28 research outputs found
Patient-specific 3D-printed splint for mallet finger injury
Despite the frequency of mallet finger injuries, treatment options can often be costly, time-consuming, and ill-fitted. Three-dimensional (3D) printing allows for the production of highly customized and inexpensive splints, which suggests potential efficacy in the prescription of casts for musculoskeletal injuries. This study explores how the use of engineering concepts such as 3D printing and topology optimization (TO) can improve outcomes for patients. 3D printing enables the direct fabrication of the patient-specific complex shapes while utilizing finite element analysis and TO in the design of the splint allowed for the most efficient distribution of material to achieve mechanical requirements while reducing the amount of material used. The reduction in used material leads to significant improvements in weight reduction and heat dissipation, which would improve breathability and less sweating for the patient, greatly increasing comfort for the duration of their recovery
Control-based 4D printing: adaptive 4D-printed systems
Building on the recent progress of four-dimensional (4D) printing to produce dynamic structures, this study aimed to bring this technology to the next level by introducing control-based 4D printing to develop adaptive 4D-printed systems with highly versatile multi-disciplinary applications, including medicine, in the form of assisted soft robots, smart textiles as wearable electronics and other industries such as agriculture and microfluidics. This study introduced and analysed adaptive 4D-printed systems with an advanced manufacturing approach for developing stimuli-responsive constructs that organically adapted to environmental dynamic situations and uncertainties as nature does. The adaptive 4D-printed systems incorporated synergic integration of three-dimensional (3D)-printed sensors into 4D-printing and control units, which could be assembled and programmed to transform their shapes based on the assigned tasks and environmental stimuli. This paper demonstrates the adaptivity of these systems via a combination of proprioceptive sensory feedback, modeling and controllers, as well as the challenges and future opportunities they present
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Direct 3D printing of a two-part silicone resin to fabricate highly stretchable structures
The direct ink writing (DIW) method of 3D-printing liquid resins has shown promising results in various applications such as flexible electronics, medical devices, and soft robots. A cost-effective extrusion system for a two-part high-viscous resin is developed in this article to fabricate soft and immensely stretchable structures. A static mixer capable of evenly mixing two viscous resins in an extremely low flow regime is designed based on the required mixing performance through a series of biphasic computational fluid dynamics analyses. The printing parameters of the extrusion system are determined empirically, and the mechanical properties of the printed samples are compared to their molded counterparts. Furthermore, some potential applications of the system in soft robotics and medical training are demonstrated. This research provides a clear guide for utilizing DIW to 3D print highly stretchable structures
Manufacture Techniques of Chitosan-Based Microcapsules to Enhance Functional Properties of Textiles
In recent years, the textile industry has been moving to novel concepts of products, which could deliver to the user, improved performances. Such smart textiles have been proven to have the potential to integrate within a commodity garment advanced feature and functional properties of different kinds. Among those functionalities, considerable interest has been played in functionalizing commodity garments in order to make them positively interact with the human body and therefore being beneficial to the user health. This kind of functionalization generally exploits biopolymers, a class of materials that possess peculiar properties such as biocompatibility and biodegradability that make them suitable for bio-functional textile production. In the context of biopolymer chitosan has been proved to be an excellent potential candidate for this kind of application given its abundant availability and its chemical properties that it positively interacts with biological tissue. Notwithstanding the high potential of chitosan-based technologies in the textile sectors, several issues limit the large-scale production of such innovative garments. In facts the morphologies of chitosan structures should be optimized in order to make them better exploit the biological activity; moreover a suitable process for the application of chitosan structures to the textile must be designed. The application process should indeed not only allow an effective and durable fixation of chitosan to textile but also comply with environmental rules concerning pollution emission and utilization of harmful substances. This chapter reviews the use of microencapsulation technique as an approach to effectively apply chitosan to the textile material while overcoming the significant limitations of finishing processes. The assembly of chitosan macromolecules into microcapsules was proved to boost the biological properties of the polymer thanks to a considerable increase in the surface area available for interactions with the living tissues. Moreover, the incorporation of different active substances into chitosan shells allows the design of multifunctional materials that effectively combine core and shell properties. Based on the kind of substances to be incorporated, several encapsulation processes have been developed. The literature evidences how the proper choices concerning encapsulation technology, chemical formulations, and process parameter allow tuning the properties and the performances of the obtained microcapsules. Furthermore, the microcapsules based finishing process have been reviewed evidencing how the microcapsules morphology can positively interact with textile substrate allowing an improvement in the durability of the treatment. The application of the chitosan shelled microcapsules was proved to be capable of imparting different functionalities to textile substrates opening possibilities for a new generation of garments with improved performances and with the potential of protecting the user from multiple harms. Lastly, a continuous interest was observed in improving the process and formulation design in order to avoid the usage of toxic substances, therefore, complying with an environmentally friendly approach
A COMPARISON OF CLOMIPHENE CITRATE AND SEQUENTIAL CLOMIPHENE CITRATE PLUS HUMAN MENOPAUSAL GONADOTROPIN FOR USE IN CONJUNCTION WITH INTRAUTERINE INSEMINATION
There are currently ‎many different protocols in use for controlled ovarian hyperstimulation (COH), but the optimal method has ‎not yet been determined. To compare the outcome of COH using ‎clomiphene citrate (CC) versus CC plus human menopausal gonadotropin (hMG) in conjunction with intrauterine insemination (IUI), we studied 117 infertile couples‎. IUI with CC was used in 92 cycles ‎(group A) and IUI with CC plus hMG was used in 66 cycles (group B). ‎Data analysis demonstrated no significant difference between the two ‎groups with respect to patients’ age, duration and type of infertility, prior COH and endometrial thickness and pattern. Group A had a little ‎longer follicular phase length than group B. ‎Pregnancy rate for group A and B were 6.52% and 12.12%, respectively (P= 0.22). ‎Endometrial pattern and thickness had no impact on pregnancy rate. ‎There were no multiple gestation and obvious hyperstimulation syndrome. ‎For patients undergoing controlled ovarian hyperstimulation with IUI, ‎CC plus hMG protocol yields higher pregnancy rate than one using CC, although this ‎difference was not statistically significant because of limitation of number of ‎cycles
Effectiveness of Educating Play Ther-apy Based on Child Parent Relationship Therapy (CPRT) According Landreth Model to Mothers on Reducing Child Behavioral Prob-lems
The psychologists for reducing child behavioral problems have suggested many different methods. Some of these methods have focused on child, some on parents and the others on educational environments. The most prevalent way for changing the child behaviors has been play therapy.In the last decades, play therapy has been focused more on the therapist-child relationship, whereas some methods have been attended to educat-ing play therapy skills to parents as an intermediate for improvement of child behaviors. One of these methods is child-parent relationship thera-py (CPRT).The aim of this research is surveying the efficiency of CPRT on reducing child problematic behavior. For surveying this aim, some preschool children aged 6-7 were assessed in two phases. In the first stage 73 chil-dren have been assessed using Child Behavior Checklist (CBCL), that 25 children had behavioral problems. 13 of their mothers were ready to contribute in this research that 6 mothers have been randomly assigned to experiment group and 7 to control group.All of these mothers filled the CBCL in pre and post test situations. The experiment group faced with play therapy skills training program in ten two-hour session and the control group waited for an optional delayed treatment. Pre and post test data was analyzed with U-man witney test and the results showed that CPRT has caused a meaningful reduction in children's behavioral problems in experiment group than control one
A bioinspired compliant 3D-printed soft gripper
A compliant three-dimensional (3D)-printed soft gripper is designed based on the bioinspired spiral spring in this study. The soft gripper is then 3D-printed using a suitable thermoplastic filament material to deliver the desired performance. The sensorless mechanism introduced in this study provides adequate compliance with a single linear actuator for interacting with delicate objects, such as manipulation of human biological materials and fruit picking. The kinematic and dynamic models of the monolithic gripper are derived analytically as well as by means of finite element analysis to synthesize its functionality. The fabricated gripper module is installed on a robot arm to demonstrate the efficacy of design for picking and placing fruits without damaging them. The presented mechanism could be customized and used in the medical and agricultural sectors with diverse geometry objects
4D printing soft robots guided by machine learning and finite element models
This paper presents a method for four-dimensional (4D) printing of soft pneumatic actuator robot (SPA)s, using nonlinear machine learning (ML) and finite element model (FEM). A FEM is developed to accurately simulate experimental actuation to obtain training data for the ML modeling. More than a thousand data training samples from the hyperelastic material FEM model generated to use as training data for the ML model, which was developed to predict the geometrical requirements of the 4D-printed SPA to realize the bending required for specific tasks. The ML model accurately predicted FEM and experimental data and proved to be a viable solution for 4D printing of soft robots and dynamic structures. This work helps to understand how to develop geometrical soft robots’ designs for nonlinear 4D printing problems using ML and FEM
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Silicon-based soft parallel robots 4D printing and multiphysics analysis
Four-dimensional (4D) printing has set the stage for a new generation of soft robotics. The applications of rigid planar parallel robotic manipulators are also significant because of their various desirable characteristics, such as lower inertia, higher payload, and high accuracy. However, rigid planar parallel robots are heavy and require different actuators and components. This study introduces a novel technique to produce a light three degrees of freedom (DOF) soft parallel manipulator at a low cost, which can be stimulated easily. This technique allows researchers to customize the actuator's design based on the requirement. The robot is made by 3D printing based on fused deposition modelling (FDM) and a direct ink writing (DIW) process. The design, development, and additive manufacturing (AM) of a soft parallel robot electrothermally driven by a linear silicon-based actuator and polylactic acid (PLA) parts are presented. Silicon-based soft actuators replace the rigid conventional linear actuators in this study to drive the planar parallel manipulator. The actuation of actuators is conducted using simple heating compared to the conventional rigid actuator. Various heating approaches and configurations are compared and analysed to find the most suitable one for the effective linear stroke of the soft actuator. The finite element model (FEM) is used to analyse the performance of the electrothermally silicon-ethanol soft actuators in ABAQUS. The kinematics of the planar parallel robotic manipulator are simulated in MATLAB to achieve its workspace. The final soft parallel robot mechanism and the active and passive links are fabricated and tested experimentally