Human Activity Recognition (HAR) is a multiresearch-discipline area that integrates multiple-sensor data in recognizing and classifying all activities conducted physically by humans. These sensors can be part of the environment, wearable technology, or smartphones. The current research addresses the issues of reducing the dimensionality of the feature vector and accurate classification concerning smartphone-based human activity by proposing a hybrid feature extraction strategy that combines the LDA and MLP methods. Furthermore, SVM optimization with SGD has been used to increase the accuracy in activity classification. In this paper, LDA has been used to extract a new feature space that better enhances class separation and tests feature label prediction. The proposed approach, named LMSS, is tested against the UCI-HAR dataset and achieves state-of-the-art level accuracy. The proposed LDA-MLP-SVM-SGD (LMSS) framework achieves competitive state-of-the-art performance, reaching 99.52 % accuracy on the UCI-HAR dataset. Statistical analysis confirms that the difference versus the strongest baseline (mGRRF+XGB, 99.36 %) was not statistically significant (p = 0.12, α = 0.05), indicating comparable effectiveness rather than a definitive performance gap.
{"title":"Leveraging LDA feature extraction to augment human activity recognition accuracy","authors":"Milad Vazan , Elaheh Sharifi , Hadi Farahani , Sadegh Madadi","doi":"10.1016/j.medengphy.2025.104453","DOIUrl":"10.1016/j.medengphy.2025.104453","url":null,"abstract":"<div><div>Human Activity Recognition (HAR) is a multiresearch-discipline area that integrates multiple-sensor data in recognizing and classifying all activities conducted physically by humans. These sensors can be part of the environment, wearable technology, or smartphones. The current research addresses the issues of reducing the dimensionality of the feature vector and accurate classification concerning smartphone-based human activity by proposing a hybrid feature extraction strategy that combines the LDA and MLP methods. Furthermore, SVM optimization with SGD has been used to increase the accuracy in activity classification. In this paper, LDA has been used to extract a new feature space that better enhances class separation and tests feature label prediction. The proposed approach, named LMSS, is tested against the UCI-HAR dataset and achieves state-of-the-art level accuracy. The proposed LDA-MLP-SVM-SGD (LMSS) framework achieves competitive state-of-the-art performance, reaching 99.52 % accuracy on the UCI-HAR dataset. Statistical analysis confirms that the difference versus the strongest baseline (mGRRF+XGB, 99.36 %) was not statistically significant (p = 0.12, <em>α</em> = 0.05), indicating comparable effectiveness rather than a definitive performance gap.</div></div>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":"146 ","pages":"Article 104453"},"PeriodicalIF":2.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145684570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-03DOI: 10.1016/j.medengphy.2025.104451
Yasuhiro Homma , Manon Bas Dit Nugues , Arnaud Dubory , Charles-Henri Flouzat-Lachaniette , Jean-Paul Meningaud , Barbara Hersant , Emmanuel Gouet , Guillaume Haïat
Summers osteotomy is a technique used to increase bone height and to improve bone density in dental implant surgery. The two main risks of this surgery, which is done by impacting an osteotome in bone tissue, are i) to perforate the sinus membrane and ii) the occurrence of benign paroxysmal vertigo, which are both related to excessive impacts during the osteotomy. Therefore, impacts must be carefully modulated. The aim of this study is to determine whether an instrumented hammer can predict bone damage before the total osteotome protrusion. 35 osteotomies were performed in 9 lamb palate samples using a hammer instrumented with a force sensor to record the variation of the force as a function of time s(t). A signal processing was developed to determine the parameter τ corresponding to the time between the first two peaks of s(t). A camera was used to determine the impact number for damage: NVideo. The surgeon determined when damage occurred, leading to NSurg. An algorithm was developed to detect bone damage based on the variation of τ as a function of the impact number, leading to Ncrit. The algorithm was always able to detect bone damage before total protrusion of the osteotome. We obtained NVideo – NCrit > -2 (respectively NSurg – NCrit > -2) for 97 % (respectively 94 %) of the cases, which indicates the algorithm was almost always able to detect bone damage at most one impact after the video (respectively the surgeon). Our results pave the way to safer Summers osteotomy.
{"title":"Using an instrumented hammer during Summers osteotomy: an animal model","authors":"Yasuhiro Homma , Manon Bas Dit Nugues , Arnaud Dubory , Charles-Henri Flouzat-Lachaniette , Jean-Paul Meningaud , Barbara Hersant , Emmanuel Gouet , Guillaume Haïat","doi":"10.1016/j.medengphy.2025.104451","DOIUrl":"10.1016/j.medengphy.2025.104451","url":null,"abstract":"<div><div>Summers osteotomy is a technique used to increase bone height and to improve bone density in dental implant surgery. The two main risks of this surgery, which is done by impacting an osteotome in bone tissue, are i) to perforate the sinus membrane and ii) the occurrence of benign paroxysmal vertigo, which are both related to excessive impacts during the osteotomy. Therefore, impacts must be carefully modulated. The aim of this study is to determine whether an instrumented hammer can predict bone damage before the total osteotome protrusion. 35 osteotomies were performed in 9 lamb palate samples using a hammer instrumented with a force sensor to record the variation of the force as a function of time <em>s(t)</em>. A signal processing was developed to determine the parameter <em>τ</em> corresponding to the time between the first two peaks of <em>s(t)</em>. A camera was used to determine the impact number for damage: <em>N<sub>Video</sub></em>. The surgeon determined when damage occurred, leading to <em>N<sub>Surg</sub></em>. An algorithm was developed to detect bone damage based on the variation of <em>τ</em> as a function of the impact number, leading to <em>N<sub>crit</sub></em>. The algorithm was always able to detect bone damage before total protrusion of the osteotome. We obtained <em>N<sub>Video</sub> – N<sub>Crit</sub></em> > -2 (respectively <em>N<sub>Surg</sub> – N<sub>Crit</sub></em> > -2) for 97 % (respectively 94 %) of the cases, which indicates the algorithm was almost always able to detect bone damage at most one impact after the video (respectively the surgeon). Our results pave the way to safer Summers osteotomy.</div></div>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":"146 ","pages":"Article 104451"},"PeriodicalIF":2.3,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145267574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-01DOI: 10.1016/j.medengphy.2025.104450
Xinyu Lu , Enxiang Shen , Jie Yuan , Xiao Yin , Zhendong Yao
The Light Emitting Diode (LED) based photoacoustic computed tomography (PACT) system offers advantages such as safety, low cost, portability, and wavelength adjustability. In order to obtain high-quality photoacoustic signals, LEDs are driven by periodic nanosecond pulses. This results in a significant variation in the current flowing through the LEDs during the turn-on and turn-off moments, generating strong electromagnetic interference (EMI) around the LED circuit. In LED-based PACT systems, the light source is typically placed near the ultrasound transducer. Under the influence of the EMI emitted from the LEDs, the coil in the ultrasound transducer picks up induced currents, causing the transducer to emit ultrasonic signals. The ultrasonic echoes are received by the transducer, mixing with the photoacoustic signals and resulting in image artifacts. In this study, we propose an optimized design for the LED-based PACT system that suppresses EMI, thereby reducing image artifacts. We designed several circuit modules to reduce EMI and incorporated external electromagnetic wave absorption techniques, then conducted EMI measurements and imaging comparison experiments to demonstrate the effectiveness of this design. The proposed approach is expected to advance the application of LED-based PACT systems in fields such as surface vascular imaging and photoacoustic endoscopy.
{"title":"EMI caused artifact removal in LED-based photoacoustic tomography system for image quality enhancement","authors":"Xinyu Lu , Enxiang Shen , Jie Yuan , Xiao Yin , Zhendong Yao","doi":"10.1016/j.medengphy.2025.104450","DOIUrl":"10.1016/j.medengphy.2025.104450","url":null,"abstract":"<div><div>The Light Emitting Diode (LED) based photoacoustic computed tomography (PACT) system offers advantages such as safety, low cost, portability, and wavelength adjustability. In order to obtain high-quality photoacoustic signals, LEDs are driven by periodic nanosecond pulses. This results in a significant variation in the current flowing through the LEDs during the turn-on and turn-off moments, generating strong electromagnetic interference (EMI) around the LED circuit. In LED-based PACT systems, the light source is typically placed near the ultrasound transducer. Under the influence of the EMI emitted from the LEDs, the coil in the ultrasound transducer picks up induced currents, causing the transducer to emit ultrasonic signals. The ultrasonic echoes are received by the transducer, mixing with the photoacoustic signals and resulting in image artifacts. In this study, we propose an optimized design for the LED-based PACT system that suppresses EMI, thereby reducing image artifacts. We designed several circuit modules to reduce EMI and incorporated external electromagnetic wave absorption techniques, then conducted EMI measurements and imaging comparison experiments to demonstrate the effectiveness of this design. The proposed approach is expected to advance the application of LED-based PACT systems in fields such as surface vascular imaging and photoacoustic endoscopy.</div></div>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":"145 ","pages":"Article 104450"},"PeriodicalIF":2.3,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145220210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-01Epub Date: 2025-07-28DOI: 10.1016/j.medengphy.2025.104404
Panagiotis E Chatzistergos, Nicola Eddison, Ilias Theodorakos, Nachiappan Chockalingam
Background: Drape-forming is a cost-effective method used worldwide to manufacture bespoke ankle foot orthoses (AFOs). It involves draping a heated polymer material sheet over a positive cast of the user's limb. Previous research has shown that the manual nature of drape-forming can influence the thickness of the final AFO and even lead to structures that are inadequately rigid to be clinically effective. This study assesses the difference between the prescribed and the final thickness of AFOs meant for use by UK's National Health Service (NHS) and estimates its potential impact on AFO rigidity.
Methods: A clinically relevant method to measure AFO thickness as part of the manufacturing process was developed and validated. This method was used by three major UK manufacturers for all bespoke rigid AFOs they provided to the NHS within a predefined period. A validated finite element model was used to estimate the impact of the observed difference between prescribed and final thickness on AFO stiffness.
Results: 86 AFOs were assessed in total. Final thickness was between 4.0% and 35.5% lower than the prescribed one (median thickness reduction= 17.4%). This discrepancy in thickness led to a relative reduction in AFO stiffness ranging between 7.0% and 80.0% (median stiffness reduction= 30.7%).
Discussion: The adequacy of AFO thickness cannot be judged based on prescription thickness. Measurements of final thickness as part of standard practice should be considered to enhance the provision of bespoke AFOs. Further research is needed to establish thresholds of acceptable manufacturing-induced deviation from the prescribed AFO thickness.
{"title":"The effect of thickness variation on the rigidity of ankle foot orthoses provided to the NHS: A case for the need for quality control.","authors":"Panagiotis E Chatzistergos, Nicola Eddison, Ilias Theodorakos, Nachiappan Chockalingam","doi":"10.1016/j.medengphy.2025.104404","DOIUrl":"https://doi.org/10.1016/j.medengphy.2025.104404","url":null,"abstract":"<p><strong>Background: </strong>Drape-forming is a cost-effective method used worldwide to manufacture bespoke ankle foot orthoses (AFOs). It involves draping a heated polymer material sheet over a positive cast of the user's limb. Previous research has shown that the manual nature of drape-forming can influence the thickness of the final AFO and even lead to structures that are inadequately rigid to be clinically effective. This study assesses the difference between the prescribed and the final thickness of AFOs meant for use by UK's National Health Service (NHS) and estimates its potential impact on AFO rigidity.</p><p><strong>Methods: </strong>A clinically relevant method to measure AFO thickness as part of the manufacturing process was developed and validated. This method was used by three major UK manufacturers for all bespoke rigid AFOs they provided to the NHS within a predefined period. A validated finite element model was used to estimate the impact of the observed difference between prescribed and final thickness on AFO stiffness.</p><p><strong>Results: </strong>86 AFOs were assessed in total. Final thickness was between 4.0% and 35.5% lower than the prescribed one (median thickness reduction= 17.4%). This discrepancy in thickness led to a relative reduction in AFO stiffness ranging between 7.0% and 80.0% (median stiffness reduction= 30.7%).</p><p><strong>Discussion: </strong>The adequacy of AFO thickness cannot be judged based on prescription thickness. Measurements of final thickness as part of standard practice should be considered to enhance the provision of bespoke AFOs. Further research is needed to establish thresholds of acceptable manufacturing-induced deviation from the prescribed AFO thickness.</p>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":"144 ","pages":"104404"},"PeriodicalIF":2.3,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145031087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Objectives: Cervical cancer is a serious threat to women's life and health and has a high mortality rate. Colposcopy is an important method for early clinical cervical cancer screening, but the traditional vaginal dilator has problems such as discomfort in use and cumbersome operation. For this reason, this study aims to design an intelligent vaginal dilatation system to automate colposcopy and enhance patient comfort.
Methods: An intelligent vaginal dilatation system combining flexible and rigid dilatation techniques is proposed. A fluid-solid coupled finite element method was used to simulate the dilation process of the system during colposcopy. The smart dilator was inserted into a simulated vaginal model in the simulation, and the fluid domain pressure inlet was set to be 1.5 kPa, and the solid material was a hyperelastic model of medical silicone rubber. Subsequently, the prototype machining was completed and in vitro dilatation displacement and pressure experiments were conducted.
Results: The simulation results showed that the maximum expansion of the system was 32.2 mm, and the average pressure on the simulated vaginal wall was 605.91 kPa. The average maximum expansion of the system in the in-vitro expansion displacement experiment was 30.49 ± 0.05 mm, which was basically the same as the simulation results. The results of the in vitro pressure experiment showed that the intelligent dilatation system had a larger force area on the vaginal wall at the same level of dilatation, and the pressure value was smaller and more uniformly distributed. Compared with the traditional duckbill dilator, it can effectively reduce the local pressure feeling and improve the uniformity of dilation.
Conclusion: The intelligent vaginal dilatation system proposed in this study is superior to traditional dilators in terms of dilatation performance, safety and comfort. The feasibility of its design and potential for clinical application were verified.
{"title":"Biomechanical evaluation of intelligent fluid-solid coupling vaginal dilatation system: Experimental and numerical analysis.","authors":"Renling Zou, Hongwei Tan, Xuan Zhang, Qingbin Fang, Xuelian Gu, Rui Guan","doi":"10.1016/j.medengphy.2025.104408","DOIUrl":"https://doi.org/10.1016/j.medengphy.2025.104408","url":null,"abstract":"<p><strong>Objectives: </strong>Cervical cancer is a serious threat to women's life and health and has a high mortality rate. Colposcopy is an important method for early clinical cervical cancer screening, but the traditional vaginal dilator has problems such as discomfort in use and cumbersome operation. For this reason, this study aims to design an intelligent vaginal dilatation system to automate colposcopy and enhance patient comfort.</p><p><strong>Methods: </strong>An intelligent vaginal dilatation system combining flexible and rigid dilatation techniques is proposed. A fluid-solid coupled finite element method was used to simulate the dilation process of the system during colposcopy. The smart dilator was inserted into a simulated vaginal model in the simulation, and the fluid domain pressure inlet was set to be 1.5 kPa, and the solid material was a hyperelastic model of medical silicone rubber. Subsequently, the prototype machining was completed and in vitro dilatation displacement and pressure experiments were conducted.</p><p><strong>Results: </strong>The simulation results showed that the maximum expansion of the system was 32.2 mm, and the average pressure on the simulated vaginal wall was 605.91 kPa. The average maximum expansion of the system in the in-vitro expansion displacement experiment was 30.49 ± 0.05 mm, which was basically the same as the simulation results. The results of the in vitro pressure experiment showed that the intelligent dilatation system had a larger force area on the vaginal wall at the same level of dilatation, and the pressure value was smaller and more uniformly distributed. Compared with the traditional duckbill dilator, it can effectively reduce the local pressure feeling and improve the uniformity of dilation.</p><p><strong>Conclusion: </strong>The intelligent vaginal dilatation system proposed in this study is superior to traditional dilators in terms of dilatation performance, safety and comfort. The feasibility of its design and potential for clinical application were verified.</p>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":"144 ","pages":"104408"},"PeriodicalIF":2.3,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145031008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-30DOI: 10.1016/j.medengphy.2025.104449
Yiran Jiao , Zengkun Liu , Stacey Reading , Marie-Claire Smith , Jianhua Lin , Yanxin Zhang
Instrumented gait analysis (IGA) has been widely used in research, but not typically in clinical practice, as it requires expertise in data analysis and interpretation. Post-stroke clinical gait assessment could be improved by integrating artificial intelligence into IGA, but previous gait assessment systems have relatively low clinical utility. This study aims to develop a clinically oriented automatic post-stroke gait assessment system based on knowledge graph (KG) to better support clinicians. A domain KG is first constructed in the field of gait analysis. This system can process IGA data to identify gait abnormalities and their potential causes based on kinematic analysis and KG. A preliminary evaluation with twenty post-stroke patients and four domain experts tested the system's performance in clinical settings, showing an average recall, precision, and F-score of 1, 0.78, and 0.89. Four clinical professionals showed high behavioural intention to use the system in clinical settings (4.33 ± 0.41 on a 5-point Likert scale based on the Technology Acceptance Model). The results depicted that this system has potential to be applied in clinical settings to provide useful supplementary insights for clinicians, which may promote the interpretation and clinical utility of IGA. The schema of this KG could be generalised or extended to gait analysis related to other diseases.
{"title":"A knowledge graph-based post-stroke gait assessment system: A pilot study","authors":"Yiran Jiao , Zengkun Liu , Stacey Reading , Marie-Claire Smith , Jianhua Lin , Yanxin Zhang","doi":"10.1016/j.medengphy.2025.104449","DOIUrl":"10.1016/j.medengphy.2025.104449","url":null,"abstract":"<div><div>Instrumented gait analysis (IGA) has been widely used in research, but not typically in clinical practice, as it requires expertise in data analysis and interpretation. Post-stroke clinical gait assessment could be improved by integrating artificial intelligence into IGA, but previous gait assessment systems have relatively low clinical utility. This study aims to develop a clinically oriented automatic post-stroke gait assessment system based on knowledge graph (KG) to better support clinicians. A domain KG is first constructed in the field of gait analysis. This system can process IGA data to identify gait abnormalities and their potential causes based on kinematic analysis and KG. A preliminary evaluation with twenty post-stroke patients and four domain experts tested the system's performance in clinical settings, showing an average recall, precision, and F-score of 1, 0.78, and 0.89. Four clinical professionals showed high behavioural intention to use the system in clinical settings (4.33 ± 0.41 on a 5-point Likert scale based on the Technology Acceptance Model). The results depicted that this system has potential to be applied in clinical settings to provide useful supplementary insights for clinicians, which may promote the interpretation and clinical utility of IGA. The schema of this KG could be generalised or extended to gait analysis related to other diseases.</div></div>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":"145 ","pages":"Article 104449"},"PeriodicalIF":2.3,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145220211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-29DOI: 10.1016/j.medengphy.2025.104448
Bowen Li , Zhen Wang , Chuanzhen Huang , Longhua Xu , Shuiquan Huang , Meina Qu , Zhengkai Xu , Dijia Zhang , Baosu Guo , Tianye Jin , Chunhui Ji
Three-dimensional (3D) bioprinting demonstrates significant potential for advancing regenerative medicine through precise fabrication of functional tissue constructs via controlled deposition of cells, biomaterials, and bioactive factors. However, balancing key parameters-printing efficiency, resolution, and cell viability-remains challenging for replicating native tissue complexity. This review comprehensively examines recent advancements in three prominent bioprinting modalities: inkjet, extrusion-based, and digital light processing (DLP). Analysis reveals inherent performance trade-offs among these technologies. Inkjet bioprinting achieves high resolution (10-80 μm) at moderate speeds but exhibits limited cell viability (74-85%). Extrusion-based methods enable higher fabrication rates (0.00785-62.83 mm³/s) with variable viability (40-90%) at reduced resolution (100-2000 μm). DLP offers superior efficiency (0.648-840 mm³/s) and ultra-high resolution (2-50 μm) with favorable viability (75-95%), although limitations persist regarding photoinitiator toxicity and light penetration depth. Critical examination identifies energy-induced cell damage as a significant factor, with shear stress and UV exposure representing key detrimental influences. Bioink properties also emerge as crucial determinants of printing outcomes. The review further integrates modeling approaches for extrusion-based bioprinting and discusses preliminary computational modeling attempts. Future directions should focus on developing low-viscosity cell-compatible bioinks, advancing hybrid printing strategies, and establishing predictive models to harmonize printing parameters with biological outcomes. Interdisciplinary collaboration remains essential to fully realize the clinical potential of bioprinted tissues and organoids.
{"title":"A comprehensive review on the printing efficiency, precision, and cell viability in 3D bioprinting","authors":"Bowen Li , Zhen Wang , Chuanzhen Huang , Longhua Xu , Shuiquan Huang , Meina Qu , Zhengkai Xu , Dijia Zhang , Baosu Guo , Tianye Jin , Chunhui Ji","doi":"10.1016/j.medengphy.2025.104448","DOIUrl":"10.1016/j.medengphy.2025.104448","url":null,"abstract":"<div><div>Three-dimensional (3D) bioprinting demonstrates significant potential for advancing regenerative medicine through precise fabrication of functional tissue constructs via controlled deposition of cells, biomaterials, and bioactive factors. However, balancing key parameters-printing efficiency, resolution, and cell viability-remains challenging for replicating native tissue complexity. This review comprehensively examines recent advancements in three prominent bioprinting modalities: inkjet, extrusion-based, and digital light processing (DLP). Analysis reveals inherent performance trade-offs among these technologies. Inkjet bioprinting achieves high resolution (10-80 μm) at moderate speeds but exhibits limited cell viability (74-85%). Extrusion-based methods enable higher fabrication rates (0.00785-62.83 mm³/s) with variable viability (40-90%) at reduced resolution (100-2000 μm). DLP offers superior efficiency (0.648-840 mm³/s) and ultra-high resolution (2-50 μm) with favorable viability (75-95%), although limitations persist regarding photoinitiator toxicity and light penetration depth. Critical examination identifies energy-induced cell damage as a significant factor, with shear stress and UV exposure representing key detrimental influences. Bioink properties also emerge as crucial determinants of printing outcomes. The review further integrates modeling approaches for extrusion-based bioprinting and discusses preliminary computational modeling attempts. Future directions should focus on developing low-viscosity cell-compatible bioinks, advancing hybrid printing strategies, and establishing predictive models to harmonize printing parameters with biological outcomes. Interdisciplinary collaboration remains essential to fully realize the clinical potential of bioprinted tissues and organoids.</div></div>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":"145 ","pages":"Article 104448"},"PeriodicalIF":2.3,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145220209","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-29DOI: 10.1016/j.medengphy.2025.104444
Amirhossein Shokrani , Atta Seck , Bin Feng , David M. Pierce
Visceral pain in the large bowel is a hallmark of irritable bowel syndrome (IBS) and the primary reason patients seek gastroenterological care. Notably, mechanical distension of the distal colon and rectum (colorectum) reliably evokes abdominal pain and thus understanding mechanotransduction of sensory nerve endings (nerve fibers) in the colorectum is crucial for understanding and treating IBS-related bowel pain. To facilitate such understanding we aimed to establish novel methods to mechanically test, image, and analyze large-strain deformations of networks of nerve fibers in the myenteric plexus of the colorectum, and thus enable quantitative analyses. We successfully delivered circumferential, displacement-driven deformations to intact segments of colorectum while maintaining the myenteric plexus in focus during fluorescent imaging to capture the deforming nerve fibers. We also established a semi-automated method to recapitulate the network morphology and a code to calculate the stretch ratios of individual nerve fibers deforming within the myenteric plexus of mouse colorectum. Our code allows plotting of stretch ratios for each fiber, stretch ratios vs. fiber angles, and stretch ratios vs. fiber lengths. Our methods not only facilitate analyses of deformations of networks of colorectal nerve fibers in the context of visceral nociception but are also applicable to analyzing the in-plane deformation of other two-dimensional fiber networks. We provide free, public access to our analysis code for MATLAB, including input files for a simple test case, at github.uconn.edu/imLab/Fiber-Network_Analyses.
{"title":"Methods for quantitative analyses of nerve fiber deformation in the myenteric plexus under loading of mouse distal colon and rectum","authors":"Amirhossein Shokrani , Atta Seck , Bin Feng , David M. Pierce","doi":"10.1016/j.medengphy.2025.104444","DOIUrl":"10.1016/j.medengphy.2025.104444","url":null,"abstract":"<div><div>Visceral pain in the large bowel is a hallmark of irritable bowel syndrome (IBS) and the primary reason patients seek gastroenterological care. Notably, mechanical distension of the distal colon and rectum (colorectum) reliably evokes abdominal pain and thus understanding mechanotransduction of sensory nerve endings (nerve fibers) in the colorectum is crucial for understanding and treating IBS-related bowel pain. To facilitate such understanding we aimed to establish novel methods to mechanically test, image, and analyze large-strain deformations of networks of nerve fibers in the myenteric plexus of the colorectum, and thus enable quantitative analyses. We successfully delivered circumferential, displacement-driven deformations to intact segments of colorectum while maintaining the myenteric plexus in focus during fluorescent imaging to capture the deforming nerve fibers. We also established a semi-automated method to recapitulate the network morphology and a code to calculate the stretch ratios of individual nerve fibers deforming within the myenteric plexus of mouse colorectum. Our code allows plotting of stretch ratios for each fiber, stretch ratios vs. fiber angles, and stretch ratios vs. fiber lengths. Our methods not only facilitate analyses of deformations of networks of colorectal nerve fibers in the context of visceral nociception but are also applicable to analyzing the in-plane deformation of other two-dimensional fiber networks. We provide free, public access to our analysis code for MATLAB, including input files for a simple test case, at <span><span>github.uconn.edu/imLab/Fiber-Network_Analyses</span><svg><path></path></svg></span>.</div></div>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":"146 ","pages":"Article 104444"},"PeriodicalIF":2.3,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-29DOI: 10.1016/j.medengphy.2025.104446
Doyoung Kim, Parsaoran Hutapea
Needle steering to achieve large curvatures and deflection has the potential to enhance percutaneous procedures, such as brachytherapy, radiofrequency ablation, and deep brain stimulation. However, the mechanics of needles with large curvatures still need to be explored. This study introduces a curvilinear insertion to comprehensively investigate needle-tissue interactions. Experiments using passive curved needles with various bent angles (7.5°, 15°, 22.5°, and 30°) are conducted in tissue-mimicking materials, comparing curvilinear and linear insertion techniques. The curvilinear insertion method significantly reduces the average transverse force by 55.76%, axial force by 45.87%, and bending moment by 57.36%. Additionally, the proposed method achieves comparable curvature with less needle tip displacement between the initial puncture and the final needle position. These reductions in force, moment, and displacement may result in minimizing tissue damage and tissue deformation. The findings suggest that curvilinear insertion offers mechanical advantages and provides valuable insights for developing advanced needles with large curvature, enabling more precise targeting in minimally invasive surgery.
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Pub Date : 2025-09-29DOI: 10.1016/j.medengphy.2025.104447
C. Lardilleux , C. Lavergne , F. Marcq , M. Faruch , C. Lacabanne , E. Dantras
A vertebroplasty bone cement, designed to exhibit mechanical properties closer to those of the vertebral bone, was investigated. Indeed, adjacent fractures are attributed to an excessive difference in elastic modulus between the vertebrae and the bone cement implying another operation to repair the newly damaged vertebra. The proposed solution to lower the mechanical properties is the introduction of gelatine in the powder of the cement. This low modulus bone cement was studied by quasi-static compression, dynamic mechanical analysis and fatigue tests. Compression testing showed a significant decrease of the elastic modulus of 33 % after 6 months of immersion in a PBS solution at 37 °C, confirmed by the dynamic mechanical analysis. This analysis also showed that immersion and the introduction of gelatine in the cement influence the relaxations of the PMMA matrix. Fatigue performance was also studied with and without gelatine and showed that it presents a characteristic life of at least 24,600 cycles for a load of 7 MPa. While compression testing indicates a reduction in mechanical performance, all others tests demonstrated that gelatine does not significantly impair the overall properties of acrylic bone cement that still possess sufficient properties to achieve its main goal to stabilise damaged vertebrae.
{"title":"Long-term performance of a low-modulus acrylic cement in a simulated physiological environment","authors":"C. Lardilleux , C. Lavergne , F. Marcq , M. Faruch , C. Lacabanne , E. Dantras","doi":"10.1016/j.medengphy.2025.104447","DOIUrl":"10.1016/j.medengphy.2025.104447","url":null,"abstract":"<div><div>A vertebroplasty bone cement, designed to exhibit mechanical properties closer to those of the vertebral bone, was investigated. Indeed, adjacent fractures are attributed to an excessive difference in elastic modulus between the vertebrae and the bone cement implying another operation to repair the newly damaged vertebra. The proposed solution to lower the mechanical properties is the introduction of gelatine in the powder of the cement. This low modulus bone cement was studied by quasi-static compression, dynamic mechanical analysis and fatigue tests. Compression testing showed a significant decrease of the elastic modulus of 33 % after 6 months of immersion in a PBS solution at 37 °C, confirmed by the dynamic mechanical analysis. This analysis also showed that immersion and the introduction of gelatine in the cement influence the relaxations of the PMMA matrix. Fatigue performance was also studied with and without gelatine and showed that it presents a characteristic life of at least 24,600 cycles for a load of 7 MPa. While compression testing indicates a reduction in mechanical performance, all others tests demonstrated that gelatine does not significantly impair the overall properties of acrylic bone cement that still possess sufficient properties to achieve its main goal to stabilise damaged vertebrae.</div></div>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":"145 ","pages":"Article 104447"},"PeriodicalIF":2.3,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145320008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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