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Krinis SLL, Chadwell A, Kenney L, Smit G. A quantitative comparison between the mHand Adapt passive adjustable hand prosthesis and its predecessor, the Delft Self-Grasping Hand. PLoS One 2024; 19:e0300469. [PMID: 38512857 PMCID: PMC10956796 DOI: 10.1371/journal.pone.0300469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 02/03/2024] [Indexed: 03/23/2024] Open
Abstract
INTRODUCTION The Delft Self-Grasping Hand (SGH) is an adjustable passive hand prosthesis that relies on wrist flexion to adjust the aperture of its grasp. The mechanism requires engagement of the contralateral hand meaning that hand is not available for other tasks. A commercialised version of this prosthesis, known as the mHand Adapt, includes a new release mechanism, which avoids the need to press a release button, and changes to the hand shape. This study is the first of its kind to compare two passive adjustable hand prostheses on the basis of quantitative scoring and contralateral hand involvement. METHODS 10 anatomically intact participants were asked to perform the Southampton Hand Assessment Procedure (SHAP) with the mHand. Functionality and contralateral hand involvement were recorded and compared against SGH data originating from a previous trial involving a nearly identical testing regime. RESULTS mHand exhibited higher functionality scores and less contralateral hand interaction time, especially during release-aiding interactions. Additionally, a wider range of tasks could be completed using the mHand than the SGH. DISCUSSION Geometric changes make the mHand more capable of manipulating smaller objects. The altered locking mechanism means some tasks can be performed without any contralateral hand involvement and a higher number of tasks do not require contralateral involvement when releasing. Some participants struggled with achieving a good initial grip due to the inability to tighten the grasp once already formed. CONCLUSION The mHand offers the user higher functionality scores with less contralateral hand interaction time and the ability to perform a wider range of tasks. However, there are some design trade-offs which may make it slightly harder to learn to use.
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Affiliation(s)
- Spyros L. L. Krinis
- Centre for Health Sciences Research, University of Salford, Salford, United Kingdom
- Department of Biomedical Engineering, Delft University of Technology, Delft, The Netherlands
| | - Alix Chadwell
- Centre for Health Sciences Research, University of Salford, Salford, United Kingdom
| | - Laurence Kenney
- Centre for Health Sciences Research, University of Salford, Salford, United Kingdom
| | - Gerwin Smit
- Department of Biomedical Engineering, Delft University of Technology, Delft, The Netherlands
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Zillen E, van der Windt B, Vallery H, Smit G. 3D-printing allows for fluid-controlled linear actuators with unconventional shapes. Heliyon 2024; 10:e26497. [PMID: 38434412 PMCID: PMC10907517 DOI: 10.1016/j.heliyon.2024.e26497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 02/14/2024] [Accepted: 02/14/2024] [Indexed: 03/05/2024] Open
Abstract
Background Pneumatic actuators are widely used in applications like (medical) robots, or prostheses. Pneumatic actuators require a complex manufacturing process and are produced in standardized dimensions to reduce costs. Over the last decade 3D-printing has emerged as a cost-effective and efficient production method in medical applications. 3D-printing can also function as a cost-efficient alternative production method for pneumatic actuators. Objective The goal of this research is to study the possibility of creating a pneumatic linear actuator with 3D-printing. Furthermore, the aim is to use the advantage of 3D-printing to create pneumatic actuators with non-circular cross-sections. Methodology To evaluate the performance of a 3D-printed pneumatic actuator, a test setup was designed and built to measure the leakage and sliding friction force. Furthermore, two pneumatic actuators with a non-conventional cross-sectional shape were designed and their performance was tested and compared with a 3D-printed cylindrical pneumatic actuator, since these tests only ran once, the results are more a guideline. During the manufacturing of the cylinders, no post-processing techniques were used. Results The functioning of a 3D-printed circular pneumatic actuator was proven with low static leakage rates of 2.5%, low dynamic leakage rates of approximately 1%, and a maximum friction force of Image 1. Furthermore, the results show that it is possible to print functioning pneumatic cylinders with a non-cylindrical concave cross-section. The non-conventional cylinders were tested up to Image 2 with maximum dynamic leakage of Image 3. Conclusion This study demonstrates a method to create functional pneumatic linear actuators with 3D-printing. It was possible to create 3D-printed actuators with a conventional shape, e.g. circular and unconventional shapes e.g. stadium/oval shape and a kidney shape. The leak rates for conventional and unconventional shapes were in the same range. This opens up the world for more design freedom in pneumatic actuators.
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Affiliation(s)
- Eva Zillen
- Delft University of Technology, Department of Biomechanical Engineering, Faculty of Mechanical Engineering, the Netherlands
| | - Bob van der Windt
- Delft University of Technology, Department of Biomechanical Engineering, Faculty of Mechanical Engineering, the Netherlands
| | - Heike Vallery
- Delft University of Technology, Department of Biomechanical Engineering, Faculty of Mechanical Engineering, the Netherlands
- RWTH Aachen, Department of Automated Control, Faculty of Mechanical Engineering, Germany
| | - Gerwin Smit
- Delft University of Technology, Department of Biomechanical Engineering, Faculty of Mechanical Engineering, the Netherlands
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Vallery H, Lachmann F, van der Helm S, Pennycott A, Smit G. Design and evaluation of the pneumatic leg prosthesis ERiK to assist elderly amputees with sit-down and stand-up movements. Wearable Technol 2023; 4:e16. [PMID: 38487767 PMCID: PMC10936377 DOI: 10.1017/wtc.2023.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 01/31/2023] [Accepted: 02/18/2023] [Indexed: 03/17/2024]
Abstract
Standing up using one leg is a challenging task for those with a transfemoral amputation, particularly for elderly users with a low activity level. Active prostheses are generally not accessible to this group and available passive prostheses do not support standing up. This article presents the design and evaluation of the "Energy Restoring Intelligent Knee" (ERiK), which stores energy during sit-down in a pneumatic cylinder and returns it during stand-up. We hypothesized that the system would reduce the time needed to perform transitions and also enable higher load sharing by the prosthetic leg. However, the results of an experimental study with seven participants with transfemoral amputation contradict these hypotheses: the participants could neither move faster nor make more use of the prosthetic leg to share their body weight during transitions. We observed that a major obstacle to the useful functionality of the leg was the absence of ankle dorsiflexion - the foot tended to slip during stand-up initiation, such that only low pre-pressures and therefore support levels could be set. The rather binary action of the pneumatics also complicated movement initiation. The lessons learned from this study may be helpful to those seeking to create better designs in the future.
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Affiliation(s)
- Heike Vallery
- Faculty of Mechanical, Maritime and Materials Engineering, TU Delft, Delft, The Netherlands
- Department of Rehabilitation Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - Frederik Lachmann
- Faculty of Mechanical, Maritime and Materials Engineering, TU Delft, Delft, The Netherlands
| | - Simon van der Helm
- Faculty of Mechanical, Maritime and Materials Engineering, TU Delft, Delft, The Netherlands
| | - Andrew Pennycott
- Faculty of Mechanical, Maritime and Materials Engineering, TU Delft, Delft, The Netherlands
| | - Gerwin Smit
- Faculty of Mechanical, Maritime and Materials Engineering, TU Delft, Delft, The Netherlands
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Sinke M, Chadwell A, Smit G. State of the art of prosthesis simulators for the upper limb: A narrative review. Ann Phys Rehabil Med 2022; 65:101635. [PMID: 35091112 DOI: 10.1016/j.rehab.2022.101635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 11/09/2021] [Accepted: 11/11/2021] [Indexed: 10/18/2022]
Abstract
BACKGROUND Research into prosthesis training and design puts a burden on the small population of people with upper-limb absence who can participate in these studies. One solution is to use a prosthetic hand simulator, which allows for attaching a hand prosthesis to an intact limb. However, whether the results of prosthesis simulator studies can be translated to people with upper-limb absence using a hand prosthesis is unclear. OBJECTIVE To review the literature on prosthetic hand simulators, provide an overview of current designs, and highlight the differences and similarities between prosthesis simulators and traditional prostheses. METHODS A Boolean combination of keywords was used to search 3 electronic databases: PubMed, Scopus and Web of Science. Relevant articles in English were selected. RESULTS In total, 52 papers were included in the review, and an overview of the state of the art was presented. We identified the key differences between prosthesis simulators and traditional prostheses as the position of the terminal device and the available degrees of freedom of the arm and (prosthetic) wrist. CONCLUSIONS This paper provides an overview of prosthesis simulator designs over the past 27 years and an overview of the similarities and differences between prosthesis simulators and prostheses. The literature does not provide enough evidence to establish whether the results obtained from simulator studies could be translated to prostheses. A recommendation for future simulator design is to constrain pro- and supination of the forearm of anatomically intact participants and add a prosthetic wrist that can pro- and supinate. Additional research is required to find the ideal terminal device position for a prosthesis simulator with respect to the person's hand.
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Affiliation(s)
- Maaike Sinke
- BioMechanical Engineering, Delft University of Technology, Mekelweg 2, 2628 CD, Delft, The Netherlands
| | - Alix Chadwell
- Health Sciences Research Centre, University of Salford, Salford, M6 6PU, UK
| | - Gerwin Smit
- BioMechanical Engineering, Delft University of Technology, Mekelweg 2, 2628 CD, Delft, The Netherlands.
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Ali A, Dodou D, Smit G, Rink R, Breedveld P. Stabilizing interventional instruments in the cardiovascular system: A classification of mechanisms. Med Eng Phys 2021; 89:22-32. [PMID: 33608122 DOI: 10.1016/j.medengphy.2021.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 01/11/2021] [Accepted: 01/17/2021] [Indexed: 10/22/2022]
Abstract
Positioning and stabilizing a catheter at the required location inside a vessel or the heart is a complicated task in interventional cardiology. In this review we provide a structured classification of catheter stabilization mechanisms to systematically assess their challenges during cardiac interventions. Commercially available, patented, and experimental prototypes of catheters were classified with respect to their stabilizing mechanisms. Subsequently, the classification was used to define requirements for future cardiac catheters and persisting challenges in catheter stabilization. The classification showed that there are two main stabilization mechanisms: surface-based and volume-based. Surface-based mechanisms apply attachment through surface anchoring, while volume-based mechanisms make use of locking through shape or force against the vessel or cardiac wall. The classification provides insight into existing catheter stabilization mechanisms and can possibly be used as a tool for future design of catheter stabilization mechanisms to keep the catheter at a specific location during an intervention. Additionally, insight into the requirements and challenges for catheter stabilization inside the heart and vasculature can lead to the development of more dedicated systems in the future, allowing for intervention- and patient-specific instrument manipulation.
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Affiliation(s)
- Awaz Ali
- PhD candidate at TU Delft, Delft University of Technology, Faculty of Mechanical, Maritime and Materials Engineering, Department of BioMechanical Engineering, Delft, Zuid-Holland, the Netherlands.
| | - Dimitra Dodou
- Associate Professor Bio-Mechanical Engineering at TU Delft, Delft University of Technology, Faculty of Mechanical, Maritime and Materials Engineering, Department of BioMechanical Engineering, Delft, Zuid-Holland, the Netherlands.
| | - Gerwin Smit
- Assistant Professor Bio-Mechanical Engineering at TU Delft, Delft University of Technology, Faculty of Mechanical, Maritime and Materials Engineering, Department of BioMechanical Engineering, Delft, Zuid-Holland, the Netherlands.
| | - Ruben Rink
- Student Bio-Mechanical Engineering at TU Delft, Delft University of Technology, Faculty of Mechanical, Maritime and Materials Engineering, Department of BioMechanical Engineering, Delft, Zuid-Holland, the Netherlands.
| | - Paul Breedveld
- Professor Bio-Mechanical Engineering at TU Delft, Delft University of Technology, Faculty of Mechanical, Maritime and Materials Engineering, Department of BioMechanical Engineering, Delft, Zuid-Holland, the Netherlands.
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Smit G. Mechanical evaluation of the "Hüfner hand" prosthesis. Prosthet Orthot Int 2021; 45:54-61. [PMID: 33834745 PMCID: PMC7978037 DOI: 10.1177/0309364620952900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 07/20/2020] [Indexed: 02/03/2023]
Abstract
BACKGROUND Current body-powered hands have very low acceptance rates. They also require high activation forces. In the past, a high acceptance rate was reported for the then-available Hüfner hand, a hand which could be controlled by relatively low activation forces. OBJECTIVE The aim of this study was to measure and quantify the mechanical performance of the Hüfner hand. STUDY DESIGN Mechanical evaluation. METHODS Two versions of the Hüfner hand were tested using a mechanical test bench. Forces and displacements were measured under four different glove conditions (no glove, leather, polyvinyl chloride (PVC), silicone). The measured results were compared to data from currently available voluntary-closing hands. RESULTS The Hüfner hand required 132-170 Nmm of work and 78-104 N cable force to pinch 15 N. The overall mechanical performance of the Hüfner hands is better than currently available body-powered hands. CONCLUSION The mechanical performance of the Hüfner hand was measured and quantified. Mechanical testing results show that the Hüfner hand has better mechanical performance than current body-powered hands. This may have contributed to its reported high acceptance rates. The design of the Hüfner hand, combined with data presented in this study, can serve as guidelines for the design of a new generation of body-powered hands.
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Affiliation(s)
- Gerwin Smit
- Delft University of Technology, Delft, The Netherlands
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Dittli J, Hofmann UAT, Bützer T, Smit G, Lambercy O, Gassert R. Remote Actuation Systems for Fully Wearable Assistive Devices: Requirements, Selection, and Optimization for Out-of-the-Lab Application of a Hand Exoskeleton. Front Robot AI 2021; 7:596185. [PMID: 33585573 PMCID: PMC7876397 DOI: 10.3389/frobt.2020.596185] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 11/06/2020] [Indexed: 01/26/2023] Open
Abstract
Wearable robots assist individuals with sensorimotor impairment in daily life, or support industrial workers in physically demanding tasks. In such scenarios, low mass and compact design are crucial factors for device acceptance. Remote actuation systems (RAS) have emerged as a popular approach in wearable robots to reduce perceived weight and increase usability. Different RAS have been presented in the literature to accommodate for a wide range of applications and related design requirements. The push toward use of wearable robotics in out-of-the-lab applications in clinics, home environments, or industry created a shift in requirements for RAS. In this context, high durability, ergonomics, and simple maintenance gain in importance. However, these are only rarely considered and evaluated in research publications, despite being drivers for device abandonment by end-users. In this paper, we summarize existing approaches of RAS for wearable assistive technology in a literature review and compare advantages and disadvantages, focusing on specific evaluation criteria for out-of-the-lab applications to provide guidelines for the selection of RAS. Based on the gained insights, we present the development, optimization, and evaluation of a cable-based RAS for out-of-the-lab applications in a wearable assistive soft hand exoskeleton. The presented RAS features full wearability, high durability, high efficiency, and appealing design while fulfilling ergonomic criteria such as low mass and high wearing comfort. This work aims to support the transfer of RAS for wearable robotics from controlled lab environments to out-of-the-lab applications.
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Affiliation(s)
- Jan Dittli
- Rehabilitation Engineering Laboratory, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Urs A. T. Hofmann
- Rehabilitation Engineering Laboratory, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Tobias Bützer
- Rehabilitation Engineering Laboratory, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Gerwin Smit
- Department of BioMechanical Engineering, Delft University of Technology, Delft, Netherlands
| | - Olivier Lambercy
- Rehabilitation Engineering Laboratory, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Roger Gassert
- Rehabilitation Engineering Laboratory, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
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Cuellar JS, Plettenburg D, Zadpoor AA, Breedveld P, Smit G. Design of a 3D-printed hand prosthesis featuring articulated bio-inspired fingers. Proc Inst Mech Eng H 2020; 235:336-345. [PMID: 33292076 DOI: 10.1177/0954411920980889] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Various upper-limb prostheses have been designed for 3D printing but only a few of them are based on bio-inspired design principles and many anatomical details are not typically incorporated even though 3D printing offers advantages that facilitate the application of such design principles. We therefore aimed to apply a bio-inspired approach to the design and fabrication of articulated fingers for a new type of 3D printed hand prosthesis that is body-powered and complies with basic user requirements. We first studied the biological structure of human fingers and their movement control mechanisms in order to devise the transmission and actuation system. A number of working principles were established and various simplifications were made to fabricate the hand prosthesis using a fused deposition modelling (FDM) 3D printer with dual material extrusion. We then evaluated the mechanical performance of the prosthetic device by measuring its ability to exert pinch forces and the energy dissipated during each operational cycle. We fabricated our prototypes using three polymeric materials including PLA, TPU, and Nylon. The total weight of the prosthesis was 92 g with a total material cost of 12 US dollars. The energy dissipated during each cycle was 0.380 Nm with a pinch force of ≈16 N corresponding to an input force of 100 N. The hand is actuated by a conventional pulling cable used in BP prostheses. It is connected to a shoulder strap at one end and to the coupling of the whiffle tree mechanism at the other end. The whiffle tree mechanism distributes the force to the four tendons, which bend all fingers simultaneously when pulled. The design described in this manuscript demonstrates several bio-inspired design features and is capable of performing different grasping patterns due to the adaptive grasping provided by the articulated fingers. The pinch force obtained is superior to other fully 3D printed body-powered hand prostheses, but still below that of conventional body powered hand prostheses. We present a 3D printed bio-inspired prosthetic hand that is body-powered and includes all of the following characteristics: adaptive grasping, articulated fingers, and minimized post-printing assembly. Additionally, the low cost and low weight make this prosthetic hand a worthy option mainly in locations where state-of-the-art prosthetic workshops are absent.
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Affiliation(s)
- Juan Sebastian Cuellar
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - Dick Plettenburg
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - Amir A Zadpoor
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - Paul Breedveld
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - Gerwin Smit
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
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Henselmans PW, Smit G, Breedveld P. Mechanical Follow-the-Leader motion of a hyper-redundant surgical instrument: Proof-of-concept prototype and first tests. Proc Inst Mech Eng H 2019; 233:1141-1150. [PMID: 31526098 PMCID: PMC6791023 DOI: 10.1177/0954411919876466] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
One of the most prominent drivers in the development of surgical procedures is the will to reduce their invasiveness, attested by minimally invasive surgery being the gold standards in many surgical procedures and natural orifices transluminal endoscopic surgery gaining acceptance. A logical next step in this pursuit is the introduction of hyper-redundant instruments that can insert themselves along multi-curved paths referred to as Follow-the-Leader motion. In the current state of the art, two different types of Follow-the-Leader instruments can be distinguished. One type of instrument is robotized; the movements of the shaft are controlled from outside the patient by actuators, for example, electric motors, and a controller storing a virtual track of the desired path. The other type of instrument is more mechanical; the movements of the shaft are controlled from inside the patient by a physical track that guides the shaft along the desired path. While in the robotized approach all degrees of freedom of the shaft require an individual actuator, the mechanical approach makes the number of degrees of freedom independent from the number of actuators. A desirable feature as an increasing number of actuators will inevitably drive up costs and increase the footprint of an instrument. Building the physical track inside the body does, however, impede miniaturization of the shaft’s diameter. This article introduces a new fully mechanical approach for Follow-the-Leader motion using a pre-determined physical track that is placed outside the body. This new approach was validated with a prototype called MemoFlex, which supports a Ø5 mm shaft (standard size in minimally invasive surgery) that contains 28-degrees-of-freedom and utilizes a simple steel rod as its physical track. Even though the performance of the MemoFlex leaves room for improvement, especially when following multiple curves, it does validate the proposed concept for Follow-the-Leader motion in three-dimensional space.
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Affiliation(s)
- Paul Wj Henselmans
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - Gerwin Smit
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - Paul Breedveld
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
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Abstract
In developing countries, the access of amputees to prosthetic devices is very limited. In a way to increase accessibility of prosthetic hands, we have recently developed a new approach for the design and 3D printing of non-assembly active hand prostheses using inexpensive 3D printers working on the basis of material extrusion technology. This article describes the design of our novel 3D-printed hand prosthesis and also shows the mechanical and functional evaluation in view of its future use in developing countries. We have fabricated a hand prosthesis using 3D printing technology and a non-assembly design approach that reaches certain level of functionality. The mechanical resistance of critical parts, the mechanical performance, and the functionality of a non-assembly 3D-printed hand prosthesis were assessed. The mechanical configuration used in the hand prosthesis is able to withstand typical actuation forces delivered by prosthetic users. Moreover, the activation forces and the energy required for a closing cycle are considerably lower as compared to other body-powered prostheses. The non-assembly design achieved a comparable level of functionality with respect to other body-powered alternatives. We consider this prosthetic hand a valuable option for people with arm defects in developing countries.
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Affiliation(s)
- Juan Sebastian Cuellar
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - Gerwin Smit
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - Paul Breedveld
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - Amir Abbas Zadpoor
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - Dick Plettenburg
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
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Abstract
In developing countries, prosthetic workshops are limited, difficult to reach, or
even non-existent. Especially, fabrication of active, multi-articulated, and
personalized hand prosthetic devices is often seen as a time-consuming and
demanding process. An active prosthetic hand made through the fused deposition
modelling technology and fully assembled right after the end of the 3D printing
process will increase accessibility of prosthetic devices by reducing or
bypassing the current manufacturing and post-processing steps. In this study, an
approach for producing active hand prosthesis that could be fabricated fully
assembled by fused deposition modelling technology is developed. By presenting a
successful case of non-assembly 3D printing, this article defines a list of
design considerations that should be followed in order to achieve fully
functional non-assembly devices. Ten design considerations for additive
manufacturing of non-assembly mechanisms have been proposed and a design case
has been successfully addressed resulting in a fully functional prosthetic hand.
The hand prosthesis can be 3D printed with an inexpensive fused deposition
modelling machine and is capable of performing different types of grasping. The
activation force required to start a pinch grasp, the energy required for
closing, and the overall mass are significantly lower than body-powered
commercial prosthetic hands. The results suggest that this non-assembly design
may be a good alternative for amputees in developing countries.
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Affiliation(s)
- Juan Sebastian Cuellar
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - Gerwin Smit
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - Amir A Zadpoor
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - Paul Breedveld
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
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Sakes A, Snaar K, Smit G, Witkamp AJ, Breedveld P. Design of a novel miniature breast biopsy needle for ductoscopy. Biomed Phys Eng Express 2018. [DOI: 10.1088/2057-1976/aab218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Sakes A, Hovland K, Smit G, Geraedts J, Breedveld P. Design of a Novel Three-Dimensional-Printed Two Degrees-of-Freedom Steerable Electrosurgical Grasper for Minimally Invasive Surgery. J Med Device 2018. [DOI: 10.1115/1.4038561] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
In current bipolar electrosurgical instruments, a high frequency electrical sinusoidal wave is passed through the patient's body from an active electrode to the return electrode to cut, coagulate, or desiccate tissues. Even though current bipolar electrosurgical instruments have proven effective in minimizing blood loss, advancement is needed to allow for improved dexterity and adaptability. With current advances in three-dimensional (3D)-print processes and its integration in the medical field, it has become possible to manufacture patient-and operation-specific instruments. In this study, we introduce the first 3D-printed steerable bipolar grasper (◻ 5 mm) for use in minimal invasive surgery. The grasper significantly improves dexterity by the addition of two planar joints allowing for ±65 deg for sideways and ±85 deg for up- and downward movement. The joints enable a significantly higher bending stiffness, 4.0 N/mm for joint 1 and 4.4 N/mm for joint 2, than that of currently available steerable instruments. The tip consists of two metallic movable jaws that can be opened and closed with angles up to 170 deg and allows for grasping and coagulating of tissues; reaching tissue temperatures of over 75 °C for an activation time of ∼5 s, respectively. In order to actuate the joint, tip, and electrosurgical system, as well as to tension the steering cables, a ring handle was designed. In summary, the 3D-printed steerable bipolar grasper provides the surgeon with electrosurgical capabilities, improved dexterity, improved stiffness, and the versatility that is needed to provide patient- and operation-specific care.
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Affiliation(s)
- Aimée Sakes
- Department BioMechanical Engineering, Faculty Mechanical, Maritime, and Materials Engineering, Delft University of Technology, Mekelweg 2, Delft 2628 CD, The Netherlands e-mail:
| | - Kevin Hovland
- Department BioMechanical Engineering, Faculty Mechanical, Maritime, and Materials Engineering, Delft University of Technology, Mekelweg 2, Delft 2628 CD, The Netherlands e-mail:
| | - Gerwin Smit
- Department BioMechanical Engineering, Faculty Mechanical, Maritime, and Materials Engineering, Delft University of Technology, Mekelweg 2, Delft 2628 CD, The Netherlands e-mail:
| | - Jo Geraedts
- Department Design Engineering, Faculty Industrial Design Engineering, Delft University of Technology, Mekelweg 2, Delft 2628 CD, The Netherlands e-mail:
| | - Paul Breedveld
- Department BioMechanical Engineering, Faculty Mechanical, Maritime, and Materials Engineering, Delft University of Technology, Mekelweg 2, Delft 2628 CD, The Netherlands e-mail:
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Abstract
BACKGROUND The group of passive prostheses consists of prosthetic hands and prosthetic tools. These can either be static or adjustable. Limited research and development on passive prostheses has been performed although many people use these prosthesis types. Although some publications describe passive prostheses, no recent review of the peer-reviewed literature on passive prostheses is available. OBJECTIVE Review the peer-reviewed literature on passive prostheses for replacement of the hand. STUDY DESIGN Literature review. METHODS Four electronic databases were searched using a Boolean combination of relevant keywords. English-language articles relevant to the objective were selected. RESULTS In all, 38 papers were included in the review. Publications on passive prosthetic hands describe their users, usage, functionality, and problems in activities of daily living. Publications on prosthetic tools mostly focus on sport, recreation, and vehicle driving. CONCLUSION Passive hand prostheses receive little attention in prosthetic research and literature. Yet one out of three people with a limb deficiency uses this type of prosthesis. Literature indicates that passive prostheses can be improved on pulling and grasping functions. In the literature, ambiguous names are used for different types of passive prostheses. This causes confusion. We present a new and clear classification of passive prostheses. Clinical relevance This review provides information on the users of passive prosthetic hands and tools, their usage and the functionality. Passive prostheses receive very little attention and low appreciation in literature. Passive prosthetic hands and tools show to be useful to many unilateral amputees and should receive more attention and higher acceptance.
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Affiliation(s)
- Bartjan Maat
- Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - Gerwin Smit
- Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - Dick Plettenburg
- Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - Paul Breedveld
- Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
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Abstract
Follow-the-leader propagation allows for the insertion of flexible surgical instruments along curved paths, reducing the access required for natural orifice transluminal endoscopic surgery. Currently, the most promising follow-the-leader instruments use the alternating memory method containing two mechanical memory-banks for controlling the motion of the flexible shaft, which reduces the number of actuators to a minimum. These instruments do, however, require concentric structures inside the shaft, limiting its miniaturization. The goal of this research was, therefore, to develop a mechanism conforming the principles of the alternating memory method that could be located at the controller-side instead of inside the shaft of the instrument, which is positioned outside the patient and is therefore less restricted in size. First, the three-dimensional motion of the shaft was decoupled into movement in a horizontal and vertical plane, which allowed for a relatively simple planar alternating memory mechanism design for controlling planar follow-the-leader motion. Next, the planar movement of the alternating memory mechanism was discretized, increasing its resilience to errors. The resulting alternating memory mechanism was incorporated and tested in a proof-of-concept prototype called the MemoSlide. This prototype does not include a flexible shaft, but was fully focused on proving the function of the alternating memory mechanism. Evaluation of the MemoSlide shows the mechanism to work very well, being able to transfer any planar path that lays within its physical boundaries along the body of the mechanism without accumulating errors.
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Affiliation(s)
- Paul Wj Henselmans
- Department of BioMechanical Engineering, Delft University of Technology, Delft, The Netherlands
| | - Stefan Gottenbos
- Department of BioMechanical Engineering, Delft University of Technology, Delft, The Netherlands
| | - Gerwin Smit
- Department of BioMechanical Engineering, Delft University of Technology, Delft, The Netherlands
| | - Paul Breedveld
- Department of BioMechanical Engineering, Delft University of Technology, Delft, The Netherlands
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Montagnani F, Smit G, Controzzi M, Cipriani C, Plettenburg DH. A passive wrist with switchable stiffness for a body-powered hydraulically actuated hand prosthesis. IEEE Int Conf Rehabil Robot 2017; 2017:1197-1202. [PMID: 28813984 DOI: 10.1109/icorr.2017.8009412] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
State of art upper limb prostheses lack several degrees of freedom (DoF) and force the individuals to compensate for them by changing the motions of their arms and body. Such movements often yield to articulation injuries, nonetheless these could be prevented by adding DoFs, for instance, an articulated passive wrist. Available stiff or compliant wrists with passive flexion/extension and/or radial/ulnar deviation are sub-optimal solutions. Indeed, stiff wrists induce the individuals wearing them to perform exaggerated compensatory movements during the reaching phase while compliant wrists proved to be unpractical while manipulating heavy objects. Here we present a wrist capable of combining the benefits of stiff and compliant wrists. It is provided with two switchable levels of passive compliance that are automatically selected. The prototype was integrated in a body-powered hydraulic hand prosthesis and actuated using the same hydraulic circuit of the hand. Detailed analysis of the parameters that affect the compliance, the critical load and the performance of the prosthesis are presented.
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Affiliation(s)
- Jelle ten Kate
- Department of BioMechanical Engineering, Delft University of Technology, Delft, The Netherlands
| | - Gerwin Smit
- Department of BioMechanical Engineering, Delft University of Technology, Delft, The Netherlands
| | - Paul Breedveld
- Department of BioMechanical Engineering, Delft University of Technology, Delft, The Netherlands
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Haverkate L, Smit G, Plettenburg DH. Assessment of body-powered upper limb prostheses by able-bodied subjects, using the Box and Blocks Test and the Nine-Hole Peg Test. Prosthet Orthot Int 2016; 40:109-16. [PMID: 25336050 DOI: 10.1177/0309364614554030] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 09/10/2014] [Indexed: 02/03/2023]
Abstract
BACKGROUND The functional performance of currently available body-powered prostheses is unknown. OBJECTIVE The goal of this study was to objectively assess and compare the functional performance of three commonly used body-powered upper limb terminal devices. STUDY DESIGN Experimental trial. METHODS A total of 21 able-bodied subjects (n = 21, age = 22 ± 2) tested three different terminal devices: TRS voluntary closing Hook Grip 2S, Otto Bock voluntary opening hand and Hosmer Model 5XA hook, using a prosthesis simulator. All subjects used each terminal device nine times in two functional tests: the Nine-Hole Peg Test and the Box and Blocks Test. RESULTS Significant differences were found between the different terminal devices and their scores on the Nine-Hole Peg Test and the Box and Blocks Test. The Hosmer hook scored best in both tests. The TRS Hook Grip 2S scored second best. The Otto Bock hand showed the lowest scores. CONCLUSION This study is a first step in the comparison of functional performances of body-powered prostheses. The data can be used as a reference value, to assess the performance of a terminal device or an amputee. CLINICAL RELEVANCE The measured scores enable the comparison of the performance of a prosthesis user and his or her terminal device relative to standard scores.
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Affiliation(s)
- Liz Haverkate
- Delft University of Technology, Delft, The Netherlands
| | - Gerwin Smit
- Delft University of Technology, Delft, The Netherlands
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Smit G, Plettenburg DH, van der Helm FCT. The lightweight Delft Cylinder Hand: first multi-articulating hand that meets the basic user requirements. IEEE Trans Neural Syst Rehabil Eng 2014; 23:431-40. [PMID: 25122837 DOI: 10.1109/tnsre.2014.2342158] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Rejection rates of upper limb prostheses are high (23%-45%). Amputees indicate that the highest design priority should be reduction of the mass of the prosthetic device. Despite all efforts, the mass of the new prosthetic hands is 35%-73% higher than that of older hands. Furthermore, current hands are thicker than a human hand, they operate slower and do not provide proprioceptive force and position feedback. This study presents the Delft Cylinder Hand, a body powered prosthetic hand which mass is 55%-68% lower than that of the lightest current prosthetic hands, operates faster, has an anthropomorphic shape, and provides proprioceptive force and position feedback. The hand has articulating fingers, actuated by miniature hydraulic cylinders. The articulating fingers adapt to the shape of the grasped object. Its functional scores are similar to that of current prosthetic devices. The hand has a higher mechanical performance than current body-powered hands. It requires 49%-162% less energy from the user and it can deliver a higher maximum pinch force (30-60 N).
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Abstract
BACKGROUND Cosmetic gloves that cover a prosthetic hand have a parasitic positive stiffness that counteracts the flexion of a finger joint. OBJECTIVES Reducing the required input torque to move a finger of a prosthetic hand by compensating the parasitic stiffness of the cosmetic glove. STUDY DESIGN Experimental, test bench. METHODS The parasitic positive stiffness and the required input torques of a polyvinyl chloride glove and a silicone glove were measured when flexing a metacarpophalangeal finger joint for 90°. To compensate this positive stiffness, an adjustable compensation mechanism with a negative stiffness was designed and built. A MATLAB model was created to predict the optimal settings of the mechanism, based on the measured stiffness, in order to minimize the required input torque of the total system. The mechanism was tested in its optimal setting with an applied glove. RESULTS The mechanism reduced the required input torque by 58% for the polyvinyl chloride glove and by 52% for the silicone glove. The total energy dissipation of the joint did not change significantly. CONCLUSIONS This study shows that the undesired positive stiffness in the joint can be compensated with a relatively simple negative stiffness mechanism, which fits inside a finger of a standard cosmetic glove. Clinical relevance This study presents a mechanism that compensates the undesired stiffness of cosmetic gloves on prosthetic hands. As a result, it requires less input force, torque and energy to move the fingers. Application of this mechanism in body-powered hands will reduce the control effort of the user.
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Affiliation(s)
- Gerwin Smit
- Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands
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Smit G, Plettenburg DH, van der Helm FCT. Design and evaluation of two different finger concepts for body-powered prosthetic hand. ACTA ACUST UNITED AC 2014; 50:1253-66. [PMID: 24458965 DOI: 10.1682/jrrd.2012.12.0223] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 05/22/2013] [Indexed: 11/05/2022]
Abstract
The goal of this study was to find an efficient method of energy transmission for application in an anthropomorphic underactuated body-powered (BP) prosthetic hand. A pulley-cable finger and a hydraulic cylinder finger were designed and tested to compare the pulley-cable transmission principle with the hydraulic cylinder transmission principle. Both fingers had identical dimensions and a low mass. The only thing that differed between the fingers was the transmission principle. The input energy was measured for a number of tasks. The pulley-cable finger required more input energy than the hydraulic cylinder finger to perform the tasks. This was especially the case in tasks that required high pinch forces. The hydraulic cylinder transmission is therefore the more efficient transmission for application in BP prosthetic fingers.
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Affiliation(s)
- Gerwin Smit
- Department of Biomechanical Engineering, Delft Institute of Prosthetics and Orthotics, Delft University of Technology, Mekelweg 2, 2628 CD, Delft, the Netherlands.
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Abstract
Current minimally invasive laparoscopic tissue–harvesting techniques for pathological purposes involve taking multiple imprecise and inaccurate biopsies, usually using a laparoscopic forceps or other assistive devices. Potential hazards, e.g., cancer spread when dealing with tumorous tissue, call for a more reliable alternative in the form of a single laparoscopic instrument capable of repeatedly taking a precise biopsy at a desired location. Therefore, the aim of this project was to design a disposable laparoscopic instrument tip, incorporating a centrally positioned glass fiber for tissue diagnostics; a cutting device for fast, accurate, and reliable biopsy of a precisely defined volume; and a container suitable for sample storage. Inspired by the sea urchin's chewing organ, Aristotle's lantern, and its capability of rapid and simultaneous tissue incision and enclosure by axial translation, we designed a crown-shaped collapsible cutter operating on a similar basis. Based on a series of in vitro experiments indicating that tissue deformation decreases with increasing penetration speed leading to a more precise biopsy, we decided on the cutter's forward propulsion via a spring. Apart from the embedded spring-loaded cutter, the biopsy harvester comprises a smart mechanism for cutter preloading, locking, and actuation, as well as a sample container. A real-sized biopsy harvester prototype was developed and tested in a universal tensile testing machine at TU Delft. In terms of mechanical functionality, the preloading, locking, and actuation mechanism as well as the cutter's rapid incising and collapsing capabilities proved to work successfully in vitro. Further division of the tip into a permanent and a disposable segment will enable taking of multiple biopsies, mutually separated in individual containers. We believe the envisioned laparoscopic optomechanical biopsy device will be a solution ameliorating time-demanding, inaccurate, and potentially unsafe laparoscopic biopsy procedures.
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Affiliation(s)
- Filip Jelínek
- BioMechanical Engineering Department, Faculty Mechanical, Maritime and Materials Engineering, Delft University of Technology, Mekelweg 2, Delft 2628 CD, Netherlands e-mail:
| | - Gerwin Smit
- BioMechanical Engineering Department, Faculty Mechanical, Maritime and Materials Engineering, Delft University of Technology, Mekelweg 2, Delft 2628 CD, Netherlands e-mail:
| | - Paul Breedveld
- BioMechanical Engineering Department, Faculty Mechanical, Maritime and Materials Engineering, Delft University of Technology, Mekelweg 2, Delft 2628 CD, Netherlands e-mail:
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Smit G, Plettenburg DH. Comparison of mechanical properties of silicone and PVC (polyvinylchloride) cosmetic gloves for articulating hand prostheses. ACTA ACUST UNITED AC 2013; 50:723-32. [DOI: 10.1682/jrrd.2011.12.0238] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Smit G, Bongers RM, Van der Sluis CK, Plettenburg DH. Efficiency of voluntary opening hand and hook prosthetic devices: 24 years of development? ACTA ACUST UNITED AC 2012; 49:523-34. [PMID: 22773256 DOI: 10.1682/jrrd.2011.07.0125] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Quantitative data on the mechanical performance of upper-limb prostheses are very important in prostheses development and selection. The primary goal of this study was to objectively evaluate the mechanical performance of adult-size voluntary opening (VO) prosthetic terminal devices and select the best tested device. A second goal was to see whether VO devices have improved in the last two decades. Nine devices (four hooks and five hands) were quantitatively tested (Hosmer model 5XA hook, Hosmer Sierra 2 Load VO hook, RSL Steeper Carbon Gripper, Otto Bock model 10A60 hook, Becker Imperial hand, Hosmer Sierra VO hand, Hosmer Soft VO hand, RSL Steeper VO hand, Otto Bock VO hand). We measured the pinch forces, activation forces, cable displacements, mass, and opening span and calculated the work and hysteresis. We compared the results with data from 1987. Hooks required lower activation forces and delivered higher pinch forces than hands. The activation forces of several devices were very high. The pinch forces of all tested hands were too low. The Hosmer model 5XA hook with three bands was the best tested hook. The Hosmer Sierra VO hand was the best tested hand. We found no improvements in VO devices compared with the data from 1987.
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Affiliation(s)
- Gerwin Smit
- Delft Institute of Prosthetics and Orthotics, Department of Biomechanical Engineering, Delft University of Technology, the Netherlands.
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Tolou N, Smit G, Nikooyan AA, Plettenburg DH, Herder JL. Stiffness Compensation Mechanism for Body Powered Hand Prostheses with Cosmetic Covering. J Med Device 2012. [DOI: 10.1115/1.4005781] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Body powered hand prostheses require high physical user effort. This is caused by the stiffness of the cosmetic covering, or cosmetic glove. This paper aims to present a new concept of a mechanism for the compensation of the nonlinear stiffness of body powered hand prostheses by using static balancers with a nonlinear behavior. This concept is based on a cooperative action of snap-through behavior in multiple bi-stable spring mechanisms to create the nonlinear balancing force. To demonstrate the efficiency of the concept, an optimized design for a case study of a child-size hand prosthesis is also presented. A pattern search method was applied for the optimization. As a result, the calculated stiffness and thereby the operating effort was reduced by 96%. It can be concluded from the conceptual and numerical results that the presented concept provides a highly efficient solution to the discussed problem.
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Affiliation(s)
- Nima Tolou
- Faculty of Mechanical, Maritime and Materials Engineering, Department of Biomechanical Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft, The Netherlands
| | - Gerwin Smit
- Faculty of Mechanical, Maritime and Materials Engineering, Department of Biomechanical Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft, The Netherlands
| | - Ali A. Nikooyan
- Faculty of Mechanical, Maritime and Materials Engineering, Department of Biomechanical Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft, The Netherlands
| | - Dick H. Plettenburg
- Faculty of Mechanical, Maritime and Materials Engineering, Department of Biomechanical Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft, The Netherlands
| | - Just L. Herder
- Faculty of Mechanical, Maritime and Materials Engineering, Department of Biomechanical Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft, The Netherlands
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Abstract
The Delft Institute of Prosthetics and Orthotics has started a research program to develop an improved voluntary closing, body-powered hand prosthesis. Five commercially available voluntary closing terminal devices were mechanically tested: three hands [Hosmer APRL VC hand, Hosmer Soft VC Male hand, Otto Bock 8K24] and two hooks [Hosmer APRL VC hook, TRS Grip 2S]. The test results serve as a design guideline for future prostheses. A test bench was used to measure activation cable forces and displacements, and the produced pinch forces. The measurements show that the hands require higher activation forces than the hooks and 1.5-8 times more mechanical work. The TRS hook requires the smallest activation force (33 N for a 15 N pinch force) and has the lowest energy dissipation (52 Nmm). The Hosmer Soft hand requires the largest activation force (131 N for a 15 N pinch force) and has the highest energy dissipation (1409 Nmm). The main recommendations for future prostheses are the following: (1) Required activation forces should be below the critical muscle force (∼18% of maximum), to enable continuous activation without muscle fatigue; and (2) hysteresis of mechanism and glove should be lowered, to increase efficiency and controllability.
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Affiliation(s)
- Gerwin Smit
- Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands.
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Tolou N, Smit G, Nikooyan AA, Plettenburg D, Herder J. Stiffness Compensation in Hand Prostheses With Cosmetic Coverings Using Statically Balanced Mechanisms. J Med Device 2010. [DOI: 10.1115/1.3443321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Although hand prostheses with a cosmetic covering are commercially available for disabled people, the operating effort due to the stiffness of the mechanism is high. This results in high power requirements. This paper aims to present a new concept of mechanisms for the compensation of the nonlinear stiffness of hand prostheses by using statically balanced mechanisms with a nonlinear behavior. This concept was based on a combination of stability phases of snap-through buckling in bistable spring mechanisms to create the nonlinear balancing force. To demonstrate the efficiency of the concept, an optimized design for a case study of a child-sized hand prosthesis is also presented. A pattern search method was applied for the optimization. As a result, the calculated stiffness and, thereby, the operating effort was reduced by 96%. It can be concluded from the conceptual and numerical results that the presented concept provides a highly efficient solution to the discussed problem.
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Joosse P, Smit G, Arendshorst R, Soedarmo S, Ponsen KJ, Goslings J. Outcome and prognostic factors of traumatic brain injury: a prospective evaluation in a Jakarta University hospital. J Clin Neurosci 2009; 16:925-8. [DOI: 10.1016/j.jocn.2008.06.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Revised: 06/19/2008] [Accepted: 06/24/2008] [Indexed: 11/24/2022]
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Abstract
AIMS To assess which types of siderophores are typically produced by Brevibacterium and how siderophore production and utilization traits are distributed within this genus. METHODS AND RESULTS During co-cultivation experiments it was found that growth of B. linens Br5 was stimulated by B. linens NIZO B1410 by two orders of magnitude. The stimulation was caused by the production of hydroxamate siderophores by B. linens NIZO B1410 that enabled the siderophore-auxotrophic strain Br5 to grow faster under the applied iron-limited growth conditions. Different patterns of siderophore production and utilization were observed within the genus Brevibacterium. These patterns did not reflect the phylogenetic relations within the group as determined by partial 16S rDNA sequencing. Most Brevibacterium strains were found to utilize hydroxamate siderophores. CONCLUSIONS Brevibacteria can produce and utilize siderophores although certain strains within this genus are siderophore-auxotrophic. SIGNIFICANCE AND IMPACT OF THE STUDY It is reported for the first time that brevibacteria produce and utilize siderophores. This knowledge can be utilized to stimulate growth of auxotrophic strains under certain conditions. Enhancing the growth rate of Brevibacterium is of importance for the application of this species, for example, for cheese manufacturing or for industrial production of enzymes or metabolites.
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Struijs PAA, Smit G, Steller EP. Radial head fractures: effectiveness of conservative treatment versus surgical intervention. A systematic review. Arch Orthop Trauma Surg 2007; 127:125-30. [PMID: 17066285 DOI: 10.1007/s00402-006-0240-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2006] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Radial head fractures are common elbow fractures. The Mason classification is used to describe the fracture. As of yet, there is no consensus on optimal treatment strategy for Mason II-IV fractures. The aim of this study was to compare the results of conservative treatment with different surgical strategies for radial head fractures. MATERIALS AND METHODS Electronic databases from 1966 to 2004 were screened. Based on our inclusion criteria, 24 studies, describing 825 patients, were included. RESULTS For Mason type II fractures, residual pain was present in 42% of the conservatively treated of the patients compared to 32% of the surgically treated patients. Good/excellent results for Broberg score were 52 and 88%, respectively. For Mason type III and IV fractures, no conservatively treated patients were described. CONCLUSIONS There is insufficient evidence to be able to draw definitive conclusions on optimal treatment of type II-IV radial head fractures. Evidence is currently limited to a maximum level II evidence. There is great need for sufficiently powered randomized controlled trials.
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Affiliation(s)
- P A A Struijs
- Department of General Surgery and traumatology, St. Lucas Andreas Hospital, Frederik Hendrikplantsoen 74-2, 1052 XW Amsterdam, The Netherlands.
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Radolić V, Vuković B, Smit G, Stanić D, Planinić J. Radon in the spas of Croatia. J Environ Radioact 2005; 83:191-8. [PMID: 15925434 DOI: 10.1016/j.jenvrad.2005.02.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2004] [Revised: 01/21/2005] [Accepted: 02/09/2005] [Indexed: 05/02/2023]
Abstract
Radon concentrations in air and geothermal water of the spa pools in Croatia were measured and the average values of 40.3 and 4.5 kBq/m3 were obtained, respectively. Great difference between radon concentrations in pool and spring water was considered as a result of mixing normal and geothermal water in the pool as well as the radon decay. Estimation of an effective dose, received by the personnel in the Bizovac spa, gave the value of 0.27 mSv/y. At the location Stubica, the transfer factor of the radon for air and thermal water in the pool was calculated, and the value of 4.9+/-0.7 x 10(-3) was obtained.
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Affiliation(s)
- V Radolić
- Department of Physics, University of Osijek, P.O. Box 144, 31000 Osijek, Croatia
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Smit BA, Engels WJM, Bruinsma J, van Hylckama Vlieg JET, Wouters JTM, Smit G. Development of a high throughput screening method to test flavour-forming capabilities of anaerobic micro-organisms. J Appl Microbiol 2004; 97:306-13. [PMID: 15239696 DOI: 10.1111/j.1365-2672.2004.02295.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM Development of a fast, automated and reliable screening method for screening of large collections of bacterial strains with minimal handling time. METHODS AND RESULTS The method is based on the injection of a small headspace sample (100 microl) from culture vials (2 ml) in 96-well format directly into the mass spectrometry (MS). A special sample tray has been developed for liquid media, and anaerobically grown cultures. In principle, all volatile components can be measured, but a representative mass fragment has to be obtained in the MS. Representative masses for 3-methylbutanal, 2-methylpropanal and benzaldehyde are 58, 72 and 105, respectively. In 1 day over 1500 samples could be analysed and the coefficient of variation for the response was <5%. CONCLUSION Screening of 72 strains belonging to the genus Lactococcus in quadruple on the production of the key-flavour compound 3-methylbutanal illustrated the effectiveness of the method. Furthermore, knowledge of the biochemistry and physiology of 3-methylbutanal formation was used to optimize the composition of the growth medium to enhance 3-methylbutanal production, and thereby improve the screening. SIGNIFICANCE AND IMPACT OF THE STUDY A commonly used method to control flavour formation in fermented food products is the selection of bacterial strains, which are able to produce the desired flavour compounds. As large collections of strains are available for such screenings, studying biodiversity of micro-organisms on the level of metabolic routes is strongly facilitated by highly automated high throughput screening methods for measuring enzyme activities or production of metabolites. Therefore, this method will be a useful tool for selecting flavour-producing strains and for enhancing starter culture development.
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Affiliation(s)
- B A Smit
- Department of Flavour, Nutrition and Ingredients, NIZO Food Research, Ede, The Netherlands
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Celie P, Klaassen R, van Rossum-Fikkert S, van Elk R, Smit G, Sixma TK. Structural analysis of acetylcholine-binding protein from the snail Bulinus truncatus. Acta Crystallogr A 2004. [DOI: 10.1107/s0108767304096801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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van den Berg G, Meijer W, Düsterhöft EM, Smit G. Gouda and related cheeses. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/s1874-558x(04)80041-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2023]
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Smit BA, Engels WJM, Wouters JTM, Smit G. Diversity of L-leucine catabolism in various microorganisms involved in dairy fermentations, and identification of the rate-controlling step in the formation of the potent flavour component 3-methylbutanal. Appl Microbiol Biotechnol 2003; 64:396-402. [PMID: 14624315 DOI: 10.1007/s00253-003-1447-8] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2003] [Revised: 08/08/2003] [Accepted: 09/07/2003] [Indexed: 10/26/2022]
Abstract
Various microorganisms, belonging to the genera Lactococcus, Lactobacillus, Streptococcus, Leuconostoc, Bifidobacterium, Propionibacterium, Brevibacterium, Corynebacterium and Arthrobacter, used in dairy fermentations such as cheese making, were analysed for their potential to convert leucine into flavour components, most notably 3-methylbutanal. A large variation between and within species was observed for various enzyme activities involved in the conversion pathway, e.g. transaminases, alpha-hydroxy acid dehydrogenase and alpha-keto acid decarboxylase. In particular, alpha-keto acid decarboxylase activity-leading to 3-methylbutanal-was found to be present in only two of the strains tested. It is proposed that this activity is rate-controlling in the conversion pathway leading to the flavour compound 3-methylbutanal.
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Affiliation(s)
- B A Smit
- Department of Flavour, Nutrition and Ingredients, NIZO food research, P.O. Box 20, 6710 BA Ede, The Netherlands
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37
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Abstract
This paper describes the clinical history of a young boy with Kearns-Sayre syndrome. The first presenting symptom of Kearns-Sayre syndrome in this boy was corneal edema with photophobia and tearing.
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Affiliation(s)
- F Boonstra
- Bartimeus Institute for Visually Handicapped Children, Zeist, The Netherlands.
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38
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Abstract
In this paper we describe a test for Nijhout's (1978, 1980a) hypothesis that the eyespot patterns on butterfly wings are the result of a threshold reaction of the epidermal cells to a concentration gradient of a diffusing degradable morphogen produced by focal cells at the centre of the future eyespot. The wings of the nymphalid butterfly, Bicyclus anynana, have a series of eyespots. each composed of a white pupil, a black disc and a gold outer ring. In earlier extirpation and transplantation experiments (Nijhout 1980a; French and Brakefield, 1995) it has been established that these eyespots are indeed organised around groups of signalling cells active during the first hours of pupal development. If these cells were to supply the positional information for eyespot formation in accordance with Nijhout's diffusion-degradation gradient model, then, when two foci are close together. the signals should sum, and this effect should be apparent in the detailed shape of the resulting pigment pattern. We give an equation for the form of the contours that would be obtained in this manner. We use this to test the morphogen gradient hypothesis on measurements of the outlines of fused eyespots obtained either by grafting focal cells close together, or by using a mutation (Spotty) that produces adjacent fused eyespots. The contours of the fused patterns were found to satisfy our equation, thus corroborating Nijhout's hypothesis to the extent possible with this particular type of experiment.
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Affiliation(s)
- A Monteiro
- Section of Evolutionary Biology, Institute of Evolutionary and Ecological Sciences, University of Leiden, The Netherlands.
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Ayad EH, Verheul A, Engels WJ, Wouters JT, Smit G. Enhanced flavour formation by combination of selected lactococci from industrial and artisanal origin with focus on completion of a metabolic pathway. J Appl Microbiol 2001; 90:59-67. [PMID: 11155123 DOI: 10.1046/j.1365-2672.2001.01219.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Combinations of lactococcal strains from various origins with divers properties were developed as new starters for new dairy products. Flavour formation by such tailor-made cultures was studied. In some cases, a strongly enhanced flavour was observed. For instance, the combination of B1157 and SK110 strains in milk resulted in a very strong chocolate-like flavour. B1157 produces only a moderate chocolate-like flavour, whereas SK110 alone fails to produce this flavour. Headspace gas chromatography results corroborate the organoleptic evaluations. High levels of branched-chain aldehydes were found when B1157 and SK110 were grown together. The enzyme activities involved in this pathway were studied; both strains contain transaminase activity. Although B1157 had a very high amino acid decarboxylating activity, its release of amino acids from milk protein was limited. SK110 was strongly limited in decarboxylating activity, although this strain is very active in proteolysis. By combining these strains, the substrates released by SK110 can directly be used by the other strain, resulting in the completion of the whole flavour-formation pathway. This opens new avenues for the preparation of tailor-made cultures.
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Affiliation(s)
- E H Ayad
- NIZO food research, Department of Flavour and Natural Ingredients, Ede, The Netherlands
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40
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Meijer W, van de Bunt B, Twigt M, de Jonge B, Smit G, Hugenholtz J. Lysis of Lactococcus lactis subsp. cremoris SK110 and its nisin-immune transconjugant in relation to flavor development in cheese. Appl Environ Microbiol 1998; 64:1950-3. [PMID: 9572979 PMCID: PMC106258 DOI: 10.1128/aem.64.5.1950-1953.1998] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
To develop a nisin-producing cheese starter, Lactococcus lactis subsp. cremoris SK110 was conjugated with transposon Tn5276-NI, which codes for nisin immunity but not for nisin production. Cheese made with transconjugant SK110::Tn5276-NI as the starter was bitter. The muropeptide of the transconjugant contained a significantly greater amount of tetrapeptides than the muropeptide of strain SK110, which could have decreased the susceptibility of the cells to lysis and thereby the release of intracellular debittering enzymes.
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Affiliation(s)
- W Meijer
- Flavour and Starters Section, Netherlands Institute for Dairy Research (NIZO), Ede, The Netherlands.
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41
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Bockelmann W, Krusch U, Engel G, Klijn N, Smit G, Heller KJ. The microflora of Tilsit cheese. Part 1. Variability of the smear flora. ACTA ACUST UNITED AC 1997. [DOI: 10.1002/food.19970410405] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Abstract
Nodulation (root nodule formation) in legume roots is initiated by the induction of cell divisions and formation of root nodule primordia in the plant root cortex, usually in front of the protoxylem ridges of the central root cylinder. We isolated a factor from the central cylinder (stele) of pea roots which enhances hormone-induced cell proliferation in root cortex explants at positions similar to those of nodule primordia. The factor was identified as uridine. Uridine may act as a morphogen in plant roots at picomolar concentrations.
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Affiliation(s)
- G Smit
- Institute of Molecular Plant Sciences, Leiden University, The Netherlands
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Straver MH, Traas VM, Smit G, Kijne JW. Isolation and partial purification of mannose-specific agglutinin from brewer's yeast involved in flocculation. Yeast 1994; 10:1183-93. [PMID: 7754707 DOI: 10.1002/yea.320100906] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Yeast cell-agglutinating activity, designated agglutinin (possible lectin), was isolated from cell walls of both non-flocculent and flocculent brewer's yeast cells. Agglutinin-mediated aggregation of yeast cells in a manner similar to flocculation with respect to specific mannose-sensitivity, pH-dependence and calcium-dependence. Agglutinating activity was found to be heat-stable and protease-insensitive. Furthermore, addition of agglutinin to flocculent cells strongly stimulated the flocculation ability of the cells, whereas addition to non-flocculent cells rendered these cells weakly flocculent. Agglutinin was found to be released from flocculent cells during the course of a flocculation assay, but not from non-flocculent cells. Presence of mannose during the assay inhibited release of agglutinin. Our results suggest that (i) mannose-specific agglutinin is continuously synthesized during growth of brewer's yeast cells, (ii) agglutinin is present in cell walls of non-flocculent cells but is unable to bind its ligand on other cells, and (iii) the ability of yeast cells to flocculate in a flocculation assay depends, among other factors, on release of agglutinin from the cells. A 10-kDa polypeptide might represent one form of agglutinin.
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Affiliation(s)
- M H Straver
- Institute of Molecular Plant Sciences, Leiden University, The Netherlands
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Abstract
Analysis of a shear supernatant from flocculent, "fimbriated" Saccharomyces cerevisiae brewer's yeast cells revealed the presence of a protein involved in flocculation of the yeast cells and therefore designated a flocculin. The molecular mass of the flocculin was estimated to be over 300 kDa, as judged from sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Gel permeation chromatography of the flocculin yielded an aggregate with an apparent molecular weight of > 2,000. The flocculin was found to be protease sensitive, and the sequence of its 16 N-terminal amino acids revealed at least 69% identity with the predicted N terminus of the putative protein encoded by the flocculation gene FLO1. The flocculin was isolated from flocculent S. cerevisiae cells, whereas only a low amount of flocculin, if any, could be isolated from nonflocculent cells. The flocculin was found to stimulate the flocculation ability of flocculent yeast cells without displaying lectinlike activity (that is, the ability to agglutinate yeast cells).
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Affiliation(s)
- M H Straver
- Institute of Molecular Plant Sciences, Leiden University, The Netherlands
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Swart S, Lugtenberg BJ, Smit G, Kijne JW. Rhicadhesin-mediated attachment and virulence of an Agrobacterium tumefaciens chvB mutant can be restored by growth in a highly osmotic medium. J Bacteriol 1994; 176:3816-9. [PMID: 8206861 PMCID: PMC205572 DOI: 10.1128/jb.176.12.3816-3819.1994] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Cyclic beta-1,2-glucan is considered to play a role in osmoadaptation of members of the family Rhizobiaceae in hypotonic media. Agrobacterium tumefaciens chvB mutants, lacking beta-1,2-glucan, exhibit a pleiotropic phenotype, including nonmotility, attachment deficiency, and avirulence. Here we report that by growth of chvB mutant cells in tryptone-yeast extract medium supplemented with 7 mM CaCl2 and 100 mM NaCl, the mutant cells become motile, attach to pea root hair tips, and are virulent on Kalanchoë leaves. Moreover, whereas chvB mutants grown in tryptone-yeast extract medium containing 7 mM CaCl2 do not produce active rhicadhesin, addition of 100 mM NaCl to this medium resulted in restoration of rhicadhesin activity. The presence of CaCl2 appeared to be required for attachment, virulence, and activity of rhicadhesin. The results support a role for cyclic beta-1,2-glucan in osmoadaptation and strengthen the notion that rhicadhesin is required for attachment and virulence of A. tumefaciens.
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Affiliation(s)
- S Swart
- Institute of Molecular Plant Sciences, Leiden University, The Netherlands
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Swart S, Logman TJ, Smit G, Lugtenberg BJ, Kijne JW. Purification and partial characterization of a glycoprotein from pea (Pisum sativum) with receptor activity for rhicadhesin, an attachment protein of Rhizobiaceae. Plant Mol Biol 1994; 24:171-83. [PMID: 8111015 DOI: 10.1007/bf00040583] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Attachment of Rhizobium and Agrobacterium bacteria to cells of their host plants is a two-step process. The first step, direct attachment of bacteria to the plant cell wall, is mediated by the bacterial protein rhicadhesin. A putative plant receptor molecule for rhicadhesin was purified from cell walls of pea roots using a bioassay based on suppression of rhicadhesin activity. This molecule appeared to be sensitive to treatments with pronase or glycosidase. Its isoelectric point is 6.4, and its apparent molecular mass was estimated to be 32 kDa before and 29 kDa after glycosidase treatment, as determined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and ultrafiltration. The sequence of the first 29 N-terminal amino acids was determined: A-D-A-D-A-L-Q-D-L-C(?)-V-A-D-Y-A-S-V-I-L- V-N-G-F-A-S-K(Q)-(P/Q)-(L)-(I). No homology with known proteins was found. In the course of this research project the extracellular matrix protein vitronectin was reported to inhibit attachment of A. tumefaciens to carrot cells [29]. A variety of adhesive proteins, including vitronectin, contain a common cell attachment determinant with the sequence R-G-D. Since we could not detect other cell wall components able to suppress rhicadhesin activity, and since an R-G-D containing hexapeptide was also active as a receptor, we speculate that the plant receptor for rhicadhesin is a glycoprotein containing an R-G-D attachment site.
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Affiliation(s)
- S Swart
- Institute of Molecular Plant Sciences, Leiden University, Netherlands
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47
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Abstract
In contrast to wild-type Agrobacterium tumefaciens strains, beta-1,2-glucan-deficient chvB mutants were found to be unable to attach to pea root hair tips. The mutants appeared to produce rhicadhesin, the protein that mediates the first step in attachment of Rhizobiaceae cells to plant root hairs, but the protein was inactive. Both attachment to root hairs and virulence of the chvB mutants could be restored by treatment of the plants with active rhicadhesin, whereas treatment of plants with beta-1,2-glucan had no effect on attachment or virulence. Moreover, nodulation ability of a chvB mutant carrying a Sym plasmid could be restored by pretreatment of the host plant with rhicadhesin. Apparently the attachment-minus and avirulence phenotype of chvB mutants is caused by lack of active rhicadhesin, rather than directly being caused by a deficiency in beta-1,2-glucan synthesis. The results strongly suggest that rhicadhesin is essential for attachment and virulence of A. tumefaciens cells. They also indicate that the mechanisms of binding of Agrobacterium and Rhizobium bacteria to plant target cells are similar, despite differences between these target cells.
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Affiliation(s)
- S Swart
- Institute of Molecular Plant Sciences, Leiden University, The Netherlands
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48
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Abstract
Flocculation is an important characteristic of microorganisms which can be problematical, but may also be exploited in fermentation processes. The molecular mechanism of flocculation is still poorly understood although, recently, cell-surface hydrophobicity of brewer's yeast has been shown to play a key role. Regulation of this factor could enable control of flocculation during fermentation.
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Affiliation(s)
- M H Straver
- Institute of Molecular Plant Sciences, Leiden University, The Netherlands
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49
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Abstract
Ability of Saccharomyces cerevisiae MPY3 cells to flocculate during fermentation in wort was found to be triggered after growth limitation by oxygen shortage and to coincide with a sharp increase in cell surface hydrophobicity of the cells. Presence of oxygen in the pitching wort influenced final cell number, flocculence of the cells and cell surface hydrophobicity. Flocculation ability of cells grown in air-depleted pitching wort was hampered, concomitant with a decrease in final cell number and in final cell surface hydrophobicity. Addition of ergosterol and Tween 80 to air-depleted wort restored normal growth of the cells as well as flocculation ability and the increase in cell surface hydrophobicity. The same parameters increased in value after addition of ergosterol and Tween 80 to a fermentation with air-saturated pitching wort. Hydrophobicity of a non-flocculent mutant of S. cerevisiae strain MPY3, fermenting in air-saturated pitching wort, did not increase at cell division arrest. These results support the hypothesis that cell surface hydrophobicity is a major determinant for yeast cells to become flocculent, and suggest that shortage of sterols and unsaturated fatty acids precedes flocculence under brewing conditions.
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Affiliation(s)
- M H Straver
- Institute of Molecular Plant Sciences, Leiden University, The Netherlands
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Smit G, Straver MH, Lugtenberg BJ, Kijne JW. Flocculence of Saccharomyces cerevisiae cells is induced by nutrient limitation, with cell surface hydrophobicity as a major determinant. Appl Environ Microbiol 1992; 58:3709-14. [PMID: 1482191 PMCID: PMC183164 DOI: 10.1128/aem.58.11.3709-3714.1992] [Citation(s) in RCA: 131] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Initiation of flocculation ability of Saccharomyces cerevisiae MPY1 cells was observed at the moment the cells stop dividing because of nitrogen limitation. A shift in concentration of the limiting nutrient resulted in a corresponding shift in cell division and initiation of flocculence. Other limitations also led to initiation of flocculence, with magnesium limitation as the exception. Magnesium-limited S. cerevisiae cells did not flocculate at any stage of growth. Cell surface hydrophobicity was found to be strongly correlated with the ability of the yeast cells to flocculate. Hydrophobicity sharply increased at the end of the logarithmic growth phase, shortly before initiation of flocculation ability. Treatments of cells which resulted in a decrease in hydrophobicity also yielded a decrease in flocculation ability. Similarly, the presence of polycations increased both hydrophobicity and the ability to flocculate. Magnesium-limited cells were found to be strongly affected in cell surface hydrophobicity. A proteinaceous cell surface factor(s) was identified as a flocculin. This heat-stable component had a strong emulsifying activity, and appears to be involved in both cell surface hydrophobicity and in flocculation ability of the yeast cells.
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Affiliation(s)
- G Smit
- Institute of Molecular Plant Sciences, Leiden University, The Netherlands
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