bluuebunny/crossref_metadata_2025_split huggingface dataset:
Validation of a Finite Element Model of the Mechanical Performance of Surgical Knots of Varying Topology
Authors: Qwam Alden Arz Y. , Geeslin Andrew G. , Gustafson Peter A. 
Published: January 2019

Background: Knot tying is considered a basic surgical skill, however, there is no consensus on the best technique. Suture breakage and slippage are failure modes during surgical repair and are related to stress concentrations which cannot be easily established with physical testing. Few computational models exist that describe the effect of knot topology on the failure mechanism. The purpose of this study was to implement the finite element method to analyze the mechanical behavior of surgical sutures according to number of throws and to validate the model against experiments.
Methods: Experiments and models of monofilament and multifilament sutures were conducted. Multiple throw knots were tested to failure in a laboratory setting and with corresponding finite element models. Gross loads were compared when the knot reached a localized material yield stress in the model or when failure occurred in laboratory tests that have the same suture topology.
Results: The results of laboratory tests and corresponding finite element models of single throw knots were compared and found to be well correlated and consistent with existing literature in strength prediction and failure location. Moreover, single throw knots have reduced failure strengths relative to non-knotted suture approximately by 120 N for both monofilament and multifilament sutures, respectively.
Clinical Relevance: This paper describes a model which can describe the initial failure process leading to knot failure. In addition, the model can evaluate the effect of knot topology on the mechanics of surgical suture. Numerically, no assessment has been completed of knot security (i.e., how likely the knot is to untie), therefore, clinical recommendations are premature. In the future, the results may provide a framework for choosing the suture and knot types for soft tissue repairs.
A Stochastic Finite Element Method for Simulating Trabecular Bone
Authors: Alrafeek Saif , Jastifer James R. , Gustafson Peter A. 
Published: January 2019

Background: Although trabecular bone is highly porous heterogeneous composite, most studies use homogenized continuum finite element (FE) approaches to model trabecular bone. Such models neglect the porous nature of the tissue. When microstructural models are desired, the use of continuum elements may require costly CT/MRI imaging and detailed meshing. The purpose of this study is to demonstrate an approach that simulates trabecular bone with less dependency on medical images while capturing of porosity.
Methods: A stochastic structural FE model was created representing the trabecular micro-architecture as beam elements. Beam orientation, length and connectivity were stochastically determined by random placement of nodes and meshing the resulting Voronoi diagram. Boundary conditions were applied on the structure to attain normalized axial and shear strain. Also, apparent mechanical properties, apparent densities and anisotropy ratio’s were calculated from the model output.
Results: The number of generated nodes within the model and cross sectional area of the random beams were observed as parameters that affect model outcome. Trabecular bone apparent density was found highly correlated to beams cross sectional area rather than the generated number of nodes. Similarly, Young’s moduli and shear moduli were dependent on beams cross sectional area. For example, a (0.015 mm2) increase in beam cross section area can produce (175 MPa, 30 MPa and 0.55 g/cm3) increases in Young’s moduli, shear moduli and apparent density, respectively.
Clinical Relevance: The proposed finite element technique provides a stochastically accurate structural representation of trabecular tissue and its reaction to applied loads. It incorporates several advantages of high fidelity methods but at lower cost and requiring only clinical imaging. Therefore, the approach may be useful for patient specific musculo-skeletal biomechanical models (e.g. osteoporosis, osteoarthritis, joint replacement and implants interface).
Pedestrian Collision Responses Using Legform Impactor Subsystem and Full-Sized Pedestrian Model on Different Workbenches
Authors: Mohammed Obaidur Rahman , Memon Shabbir , Lankarani Hamid M. 
Published: January 2019

Car-pedestrian collision fatalities have been reported for a significant number of roadside accidents around the world. In order to reduce the lower extremity injuries in car-pedestrian collisions, it is important to determine the impact forces on the pedestrian and conditions that the car frontal side impacts on the lower extremities of the pedestrian. The Working Group 17 (WG17) of the European Enhanced Vehicle-safety Committee (EEVC) has developed a legform subsystem impactor and procedure for assessing pedestrian collisions and potential injuries. This research describes a methodology for the evaluation of the legform impactor kinematics after a collision utilizing finite element (FE) models of the legform and cars and comparing the simulation results with the ones from a multi-body legform model as well as a 50th percentile male human pedestrian model responses.
Two approaches are carried out in the process. First, the collision strike simulations with the FE model using an FE lower legform is considered and validated against the EVVC/WG17 regulation criteria. Secondly, the collision strike simulations with a multi-body legform and an ellipsoidal multi-body car model are conducted to compare the responses from the FE model and the multi-body model. The results from the impact simulations of FE legform and the multi-body legform are also compared with the ones from a full-size pedestrian model at constant speeds. All the models and simulation in this are using the LS-DYNA nonlinear FE code, while the multibody legform, car, and full-sized pedestrian models are developed and evaluated in MADYMO.
The results from this study demonstrate the differences between the subsystem legform and the full-size pedestrian responses as well as suitability of various FE and multibody models related to pedestrian impact responses. Different workbenches comparisons with finite model and ellipsoidal models gives more better correlation to this research.
Systematic Study of the Effect of Non-Uniform Seal Stiffness on the Contact Stress in Flat-Faced Soft-Seated Spring Operated Pressure Relief Valves
Authors: Schimanowski Alex , Seibel Arthur , Schlattmann Josef 
Published: January 2019

Spring operated pressure relief valves (SOPRVs) are essential components of technical systems. As parts of safety systems, they protect people and the environment from technological hazards. Their ability to open at a predefined pressure is considered the most important feature. The reliability of this function depends on numerous operational and design factors.
In this paper, we examine the effects of design measures on the mechanical loads in seat seals of SOPRVs. In particular, we evaluate the applicability of the principle of non-uniform system stiffness in order to systematically control the mechanical loads in seat seals for an exemplary case of a flat faced soft seated SOPRV. We systematically vary design parameters and accurately estimate the contact stresses as well as the set pressure by performing non-linear finite element analyses. We focus on the quasi-static case of a closed seal, since dynamic effects of the opening and closing processes are not within the scope of this work. In our contribution, we show that the application of these design measures can significantly influence both the initial contact stresses and the set pressure at a constant spring force. In particular, the effects of the taper angle are analyzed and discussed.
Enhanced Heat Transfer in Radial Heat Sinks for LED Lamps
Authors: Cano-Banda Fernando , Gallardo-Gutierrez Ana , Garcia-Gonzalez Jesus , Hernandez-Guerrero Abel , Luviano-Ortiz Luis 
Published: January 2019

A radial design of a passive heat sink for cooling LED illumination devices is analyzed numerically in order to identify the geometric shape that promotes better heat dissipation rates. Natural convection with the surrounding is considered during the operation of the heat sink. Due to the fact that natural convection is the main mechanism of heat transfer, the shape of the heat sink has a high influence in the heat dissipated. An analysis of the influence of different parameters of a heat sink is conducted in the presented study.
The radial heat sink under analysis consists in a flat disc with rectangular fins on it, and the fins are distributed with a radial longitudinal orientation in a circular row arrangement. The number of rows can vary but there is a constant relation of two times the number of fins between the number of fins in an inner row and the next outer row. In order to find a correct configuration to improve the dissipation of heat, parameters like the number of fins, the length of the fins and the separation between fins are studied.
The average Nusselt number and thermal resistance for each geometric configuration are compared. The output analysis provides the best shape for a maximum heat transfer.
Pelvic Injury Survival Analysis for a Finite Element Human Body Model Using Multiple Data Sets
Authors: Weaver Caitlin M. , Miller Anna N. , Stitzel Joel D. 
Published: January 2019

Finite element (FE) computational human body models (HBMs) have gained popularity over the past several decades as human surrogates for use in blunt injury research. FE HBMs are critical for the analysis of local injury mechanisms. These metrics are challenging to measure experimentally and demonstrate an important advantage of HBMs. The objective of this study is to evaluate the injury risk predictive power of localized metrics to predict the risk of pelvic fracture in a FE HBM.
The Global Human Body Models Consortium (GHBMC) 50th percentile detailed male model (v4.3) was used for this study. Cross-sectional and cortical bone surface instrumentation was implemented in the GHBMC pelvis. Lateral impact FE simulations were performed using input data from tests performed on post mortem human subjects (PMHS). Predictive power of the FE force and strain outputs on localized fracture risk was evaluated using the receiver operator characteristic (ROC) curve analysis.
The ROC curve analysis showed moderate predictive power for the superior pubic ramus and sacrum. Additionally, cross-sectional force was compared to a range of percentile outputs of maximum principal, minimum principal, and effective cortical element strains. From this analysis it was determined that cross-sectional force was the best predictor of localized pelvic fracture.
Multibody Dynamics Approaches for Study on Good and Bad Whole-Body Vibrations
Authors: Duan Shanzhong (Shawn) 
Published: January 2019

Whole-body vibrations (WBV) have been used for enhancing muscle strength and bone density of human bodies, training athletes and dancers, and helping people with disabling conditions and rehabilitations. On the other hand, WBV-induced occupational diseases have been reported. Researchers in automotive, farm equipment, and heavy machinery have put forward a few models for studying harmful vibrations on human bodies.
This paper will review the effects of frequencies and magnitudes of WBV on a human body. Discussion of effects of frequencies and magnitudes on a human body will provide a preliminary boundary line between good and bad whole-body vibrations. Two multibody dynamics models and associated application cases will be proposed to show how the models may be used to represent whole-body vibrations under both good and bad vibrations. Three basic vibration elements associated with whole-body vibrations of the human body are handled as follows: (1) ligaments are modeled as spring elements; (2) muscles and tendons are modeled as damping elements; (3) bones are modeled as rigid bodies with masses/inertias and connected by idealized massless joints. In such a biomechanical vibration system, the spring elements (ligaments) help hold the human body skeleton structure in a stable condition, pass spring forces and potential energy to rigid bodies (bones) for bone vibrational motions. The damping elements (muscles and tendons) play roles of a damper and absorb energy input from the whole-body vibration resource.
Based on the proposed multibody dynamics models, Kane’s method is then used to develop equations of motion. The equations will be further used for development of simulation algorithms to understand frequencies and magnitudes of both good and bad whole-body vibrations.
The models may be utilized to understand why frequencies and magnitudes of whole-body vibrations will provide benefits to human health under one situation but cause occupational diseases under another scenario.
The Egg Abundance of Eastern Baltic Cod Gadus morhua callarias (Gadidae) in the 20th Century as a Population Status Indicator
Authors: Karaseva E. M. 
Published: January 2019

Abstract
Data on the egg abundance of cod Gadus morhua callarias in the ichthyoplankton of deepwater basins of the Baltic Sea in 1903–2000 are presented. The maxima of the total cod egg abundance that were observed in 1947–1956 and 1976–1981 are associated with the activation of cod reproduction in the northeastern areas of the sea and coincide with the period of growth in the salinity of the near-bottom water layer. The cod reproduction is characterized by alternating periods of expansion of spawning ground area (owing to the Gotland Basin in the northeast) and its decrease, with the maintenance of the annual reproduction only in the Bornholm Basin (the southwest of the sea). It is assumed that the dynamics of the egg abundance in the periods of mass cod spawning in northeastern areas was opposite in the Gotland and Bornholm basins.
Protocol for a cluster randomised controlled trial evaluating a parenting with home visitation programme to prevent physical and emotional abuse of children in Indonesia: the Families First Programme
Authors: Ruiz-Casares Mónica , Lilley Sarah , Thombs Brett D , Platt Robert William , Scott Susan , Isdijoso Widjajanti , Hermanus Emmy , Andrina Michelle , Mayo Nancy 
Published: January 2019

IntroductionEvery year, up to 1 billion children are victims of violence worldwide. Most child abuse takes place in the context of punishment. The Families First Programme, an adaptation of the Positive Discipline in Everyday Parenting Programme to the West Java context, is a parenting support programme anchored on children’s rights that gives parents guidance on child development, parenting and positive discipline practices. This trial will evaluate the effectiveness of the Families First Programme compared with a waitlist control group.Methods and analysisThis is a pragmatic, parallel-group, stratified, cluster-randomised controlled trial. Twenty rural and urban villages in the Cianjur District, Indonesia, involving 720 caregivers of children up to 7 years of age, will be randomised. Villages will receive either a parenting programme consisting of 10 group sessions and four home visits over 3 months and standard community health and social services or just the latter. After completion of the trial period, the programme will be offered to those in the delayed group. Outcome data will be collected before randomisation (baseline), immediately postintervention (3 months postrandomisation) and 6 months later (9 months postrandomisation). The primary outcome will be frequency of physical and emotional punishment as measured by a weighted sum from three self-report items. Primary outcome analysis will use Poisson regression with generalised estimating equations and assess the interaction between intervention and time over baseline and 3 and 9 months postrandomisation assessments. Concurrent process evaluation will be conducted to assess programme satisfaction and facilitators and barriers to the implementation of the programme generalisable to other settings.Ethics and disseminationEthics approval was obtained from McGill University and Universitas Katolik Indonesia Atma Jaya. Results will be published in peer-reviewed journals and presented at scientific conferences and events for decision-makers, including in the participating communities.Trial registration numberNCT03374761.
Impact of rural Family Physician programme on maternal and child health indicators in Iran: an interrupted time series analysis
Authors: Jabbari Beyrami Hossein , Doshmangir Leila , Ahmadi Ayat , Asghari Jafarabadi Mohammad , Khedmati Morasae Esmaeil , Gordeev Vladimir S 
Published: January 2019

ObjectivesThe establishment of the Family Physician (FP) programme in the rural areas of Iran in 2005 has made health services accessible and affordable. This paper aims to assess the overall trends of maternal and child health (MCH) indicators in a 20-year period and possible effects of the FP programme (intervention) on these indicators in Iran.Design and settingAn interrupted time series analysis was conducted on 20 annual MCH-related data points from 1994 to 2013. The intervention time was at the 12th data point in 2005.OutcomesMCH indicators were grouped into three categories:structure(mother’s age, education, occupation and gravidity),process(number of antenatal care visits (ACVs), laboratory tests, ultrasounds and natural vaginal deliveries (NVDs)) andoutcomes(maternal mortality ratio (MMR), neonatal mortality rate (NMR), birth weight (BW), history of abortion and/or stillbirth, and haemoglobin level (Hb)).ResultsThe adjusted slope of the ACV trend decreased sharply after the intervention (b=−0.36, p<0.01), whereas it increased for the frequency of ultrasounds (b=0.2, p<0.01) and did not change for number of laboratory tests (b=−0.09, p=0.95). The intensification of the descending slope observed for NVD (b=−1.91, p=0.03) disappeared after the adjustment for structural confounders (b=1.33, p=0.26). There was no significant slope change for MMR (b=1.12, p=0.28) and NMR (b=0.67, p=0.07) after the intervention. The slope for the history of abortion trend was constant before and after the intervention, but it considerably intensified for the history of stillbirths after the intervention (b=1.72, p<0.01). The decreasing trend of BW turned into a constant mode after the intervention (b=33.2, p<0.01), but no change was observed for Hb (b=−0.02, p=0.78).ConclusionAlthough the FP programme had a positive effect on theprocessand proximaloutcomeindicators (BW), no dramatic effect on mortality outcome indicators was distinguished. It shows that there should be determinants or mediators of mortalityoutcomesin this setting, other than accessibility and affordability of MCH services.
Association between hepatitis C virus infection and osteoporotic fracture risk among postmenopausal women: a cross-sectional investigation in Taiwan
Authors: Lin Ming-Shyan , Chen Po-Han , Wang Po-Chang , Lin Huang-Shen , Huang Tung-Jung , Chang Shih-Tai , Chiu Wen-Nan , Chen Mei-Yen 
Published: January 2019

PurposeEarly low bone mass is a risk factor for osteoporotic fractures associated with multiple factors, including menopause and chronic liver diseases. Hepatitis C virus (HCV) also plays a major role in chronic liver disease and has many extrahepatic consequences, such as decreased bone mineral density (BMD). This study aimed to examine the hypothesis that HCV seropositivity is independently associated with menopausal BMD loss.MethodsThis community-based, cross-sectional study was based in two rural townships in Yunlin County, Taiwan. A total of 636 menopausal women aged 45–80 years who underwent annual health checks were included. Viral markers of HCV, dual-energy X-ray absorptiometry and fracture risk assessment tool (FRAX) scores were measured. Logistic regression analysis was performed to assess the association between various predictors and the presence of low BMD.ResultsThe participants (median age: 65 years) had a HCV seropositivity rate of 32.2%. BMD was significantly lower in the HCV-seropositive participants in different anatomic locations than in the seronegative individuals (lumbar spine: −1.5 vs −1.1; total hip: −0.9 vs −0.6; femoral neck: −1.2 vs −1.0; p<0.05). HCV-seropositive subjects had higher rates of major osteoporotic fractures (11.3%±7.6%vs 9.0±6.8%; p<0.001) and hip fractures (3.4%±4.7%vs 2.3±4.9%; p=0.006) and a higher risk of lower BMD (osteopenia and osteoporosis) based on a multivariable regression analysis (adjusted OR: 1.8; 95% CI 1.16 to 2.81; p=0.009).ConclusionsHCV infection may be an independent risk factor for menopausal BMD loss and fractures predicted by FRAX.
Preadmission use of benzodiazepines and stroke outcomes: the Biostroke prospective cohort study
Authors: Colin Olivier , Labreuche Julien , Deguil Julie , Mendyk Anne-Marie , Deken Valérie , Cordonnier Charlotte , Deplanque Dominique , Leys Didier , Bordet Régis 
Published: January 2019

ObjectivesWe tested the hypothesis that stroke outcomes in patients with preadmission use of benzodiazepine are worse.MethodIn a prospective cohort study, we recruited patients with acute ischaemic stroke. Mortality, functional outcomes and cognition were evaluated at 8 and 90 days after stroke.Results370 patients were included. 62 (18.5%) of the 336 remaining patients were treated with benzodiazepines when stroke occurred, and they did not receive any other psychotropic drug. The mortality rate was higher in benzodiazepines users than non-users at day 8 (2.2% vs 8.1%, p=0.034) and day 90 (8.1% vs 25.9%, p=0.0001). After controlling for baseline differences using propensity-score matching, only the difference in mortality rate at day 90 was of borderline of significance, with a matched OR of 3.93 (95% CI, 0.91 to 16.98). In propensity-score-adjusted cohort, this difference remained significant with a similar treatment effect size (adjusted OR, 3.50; 95% CI, 1.57 to 7.76). A higher rate of poor functional outcome at day 8 and day 90 defined bymodified Rankin scale (mRS) ≥2 or by theBarthel index (BI) <95 was found in benzodiazepines users. In propensity-score-adjusted cohort, only the difference in mRS≥2 at day 90 remained significant (adjusted OR, 1.89; 95% CI, 1.02 to 3.48). In survivors at day 8 and at day 90, there was no significant difference in cognitive evaluation.ConclusionOur study has shown that preadmission use of benzodiazepines could be associated with increased post-stroke mortality at 90 days. These findings do not support a putative neuroprotective effect of γ-aminobutyric acidAreceptors agonists and should alert clinicians of their potential risks.Trial registration numberNCT00763217.