Traction Force Research Articles

O-229 Neck scarf of ureter and Intraoperative ICG-fluorescence for preventing ureters injuries in Da Vinci Robotic deep infiltrating endometriosis excision

Abstract Study question To prevent ureters injury during deep infiltrating endometriosis excision. Summary answer Identify the ureter course with ICG and near-infrared fluorescence (NIRF) imaging mode and traction with a vessel loop like neck scarf in white light mode. What is known already Deep infiltrating endometriosis is one of the most challenging gynecologic operation due to the distorted anatomy by the fibrosis of endometriosis gland.Identification of ureters through intraurethral ICG instillation and NIRF imaging has been reported to be useful during robotic surgery. However, surgeons cannot do robotic ureterolysis in Firefly NIRF imaging mode. When shift back to the white light mode, surgeons could only try to remember the ureter course during the ureterolysis procedure.When the ureter course was in doubt, the surgeon must shift back to the ICG-NIRF image mode again. Study design, size, duration From 2017 Jan1 till 2024 Jan 7, a single surgeon perform 47 consecutive patients with DIE received robotic surgery with ureterolysis from pelvic brim to the level of uterine vessels crossing them. Yellow and blue rubber bands were used to collar the ureters as a neck scarf, with Da Vinci robot system (SI, XI)The third arm as an stable assistant to traction the neck scarf to traction ureter indirectly in different direction when ureterolysis. Participants/materials, setting, methods We perform cystoscopy and intraurethral ICG injection with or without ureteral stent placement and Inject ICG-fluorescence with Firefly fluorescence imaging if the ureters were hard to find due to adhesion and fibrosis. Under the Firefly NIRF imaging mode,the location of ureter over the pelvic brim was found and the vessel loops were set up. Then shift back to white light mode to do the ureterolysis. Main results and the role of chance 47 consecutive patients with deep infiltrating endometriosis were safely operated without fistula, ureter injury, laceration during one month to 5 years period follow up. In them 2 patients need cystoscopy and ICG-NIRF help to setting up the vessel’s loops. Conclusion The surgeons could always keep the ureter safety during difficult endometriosis dissection with the vessel loops over the ureter as a neck scarf.There will be an indirect traction force pulled by robotic assistant forceps in the regular robotic laparoscopy light source mode during ureterolysis. The Firefly NIRF imaging mode could be used to help in setting up the neck scarf of ureters when the adhesion and fibroisis made the ureters course obscure. Limitations, reasons for caution Indocyanine Green is a fluorescent substance visible in near-infrared light. It is FDA-approved with IV injection for the identification of anatomical structures.The intra-ureteral ICG injection is off-label use. Wider implications of the findings Our techniques could be applied to all pelvic surgeries especially DIE, broad ligament and cervix myoma, scar defect repair and gynecologic cancer surgery, to preventing the ureters injured. However, further studies will be warranted. Trial registration number non-clinical trials

Multiphysics modeling of 3D traction force microscopy with application to cancer cell-induced degradation of the extracellular matrix

Abstract3D Traction Force Microscopy (3DTFM) constitutes a powerful methodology that enables the computation of realistic forces exerted by cells on the surrounding extracellular matrix (ECM). The ECM is characterized by its highly dynamic structure, which is constantly remodeled in order to regulate most basic cellular functions and processes. Certain pathological processes, such as cancer and metastasis, alter the way the ECM is remodeled. In particular, cancer cells are able to invade its surrounding tissue by the secretion of metalloproteinases that degrade the extracellular matrix to move and migrate towards different tissues, inducing ECM heterogeneity. Typically, 3DTFM studies neglect such heterogeneity and assume homogeneous ECM properties, which can lead to inaccuracies in traction reconstruction. Some studies have implemented ECM degradation models into 3DTFM, but the associated degradation maps are defined in an ad hoc manner. In this paper, we present a novel multiphysics approach to 3DTFM with evolving mechanical properties of the ECM. Our modeling considers a system of partial differential equations based on the mechanisms of activation of diffusive metalloproteinase MMP2 by membrane-bound metalloproteinase MT1-MMP. The obtained ECM density maps in an ECM-mimicking hydrogel are then used to compute the heterogeneous mechanical properties of the hydrogel through a multiscale approach. We perform forward and inverse TFM simulations both accounting for and omitting degradation, and results are compared to ground truth reference solutions in which degradation is considered. The main conclusions resulting from the study are: (i) the inverse methodology yields results that are significantly more accurate than those provided by the forward methodology; (ii) ignoring ECM degradation results in a considerable overestimation of tractions and non negligible errors in all analyzed cases.

Poster 192: The Incidence and Breadth of Postoperative Pudendal Nerve Palsy and Its Relationship to Table Traction During Hip Arthroscopy With a Perineal Post

Objectives: Pudendal nerve palsy (PNP) is a poorly characterized but common postoperative complication of hip arthroscopy (HA) with a perineal post that can result in external genital numbness and sexual dysfunction in both men and women. Previous attempts to quantify the incidence of these symptoms have relied on patient-initiated reports, chart review, unvalidated questionnaires or have neglected the female experience altogether – failures which likely underestimate the incidence of this complication. We aimed to describe the incidence of postoperative PNP, the breadth of symptoms patient experience and their duration, as well as establish the relationship between PNP and table traction. Methods: We utilized a multisurgeon prospective cohort of HA patients a single academic center. All patients underwent primary unilateral hip arthroscopy, osteochondroplasty and labral repair in a supine position with a perineal post. Patients with preexisting PNP symptoms, including sexual dysfunction, and those who were not sexually active were excluded. Intraoperative traction duration and force were recorded using a Tekscan sensor applied to the perineal post. A PNP screening questionnaire and standardized, validated sexual function questionnaires were administered confidentially to patients at 2 weeks, 6 weeks, 3 months, and 6 months postoperatively. Patient-reported hip function scores (iHOT-33) were completed preoperatively and at 6 months postoperatively. Results: A total of 100 patients were enrolled. The mean age was 36.2 ± 9.4 years old, 56 patients (56%) were male. The mean traction duration was 80 ± 19 minutes. In the acute postoperative period, 77 patients (77%) experienced symptoms consistent with PNP. The most common sensory symptom described was perineal numbness (n = 77, 77%), followed by paresthesias (n=26, 26%). Seventeen men (17%) and 13 women (13%) reported symptoms of sexual dysfunction postoperatively, in the form of erectile dysfunction (men) or reduced sexual lubrication/dyspareunia/anorgasmia (women). Of patients who experienced PNP symptoms (n = 77), 21% had symptoms resolve by 6 weeks, 71% by 3 months, 90% by 6 months. Two male patients (3.6%) had persistent erectile dysfunction beyond 6 months postoperatively. Persistence of PNP symptoms beyond 6 weeks was associated with lower 33-item International Hip Outcome Tool (iHOT-33) scores at 6 months (mean difference: 18.4 [95% CI: 6.5-30.4], p = 0.003). Analysis of the calibrated sensor data to establish the relationship between traction force, pressure, and duration with PNP is pending. Conclusions: In this preliminary analysis of a planned 100-patient cohort, patients experienced a high rate of PNP and sexual dysfunction symptoms following HA with perineal post, far higher than previous reports. Most symptoms resolved within the first 3 months postoperatively. Anticipated results from the sensor data within this ongoing study are likely to provide insight into the relationship between traction force and/or duration and PNP incidence. A postless HA setup could be considered as an alternative given the described morbidity.

Mutual antagonism between CD44 and integrins in glioblastoma cell traction and migration.

Cell migration is the major driver of invasion and metastasis during cancer progression. For cells to migrate, they utilize the actin-myosin cytoskeleton and adhesion molecules, such as integrins and CD44, to generate traction forces in their environment. CD44 primarily binds to hyaluronic acid (HA) and integrins primarily bind to extracellular matrix (ECM) proteins such as collagen. However, the role of CD44 under integrin-mediated conditions and vice versa is not well known. Here, we performed traction force microscopy (TFM) on U251 cells seeded on collagen I-coated polyacrylamide gels to assess the functional mechanical relationship between integrins and CD44. Performing TFM on integrin-mediated adhesion conditions, i.e., collagen, we found that CD44KO U251 cells exerted more traction force than wild-type (WT) U251 cells. Furthermore, untreated WT and CD44-blocked WT exhibited comparable results. Conversely, in CD44-mediated adhesive conditions, integrin-blocked WT cells exerted a higher traction force than untreated WT cells. Our data suggest that CD44 and integrins have a mutually antagonistic relationship where one receptor represses the other's ability to generate traction force on its cognate substrate.

Poster 187: Describing the Contribution of the Vacuum Effect and Hip Capsule in Restraint to Axial Traction in Patients Undergoing Hip Arthroscopy

Objectives: In recent investigations, there has been increased focus on hip laxity and hip capsular instability, particularly in the setting of hip arthroscopy. The capsule and its internal negative pressure effects have been shown to be major contributors to hip joint stability, however, the relative contributory role of these elements remains unknown. Intraoperatively, improved understanding of hip capsule biomechanics is imperative for optimization of arthroscopic technique to access the central compartment with minimal soft tissue trauma. In turn, this can help reduce the risk of hip instability and maximize patient outcomes. The purpose of this study was to define the stiffness coefficient of the hip capsule and vacuum phenomenon in response to hip axial traction. Our hypothesis was that the vacuum phenomenon would have a greater relative contribution to axial distraction stiffness at mid-range distraction, and that the hip capsule stiffness coefficient would be greater at terminal distraction. Methods: A review of a prospectively collected database of patients undergoing hip arthroscopy was conducted from 1 July 2021 to 31 June 2022. Patients in this database underwent hip arthroscopy for the treatment of femoroacetabular impingement syndrome (FAIS). Inclusion criteria were 1) completion of the study traction protocol and 2) completion of hip joint venting prior to capsulotomy. Exclusion criteria were 1) previous hip surgery and 2) lack of hip distraction at 50 pounds of axial traction. The study traction protocol involved applying axial traction prior to instrumentation (Native State) of the hip using a post-free distraction system. Hips were then vented using a spinal needle and the traction protocol was repeated (Vented State). Traction intervals were 0, 50, and 100 lbs of force. Fluoroscopic images were taken at each traction interval and standardized to preoperative radiographs, which allowed for a calculation of the lateral joint space width at each interval. Overall distraction distance was calculated as the difference between 0 lbs traction and 50 and 100 lbs traction. The stiffness coefficient was calculated as k = traction force interval/distraction distance in both the Native and Vented States. Comparisons using paired-samples t-tests were conducted between the stiffness coefficients of the Native State and Vented State at 50 lbs and at 100 lbs. A p-value of <0.05 was utilized to indicate statistical significance. Results: Twenty-one patients were identified who met inclusion criteria. Mean age was 34.4 ± 13.4 years with 100% female and a mean BMI of 24.2 ± 4.8 points. Mean stiffness coefficient at 50 lbs in the Native State (10.9 ± 3.3) was significantly higher than the Vented State (4.9 ± 0.7, p < 0.001), with similar findings at 100 lbs in the Native State (10.1 ± 1.7) and Vented State (8.7 ± 1.3, p < 0.001). In the Vented State, the stiffness coefficient was significantly greater at 100 lbs (8.7 ± 1.3) than at 50 lbs (4.9 ± 0.7, p < 0.001). Conclusions: Our results provide an objective characterization of the individual contributions of the hip soft tissue restraints and the vacuum phenomenon to hip resistance to axial traction. At 50 pounds of traction, the vacuum effect contributes to ~55% of the axial distraction stiffness (resistance to axial distraction). At 100 pounds of traction force, the vacuum effect contributes only ~14% of the axial distraction stiffness. The resistance of the hip to axial distraction is of substantial clinical significance as minimization of traction force decreases intraoperative soft tissue trauma. This, however, needs to be balanced with obtaining sufficient working space within the hip joint. There is still substantial controversy regarding the biomechanics of the hip and the optimal methods for minimizing traction force related injury (e.g., post-less traction, minimization of traction time, air arthrogram, and joint venting). These data demonstrate that soft tissues have a proportionally greater effect on restraint of the of the hip at terminal distraction (~1 cm distraction), whereas the vacuum effect has a greater influence on mid-range distraction (~0.5 cm distraction). The proposed model for this phenomenon is that the negative pressure and the soft tissue tension work in parallel to restrain the hip joint. The increased influence of the soft tissue tension at end-range distraction may be due to a check rein effect of the soft tissues; once the iliofemoral ligament has been tensioned to its maximum length its stiffness and capacity for transfer of tensile force increases rapidly. In conclusion, at 50 pounds of traction, the vacuum effect contributes to ~55% of the axial distraction stiffness (resistance to axial distraction). At 100 pounds of traction force, the vacuum effect contributes only ~14% of the axial distraction stiffness. These results demonstrate that the vacuum effect is a significant restraint to axial traction applied across the hip at mid-range distraction. Additionally, the hip capsule has a relatively greater contribution to terminal distraction stiffness.

ELEMENTS OF THE THEORY OF DYNAMIC DEVELOPED SUSPENSION MILITARY VEHICLE

The wheel drives of a military vehicle are intended for its movement to satisfy the performance of technological tasks in the zone close to combat, but this requirement is not fully satisfied. This is related to the performance of the above tasks in difficult conditions, in off-road conditions. In order to ensure the mandatory performance and reliability of technological movements in such conditions, construction specialists focused their actions on improving the running gear, especially the suspensions. The article deals with the theoretical research of the design of the developed suspension of a military vehicle. The movement of the car is carried out with the help of wheeled motors, which partially satisfy the performance of technological tasks in the zone close to combat. The main drawback is the fulfillment of the requirements for moving a military vehicle in off-road conditions, and in some cases, the impossibility of moving it. In order to increase the reliability of the technology of moving a car in offroad conditions, the development of world-class specialists is aimed at improving the design of its suspension, as well as the technology of moving it in off-road conditions of a military vehicle, the number of movements of the system, and the movement of the center of mass of this system. The purpose of the study is to improve the technological scheme of loading the wheel drive when it moves the support, the transformation of the energy supplied to the wheel drive and the quantitative movements kinematically distributed in the wheel drive into the controlled relative to the wheel disc movement of the car with the addition of the traction force of the car with the portable forces of quantitative movement, which is an auxiliary factor to the innovative technology of its movement. The scientific and practical direction of the work consists in the fact that for the first time the considered technology in which the law of change of mechanical energy is applied during the rotation of the wheel drive over an obstacle, i.e., the energy supplied to the wheel drive and the quantitative movements kinematically distributed in the wheel drive in the controlled motion of the car relative to the wheel disc with summing up the traction force of the car with the portable forces of the quantitative movement, and this allows us to approach the consideration of the implementation of the torque on the wheel drive more expediently. The methodology of the study was to establish a mathematical relationship between the quantitative movements kinematically distributed in the wheel drive in the car movement controlled relative to the wheel disc and the parameter of quantitative movements, as well as with the dynamic mobility of the car itself. The result of the research is the development of the elements of the theory of quantitative movements kinematically distributed in the wheel drive. When revealing the concept of "dynamically developed suspension", equations were used that mathematically confirm the connection with the quantitative movements kinematically distributed in the wheel drive in the controlled movement of the car relative to the wheel disc, which allows overcoming obstacles on the way and supporting surface in certain conditions of vehicle operation. The value of the conducted research, the results of the conducted work will allow to make a contribution to the automotive industry. The proposed car model is suitable for use in order to increase the ability of vehicles to overcome obstacles.

Longitudinal Train Dynamics Model for CC203/CC206 Locomotive Simulator

This paper presents train modeling used in a simulator platform for driver training. It was developed for the CC203/CC204 locomotive. The driver will gain experience as in a real locomotive from the perceived platform movements if the movements match real conditions as accurately as possible, including the distance travelled. To this aim, a longitudinal model of the train was developed based on measurement data obtained from the Argo Parahyangan train traveling from Bandung to Jakarta. A second-order linear time invariant model was obtained by a black box identification approach, in which the input and the output of the model are the resultant force (a traction and a slope-friction force) and the train’s position, respectively. While the speed is directly obtained from measurement data, the traction force of the locomotive is predicted using the traction characteristic of the locomotive, train’s measured speed, and latitude time history during a train trip. The model is then validated by running a simulation for one complete trip of the train. In the simulation, the same input as in the model identification is applied and the mileage obtained from simulation result is compared to data of the real train trip with a fitness level of 94.09%.

DEVELOPMENT OF A MATHEMATICAL MODEL FOR DETERMINING TRACTION AND ENERGY PERFORMANCE INDICATORS OF A MANEUVERING LOCOMOTIVE

Fuel consumption for traction significantly depends on the locomotive's operating mode, and by selecting a rational mode during station maneuvers or transit, it is possible to reduce fuel consumption. Previous works on this topic do not provide sufficient analysis of locomotive motion with varying numbers of connected engines. To optimize energy resource consumption, a combination of methods for the rational use of the locomotive is necessary. The traction and energy performance indicators for the maneuvering work of the ČME3 locomotive are calculated by performing traction calculations. In this paper, a mathematical model has been developed to determine these indicators when operating with 4 and 2 parallel-connected traction electric motors. Graphs were constructed to illustrate the relationship between traction force and locomotive speed, the time required to cover a given distance, fuel consumption for a specified distance, and the temperature rise above ambient conditions concerning 6 parallel-connected traction electric motors for the 3rd, 4th, and 5th positions of the engineer's controller. The locomotives were compared while covering the same stretch of track with the same train weight, considering wheel-rail adhesion constraints.Analyzing the obtained dependencies allows the conclusion that using different configurations of connected engines can result in fuel savings of up to 15 % during maneuvering operations, depending on operational conditions. Furthermore, the engine temperature remains within acceptable limits for insulation class F, based on the results of approximating existing locomotive characteristics and deriving analytical expressions (6, 7, 8, 24). Mathematical models of the motion of the ЧМЕ3 locomotive were created for various engine connection scenarios using the obtained mathematical formulas (9, 10, 11, 13, 20, 21, 22, 23, 24).

HITCH DEVICE MODERNIZATION FOR TRANSLOADING OF BALE CARGO

The operation of unloading bales from a covered railway wagon is one of the most labor-intensive and dangerous operations when transporting bale cargo. The article proposes a modernized outside-mounted load-handling device for a universal light-sized forklift. The device is a mechanical equipment for transloading of bale cargo. The device includes a push-pull attachment (a purchased part) on which a frame, a lever clamp and a hydraulic cylinder are mounted. Тtrolleys are installed on the forks of the loader. The trolley is equipped with a roller in the front part and a frame in the back part for longitudinal movement on the forks. The trolley also has a support for the movable pusher plate and a grip for lifting the front edge of the bale. The trolleys are connected to the stationary pusher plate by a lever-type limiter. Before the start of gripping, the forklift is tilted forward at an angle from 3 to 5°, the trolleys are in the most forward position and are supported by a pusher. In this case, the rollers are in the position where they have moved off the forks. By moving the forklift forward, the trolley grips are inserted under the bale. The pusher is brought into the folded state. The loader moves forward, the noses of the forks abut against the roller and it rolls onto the forks, lifting the front edge of the bale. The forks are fully inserted under the bale. The clamp comes into operation, holding the load on the forks. This allows the bales to be removed from the stack and transported. The trolley was designed using CAD KOMPAS-3D. The proposed device is capable of picking up bales stacked without gaps and can be used inside a covered railway wagon. Commonly used side-clamp devices are not capable of this. The mathematical relation of the required traction force of the loader on the geometric parameters of the trolley is derived. It has been established that the required traction force is 60 to 70 % of the maximum traction force achieved by light-sized forklifts with a lifting capacity of 1000 kg.

Single-cell topographical profiling of the immune synapse reveals a biomechanical signature of cytotoxicity

Immune cells have intensely physical lifestyles characterized by structural plasticity and force exertion. To investigate whether specific immune functions require stereotyped mechanical outputs, we used super-resolution traction force microscopy to compare the immune synapses formed by cytotoxic T cells with contacts formed by other T cell subsets and by macrophages. T cell synapses were globally compressive, which was fundamentally different from the pulling and pinching associated with macrophage phagocytosis. Spectral decomposition of force exertion patterns from each cell type linked cytotoxicity to compressive strength, local protrusiveness, and the induction of complex, asymmetric topography. These features were validated as cytotoxic drivers by genetic disruption of cytoskeletal regulators, live imaging of synaptic secretion, and in silico analysis of interfacial distortion. Synapse architecture and force exertion were sensitive to target stiffness and size, suggesting that the mechanical potentiation of killing is biophysically adaptive. We conclude that cellular cytotoxicity and, by implication, other effector responses are supported by specialized patterns of efferent force.

Mechanical Behavior of Five Different Morse Taper Implants and Abutments with Different Conical Internal Connections and Angles: An In Vitro Experimental Study.

The present study evaluated the mechanical behavior of five designs of Morse taper (MT) connections with and without the application of loads. For this, the detorque of the fixing screw and the traction force required to disconnect the abutment from the implant were assessed. A total of 100 sets of implants/abutments (IAs) with MT-type connections were used, comprising five groups (n = 20/group): (1) Group Imp 11.5: IA sets with a cone angulation of 11.5°; (2) Group SIN 11.5: with a cone angulation of 11.5°; (3) Group SIN 16: with a cone angulation of 16°; (4) Group Neo 16: with a cone angulation of 16°; and (5) Group Str 15: with a cone angulation of 15°. All sets received the torque recommended by the manufacturer. After applying the torque, the counter torque of the fixing screws was measured in ten IA sets of each group without the application of cyclic loads (frequencies ≤ 2 Hz, 360,000 cycles, and force at 150 Ncm). The other ten sets of each group were subjected to cyclic loads, after which the detorque was measured. Afterwards, the force for disconnection between the implant and the abutment was measured by traction on all the samples. The untwisting of the abutment fixation screws showed a decrease in relation to the initial torque applied in all groups. In the unloaded samples, it was found to be -25.7% in Group 1, -30.4% in Group 2, -36.8% in Group 3, -29.6% in Group 4, and -25.7% in Group 5. After the applied loads, it was found to be -44% in Group 1, -43.5% in Group 2, -48.5% in Group 3, -47.2% in Group 4, and -49.8% in Group 5. The values for the IA sets were zero for SIN 16 (Group 3) and Neo16 (Group 4), both without and with loads. In the other three groups, without loads, the disconnection value was 56.3 ± 2.21 N (Group 1), 30.7 ± 2.00 N (Group 2), and 26.0 ± 2.52 N (Group 5). After applying loads, the values were 63.5 ± 3.06 N for Group 1, 34.2 ± 2.45 N in Group 2, and 23.1 ± 1.29 N in Group 5. It was concluded that in terms of the mechanical behavior of the five designs of MT IA sets, with and without the application of loads, the Imp 11.5, SIN 11.5, and Srt 15 groups showed better results compared to the SIN 16 and Neo 16 groups, showing that lower values of cone angulation increase the friction between the parts (IA), thus avoiding the need to maintain the torque of the fixing screw to maintain the union of the sets.

Finite Element Axisymmetric Models for Conical Wedge Anchorage Used in the Production of Prestressed Steel Reinforced Concretes

The anchor system plays a very important part of the prestressed structure, that contacts and transmits force to the cables when stretching to create residual stress. The operating conditions of the anchor system in general and the anchor core in particular are extremely harsh. In this paper, <I>ABAQUS</I> software was applied to model and numerically simulate the axisymmetric loading process of the anchor core in manufacturing prestressed concrete sleepers, to study the effects of tensile forces to the pressure resistance of the cylinder. To verify the analytical results, a Finite Element (<I>FE</I>)-model with the same material and geometrical properties was created. The difference is the assumption of plane stress in the analytical solution, can be solved using two - dimensional finite elements, which are most conveniently described in cylindrical (<i>r, θ, z</i>) coordinates. This articles also especially focused on calculating the change of stress on the edges of the anchor core teeth with different tensile forces. We also refered to experimental results to get data on traction force and working conditions to build a calculation model and select input parameters. Comparison of the stress generated on the teeth of the anchor core was performed with three different tensions of <i>171, 181</i> and <i>191 kN</i>. The maximum and concentrated stress at the top and root of the anchor core when tensioning the cable has been calculated.

Tracking single hiPSC-derived cardiomyocyte contractile function using CONTRAX an efficient pipeline for traction force measurement

Cardiomyocytes derived from human induced pluripotent stem cells (hiPSC-CMs) are powerful in vitro models to study the mechanisms underlying cardiomyopathies and cardiotoxicity. Quantification of the contractile function in single hiPSC-CMs at high-throughput and over time is essential to disentangle how cellular mechanisms affect heart function. Here, we present CONTRAX, an open-access, versatile, and streamlined pipeline for quantitative tracking of the contractile dynamics of single hiPSC-CMs over time. Three software modules enable: parameter-based identification of single hiPSC-CMs; automated video acquisition of >200 cells/hour; and contractility measurements via traction force microscopy. We analyze >4,500 hiPSC-CMs over time in the same cells under orthogonal conditions of culture media and substrate stiffnesses; +/− drug treatment; +/− cardiac mutations. Using undirected clustering, we reveal converging maturation patterns, quantifiable drug response to Mavacamten and significant deficiencies in hiPSC-CMs with disease mutations. CONTRAX empowers researchers with a potent quantitative approach to develop cardiac therapies.

Letter to the editor regarding the article “The effect of traction force on eyelid blood perfusion during closure of defects”

Letter to the editor regarding the article “The effect of traction force on eyelid blood perfusion during closure of defects”

The Role of Vimentin in Human Corneal Fibroblast Spreading and Myofibroblast Transformation.

Vimentin has been reported to play diverse roles in cell processes such as spreading, migration, cell-matrix adhesion, and fibrotic transformation. Here, we assess how vimentin impacts cell spreading, morphology, and myofibroblast transformation of human corneal fibroblasts. Overall, although knockout (KO) of vimentin did not dramatically impact corneal fibroblast spreading and mechanical activity (traction force), cell elongation in response to PDGF was reduced in vimentin KO cells as compared to controls. Blocking vimentin polymerization using Withaferin had even more pronounced effects on cell spreading and also inhibited cell-induced matrix contraction. Furthermore, although absence of vimentin did not completely block TGFβ-induced myofibroblast transformation, the degree of transformation and amount of αSMA protein expression was reduced. Proteomics showed that vimentin KO cells cultured in TGFβ had a similar pattern of protein expression as controls. One exception included periostin, an ECM protein associated with wound healing and fibrosis in other cell types, which was highly expressed only in Vim KO cells. We also demonstrate for the first time that LRRC15, a protein previously associated with myofibroblast transformation of cancer-associated fibroblasts, is also expressed by corneal myofibroblasts. Interestingly, proteins associated with LRRC15 in other cell types, such as collagen, fibronectin, β1 integrin and α11 integrin, were also upregulated. Overall, our data show that vimentin impacts both corneal fibroblast spreading and myofibroblast transformation. We also identified novel proteins that may regulate corneal myofibroblast transformation in the presence and/or absence of vimentin.

Using individual tractor wheel drive through electric traction

In agriculture, tractors serve as the principal machinery for performing traction and driving operations. They are mainly powered by diesel engines with an efficiency of about 40 percent. Electric motors boast an efficiency of 95 percent, presenting the opportunity to serve as independent drives for tractor wheels. The study review existing individual wheel drive systems, revealing operational efficiency improvements of up to 20 percent. A comparative analysis was conducted between tractors using traditional power units and those equipped with electric drive systems. The study also examined factors affecting tractor traction and explored methods to enhance the traction capabilities of these vehicles. (Research purpose) The study aims to evaluate the feasibility of using electric traction for individual drive systems in tractor wheels. (Materials and methods) A concept for controlling individual wheel drives has been developed, as well as an algorithm specifically for managing electric wheels. Additionally, a method has been proposed for detecting slippage, which triggers the switching of the electric wheel drive to the appropriate mode. Furthermore, a new indicator, the «slip factor,» has been introduced to correlate slip with adhesion coefficients. The value of this parameter is used as a criterion for transitioning the electric drive to a different operational mode. (Results and discussion) Traction tests were conducted on the MTZ-82.1 tractor across various supporting surfaces. The measured slip factors were as follows: 0.71 for a cropped field, 0.86 for stubble, 1.19 for fallow land, and 1.74 for asphalt pavement. To accurately assess the wheel’s performance under real conditions, torque measurements were taken using a specialized locking device. These measurements revealed angular displacements of the shaft by 0.2 degrees when subjected to a tangential traction force of 3 kilonewtons on the wheel. (Conclusions) The slip factor for the MTZ-82.1 tractor has been determined. A mathematical model has been proposed that links the wheel’s adhesion properties with slipping. The model proves to be applicable up to a slip limit of 30 percent. This multifactorial approach enables the creation of an adaptive program to enhance wheel efficiency. Additionally, the capability to measure wheel torque has been established.

Correlated variables and changes in fascial stiffness and pelvic mobility following the myofascial induction method utilizing the crossed hands technique

BackgroundMyofascial Induction Therapy (MIT) is a physiotherapeutic (PT) intervention addressing musculoskeletal disorders. Standardizing MIT as a manual PT intervention ensures consistency and replicability. AimTo describe correlated variables and changes in fascial stiffness and pelvic mobility after applying the Crossed Hands Technique based on MIT. MethodsA quasi-experimental study involved 15 PTs trained in myofascial induction and 15 healthy individuals. Environmental (ambient temperature, stretcher height, width), patient (subscapular fatty fold, BMI, height, chest length, lumbopelvic mobility, fascial stiffness), and PT variables (pressure, traction, hand temperature, kinematic changes) were assessed during lumbodorsal hands-cross at 1-min intervals for 5 min. Pelvic mobility was measured using kinovea photogrammetry and dorsolumbar stiffness using a durometer. Descriptive analysis and correlations were applied. ResultsPTs had a mean 5.3 years of MIT experience. The average force was 5.5 N, traction force 0.39 N. Post-technique, individuals showed 4° increased pelvic mobility, minimal stiffness changes at T7 and L4 levels. Kinematic variables for the PTs revealed an average shoulder flexion of 40° and bilateral elbow flexion of 18°. Following the application of the technique, individuals who received MIT experienced a 4° increase in pelvic mobility, with only minor changes in stiffness observed at both the T7 and L4 levels. ConclusionsThe Crossed Hands Technique involves key variables like force and traction, varying over time. Clinical outcomes are influenced by patient and environmental factors. Notably, the physiotherapist's hand temperature, right shoulder internal rotation, right foot abduction, and fourth finger opening show significant correlations with tissue stiffness changes.

Development of a Cost-Effective UAV for Extended Duration Disaster Management Operations using Expanded Polystyrene

Commercial UAVs specifically developed for disaster management purposes are frequently priced at an exorbitant level. Usually, unmanned aerial vehicles (UAVs) have a flight length of 15-30 minutes. However, crisis management operations often demand longer mission durations, occasionally in difficult weather circumstances. In order to tackle this problem, Expanded Polystyrene (EPS) was selected as the material for the body and wings of the UAV due to its cost-effectiveness in comparison to materials such as fiberglass, carbon fibre, epoxy, Kevlar, and wooden balsa. The EPS material utilized exhibits a tensile strength of 88 pounds per square inch (psi). For flight testing, a LiPo 3S battery with a voltage of 11.1 volts was used in the UAV. The virtual wind tunnel test was carried out with precise parameters, including an air density of 1.225 kg/m³ and a wind speed of 50 m/s. In order to improve the wing's structural integrity, a lightweight aluminium bar was incorporated. The initial design of the UAV wing showcased an elongated glider-like structure, enabling prolonged flight durations using a solitary propeller. The simulation findings showed that the UAV successfully controlled the drag coefficient with time, maintaining a traction force of 200N during testing. The UAV's capacity to endure gusts of up to 70 knots, achieve elevations of 5000 feet, and travel lengths of up to 90 km was demonstrated in practical trials, contingent upon the control systems employed. Ultimately, the newly designed UAV has the capability to sustain flight for a duration of 8 hours, thereby overcoming the constraints typically encountered with commercial UAVs employed in disaster management.

Ex vivo Study of Partial Bladder Resection in a Porcine Model.

Partial cystectomy aims to preserve bladder function, yet its urodynamic impacts remain unclear. We investigate these effects using an ex vivo porcine model, evaluating bladder volume, compliance, and wall thickness, alongside with thermal damage after bi- and monopolar resection. Within an artificial human pelvis, we conducted partial bladder wall resections (5 cm2, 10 cm2). Urodynamic tests and sonography assessed volume, compliance, and thickness changes. Traction force for catheter retrieval and thermal collagen destruction were measured. Bladder compliance decreased by 1.12 and 1.5 after 5 cm2 and 10 cm2 resections, respectively, with volume reductions of 3-6% and 10-18%. Wall thickness decreased by 20% and 30% post-resection. Comparable thermal damage was observed with mono- and bipolar resection methods. Our study outlines urodynamic impacts and technical considerations of partial cystectomy, affirming its endoscopic feasibility while highlighting potential bladder dysfunction risks.

Vimentin promotes collective cell migration through collagen networks via increased matrix remodeling and spheroid fluidity.

The intermediate filament (IF) protein vimentin is associated with many diseases with phenotypes of enhanced cellular migration and aggressive invasion through the extracellular matrix (ECM) of tissues, but vimentin's role in in-vivo cell migration is still largely unclear. Vimentin is important for proper cellular adhesion and force generation, which are critical to cell migration; yet the vimentin cytoskeleton also hinders the ability of cells to squeeze through small pores in ECM, resisting migration. To identify the role of vimentin in collective cell migration, we generate spheroids of wide-type and vimentin-null mouse embryonic fibroblasts (mEFs) and embed them in a 3D collagen matrix. We find that loss of vimentin significantly impairs the ability of the spheroid to collectively expand through collagen networks and remodel the collagen network. Traction force analysis reveals that vimentin null spheroids exert less contractile force than their wild-type counterparts. In addition, spheroids made of mEFs with only vimentin unit length filaments (ULFs) exhibit similar behavior as vimentin-null spheroids, suggesting filamentous vimentin is required to promote 3D collective cell migration. We find the vimentin-mediated collective cell expansion is dependent on matrix metalloproteinase (MMP) degradation of the collagen matrix. Further, 3D vertex model simulation of spheroid and embedded ECM indicates that wild-type spheroids behave more fluid-like, enabling more active pulling and reconstructing the surrounding collagen network. Altogether, these results signify that VIF plays a critical role in enhancing migratory persistence in 3D matrix environments through MMP transportation and tissue fluidity.