BACKGROUND: Models for ultrasound-guided regional anaesthesia (USGRA) are important for research and training. However, the limited data available show great differences in quality of needle and tissue visualisation with regard to the applied model. This study aims to compare common USGRA models and human tissue with regard to their influence ...

Subject-specific musculo-skeletal models of the lower extremity are an important tool for investigating various biomechanical problems, for instance the results of surgery such as joint replacements and tendon transfers. The aim of this study was to assess the potential effects of errors in musculo-skeletal geometry on subject-specific model results. We ...

Video-based walking track systems have been developed for gait analysis in rat models. However, there is no previous study using video-based tracking systems to address the gait parameters to evaluate the recovery of Achilles tendon rupture models. This study conducted a comprehensive gait analysis using a video-based image processing system. ...

Biomechanical models of the fingers are used to gain a greater understanding of internal loading. This can help guide the treatment of injuries and pathologies. However, to be valid these models require accurate measurement of body kinematics, external reaction forces and soft tissue architecture. This study aimed to quantify the ...

The motivation of this research is to non-invasively monitor the wrist tendon's displacement and velocity, for purposes of controlling a prosthetic device. This feasibility study aims to determine if the proposed technique using Doppler ultrasound is able to accurately estimate the tendon's instantaneous velocity and displacement. This study is conducted ...

Background  Knowledge about human cyclic fasting motility (MMC) and the postprandial response is mostly based on manometric findings in the upper small intestine. Hardly any data exist on human ileal motility, as the acquisition of data has been limited by methodological concerns. The aim was to study human jejunal and ...

  Model fruit pulp-based gels were prepared by varying mango pulp (0% to 50%), sucrose (0% to 20%), and agar (1% to 3%) and according to a response surface experimental design followed by drying at a low temperature of 40 °C upto 15 h in a tray dryer assisted by ...

Tendons transfer muscular forces efficiently and painlessly, facilitating joint motion. Whilst the tribology of articular cartilage is constantly explored, a poorer understanding remains of tendon lubrication and friction. This study reports experimental data describing the tribological characteristics of tendon and its surrounding tissue, before presenting an arithmetic solution to facilitate ...

Individual-based models describing the migration and proliferation of a population of cells frequently restrict the cells to a predefined lattice. An implicit assumption of this type of lattice-based model is that a proliferative population will always eventually fill the lattice. Here, we develop a new lattice-free individual-based model that incorporates ...

Electrical waves traveling throughout the myocardium elicit muscle contractions responsible for pumping blood throughout the body. The shape and direction of these waves depend on the spatial arrangement of ventricular myocytes, termed fiber orientation. In computational studies simulating electrical wave propagation or mechanical contraction in the heart, accurately representing fiber ...

A novel constitutive model that describes stress relaxation in transversely isotropic soft collagenous tissues such as ligaments and tendons is presented. The model is formulated within the nonlinear integral representation framework proposed by Pipkin and Rogers (J. Mech. Phys. Solids. 16:59-72, 1968). It represents a departure from existing models in ...

BACKGROUND: This numerical study analysed the mechanics of cuff tear arthropathy with the AnyBody shoulder model. METHODS: The model simulated three frequent characteristics of cuff tear arthropathy: A supero-posterior massive rotator cuff tear, a proximal and static migration of the humeral head, and a contact between the humeral head and ...

PURPOSE: Early motion protocols after flexor tendon repair often require hand therapy in edematous digits. Self-adherent wraps are used in the postoperative period to reduce edema. The purpose of this study was to determine whether the presence of a self-adherent wrap affected the work of flexion during early motion protocols. ...

Control and modelling of continuum robots are challenging tasks for robotic researchers. Most works on modelling are limited to piecewise constant curvature. In many cases they neglect to model the actuators or avoid a continuum approach. In particular, in the latter case this leads to a complex model hardly implemented. ...

This study presents Artificial Neural Networks (ANN) as a tool for designing injectable intratumoral formulations of the anticancer drug β-lapachone. This methodology permits insight into the interactions between variables and determines the design space of the formulation without the restrictions of an experimental design. An ANN model for two critical ...

Amphoteric hydrogels contain both ionizable acidic and basic groups attached on the polymer chains, which can change their volume in response to the slight alteration of the surrounding environmental p H. In this paper, a theory of equilibrium swelling of amphoteric p H-sensitive hydrogels which is an extension of the ...

Every year, 500,000 osteoporotic vertebral compression fractures occur in Europe. Quantitative computed tomography (QCT)-based finite element (FE) voxel models predict ultimate force whether they simulate vertebral bodies embedded in polymethylmethacrylate (PMMA) or vertebral sections with both endplates removed. To assess the effect of endplate removal in those predictions, non-linear FE ...

A detailed 3D anatomical model of the patellofemoral joint was developed to study the tracking, force, contact and stability characteristics of the joint. The quadriceps was considered to include six components represented by 15 force vectors. The patellar tendon was modeled using four bundles of viscoelastic tensile elements. Each of ...

Hazard function estimation is an important part of survival analysis. Interest often centers on estimating the hazard function associated with a particular cause of death. We propose three nonparametric kernel estimators for the hazard function, all of which are appropriate when death times are subject to random censorship and censoring ...

A variety of reforms to traditional approaches to provider payment and benefit design are being implemented in the United States. There is increasing interest in applying these financial incentives to orthopaedics, although it is unclear whether and to what extent they have been implemented and whether they increase quality or ...

The Yukawa model in the quenched approximation is expressed as a disordered statistical mechanics model on a four-dimensional Euclidean lattice. We study this model, giving particular attention to the singularities of the Dirac operator in the phase diagram. A careful analysis of a particular limiting case shows that finite volume ...

Vocal folds are anatomically and biomechanically unique, thus complicating the design and implementation of tissue engineering strategies for repair and regeneration. Integration of an enhanced understanding of tissue biomechanics, wound healing dynamics and innovative gel-based therapeutics has generated enthusiasm for the notion that an efficacious treatment for vocal fold scarring ...

Lattice models of proteins have been extensively used to study protein thermodynamics, folding dynamics and evolution. Our study considers two different hydrophobic-polar models on the two-dimensional square lattice: the purely hydrophobic-polar (HP) model and a model where a compactness-favoring term is added. We exhaustively enumerate all the possible structures in ...

The mouse has proven to be an advantageous animal model system in basic science research focused on aiding in development and evaluation of potential treatments; however, the small size of mouse tendons makes consistent and reproducible injury models and subsequent biomechanical evaluation challenging for studying tendon healing. In this study, ...

Different mobilization protocols have been proposed for rehabilitation after hand flexor tendon repair to provide tendon excursion sufficient to prevent adhesions. Several cadaver studies have shown that the position of the neighboring fingers influences tendon excursions of the injured finger. We hypothesized that the positions of adjacent fingers influence the ...

Computationally efficient modeling of complex neuromuscular systems for dynamics and control simulations often requires accurate analytical expressions for moment arms over the entire range of motion. Conventionally, polynomial expressions are regressed from experimental data. But these polynomial regressions can fail to extrapolate, may require large datasets to train, are not ...

During neonatal development, tendons undergo a well orchestrated process whereby extensive structural and compositional changes occur in synchrony to produce a normal tissue. Conversely, during the repair response to injury, structural and compositional changes occur, but a mechanically inferior tendon is produced. As a result, developmental processes have been postulated ...

Tenofovir (TFV) is a proven microbicide when administered topically as a vaginal gel. To improve its efficacy, TFV was combined with the nonnucleoside reverse-transcriptase inhibitor UC781 in a vaginal gel. Mixture design of experiments theory was used to define a range of gel compositions with varying rheological properties and to ...

Engineered heart tissue (EHT) is a potential thera-py for heart failure and the basis of functional in vitro assays of novel cardiovascular treatments. Self-organizing EHT can be generated in fiber form, which makes the assessment of contrac-tile function convenient with a force transducer. Contractile func-tion is a key parameter of ...

A characteristic feature of motile cells as they undergo a change in motile behavior is the development of fluctuating exploratory motions of the leading-edge, driven by actin polymerization. We review quantitative models of these protrusion and retraction phenomena. Theoretical studies have been motivated by advances in experimental and computational methods ...

BACKGROUND: Biomechanical models are a useful tool to estimate tendon tensions. Unfortunately, in previous fingers' models, each finger acts independently from the others. This is contradictory with hand motor control theories which show that fingers are functionally linked in order to balance the wrist/forearm joint with minimal tendon tensions. (i.e. ...

Several three-dimensional (3D) lower-limb musculo-skeletal models have been developed for gait analysis and different hip, knee and ankle joint models have been considered in the literature. Conversely to the influence of the musculo-tendon geometry, the influence of the joint models--i.e. number of degrees of freedom and passive joint moments--on the ...

The heterogeneous composition and mechanical properties of the supraspinatus tendon offer an opportunity for studying the structure-function relationships of fibrous musculoskeletal connective tissues. Previous uniaxial testing has demonstrated a correlation between the collagen fiber angle distribution and tendon mechanics in response to tensile loading both parallel and transverse to the ...

Background and Objective: A probabilistic patient-level Markov model was previously developed to simulate lifetime clinical and economic outcomes of cinacalcet treatment in secondary hyperparathyroidism (SHPT) patients using local data from Italy. The present study extends the application of the model to four other European countries - Spain, Portugal, Switzerland and ...

Abstract: Objectives: The NICE health economic model for assessing the cost-effectiveness of celecoxib plus a proton pump inhibitor (PPI) compared to diclofenac plus PPI in the treatment of osteoarthritis has been updated using new adverse event (AE) risks from the CONDOR trial. In light of this new information, this study ...

OBJECTIVES: Results of meta-analyses typically conclude that future large studies may be mandated. However, the predictive ability of these estimates is deficient. We explored meta-analytic prediction intervals as means for providing a clear and appropriate future treatment summary reflecting current estimates. STUDY DESIGN: A meta-epidemiological study of binary outcome critical ...

Objective. (1) To develop a method for quantification of osteotome sharpness in a rhinoplasty model, using artificial bone; (2) to demonstrate changes in osteotome sharpness over multiple uses; and (3) to compare osteotomes from different manufacturers in terms of sharpness and cost.Study Design. Prospective surgical model.Setting. Academic hospital and engineering ...

BACKGROUND: In sub-Saharan Africa, patients with advanced HIV experience high mortality during the first few months of antiretroviral therapy (ART), largely attributable to tuberculosis (TB). We evaluated the cost-effectiveness of TB diagnostic strategies to reduce this early mortality. METHODS: We developed a decision-analytic model to estimate the incremental cost, deaths ...

ABSTRACT: BACKGROUND: The productive capacity of retired people is usually not valued. However, some retirees produce much more than we might expect. This diary-based study identifies the activities of older people, and suggests some value mechanisms. One question raised is whether it is possible to scale up this diary study ...

INTRODUCTION: The popularity of smoking cost-effectiveness (CE) analysis has grown rapidly. Differences in models and inputs mean results may not be comparable, and researchers may have to take them on trust because the methods are beyond their expertise and not always transparent. We describe a direct method and tables of ...

BACKGROUND: Cost-effectiveness analyses of behavioral interventions typically use a dichotomous outcome criterion. However, achieving behavioral change is a complex process involving several steps towards a change in behavior. Delayed effects may occur after an intervention period ends, which can lead to underestimation of these interventions. To account for such delayed ...

The aim of this paper is to present a novel, universal, methodology for the design of low cost tubular digesters. This method improves on the established methodology by avoiding assumptions that tend to reduce the final hydraulic retention time (HRT) of digesters once installed. This work recommends designing the digester ...

Host density thresholds are a fundamental component of the population dynamics of pathogens, but empirical evidence and estimates are lacking. We studied host density thresholds in the dynamics of ectoparasitic sea lice (Lepeophtheirus salmonis) on salmon farms. Empirical examples include a 1994 epidemic in Atlantic Canada and a 2001 epidemic ...

Cells sense the geometry and stiffness of their adhesive environment by active contractility. For strong adhesion to flat substrates, two-dimensional contractile network models can be used to understand how force is distributed throughout the cell. Here we compare the shape and force distribution for different variants of such network models. ...

Fibrin and collagen, biopolymers occurring naturally in the body, are biomaterials commonly-used as scaffolds for tissue engineering. How collagen and fibrin interact to confer macroscopic mechanical properties in collagen-fibrin composite systems remains poorly understood. In this study, we formulated collagen-fibrin co-gels at different collagen-to-fibrin ratios to observe changes in the ...

In cost-effectiveness analysis, interest could lie foremost in the incremental cost-effectiveness ratio (ICER), which is the ratio of the incremental cost to the incremental benefit of two competing interventions. The average cost-effectiveness ratio (ACER) is the ratio of the cost to benefit of an intervention without reference to a comparator. ...

Fibrin gels are a promising biomaterial for tissue engineering. However, current fabrication methods are time intensive with inherent variation. There is a pressing need to develop new and consistent approaches for producing fibrin-based hydrogels for examination. We developed a high throughput method for creating fibrin gels using molds fabricated from ...

As an alterative version of the lattice Boltzmann models, the multiple relaxation time (MRT) lattice Boltzmann model introduces much less numerical boundary slip than the single relaxation time (SRT) lattice Boltzmann model if some special relationship between the relaxation time parameters is chosen. On the other hand, most current versions ...

Kelp Bass (Paralabrax clathratus) and California Sheephead (Semicossyphus pulcher) are economically and ecologically valuable rocky reef fishes in southern California, making them likely indicator species for evaluating resource management actions. Multiple spatial datasets, aerial and satellite photography, underwater observations and expert judgment were used to produce a comprehensive map of ...

Laska et al. ( 1994 ) proposed a model-free method of detecting synergy in two drug combinations that requires no assumptions about the underlying dose-response curves of the drugs, just an estimate of the potency ratio of the two drugs. It was noted that the power of this method is ...