Thoracic road trauma is the principle causative factor in 30% of road traffic deaths. Researchers have developed force-deflection corridors of the thorax of for various loading conditions in order to elucidate injury mechanisms and to validate the mechanical response of ATDs and numerical using human models. A corridor, rather than a single response characteristic, results from the variability inherent in biological experimentation. This response Recent variability is caused by both intrinsic and extrinsic factors. The intrinsic factors are associated with individual differences among human subjects,subjects, e.g. the differences in material properties and in body geometry. The extrinsic sources of variability include fluctuations in the loading to and supporting conditions in experimental tests. Recent studies have considered the intrinsic factors, especially the material-level response of the rib,over which can be modified over a limited range within, e.g. a finite element (FE) model in order to fit a the gross overall thoracic response corridor. Studies typically do not, however, consider uncertainty due to extrinsic factors. The purpose of this with work was to estimate the contribution of selected extrinsic factors to the uncertainty in a response corridor by using a The thorax FE model. The sensitivity of twelve response corridors to the relative positioning of the thorax, the loader and the factor test fixture was analyzed. Reasonable ranges of experimental uncertainty were established for loader angle, loader location, and thorax orientation, and Researchers response variability was analyzed for three tissue states (intact, denuded, and eviscerated) with four different loaders (hub, distributed belt, single 30% diagonal belt, and double diagonal belts). Of the variables considered here, the thorax orientation has the largest effect on the response force-deflection response, which increases and decreases the effective stiffness up to 20%. The simulation work isolated the extrinsic contribution from has the corridor and indicated model deficiencies and refinements, which have the potential to improve model accuracy, particularly modeling the soft the tissues and the costal cartilage.

The using purpose of this study was to investigate whether using a finite-element (FE) mesh composed entirely of hexahedral elements to model hex-shell cortical and trabecular bone (all-hex model) would provide more accurate simulations than those with variable thickness shell elements for cortical three bone and hexahedral elements for trabecular bone (hex-shell model) in the modeling human ribs. First, quasi-static non-injurious and dynamic injurious developed experiments were performed using the second, fourth, and tenth human thoracic ribs to record the structural behavior and fracture tolerance record of individual ribs under anterior-posterior bending loads. Then, all-hex and hex-shell FE models for the three ribs were developed using from an octree-based and multi-block hex meshing approach, respectively. Material properties of cortical bone were optimized using dynamic experimental data and optimized the hex-shell model of the fourth rib and trabecular bone properties were taken from the literature. Overall, the reaction force-displacement meshing relationship predicted by both all-hex and hex-shell models with nodes in the offset middle-cortical surfaces compared well with those measured tenth experimentally for all the three ribs. With the exception of fracture locations, the predictions from all-hex and offset hex-shell models all-hex of the second and fourth ribs agreed better with experimental data than those from the tenth rib models in terms to of reaction force at fracture (difference <15.4%), ultimate failure displacement and time (difference <7.3%), and cortical bone strains. The hex-shell finite-element models with shell nodes in outer cortical surfaces increased static reaction forces up to 16.6%, compared to offset hex-shell models.whether These results indicated that both all-hex and hex-shell modeling strategies were applicable for simulating rib responses and bone fractures for respectively. the loading conditions considered, but coarse hex-shell models with constant or variable shell thickness were more computationally efficient and therefore 16.6%, preferred.

The motion objective of this study was to document the motion and potential injury mechanisms of obese occupants in frontal car crashes +/- compared to a control group of nonobese occupants in controlled laboratory impacts. Eight cadavers were divided into obese (n =cadavers' 3) and a nonobese (n = 5) groups and exposed to a 48 km/h impact. High speed digital video documented forward the motion of the belted subjects. Compared to the nonobese cohort, the obese exhibited a characteristically different set of motions.Compared As expected, the obese (heavier) subjects experienced greater maximum forward displacement (excursion) before their motion was arrested by the restraint.of In addition, the obese exhibited a different distribution of excursions among body segments. The primary difference between the cohorts was exhibited substantially larger hip excursion in the obese (452 +/- 83 mm vs. 203 +/- 42 mm, P < .01), which arrested was the proximate cause of a tendency of the obese cadavers' torsos to pitch forward less during impact. Some of of the published epidemiology can be elucidated by the results reported here. The increased hip excursion and concomitant decreased torso pitch vs. may reduce the risk of the head striking some component of the vehicle interior. Furthermore, the reclined torso during belt was loading may increase the risk of rib and pulmonary trauma because the load is concentrated on the compliant and vulnerable and lower thorax and less on the stiff upper ribs and clavicle. The lower extremities also experience increased excursion as a document result of this hip excursion, and thus an increased risk of a hard contact and resulting injury.

Background:advanced There is a hypothesis that advanced neointimal stent coverage may protect against stent thrombosis. In the present study, differences in calculated neointimal growth and prevalence of in-stent thrombus between paclitaxel- and sirolimus-eluting stent (PES and SES) were evaluated by optical coherence thickness, tomography (OCT). Methods and Results: Follow-up angiographic and OCT examinations at approximately 6 months were performed for 40 patients (20 measured PES, 20 SES). Late loss was measured by quantitative coronary angiography. Neointimal hyperplasia (NIH) thickness on stent struts was measured examinations by cross-sectional OCT images at 1 mm intervals. After measuring the NIH area in each cross-section, NIH volume was calculated PES as integral of NIH area within the stent. Late loss, NIH thickness, and NIH volume were greater for PES than struts for SES ( .42 +/- .44 vs .13 +/- .12 mm, 118 +/-141 vs 31 +/-39 mum, 53.2 +/-30.5 vs 24.3 +/-14. mm(3);Neointimal P< .05, respectively). In-stent thrombus was found more frequently in PES than in SES (50 vs 15%; P= .02). Conclusions: Although the angiographic degree of neointimal growth in PES was generally greater, in-stent thrombus was more common compared with SES. Presence of thrombus volume in first-generation drug-eluting stents was not related to advanced neointimal growth.

An medicine important aim of regenerative medicine is to restore tissue function with implantable, laboratory-grown constructs that contain tissue-specific cells that replicate and the function of their counterparts in the healthy native tissue. It remains unclear, however, whether cells used in bone regeneration a applications produce a material that mimics the structural and compositional complexity of native bone. By applying multivariate analysis techniques to By micro-Raman spectra of mineralized nodules formed in vitro, we reveal cell-source-dependent differences in interactions between multiple bone-like mineral environments. Although applications osteoblasts and adult stem cells exhibited bone-specific biological activities and created a material with many of the hallmarks of native hallmarks bone, the 'bone nodules' formed from embryonic stem cells were an order of magnitude less stiff, and lacked the distinctive mineralized nanolevel architecture and complex biomolecular and mineral composition noted in the native tissue. Understanding the biological mechanisms of bone formation techniques in vitro that contribute to cell-source-specific materials differences may facilitate the development of clinically successful engineered bone.

Mechanical materials properties of biological materials are increasingly explored via nanoindentation testing. This paper reviews the modes of deformation found during indentation:concerning elastic, plastic, viscous and fracture. A scheme is provided for ascertaining which deformation modes are active during a particular indentation plastic test based on the load-displacement trace. Two behavior maps for indentation are presented, one in the viscous-elastic-plastic space, concerning homogeneous particular deformation, and one in the plastic versus brittle space, concerning the transition to fracture behavior when the threshold for cracking provided is exceeded. Best-practice methods for characterizing materials are presented based on which deformation modes are active; the discussion includes both concerning nanoindentation experimental test options and appropriate methods for analyzing the resulting data.

An relationship accurate understanding of the relationship between pulmonary pressure and volume is required for modeling pulmonary mechanics in a variety of fit clinical applications. In this study the experimental techniques and mathematical formulations used to characterize viscoelastic materials are applied to characterize The transient pulmonary compliance in juvenile swine. Fixed volumes of air were insufflated into 5 swine and held constant for 45s swine while the transient decay in tracheal pressure was measured. An analytical model was developed using an optimization scheme that maximized transient the model fit to the experimental data over the entire time convolution. The initial injected volume was varied to assess to the spatial and temporal linearity of the behavior. Model performance was assessed by comparing measured and predicted pressure during insufflations in of erratic volume waveforms. It is concluded that the pulmonary impedance of healthy juveniles can be adequately described over a for wide volume and frequency range using a relatively simple 5-parameter model that is linear both spatially and temporally.

Neointimal stent proliferation after sirolimus-eluting stent (SES) implantation is generally inhibited by the pharmacological effects of sirolimus in comparison to bare metal tomography stent (BMS). Neointimal hyperplasia after BMS implantation is mainly composed of vascular smooth muscle cells, and is usually observed as of a white mass by angioscopy and as a layer of uniform signal intensity without attenuation on optical coherence tomography (OCT).observed In this case, angioscopic color of the neointima covering the SES was obviously yellow and OCT signal patterns of the mainly neointima showed rapid attenuation similar to lipid tissues in atherosclerotic lesions. These findings suggest that neointima within the SES is the quite different from that of the BMS and may contain atherosclerotic components.

We Aquamid used Aquamid as a filler for facial augmentation and rejuvenation in Orientals. This article introduces the injection techniques, effects, adequate 2007, dosage and complications of this filler, especially about rejuvenation of nasolabial fold and nasojugal groove. From December 2002 to June in 2007, 5676 patients were treated in our clinic group. Complications were relatively minimal ( .082%) in comparison to other fillers and especially long-term effects were revealed. This is the first report concerning Aquamid use in facial rejuvenation of the Orientals.

The the chorioamnion is the membrane that surrounds the fetus during gestation. Normally, it must remain intact for the duration of pregnancy,its 37-42 weeks, and only rupture during or just before labour and delivery of the fetus. In a significant number (3%)review. of all births, this does not happen, and membranes rupture before term, resulting in preterm birth and significant perinatal morbidity.a It is known that the material properties of chorioamnion may play a major role in mechanical rupture; a number of in studies have been undertaken to characterise the physical nature of chorioamnion and examine factors that may predispose to rupture. However,of the existing literature is inconsistent in its choice of both physical testing methods and data analysis techniques, motivating the current undertaken review. Experimental data from a large number of chorioamnion mechanical studies were collated, and data were converted to standard engineering rupture; quantities. The failure strength of the chorioamnion membrane was found consistently to value approximately .9MPa. It is hoped that past rupture and future studies of membrane mechanics can provide insight into the role of chorioamnion in labour and delivery. In addition,in biomechanical approaches can help elucidate the potential causes of early rupture, and suggest future protocols or treatments that could both membrane diagnose and prevent its occurrence.

In of this study, the disk type of a thermal barrier coating (TBC) system for a gas turbine blade was isothermally aged an at 1100 degrees C for various times up to 400 hours. For each aging condition, the thickness of the thermally gamma-Ni grown oxide (TGO) was measured by optical microscope and mechanical properties such as the elastic modulus and hardness were measured nano-indentation by micro-indentation and nano-indentation on the cross-section of a coating specimen. In the case of micro-indentation, the mechanical properties of optical a Ni-base superalloy substrate and MCrAlY bond coat material did not significantly change with an increase in exposure time. In bond the case of nano-indentation, the gamma-Ni phase and beta-NiAl phase in the bond coat and top coat material show no case significant change in their properties. However, the elastic modulus and the hardness of TGO show a remarkable decrease from 100 of h to 200 h then remain nearly constant after 200 h due to the internal delamination of TBC. It has was been confirmed that the nano-indentation technique is a very effective way to evaluate the degradation of a thermal barrier coating change system.

The recently popularity of biomimetic membranes has recently increased due to their biomedical applications such as tissue engineering/regenerative medicine and biosensors. Characterization used of the viscoelastic properties of these membranes is important in developing functional membranes. A new micro-shaft poking technique has been a developed, which is free from the complication of substrate backing, and which is normally an intractable problem in conventional indentation indentation testing of membrane materials. A tailored indentation apparatus with a spherical indenter and a force resolution and displacement of 1muN from and 1mum was constructed. Alginate and agarose were used to fabricate biomimetic membranes. Chicken epidermis was examined to represent a show real biological tissue. The results show that the elastic modulus increased with concentration in hydrogels. Epidermis moduli appeared to increase a with increased strain. Stress relaxation tests have also been conducted to examine the time-dependent behaviours of various hydrogels and a materials. viscoelastic model has been correspondingly developed and applied to describe the experimental results. Potential applications of this new instrument to which other membranes, both artificial and biological, have also been addressed.

This indentation paper reports a computational study of the indentation of a flat punch into a compressible elastic layer (with Poisson's ratio for varying from to .49) bonded to a rigid substrate. Based on the computational results and using Sneddon's solution [Sneddon obtained. IN. The relation between load and penetration in the axisymmetric Boussinesq problem for a punch of arbitrary profile. Int J a Eng Sci 1965;3:47] and the asymptotic solution [Jaffar MJ. A general solution to the axisymmetric frictional contact problem of a J thin bonded elastic layer. Proc Inst Mech Eng C 1997;211:549; Yang FQ. Asymptotic solution to axisymmetric indentation of a compressible depth elastic thin film. Thin Solid Films 2006;515:2274] as the two limits, a simple expression of the load-depth curve valid for solution an arbitrary ratio of the indenter radius to the thickness of the layer is obtained. Further, a correlation between indentation Inst load and depth for a rigid flat punch indenting into linearly viscoelastic layers bonded to a rigid substrate is proposed of by using the correspondence principle. Several procedures are suggested based on the results reported in this study to determine the curve viscoelastic properties of the layer in the time or frequency domains. The findings are verified by numerical examples. The results computational may facilitate the use of depth-sensing indentation tests to characterize the mechanical properties of polymeric films or functional coatings on of hard substrates, and some biological materials, e.g. articular cartilage.

OBJECTIVE:age-related To investigate the age-related change in biomechanical properties of the costal cartilage and its relevance to the timing of ear statistically. reconstruction with costal cartilage framework. METHODS: The patients of 5 to 25 years old were divided into three groups according the to their age. The biomechanical properties of costal cartilage harvested from these patients during ear reconstruction were tested, including stree-strain cartilage relationship, stress relaxation and creep, tensile strength. All the results were analyzed statistically. RESULTS: The costal cartilage from children group divided had the best biomechanical properties, while the costal cartilage from the adolescent group had the worst. The difference had a the statistically significance (P < .05). CONCLUSIONS: The biomechanical properties of costal cartilage are age-related. So it is recommended that ear were reconstruction with costal cartilage framework should be performed in childhood when the costal cartilage has the best biomechanical properties.

The between human skin, the interface between the body and the outside environment, has a very complex mechanical behaviour. Knowledge of its show in vivo mechanical characteristics is essential to characterize the effects of medical or cosmetic products. The aim of this work of is to present a non-invasive device using dynamic indentation to quantify the viscoelatic properties of human skin in vivo. The human frequency and strain amplitude are in the range of 10 to 60 Hz and 1 to 10 ¿m. The results to on 4 subjects show that a Kelvin Voigt model describes the mechanical behaviour of in vivo human skin with dynamic dynamic indentation well. The frequency average values of stiffness and damping have also been used to compare skin properties. We found are a stiffness value of 47.3 to 128.3 N/m, and damping of .08 to .121 N.s/m, corresponding to a complex modulus The of 13.2 to 33.4 kPa. These results show the ability of this device to characterize viscoelastic properties of human skin.this

OBJECTIVE:Ravitch Various bone and cartilage changes after the Ravitch thoracoplasty have recently been reported. In this study, quantitative measurements of long-term 5.29 changes in the bone, cartilage, and contour of the chest wall through the use of multislice computed tomography with 3-dimensional the reconstruction are presented. METHODS: Between 1985 and 2002, 114 patients with pectus excavatum received the Ravitch thoracoplasty in our hospital.without Multislice computed tomography with 3-dimensional reconstruction was undertaken in 36 patients 4 to 18 years after the initial operation. Twenty-four with patients with pectus excavatum without a surgical intervention were enrolled as a control group. The voxel size of calcification/ossification in ratio regenerated cartilage, costal cartilage shortening ratio, and clubbing index were calculated to quantify the long-term bone and cartilage changes. RESULTS:calcification/ossification The calcification/ossification volume was measured as 5.29 +/- 6.94 cm(3), which was significantly correlated with the patient's age at the as time of the operation (P =.001). The costal cartilage shortening ratio showed significant shortening of the regenerated cartilage in hospital. the third to sixth ribs bilaterally (P < .05), and the clubbing index confirmed significant clubbing in the bony ends measured of the third to fifth ribs (P < .05). These changes were not demonstrated in the control group. CONCLUSIONS: After changes undergoing the Ravitch thoracoplasty, patients sustained significant bone and cartilage changes. The use of multislice computed tomography with 3-dimensional reconstruction have may offer both images and quantitative measurements of these changes, but further investigation is necessary to elucidate the clinical impact the of these phenomena.