Review of assistive devices for the prevention of pressure ulcers: an engineering perspective.

PURPOSE: Pressure ulcers (PUs) are prevalent among immobile bed or wheelchair-reliant individuals who experience prolonged sedentary positions. Pressure relief and frequent repositioning of body posture help to mitigate complications associated with PUs. Adherence with regular repositioning is difficult to maintain due to nursing labour shortages or constraints of in-home caregivers. Manual repositioning, transferring, and lifting of immobile patients are physically demanding tasks for caregivers. This review aimed to explore and categorize these devices, discuss the significant technical challenges that need addressing, and identify potential design opportunities. MATERIALS AND METHODS: In this review, a literature search was conducted using PubMED, Science Direct, Google Scholar and IEEE Xplore databases including studies from 1995 until Feb 2023 with keywords such as pressure ulcer, assistive device, pressure relief, repositioning, transfer, etc. Both commercial and research-level devices were included in the search. RESULTS: 142 devices or technologies were identified and classified into four main categories that were further subcategorized. Within each category, the devices were investigated in terms of their mechanical design, actuation methods, control strategies, sensing technologies, and level of autonomy. Limitations of current technologies are design complexity, lack of patient comfort, and a lack of autonomy requiring caregivers frequent intervention. CONCLUSIONS: Several devices have been developed to help with prevention and mitigation of PUs. There remain challenges that hinder the widespread accessibility and use of current technologies. Advancements in assistive technologies for pressure ulcer mitigation could lie at the intersection of robotics, sensors, perception, user-centered design, and autonomous systems.IMPLICATIONS FOR REHABILITATIONFuture advancements in assistive technologies for pressure ulcer mitigation could lie at the intersection of robotics, sensors, perception, user-centered design, and autonomous systems.Most existing technologies for prevention of pressure ulcers are focused on the mechanical advantage rather than user's needs and preferences. Future designers, engineers, and product developers must be educated to conduct user needs studies concurrently with the development of technology to design the devices based on the user's needs to ensure a balanced design outcome.

Design and Validation of a Soft Robotic Simulator for Transseptal Puncture Training.

OBJECTIVE: Transseptal puncture (TP) is the technique used to access the left atrium of the heart from the right atrium during cardiac catheterization procedures. Through repetition, electrophysiologists and interventional cardiologists experienced in TP develop manual skills to navigate the transseptal catheter assembly to their target on the fossa ovalis (FO). Cardiology fellows and cardiologists that are new to TP currently train on patients to develop this skill, resulting in increased risk of complications. The goal of this work was to create low-risk training opportunities for new TP operators. METHODS: We developed a Soft Active Transseptal Puncture Simulator (SATPS), designed to match the dynamics, static response, and visualization of the heart during TP. The SATPS includes three subsystems: (i) A soft robotic right atrium with pneumatic actuators mimics the dynamics of a beating heart. (ii) A fossa ovalis insert simulates cardiac tissue properties. (iii) A simulated intracardiac echocardiography environment provides live visual feedback. Subsystem performance was verified with benchtop tests. Face and content validity were evaluated by experienced clinicians. RESULTS: Subsystems accurately represented atrial volume displacement, tenting and puncture force, and FO deformation. Passive and active actuation states were deemed suitable for simulating different cardiac conditions. Participants rated the SATPS as realistic and useful for training cardiology fellows in TP. CONCLUSION: The SATPS can help improve catheterization skills of novice TP operators. SIGNIFICANCE: The SATPS could provide novice TP operators the opportunity to improve their TP skills before operating on a patient for the first time, reducing the likelihood of complications.

Designing Fiber-Reinforced Soft Actuators for Planar Curvilinear Shape Matching.

Fiber-reinforced soft pneumatic actuators can generate a wide variety of deformation behavior, making them popular in the field of soft robotics. Designing an actuator to meet a specified deformed shape is an important step toward the design of soft robots. We present a two-step methodology to design an actuator that matches a given planar curve on pressurization. In the first step, the curve is divided into a series of constant curvature (CC) segments that best approximate its shape. The second step involves designing a bending actuator by determining its fiber orientations for each CC segment. Further, this two-step method is extended to match two curves: a final deformed curve and an intermediate curve at a lower actuation pressure. On combining all the CC segments, the resulting actuator lies along a straight line unpressurized, and on pressurization deforms to trace the desired final curve through a preset intermediate curve. To demonstrate the method, we show different examples: an omega curve for an inchworm robot, an acronym SoRo for the Soft Robotics Journal, and a two-stage bending actuator.

Towards Pneumatic Spiral Grippers: Modeling and Design Considerations.

There are a number of instances in nature where long and slender objects are grasped by a continuum arm spirally twirling around the object, thereby increasing the area of contact and stability between the gripper and the object. This paper investigates the design and modeling of spiral grippers using pneumatic fiber-reinforced actuators. The paper proposes two reduced order models, a pure helical model, and a spatial Cosserat rod model to capture the deformed behavior of the gripper using the mechanics of fiber-reinforced actuators in the presence of self-weight. While the former model can yield closed form expressions that aid in design, the deformation parameters deviate by greater than 40% of its length for actuators longer than 200 mm. However, the Cosserat rod model deviates by less than 8% of its length for two different prototypes validated in this work. The deformation of the gripper is then correlated to the number of spiral turns achievable about the object, which determines the quality of the grip. Together, they enable a systematic framework where the gripper parameters can be designed for a given range of object sizes to be handled. This framework is experimentally validated by successful gripping of a range of slender objects that lie between a 20 mm diameter tubelight and a 60 mm diameter PVC pipe.

Design and analysis of coiled fiber reinforced soft pneumatic actuator.

Fiber reinforced elastomeric enclosures (FREEs) are soft pneumatic actuators that can contract and generate forces upon pressurization. Typical engineering applications utilize FREEs in their straight cylindrical configuration and derive actuation displacement and forces from their ends. However, there are several instances in nature, such as an elephant trunk, snakes and grapevine tendrils, where a spiral configuration of muscle systems is used for gripping, thereby establishing a mechanical connection with uniform force distribution. Inspired by these examples, this paper investigates the constricting behavior of a contracting FREE actuator deployed in a spiral or coiled configuration around a cylindrical object. Force balance is used to model the blocked force of the FREE, which is then related to the constriction force using a string model. The modeling and experimental findings reveal an attenuation in the blocked force, and thus the constriction force caused by the coupling of peripheral contact forces acting in the spiral configuration. The usefulness of the coiled FREE configuration is demonstrated in a soft arm orthosis for crutch users that provides a constriction force around the forearm. This design minimizes injury risk by reducing wrist load and improving wrist posture.

Selected aryl thiosemicarbazones as a new class of multi-targeted monoamine oxidase inhibitors.

A series of 13 phenyl substituted thiosemicarbazones (SB1-SB13) were synthesized and evaluated for their inhibitory potential towards human recombinant monoamine oxidase A and B (MAO-A and MAO-B, respectively) and acetylcholinesterase. The solid state structure of SB4 was ascertained by the single X-ray diffraction technique. Compounds SB5 and SB11 were potent for MAO-A (IC50 1.82 ± 0.14) and MAO-B (IC50 0.27 ± 0.015 µM), respectively. Furthermore, SB11 showed a high selectivity index (SI > 37.0) for MAO-B. The effects of fluorine orientation revealed that SB11 (m-fluorine) showed 28.2 times higher inhibitory activity than SB12 (o-fluorine) against MAO-B. Furthermore, inhibitions by SB5 and SB11 against MAO-A and MAO-B, respectively, were recovered to near reference levels in reversibility experiments. Both SB5 and SB11 showed competitive inhibition modes, with K i values of 0.97 ± 0.042 and 0.12 ± 0.006 µM, respectively. These results indicate that SB5 and SB11 are selective, reversible and competitive inhibitors of MAO-A and MAO-B, respectively. Compounds SB5, SB7 and SB11 showed moderate inhibition against acetylcholinesterase with IC50 values of 35.35 ± 0.47, 15.61 ± 0.057 and 26.61 ± 0.338 µM, respectively. Blood-brain barrier (BBB) permeation was studied using the parallel artificial membrane permeation assay (PAMPA) method. Molecular docking studies were carried out using AutoDock 4.2.

Pharmacophore Modeling, 3D-QSAR and Molecular Docking of Furanochalcones as Inhibitors of Monoamine Oxidase-B.

Monoamine oxidase B inhibitors are of particular importance in the treatment of neurodegenerative disorders such as Alzheimer's and Parkinson's disease. Herein described is pharmacophore generation and atom-based 3D-QSAR analysis of previously reported furan based MAO-B inhibitors in order to get insight into their structural requirements responsible for high affinity. The best pharmacophore model generated with the five-point hypotheses of ADHRR: hydrogen bond acceptor (A), hydrogen bond donor (D), hydrophobic (H) and two aromatic rings (R1 & R2). On the basis of generated model, a statistically valid 3D-QSAR with good predictability was developed. Molecular docking of lead compound showed binding energy of -8.66 kcal/mol with a predicted inhibition constant of 0.448 µM towards MAO-B.

Synthesis and antihyperlipidemic activity of some novel condensed 2-chloroalkyl-4-chloro/hydroxy-5,6-disubstituted pyrimidines.

Synthesis and antihyperlipidemic activity of a series of novel condensed 2-chloroalkyl-4-chloro/hydroxy-5,6-di-substituted pyrimidines are described. The design of these compounds is based on the earlier QSAR study on the antihyperlipidemic 2-substituted methylthienopyrimidin-4-ones. The newly synthesized condensed 4-chloro-2-chloroalkylpyrimidines (IIIa-n) have exhibited much superior antihyperlipidemic activity, compared to their earlier reported 4-hydroxy analogs. Notably, in this series, five compounds, IIIa, IIIb, IIIc, IIIi and IIIm showed good ability to reduce total cholesterol and two compounds, IIIa and IIIk exhibited better reduction in serum triglycerides. All the newly synthesized compounds have been evaluated by the Triton WR 1339 induced hyperlipidemia in albino Wistar rats model for antihyperlipidemic activity, and their activity is superior to that exhibited by the standard gemfibrozil used in the study. A 3D QSAR study has also been performed to delineate the effect of the substituents at 5 and 6 positions on the antihyperlipidemic activity of 2-chloromethyl-5,6-substituted thieno(2,3-d) pyrimidin-4(3H)-ones (IIa-e).