effective method for sensing and robot control in a wireless way. Thus, the device can be used to control the movement of robots in real-time and exhibits a good stable performance. A specific algorithm was used in this patch to convert the 1D serial number into a 2D coordinate system, so that the click of the finger can be converted into a sliding track, so as to achieve the trajectory generation of a robot in a wireless way. It is believed that the device-based human–machine interaction with minimalist design has great potential in applications for contact perception, 2D control, robotics, and wearable electronics.

Device for modeling of intra-arterial circulation: application in experimental cardiology

Abstract Purpose of study Using an original device for modeling of intra-arterial blood circulation, to study the features of intravascular hemodynamics with a regular heart rhythm and with various rhythm disturbances. Material and methods We used an original device developed by us to simulate intra-arterial circulation (Document of invention No. RU 202780 U1). The main part of the device is a glass tube of a rotameter with a length of 365 mm, an inlet end with a diameter of 20 mm, an outlet end of 16.5 mm, which is a model of an arterial vessel. Flexible silicone tubes are attached to the rotameter on both sides, with free ends connected to an electric pump, with various modes of operation (imitation of pulse waves with regular rhythm, premature ventricular contractions (PVCs), atrial fibrillation (AF). An aqueous solution of glycerin was introduced into a closed system diluted with water corresponding to the viscosity of the blood. A 5 mm long silk thread was alternately installed inside the tube, an intravascular piezoelectric crystal pressure probe connected to an oscilloscope. Also it was injected inside the tube a dye - clerical ink. Results With electric pump, we simulated the spreading of the pulse wave in regular heart rate, PVCs and AF. We observed the effect of a pressure wave (deflection of a silk thread, the appearance of a turbulent flow when using a dye) on the walls of the rotameter, with the formation of standing, reflected waves during the PVCs and AF. The pressure probe registered an increase in pressure inside the tube during the spread of the 1st post-extrasystolic contraction wave up to 58%, the wave after a long pause of more than 2 seconds with AF by 44% compared to the regular rhythm. Conclusion A device for modeling of intra-arterial circulation allows a wide range of experimental work in cardiology, normal and pathological physiology, and biophysics. Funding Acknowledgement Type of funding sources: None.

Abstract P343: Physiologic Mechanical Stress In An Induced Pluripotent Stem Cell Derived Cardiomyocyte Model Of Duchene Muscular Dystrophy-related Cardiomyopathy Treated With A Membrane Resealant

Heart failure is leading cause of morbidity and mortality in the X-linked disease Duchenne muscular dystrophy (DMD). DMD is due to mutations the gene encoding dystrophin. Dystrophin localizes to the costamere in skeletal and cardiac muscle and is part of the larger dystrophin complex, which forms a critical connection linking the sarcomere to extracellular matrix. Disruptions in this complex lead to membrane fragility and multiple forms of muscular dystrophy, most of which have significant cardiac involvement. Therapeutic strategies for DMD include FDA-approved agents for exon skipping, as well as micro-dystrophins gene therapy, which is currently in clinical trials. Despite this progress, there is inadequate information as to how these and other novel agents will affect the DMD heart. Given the critical importance of cardiac muscle efficacy for any therapeutic for DMD and importance of membrane fragility in the disease phenotype, we assessed the susceptibility of patient-derived induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) harboring an out-of-frame exon 46-47 DMD deletion. iPSC-CMs were reprogrammed via a standard approach and differentiated, expanded, and purified by published methods. Troponin T flow cytometry was performed to and a minimum troponin T positivity &gt;85% positivity was set for inclusion. DMD and control cells were plated onto flexible silicone membranes and subjected to equibiaxial strain as physiologic mechanical stressor, consistent with the inciting pathologic insult in DMD. Troponin and LDH release were assessed as clinically-relevant biomarkers of injury. Physiologic stress parameters were defined using troponin and LDH release relative to unstressed conditions. A membrane resealant being developed for treating DMD was shown to reduce troponin and LDH release in DMD iPSC-CMs, and also showed benefit in control cells. This work provides a ready platform for assessing therapeutics that target not only DMD-related cardiomyopathy, but other forms of cardiomyopathy and myocardial injury.

Vibration Actuator System with Small-Scale Size Capable of Visual Inspection of Large Complex Iron Structures

Deterioration of social infrastructure equipment has become a major problem in countries around the world. In the present study, a novel vibration actuator system capable of movement on an iron structure having complicated surfaces, such as steps, is proposed. A vibration actuator capable of reciprocating movement with a small-scale size was prototyped and tested. In consideration of mobility, the size of the vibration actuator is designed to be smaller than 50 mm and the total mass is lighter than 20 g. The experimental result demonstrates that the maximum efficiency of the vibration actuator was 28.1%, and the maximum pulling power was 1.8 N. Furthermore, a vibration actuator system in which two vibration actuators and a wheel having a magnetic force connected by a flexible silicone rubber material was prototyped. This actuator system can move over a step of 48 mm in the horizontal plane and 25 mm in the vertical plane without control. Finally, a machine test was conducted on the frame surface moving, which is difficult even for robots. This actuator system can move at an average speed of 12.1 mm/s within the frame.

Biohybrid generators based on living plants and artificial leaves: influence of leaf motion and real wind outdoor energy harvesting

Plants translate wind energy into leaf fluttering and branch motion by reversible tissue deformation. Simultaneously, the outermost structure of the plant, i.e. the dielectric cuticula, and the inner ion-conductive tissue can be used to convert mechanical vibration energy, such as that produced during fluttering in the wind, into electricity by surface contact electrification and electrostatic induction. Constraining a tailored artificial leaf to a plant leaf can enhance oscillations and transient mechanical contacts and thereby increase the electricity outcome. We have studied the effects of wind-induced mechanical interactions between the leaf of a plant (Rhododendron) and a flexible silicone elastomer-based artificial leaf fixed at the petiole on power output and whether performance can be further tuned by altering the vibrational behavior of the artificial leaf. The latter is achieved by modifying a concentrated mass at the tip of the artificial leaf and observing plant-generated current and voltage signals under air flow. In this configuration, the plant-hybrid wind-energy converters can directly power light-emitting diodes and a temperature sensor. Detailed output analysis has revealed that, under all conditions, an increase in wind speed leads to nearly linearly increased voltages and currents. Accordingly, the cumulative sum energy reaches its highest values at the highest wind speed and resulting oscillations of the plant-artificial leaf system. The mass at the tip can, in most cases, be used to increase the voltage amplitude and frequency. Nevertheless, this behavior was found to depend on the individual configuration of the system, such as the leaf morphology. Analysis of these factors under controlled conditions is crucial for optimizing systems meant to operate in unstructured outdoor scenarios. We have established, in a first approach, that the artificial leaf-plant hybrid generator is capable of autonomously generating electricity outdoors under real outdoor wind conditions, even at a low average wind speed of only 1.9 m s−1.

Satisfaction with an In-House Nasal Foreign Body Removal Manikin: A Randomized Controlled Trial

IntroductionNasal foreign bodies can lead to life-threatening conditions. Hence, it is a necessity that physicians be well trained in the appropriate procedures for removal of nasal foreign bodies. However, training on real patients is not only unpractical it is also too dangerous, due to risk of foreign body aspiration during the procedure. Therefore, our goal was to construct a manikin, with a specific design, to serve all possible needs for training.MethodsWe developed an in-house manikin from 2 materials; these being flexible polyurethane foam and silicone. Silicone, which has elasticity similar to nasal alae, was used to develop the detachable nose and nasal cavity, whilst polyurethane foam, which is light and easy to carry, was used to develop the head. The in-house manikin was compared with a commercial manikin for satisfaction after a nasal foreign body removal procedure was performed in both groups, by 37 physicians, after conducting a randomized controlled trial with a crossover design.ResultsThe satisfaction scores of the in-house manikin were statistically significantly higher than the satisfaction scores of the commercial manikin for 6 dimensions: proper size, ease of use, ease of maintenance, flexibility of nasal alae relative to actual anatomy, similarity of the nasal cavity relative to actual anatomy and confidence that the manikin can upskill the medical students ability to practice on real patients (p value < 0.05).ConclusionThis in-house nasal foreign body removal manikin design had high satisfaction for training and could be used to develop further nasal foreign body removal manikins in the future.

Differential response of inner and outer zone meniscal cells to tensile load under non-inflammatory and inflammatory conditions

Differential response of inner and outer zone meniscal cells to tensile load under non-inflammatory and inflammatory conditions