Silk Based Bioinks for Soft Tissue Reconstruction Using 3-Dimensional (3D) Printing with in vitro and in vivo Assessments

PubMed Central

Rodriguez, María J.; Brown, Joseph; Giordano, Jodie; Lin, Samuel J.; Omenetto, Fiorenzo G.; Kaplan, David L.

2016-01-01

In the field of soft tissue reconstruction, custom implants could address the need for materials that can fill complex geometries. Our aim was to develop a material system with optimal rheology for material extrusion, that can be processed in physiological and non-toxic conditions and provide structural support for soft tissue reconstruction. To meet this need we developed silk based bioinks using gelatin as a bulking agent and glycerol as a non-toxic additive to induce physical crosslinking. We developed these inks optimizing printing efficacy and resolution for patient-specific geometries that can be used for soft tissue reconstruction. We demonstrated in vitro that the material was stable under physiological conditions and could be tuned to match soft tissue mechanical properties. We demonstrated in vivo that the material was biocompatible and could be tuned to maintain shape and volume up to three months while promoting cellular infiltration and tissue integration. PMID:27940389

Silk based bioinks for soft tissue reconstruction using 3-dimensional (3D) printing with in vitro and in vivo assessments.

PubMed

Rodriguez, María J; Brown, Joseph; Giordano, Jodie; Lin, Samuel J; Omenetto, Fiorenzo G; Kaplan, David L

2017-02-01

In the field of soft tissue reconstruction, custom implants could address the need for materials that can fill complex geometries. Our aim was to develop a material system with optimal rheology for material extrusion, that can be processed in physiological and non-toxic conditions and provide structural support for soft tissue reconstruction. To meet this need we developed silk based bioinks using gelatin as a bulking agent and glycerol as a non-toxic additive to induce physical crosslinking. We developed these inks optimizing printing efficacy and resolution for patient-specific geometries that can be used for soft tissue reconstruction. We demonstrated in vitro that the material was stable under physiological conditions and could be tuned to match soft tissue mechanical properties. We demonstrated in vivo that the material was biocompatible and could be tuned to maintain shape and volume up to three months while promoting cellular infiltration and tissue integration. Copyright © 2016 Elsevier Ltd. All rights reserved.

Clinical Evaluation of positioning verification using digital tomosynthesis (DTS) based on bony anatomy and soft tissues for prostate image-guided radiation therapy (IGRT)

PubMed Central

Yoo, Sua; Wu, Q. Jackie; Godfrey, Devon; Yan, Hui; Ren, Lei; Das, Shiva; Lee, William R.; Yin, Fang-Fang

2008-01-01

Purpose To evaluate on-board digital tomosynthesis (DTS) for patient positioning in comparison with 2D-radiographs and 3D-CBCT. Methods and Materials A total of 92 image sessions from 9 prostate cancer patients were analyzed. An on-board image set was registered to a corresponding reference image set. Four pairs of image sets were used; DRR vs. on-board orthogonal paired radiograph for the 2D method, coronal-reference-DTS (RDTS) vs. on-board coronal-DTS for the coronal-DTS method, sagittal-RDTS vs. on-board sagittal-DTS for the sagittal-DTS method, and planning CT vs. CBCT for the CBCT method. Registration results were compared. Results The systematic errors in all methods were less than 1 mm/1°. When registering bony anatomy, the mean vector differences were 0.21±0.11 cm between 2D and CBCT, 0.11±0.08 cm between CBCT and coronal-DTS, and 0.14±0.07 cm between CBCT and sagittal-DTS. The correlation of CBCT to DTS was stronger (coefficients=0.92–0.95) than the correlation between 2D and CBCT or DTS (coefficients=0.81–0.83). When registering soft tissue, the mean vector differences were 0.18±0.11 cm between CBCT and coronal-DTS and 0.29±0.17 cm between CBCT and sagittal-DTS. The correlation coefficients of CBCT to sagittal-DTS and to coronal-DTS were 0.84 and 0.92, respectively. Conclusions DTS could provide equivalent results to CBCT when bony anatomy is used as landmarks for prostate IGRT. For soft tissue-based positioning verification, coronal-DTS produced equivalent results to CBCT and sagittal-DTS alone was insufficient. DTS could allow comparable soft tissue-based target localization with faster scanning time and less imaging dose compared to CBCT. PMID:19100923

Soft tissue modelling through autowaves for surgery simulation.

PubMed

Zhong, Yongmin; Shirinzadeh, Bijan; Alici, Gursel; Smith, Julian

2006-09-01

Modelling of soft tissue deformation is of great importance to virtual reality based surgery simulation. This paper presents a new methodology for simulation of soft tissue deformation by drawing an analogy between autowaves and soft tissue deformation. The potential energy stored in a soft tissue as a result of a deformation caused by an external force is propagated among mass points of the soft tissue by non-linear autowaves. The novelty of the methodology is that (i) autowave techniques are established to describe the potential energy distribution of a deformation for extrapolating internal forces, and (ii) non-linear materials are modelled with non-linear autowaves other than geometric non-linearity. Integration with a haptic device has been achieved to simulate soft tissue deformation with force feedback. The proposed methodology not only deals with large-range deformations, but also accommodates isotropic, anisotropic and inhomogeneous materials by simply changing diffusion coefficients.

Quantification of biological tissue and construction of patient equivalent phantom (skull and chest) for infants (1-5 years old)

NASA Astrophysics Data System (ADS)

Alves, A. F.; Pina, D. R.; Bacchim Neto, F. A.; Ribeiro, S. M.; Miranda, J. R. A.

2014-03-01

Our main purpose in this study was to quantify biological tissue in computed tomography (CT) examinations with the aim of developing a skull and a chest patient equivalent phantom (PEP), both specific to infants, aged between 1 and 5 years old. This type of phantom is widely used in the development of optimization procedures for radiographic techniques, especially in computed radiography (CR) systems. In order to classify and quantify the biological tissue, we used a computational algorithm developed in Matlab ®. The algorithm performed a histogram of each CT slice followed by a Gaussian fitting of each tissue type. The algorithm determined the mean thickness for the biological tissues (bone, soft, fat, and lung) and also converted them into the corresponding thicknesses of the simulator material (aluminum, PMMA, and air). We retrospectively analyzed 148 CT examinations of infant patients, 56 for skull exams and 92 were for chest. The results provided sufficient data to construct a phantom to simulate the infant chest and skull in the posterior-anterior or anterior-posterior (PA/AP) view. Both patient equivalent phantoms developed in this study can be used to assess physical variables such as noise power spectrum (NPS) and signal to noise ratio (SNR) or perform dosimetric control specific to pediatric protocols.

A formulation of tissue- and water-equivalent materials using the stoichiometric analysis method for CT-number calibration in radiotherapy treatment planning.

PubMed

Yohannes, Indra; Kolditz, Daniel; Langner, Oliver; Kalender, Willi A

2012-03-07

Tissue- and water-equivalent materials (TEMs) are widely used in quality assurance and calibration procedures, both in radiodiagnostics and radiotherapy. In radiotherapy, particularly, the TEMs are often used for computed tomography (CT) number calibration in treatment planning systems. However, currently available TEMs may not be very accurate in the determination of the calibration curves due to their limitation in mimicking radiation characteristics of the corresponding real tissues in both low- and high-energy ranges. Therefore, we are proposing a new formulation of TEMs using a stoichiometric analysis method to obtain TEMs for the calibration purposes. We combined the stoichiometric calibration and the basic data method to compose base materials to develop TEMs matching standard real tissues from ICRU Report 44 and 46. First, the CT numbers of six materials with known elemental compositions were measured to get constants for the stoichiometric calibration. The results of the stoichiometric calibration were used together with the basic data method to formulate new TEMs. These new TEMs were scanned to validate their CT numbers. The electron density and the stopping power calibration curves were also generated. The absolute differences of the measured CT numbers of the new TEMs were less than 4 HU for the soft tissues and less than 22 HU for the bone compared to the ICRU real tissues. Furthermore, the calculated relative electron density and electron and proton stopping powers of the new TEMs differed by less than 2% from the corresponding ICRU real tissues. The new TEMs which were formulated using the proposed technique increase the simplicity of the calibration process and preserve the accuracy of the stoichiometric calibration simultaneously.

Effect of tissue composition on dose distribution in brachytherapy with various photon emitting sources

PubMed Central

Ghorbani, Mahdi; Salahshour, Fateme; Haghparast, Abbas; Knaup, Courtney

2014-01-01

Purpose The aim of this study is to compare the dose in various soft tissues in brachytherapy with photon emitting sources. Material and methods 103Pd, 125I, 169Yb, 192Ir brachytherapy sources were simulated with MCNPX Monte Carlo code, and their dose rate constant and radial dose function were compared with the published data. A spherical phantom with 50 cm radius was simulated and the dose at various radial distances in adipose tissue, breast tissue, 4-component soft tissue, brain (grey/white matter), muscle (skeletal), lung tissue, blood (whole), 9-component soft tissue, and water were calculated. The absolute dose and relative dose difference with respect to 9-component soft tissue was obtained for various materials, sources, and distances. Results There was good agreement between the dosimetric parameters of the sources and the published data. Adipose tissue, breast tissue, 4-component soft tissue, and water showed the greatest difference in dose relative to the dose to the 9-component soft tissue. The other soft tissues showed lower dose differences. The dose difference was also higher for 103Pd source than for 125I, 169Yb, and 192Ir sources. Furthermore, greater distances from the source had higher relative dose differences and the effect can be justified due to the change in photon spectrum (softening or hardening) as photons traverse the phantom material. Conclusions The ignorance of soft tissue characteristics (density, composition, etc.) by treatment planning systems incorporates a significant error in dose delivery to the patient in brachytherapy with photon sources. The error depends on the type of soft tissue, brachytherapy source, as well as the distance from the source. PMID:24790623

ESR response of phenol compounds for dosimetry of gamma photon beams

NASA Astrophysics Data System (ADS)

Marrale, M.; Longo, A.; Panzeca, S.; Gallo, S.; Principato, F.; Tomarchio, E.; Parlato, A.; Buttafava, A.; Dondi, D.; Zeffiro, A.

2014-11-01

In the present paper we investigate the features of IRGANOX® 1076 phenols as a material for electron spin resonance (ESR) dosimetry. We experimentally analyzed the ESR response of pellets of IRGANOX® 1076 phenols irradiated with 60Co photons. The best experimental parameters (modulation amplitude and microwave power) for dosimetric applications have been obtained. The dependence of ESR signal as function of γ dose is found to be linear in the dose range studied (12-60 Gy) and the lowest measurable dose is found to be of the order of 1 Gy. The signal after irradiation is very stable in the first thirty days. From the point of view of the tissue equivalence, these materials have mass energy absorption coefficient values comparable with those of soft tissue.

Monitoring proton radiation therapy with in-room PET imaging

NASA Astrophysics Data System (ADS)

Zhu, Xuping; España, Samuel; Daartz, Juliane; Liebsch, Norbert; Ouyang, Jinsong; Paganetti, Harald; Bortfeld, Thomas R.; El Fakhri, Georges

2011-07-01

We used a mobile positron emission tomography (PET) scanner positioned within the proton therapy treatment room to study the feasibility of proton range verification with an in-room, stand-alone PET system, and compared with off-line equivalent studies. Two subjects with adenoid cystic carcinoma were enrolled into a pilot study in which in-room PET scans were acquired in list-mode after a routine fractionated treatment session. The list-mode PET data were reconstructed with different time schemes to generate in-room short, in-room long and off-line equivalent (by skipping coincidences from the first 15 min during the list-mode reconstruction) PET images for comparison in activity distribution patterns. A phantom study was followed to evaluate the accuracy of range verification for different reconstruction time schemes quantitatively. The in-room PET has a higher sensitivity compared to the off-line modality so that the PET acquisition time can be greatly reduced from 30 to <5 min. Features in deep-site, soft-tissue regions were better retained with in-room short PET acquisitions because of the collection of 15O component and lower biological washout. For soft tissue-equivalent material, the distal fall-off edge of an in-room short acquisition is deeper compared to an off-line equivalent scan, indicating a better coverage of the high-dose end of the beam. In-room PET is a promising low cost, high sensitivity modality for the in vivo verification of proton therapy. Better accuracy in Monte Carlo predictions, especially for biological decay modeling, is necessary.

Shear wave propagation in anisotropic soft tissues and gels

PubMed Central

Namani, Ravi; Bayly, Philip V.

2013-01-01

The propagation of shear waves in soft tissue can be visualized by magnetic resonance elastography (MRE) [1] to characterize tissue mechanical properties. Dynamic deformation of brain tissue arising from shear wave propagation may underlie the pathology of blast-induced traumatic brain injury. White matter in the brain, like other biological materials, exhibits a transversely isotropic structure, due to the arrangement of parallel fibers. Appropriate mathematical models and well-characterized experimental systems are needed to understand wave propagation in these structures. In this paper we review the theory behind waves in anisotropic, soft materials, including small-amplitude waves superimposed on finite deformation of a nonlinear hyperelastic material. Some predictions of this theory are confirmed in experimental studies of a soft material with controlled anisotropy: magnetically-aligned fibrin gel. PMID:19963987

SU-C-213-01: 3D Printed Patient Specific Phantom Composed of Bone and Soft Tissue Substitute Plastics for Radiation Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ehler, E; Sterling, D; Higgins, P

Purpose: 3D printed phantoms constructed of multiple tissue approximating materials could be useful in both clinical and research aspects of radiotherapy. This work describes a 3D printed phantom constructed with tissue substitute plastics for both bone and soft tissue; air cavities were included as well. Methods: 3D models of an anonymized nasopharynx patient were generated for air cavities, soft tissues, and bone, which were segmented by Hounsfield Unit (HU) thresholds. HU thresholds were chosen to define air-to-soft tissue boundaries of 0.65 g/cc and soft tissue-to-bone boundaries of 1.18 g/cc based on clinical HU to density tables. After evaluation of severalmore » composite plastics, a bone tissue substitute was identified as an acceptable material for typical radiotherapy x-ray energies, composed of iron and PLA plastic. PET plastic was determined to be an acceptable soft tissue substitute. 3D printing was performed on a consumer grade dual extrusion fused deposition model 3D printer. Results: MVCT scans of the 3D printed heterogeneous phantom were acquired. Rigid image registration of the patient and the 3D printed phantom scans was performed. The average physical density of the soft tissue and bone regions was 1.02 ± 0.08 g/cc and 1.39 ± 0.14 g/cc, respectively, for the patient kVCT scan. In the 3D printed phantom MVCT scan, the average density of the soft tissue and bone was 1.01 ± 0.09 g/cc and 1.44 ± 0.12 g/cc, respectively. Conclusion: A patient specific phantom, constructed of heterogeneous tissue substitute materials was constructed by 3D printing. MVCT of the 3D printed phantom showed realistic tissue densities were recreated by the 3D printing materials. Funding provided by intra-department grant by University of Minnesota Department of Radiation Oncology.« less

Fractional-order Viscoelasticity (FOV): Constitutive Development Using the Fractional Calculus: First Annual Report

NASA Technical Reports Server (NTRS)

Freed, Alan; Diethelm, Kai; Luchko, Yury

2002-01-01

This is the first annual report to the U.S. Army Medical Research and Material Command for the three year project "Advanced Soft Tissue Modeling for Telemedicine and Surgical Simulation" supported by grant No. DAMD17-01-1-0673 to The Cleveland Clinic Foundation, to which the NASA Glenn Research Center is a subcontractor through Space Act Agreement SAA 3-445. The objective of this report is to extend popular one-dimensional (1D) fractional-order viscoelastic (FOV) materials models into their three-dimensional (3D) equivalents for finitely deforming continua, and to provide numerical algorithms for their solution.

Updated Lagrangian finite element formulations of various biological soft tissue non-linear material models: a comprehensive procedure and review.

PubMed

Townsend, Molly T; Sarigul-Klijn, Nesrin

2016-01-01

Simplified material models are commonly used in computational simulation of biological soft tissue as an approximation of the complicated material response and to minimize computational resources. However, the simulation of complex loadings, such as long-duration tissue swelling, necessitates complex models that are not easy to formulate. This paper strives to offer the updated Lagrangian formulation comprehensive procedure of various non-linear material models for the application of finite element analysis of biological soft tissues including a definition of the Cauchy stress and the spatial tangential stiffness. The relationships between water content, osmotic pressure, ionic concentration and the pore pressure stress of the tissue are discussed with the merits of these models and their applications.

The in vivo plantar soft tissue mechanical property under the metatarsal head: implications of tissues׳ joint-angle dependent response in foot finite element modeling.

PubMed

Chen, Wen-Ming; Lee, Sung-Jae; Lee, Peter Vee Sin

2014-12-01

Material properties of the plantar soft tissue have not been well quantified in vivo (i.e., from life subjects) nor for areas other than the heel pad. This study explored an in vivo investigation of the plantar soft tissue material behavior under the metatarsal head (MTH). We used a novel device collecting indentation data at controlled metatarsophalangeal joint angles. Combined with inverse analysis, tissues׳ joint-angle dependent material properties were identified. The results showed that the soft tissue under MTH exhibited joint-angle dependent material responses, and the computed parameters using the Ogden material model were 51.3% and 30.9% larger in the dorsiflexed than in the neutral positions, respectively. Using derived parameters in subject-specific foot finite element models revealed only those models that used tissues׳ joint-dependent responses could reproduce the known plantar pressure pattern under the MTH. It is suggested that, to further improve specificity of the personalized foot finite element models, quantitative mechanical properties of the tissue inclusive of the effects of metatarsophalangeal joint dorsiflexion are needed. Copyright © 2014 Elsevier Ltd. All rights reserved.

A new ChainMail approach for real-time soft tissue simulation.

PubMed

Zhang, Jinao; Zhong, Yongmin; Smith, Julian; Gu, Chengfan

2016-07-03

This paper presents a new ChainMail method for real-time soft tissue simulation. This method enables the use of different material properties for chain elements to accommodate various materials. Based on the ChainMail bounding region, a new time-saving scheme is developed to improve computational efficiency for isotropic materials. The proposed method also conserves volume and strain energy. Experimental results demonstrate that the proposed ChainMail method can not only accommodate isotropic, anisotropic and heterogeneous materials but also model incompressibility and relaxation behaviors of soft tissues. Further, the proposed method can achieve real-time computational performance.

Next Generation Tissue Engineering of Orthopedic Soft Tissue-to-Bone Interfaces.

PubMed

Boys, Alexander J; McCorry, Mary Clare; Rodeo, Scott; Bonassar, Lawrence J; Estroff, Lara A

2017-09-01

Soft tissue-to-bone interfaces are complex structures that consist of gradients of extracellular matrix materials, cell phenotypes, and biochemical signals. These interfaces, called entheses for ligaments, tendons, and the meniscus, are crucial to joint function, transferring mechanical loads and stabilizing orthopedic joints. When injuries occur to connected soft tissue, the enthesis must be re-established to restore function, but due to structural complexity, repair has proven challenging. Tissue engineering offers a promising solution for regenerating these tissues. This prospective review discusses methodologies for tissue engineering the enthesis, outlined in three key design inputs: materials processing methods, cellular contributions, and biochemical factors.

Next Generation Tissue Engineering of Orthopedic Soft Tissue-to-Bone Interfaces

PubMed Central

Boys, Alexander J.; McCorry, Mary Clare; Rodeo, Scott; Bonassar, Lawrence J.; Estroff, Lara A.

2017-01-01

Soft tissue-to-bone interfaces are complex structures that consist of gradients of extracellular matrix materials, cell phenotypes, and biochemical signals. These interfaces, called entheses for ligaments, tendons, and the meniscus, are crucial to joint function, transferring mechanical loads and stabilizing orthopedic joints. When injuries occur to connected soft tissue, the enthesis must be re-established to restore function, but due to structural complexity, repair has proven challenging. Tissue engineering offers a promising solution for regenerating these tissues. This prospective review discusses methodologies for tissue engineering the enthesis, outlined in three key design inputs: materials processing methods, cellular contributions, and biochemical factors. PMID:29333332

New Soft Tissue Implants Using Organic Elastomers

NASA Astrophysics Data System (ADS)

Ku, David N.

Typical biomaterials are stiff, difficult to manufacture, and not initially developed for medical implants. A new biomaterial is proposed that is similar to human soft tissue. The biomaterial provides mechanical properties similar to soft tissue in its mechanical and physical properties. Characterization is performed for modulus of elasticity, ultimate strength and wear resistance. The material further exhibits excellent biocompatibility with little toxicity and low inflammation. The material can be molded into a variety of anatomic shapes for use as a cartilage replacement, heart valve, and reconstructive implant for trauma victims. The biomaterial may be suitable for several biodevices of the future aimed at soft-tissue replacements.

SU-E-T-756: Tissue Inhomogeneity Corrections in Intra-Operative Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sethi, A; Chinsky, B; Gros, S

Purpose: Investigate the impact of tissue inhomogeneities on dose distributions produced by low-energy X-rays in intra-operative radiotherapy (IORT). Methods: A 50-kV INTRABEAM X-ray device with superficial (Flat and Surface) applicators was commissioned at our institution. For each applicator, percent depth-dose (PDD), dose-profiles (DP) and output factors (OF) were obtained. Calibrated GaFchromic (EBT3) films were used to measure dose distributions in solid water phantom at various depths (2, 5, 10, and 15 mm). All recommended precautions for film-handling, film-exposure and scanning were observed. The effects of tissue inhomogeneities on dose distributions were examined by placing air-cavities and bone and tissue equivalentmore » materials of different density (ρ), atomic number (Z), and thickness (t = 0–4mm) between applicator and film detector. All inhomogeneities were modeled as a cylindrical cavity (diameter 25 mm). Treatment times were calculated to deliver 1Gy dose at 5mm depth. Film results were verified by repeat measurements with a thin-window parallel plate ion-chamber (PTW 34013A) in a water tank. Results: For a Flat-4cm applicator, the measured dose rate at 5mm depth in solid water was 0.35 Gy/min. Introduction of a cylindrical air-cavity resulted in an increased dose past the inhomogeneity. Compared to tissue equivalent medium, dose enhancement due to 1mm, 2mm, 3mm and 4mm air cavities was 10%, 16%, 24%, and 35% respectively. X-ray attenuation by 2mm thick cortical bone resulted in a significantly large (58%) dose decrease. Conclusion: IORT dose calculations assume homogeneous tissue equivalent medium. However, soft X-rays are easily affected by non-tissue equivalent materials. The results of this study may be used to estimate and correct IORT dose delivered in the presence of tissue inhomogeneities.« less

Mechanical characterization of soft materials using transparent indenter testing system and finite element simulation

NASA Astrophysics Data System (ADS)

Xuan, Yue

Background. Soft materials such as polymers and soft tissues have diverse applications in bioengineering, medical care, and industry. Quantitative mechanical characterization of soft materials at multiscales is required to assure that appropriate mechanical properties are presented to support the normal material function. Indentation test has been widely used to characterize soft material. However, the measurement of in situ contact area is always difficult. Method of Approach. A transparent indenter method was introduced to characterize the nonlinear behaviors of soft materials under large deformation. This approach made the direct measurement of contact area and local deformation possible. A microscope was used to capture the contact area evolution as well as the surface deformation. Based on this transparent indenter method, a novel transparent indentation measurement systems has been built and multiple soft materials including polymers and pericardial tissue have been characterized. Seven different indenters have been used to study the strain distribution on the contact surface, inner layer and vertical layer. Finite element models have been built to simulate the hyperelastic and anisotropic material behaviors. Proper material constants were obtained by fitting the experimental results. Results.Homogeneous and anisotropic silicone rubber and porcine pericardial tissue have been examined. Contact area and local deformation were measured by real time imaging the contact interface. The experimental results were compared with the predictions from the Hertzian equations. The accurate measurement of contact area results in more reliable Young's modulus, which is critical for soft materials. For the fiber reinforced anisotropic silicone rubber, the projected contact area under a hemispherical indenter exhibited elliptical shape. The local surface deformation under indenter was mapped using digital image correlation program. Punch test has been applied to thin films of silicone rubber and porcine pericardial tissue and results were analyzed using the same method. Conclusions. The transparent indenter testing system can effectively reduce the material properties measurement error by directly measuring the contact radii. The contact shape can provide valuable information for the anisotropic property of the material. Local surface deformation including contact surface, inner layer and vertical plane can be accurately tracked and mapped to study the strain distribution. The potential usage of the transparent indenter measurement system to investigate biological and biomaterials was verified. The experimental data including the real-time contact area combined with the finite element simulation would be powerful tool to study mechanical properties of soft materials and their relation to microstructure, which has potential in pathologies study such as tissue repair and surgery plan. Key words: transparent indenter, large deformation, soft material, anisotropic.

Characterization of MOSFET dosimeter angular dependence in three rotational axes measured free-in-air and in soft-tissue equivalent material.

PubMed

Koivisto, Juha; Kiljunen, Timo; Wolff, Jan; Kortesniemi, Mika

2013-09-01

When performing dose measurements on an X-ray device with multiple angles of irradiation, it is necessary to take the angular dependence of metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters into account. The objective of this study was to investigate the angular sensitivity dependence of MOSFET dosimeters in three rotational axes measured free-in-air and in soft-tissue equivalent material using dental photon energy. Free-in-air dose measurements were performed with three MOSFET dosimeters attached to a carbon fibre holder. Soft tissue measurements were performed with three MOSFET dosimeters placed in a polymethylmethacrylate (PMMA) phantom. All measurements were made in the isocenter of a dental cone-beam computed tomography (CBCT) scanner using 5º angular increments in the three rotational axes: axial, normal-to-axial and tangent-to-axial. The measurements were referenced to a RADCAL 1015 dosimeter. The angular sensitivity free-in-air (1 SD) was 3.7 ± 0.5 mV/mGy for axial, 3.8 ± 0.6 mV/mGy for normal-to-axial and 3.6 ± 0.6 mV/mGy for tangent-to-axial rotation. The angular sensitivity in the PMMA phantom was 3.1 ± 0.1 mV/mGy for axial, 3.3 ± 0.2 mV/mGy for normal-to-axial and 3.4 ± 0.2 mV/mGy for tangent-to-axial rotation. The angular sensitivity variations are considerably smaller in PMMA due to the smoothing effect of the scattered radiation. The largest decreases from the isotropic response were observed free-in-air at 90° (distal tip) and 270° (wire base) in the normal-to-axial and tangent-to-axial rotations, respectively. MOSFET dosimeters provide us with a versatile dosimetric method for dental radiology. However, due to the observed variation in angular sensitivity, MOSFET dosimeters should always be calibrated in the actual clinical settings for the beam geometry and angular range of the CBCT exposure.

Characterization of MOSFET dosimeter angular dependence in three rotational axes measured free-in-air and in soft-tissue equivalent material

PubMed Central

Koivisto, Juha; Kiljunen, Timo; Wolff, Jan; Kortesniemi, Mika

2013-01-01

When performing dose measurements on an X-ray device with multiple angles of irradiation, it is necessary to take the angular dependence of metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters into account. The objective of this study was to investigate the angular sensitivity dependence of MOSFET dosimeters in three rotational axes measured free-in-air and in soft-tissue equivalent material using dental photon energy. Free-in-air dose measurements were performed with three MOSFET dosimeters attached to a carbon fibre holder. Soft tissue measurements were performed with three MOSFET dosimeters placed in a polymethylmethacrylate (PMMA) phantom. All measurements were made in the isocenter of a dental cone-beam computed tomography (CBCT) scanner using 5º angular increments in the three rotational axes: axial, normal-to-axial and tangent-to-axial. The measurements were referenced to a RADCAL 1015 dosimeter. The angular sensitivity free-in-air (1 SD) was 3.7 ± 0.5 mV/mGy for axial, 3.8 ± 0.6 mV/mGy for normal-to-axial and 3.6 ± 0.6 mV/mGy for tangent-to-axial rotation. The angular sensitivity in the PMMA phantom was 3.1 ± 0.1 mV/mGy for axial, 3.3 ± 0.2 mV/mGy for normal-to-axial and 3.4 ± 0.2 mV/mGy for tangent-to-axial rotation. The angular sensitivity variations are considerably smaller in PMMA due to the smoothing effect of the scattered radiation. The largest decreases from the isotropic response were observed free-in-air at 90° (distal tip) and 270° (wire base) in the normal-to-axial and tangent-to-axial rotations, respectively. MOSFET dosimeters provide us with a versatile dosimetric method for dental radiology. However, due to the observed variation in angular sensitivity, MOSFET dosimeters should always be calibrated in the actual clinical settings for the beam geometry and angular range of the CBCT exposure. PMID:23520268

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nguyen, Thao D.; Grazier, John Mark; Boyce, Brad Lee

Biological tissues are uniquely structured materials with technologically appealing properties. Soft tissues such as skin, are constructed from a composite of strong fibrils and fluid-like matrix components. This was the first coordinated experimental/modeling project at Sandia or in the open literature to consider the mechanics of micromechanically-based anisotropy and viscoelasticity of soft biological tissues. We have exploited and applied Sandia's expertise in experimentation and mechanics modeling to better elucidate the behavior of collagen fibril-reinforced soft tissues. The purpose of this project was to provide a detailed understanding of the deformation of ocular tissues, specifically the highly structured skin-like tissue inmore » the cornea. This discovery improved our knowledge of soft/complex materials testing and modeling. It also provided insight into the way that cornea tissue is bio-engineered such that under physiologically-relevant conditions it has a unique set of properties which enhance functionality. These results also provide insight into how non-physiologic loading conditions, such as corrective surgeries, may push the cornea outside of its natural design window, resulting in unexpected non-linear responses. Furthermore, this project created a clearer understanding of the mechanics of soft tissues that could lead to bio-inspired materials, such as highly supple and impact resistant body armor, and improve our design of human-machine interfaces, such as micro-electrical-mechanical (MEMS) based prosthetics.« less

Components of soft tissue deformations in subjects with untreated angle's Class III malocclusions: thin-plate spline analysis.

PubMed

Singh, G D; McNamara, J A; Lozanoff, S

1998-01-01

While the dynamics of maxillo-mandibular allometry associated with treatment modalities available for the management of Class III malocclusions currently are under investigation, developmental aberration of the soft tissues in untreated Class III malocclusions requires specification. In this study, lateral cephalographs of 124 prepubertal European-American children (71 with untreated Class III malocclusion; 53 with Class I occlusion) were traced, and 12 soft-tissue landmarks digitized. Resultant geometries were scaled to an equivalent size and mean Class III and Class I configurations compared. Procrustes analysis established statistical difference (P < 0.001) between the mean configurations. Comparing the overall untreated Class III and Class I configurations, thin-plate spline (TPS) analysis indicated that both affine and non-affine transformations contribute towards the deformation (total spline) of the averaged Class III soft tissue configuration. For non-affine transformations, partial warp 8 had the highest magnitude, indicating large-scale deformations visualized as a combination of columellar retrusion and lower labial protrusion. In addition, partial warp 5 also had a high magnitude, demonstrating upper labial vertical compression with antero-inferior elongation of the lower labio-mental soft tissue complex. Thus, children with Class III malocclusions demonstrate antero-posterior and vertical deformations of the maxillary soft tissue complex in combination with antero-inferior mandibular soft tissue elongation. This pattern of deformations may represent gene-environment interactions, resulting in Class III malocclusions with characteristic phenotypes, that are amenable to orthodontic and dentofacial orthopedic manipulations.

Can the shell of the green-lipped mussel Perna viridis from the west coast of Peninsular Malaysia be a potential biomonitoring material for Cd, Pb and Zn?

NASA Astrophysics Data System (ADS)

Yap, C. K.; Ismail, A.; Tan, S. G.; Abdul Rahim, I.

2003-07-01

The distributions of Cd, Pb and Zn in the total soft tissues and total shells of the green-lipped mussel Perna viridis were studied in field collected samples as well as from laboratory experimental samples. The results showed that Cd, Pb and Zn were readily accumulated in the whole shells. In mussels sampled from 12 locations along the west coast of Peninsular Malaysia, the ratios of the shell metals to the soft tissue metals were different at each sampling site. Nevertheless, the Cd and Pb levels in the shells were always higher than those in the soft tissues, while the Zn level was higher in the soft tissues than in the shells. In comparison with soft tissues, the degrees of variability for Pb and Cd concentrations in the shells were lower. The lower degrees of variability and significant ( P<0.05) correlation coefficients of Cd and Pb within the shells support the use of the mussel shell as a suitable biomonitoring material for the two metals rather than the soft tissue since this indicated that there is more precision (lower CV) in the determination of metal concentrations in the shell than in the soft tissue. Experimental work showed that the pattern of depuration in the shell was not similar to that of the soft tissue although their patterns of accumulation were similar. This indicated that the depuration of heavy metals in the shell was not affected by the physiological conditions of the mussels. Although Zn could be regulated by the soft tissue, the incorporated Cd, Pb and Zn remained in the shell matrices. The present results support the use of the total shell of P. viridis as a potential biomonitoring material for long-term contamination of Cd, Pb and Zn.

Experimentally determined spectral optimization for dedicated breast computed tomography.

PubMed

Prionas, Nicolas D; Huang, Shih-Ying; Boone, John M

2011-02-01

The current study aimed to experimentally identify the optimal technique factors (x-ray tube potential and added filtration material/thickness) to maximize soft-tissue contrast, microcalcification contrast, and iodine contrast enhancement using cadaveric breast specimens imaged with dedicated breast computed tomography (bCT). Secondarily, the study aimed to evaluate the accuracy of phantom materials as tissue surrogates and to characterize the change in accuracy with varying bCT technique factors. A cadaveric breast specimen was acquired under appropriate approval and scanned using a prototype bCT scanner. Inserted into the specimen were cylindrical inserts of polyethylene, water, iodine contrast medium (iodixanol, 2.5 mg/ml), and calcium hydroxyapatite (100 mg/ml). Six x-ray tube potentials (50, 60, 70, 80, 90, and 100 kVp) and three different filters (0.2 mm Cu, 1.5 mm Al, and 0.2 mm Sn) were tested. For each set of technique factors, the intensity (linear attenuation coefficient) and noise were measured within six regions of interest (ROIs): Glandular tissue, adipose tissue, polyethylene, water, iodine contrast medium, and calcium hydroxyapatite. Dose-normalized contrast to noise ratio (CNRD) was measured for pairwise comparisons among the six ROIs. Regression models were used to estimate the effect of tube potential and added filtration on intensity, noise, and CNRD. Iodine contrast enhancement was maximized using 60 kVp and 0.2 mm Cu. Microcalcification contrast and soft-tissue contrast were maximized at 60 kVp. The 0.2 mm Cu filter achieved significantly higher CNRD for iodine contrast enhancement than the other two filters (p = 0.01), but microcalcification contrast and soft-tissue contrast were similar using the copper and aluminum filters. The average percent difference in linear attenuation coefficient, across all tube potentials, for polyethylene versus adipose tissue was 1.8%, 1.7%, and 1.3% for 0.2 mm Cu, 1.5 mm Al, and 0.2 mm Sn, respectively. For water versus glandular tissue, the average percent difference was 2.7%, 3.9%, and 4.2% for the three filter types. Contrast-enhanced bCT, using injected iodine contrast medium, may be optimized for maximum contrast of enhancing lesions at 60 kVp with 0.2 mm Cu filtration. Soft-tissue contrast and microcalcification contrast may also benefit from lower tube potentials (60 kVp). The linear attenuation coefficients of water and polyethylene slightly overestimate the values of their corresponding tissues, but the reported differences may serve as guidance for dosimetry and quality assurance using tissue equivalent phantoms.

Soft Tissue Phantoms for Realistic Needle Insertion: A Comparative Study.

PubMed

Leibinger, Alexander; Forte, Antonio E; Tan, Zhengchu; Oldfield, Matthew J; Beyrau, Frank; Dini, Daniele; Rodriguez Y Baena, Ferdinando

2016-08-01

Phantoms are common substitutes for soft tissues in biomechanical research and are usually tuned to match tissue properties using standard testing protocols at small strains. However, the response due to complex tool-tissue interactions can differ depending on the phantom and no comprehensive comparative study has been published to date, which could aid researchers to select suitable materials. In this work, gelatin, a common phantom in literature, and a composite hydrogel developed at Imperial College, were matched for mechanical stiffness to porcine brain, and the interactions during needle insertions within them were analyzed. Specifically, we examined insertion forces for brain and the phantoms; we also measured displacements and strains within the phantoms via a laser-based image correlation technique in combination with fluorescent beads. It is shown that the insertion forces for gelatin and brain agree closely, but that the composite hydrogel better mimics the viscous nature of soft tissue. Both materials match different characteristics of brain, but neither of them is a perfect substitute. Thus, when selecting a phantom material, both the soft tissue properties and the complex tool-tissue interactions arising during tissue manipulation should be taken into consideration. These conclusions are presented in tabular form to aid future selection.

Soft Tissue Deformations Contribute to the Mechanics of Walking in Obese Adults

PubMed Central

Fu, Xiao-Yu; Zelik, Karl E.; Board, Wayne J.; Browning, Raymond C.; Kuo, Arthur D.

2014-01-01

Obesity not only adds to the mass that must be carried during walking, but also changes body composition. Although extra mass causes roughly proportional increases in musculoskeletal loading, less well understood is the effect of relatively soft and mechanically compliant adipose tissue. Purpose To estimate the work performed by soft tissue deformations during walking. The soft tissue would be expected to experience damped oscillations, particularly from high force transients following heel strike, and could potentially change the mechanical work demands for walking. Method We analyzed treadmill walking data at 1.25 m/s for 11 obese (BMI > 30 kg/m2) and 9 non-obese (BMI < 30 kg/m2) adults. The soft tissue work was quantified with a method that compares the work performed by lower extremity joints as derived using assumptions of rigid body segments, with that estimated without rigid body assumptions. Results Relative to body mass, obese and non-obese individuals perform similar amounts of mechanical work. But negative work performed by soft tissues was significantly greater in obese individuals (p= 0.0102), equivalent to about 0.36 J/kg vs. 0.27 J/kg in non-obese individuals. The negative (dissipative) work by soft tissues occurred mainly after heel strike, and for obese individuals was comparable in magnitude to the total negative work from all of the joints combined (0.34 J/kg vs. 0.33 J/kg for obese and non-obese adults, respectively). Although the joints performed a relatively similar amount of work overall, obese individuals performed less negative work actively at the knee. Conclusion The greater proportion of soft tissues in obese individuals results in substantial changes in the amount, location, and timing of work, and may also impact metabolic energy expenditure during walking. PMID:25380475

Fabrication of polyurethane and polyurethane based composite fibres by the electrospinning technique for soft tissue engineering of cardiovascular system.

PubMed

Kucinska-Lipka, J; Gubanska, I; Janik, H; Sienkiewicz, M

2015-01-01

Electrospinning is a unique technique, which provides forming of polymeric scaffolds for soft tissue engineering, which include tissue scaffolds for soft tissues of the cardiovascular system. Such artificial soft tissues of the cardiovascular system may possess mechanical properties comparable to native vascular tissues. Electrospinning technique gives the opportunity to form fibres with nm- to μm-scale in diameter. The arrangement of obtained fibres and their surface determine the biocompatibility of the scaffolds. Polyurethanes (PUs) are being commonly used as a prosthesis of cardiovascular soft tissues due to their excellent biocompatibility, non-toxicity, elasticity and mechanical properties. PUs also possess fine spinning properties. The combination of a variety of PU properties with an electrospinning technique, conducted at the well tailored conditions, gives unlimited possibilities of forming novel polyurethane materials suitable for soft tissue scaffolds applied in cardiovascular tissue engineering. This paper can help researches to gain more widespread and deeper understanding of designing electrospinable PU materials, which may be used as cardiovascular soft tissue scaffolds. In this paper we focus on reagents used in PU synthesis designed to increase PU biocompatibility (polyols) and biodegradability (isocyanates). We also describe suggested surface modifications of electrospun PUs, and the direct influence of surface wettability on providing enhanced biocompatibility of scaffolds. We indicate a great influence of electrospinning parameters (voltage, flow rate, working distance) and used solvents (mostly DMF, THF and HFIP) on fibre alignment and diameter - what impacts the biocompatibility and hemocompatibility of such electrospun PU scaffolds. Moreover, we present PU modifications with natural polymers with novel approach applied in electrospinning of PU scaffolds. This work may contribute with further developing of novel electrospun PUs, which may be applied as soft tissue scaffolds of the cardiovascular system. Copyright © 2014. Published by Elsevier B.V.

Injectable fillers: review of material and properties.

PubMed

Attenello, Natalie Huang; Maas, Corey S

2015-02-01

With an increasing understanding of the aging process and the rapidly growing interest in minimally invasive treatments, injectable facial fillers have changed the perspective for the treatment and rejuvenation of the aging face. Other than autologous fat and certain preformed implants, the collagen family products were the only Food and Drug Administration approved soft tissue fillers. But the overwhelming interest in soft tissue fillers had led to the increase in research and development of other products including bioengineered nonpermanent implants and permanent alloplastic implants. As multiple injectable soft tissue fillers and biostimulators are continuously becoming available, it is important to understand the biophysical properties inherent in each, as these constitute the clinical characteristics of the product. This article will review the materials and properties of the currently available soft tissue fillers: hyaluronic acid, calcium hydroxylapatite, poly-l-lactic acid, polymethylmethacrylate, and autologous fat (and aspirated tissue including stem cells). Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Influence of abutment material on peri-implant soft tissues in anterior areas with thin gingival biotype: a multicentric prospective study.

PubMed

Lops, Diego; Stellini, Edoardo; Sbricoli, Luca; Cea, Niccolò; Romeo, Eugenio; Bressan, Eriberto

2017-10-01

The aim of the present clinical trial was to analyze, through spectrophotometric digital technology, the influence of the abutment material on the color of the peri-implant soft tissue in patients with thin gingival biotype. Thirty-seven patients received an endosseous dental implant in the anterior maxilla. At time of each definitive prosthesis delivery, an all-ceramic crown has been tried on gold, titanium and zirconia abutment. Peri-implant soft-tissue color has been measured through a spectrophotometer after the insertion of each single abutment. Also facial peri-implant soft-tissue thickness was measured at the level of the implant neck through a caliper. A specific software has been utilized to identify a standardized tissue area and to collect the data before the statistical analysis in Lab* color space. ΔE parameters of the selected abutments were tested for correlation with mucosal thickness. Pearson correlation test was used. Only 15 patients met the study inclusion criteria on peri-implant soft-tissue thickness. Peri-implant soft-tissue color was different from that around natural teeth, no matter which type of restorative material was selected. Measurements regarding all the abutments were above the critical threshold of ΔE 8.74 for intraoral color distinction by the naked eye. The ΔE mean values of gold and zirconium abutments were similar (11.43 and 11.37, respectively) and significantly lower (P = 0.03 and P = 0.04, respectively) than the titanium abutment (13.55). In patients with a facial soft-tissue thickness ≤2 mm, the ΔE mean value of gold and zirconia abutments was significantly lower than that of titanium abutments (P = 0.03 and P = 0.04, respectively) and much more close to the reference threshold of 8.74. For peri-implant soft tissue of ≤2 mm, gold or zirconia abutments could be selected in anterior areas treatment. Moreover, the thickness of the peri-implant soft tissue seemed to be a crucial factor in the abutment impact on the color of soft tissues with a thickness of ≤2 mm. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Scale-up of nature's tissue weaving algorithms to engineer advanced functional materials.

PubMed

Ng, Joanna L; Knothe, Lillian E; Whan, Renee M; Knothe, Ulf; Tate, Melissa L Knothe

2017-01-11

We are literally the stuff from which our tissue fabrics and their fibers are woven and spun. The arrangement of collagen, elastin and other structural proteins in space and time embodies our tissues and organs with amazing resilience and multifunctional smart properties. For example, the periosteum, a soft tissue sleeve that envelops all nonarticular bony surfaces of the body, comprises an inherently "smart" material that gives hard bones added strength under high impact loads. Yet a paucity of scalable bottom-up approaches stymies the harnessing of smart tissues' biological, mechanical and organizational detail to create advanced functional materials. Here, a novel approach is established to scale up the multidimensional fiber patterns of natural soft tissue weaves for rapid prototyping of advanced functional materials. First second harmonic generation and two-photon excitation microscopy is used to map the microscopic three-dimensional (3D) alignment, composition and distribution of the collagen and elastin fibers of periosteum, the soft tissue sheath bounding all nonarticular bone surfaces in our bodies. Then, using engineering rendering software to scale up this natural tissue fabric, as well as multidimensional weaving algorithms, macroscopic tissue prototypes are created using a computer-controlled jacquard loom. The capacity to prototype scaled up architectures of natural fabrics provides a new avenue to create advanced functional materials.

Soft tissue wound healing at teeth, dental implants and the edentulous ridge when using barrier membranes, growth and differentiation factors and soft tissue substitutes.

PubMed

Vignoletti, Fabio; Nunez, Javier; Sanz, Mariano

2014-04-01

To review the biological processes of wound healing following periodontal and periimplant plastic surgery when different technologies are used in a) the coverage of root and implant dehiscences, b) the augmentation of keratinized tissue (KT) and c) the augmentation of soft tissue volume. An electronic search from The National Library of Medicine (MEDLINE-PubMed) was performed: English articles with research focus in oral soft tissue regeneration, providing histological outcomes, either from animal experimental studies or human biopsy material were included. Barrier membranes, enamel matrix derivatives, growth factors, allogeneic and xenogeneic soft tissue substitutes have been used in soft tissue regeneration demonstrating different degrees of regeneration. In root coverage, these technologies were able to improve new attachment, although none has shown complete regeneration. In KT augmentation, tissue-engineered allogenic products and xenogeneic collagen matrixes demonstrated integration within the host connective tissue and promotion of keratinization. In soft tissue augmentation and peri-implant plastic surgery there are no histological data currently available. Soft tissue substitutes, growth differentiation factors demonstrated promising histological results in terms of soft tissue regeneration and keratinization, whereas there is a need for further studies to prove their added value in soft tissue augmentation. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Assessing behind armor blunt trauma in accordance with the National Institute of Justice Standard for Personal Body Armor Protection using finite element modeling.

PubMed

Roberts, Jack C; Ward, Emily E; Merkle, Andrew C; O'Connor, James V

2007-05-01

To assess the possibility of injury as a result of behind armor blunt trauma (BABT), a study was undertaken to determine the conditions necessary to produce the 44-mm clay deformation as set forth in the National Institute of Justice (NIJ) Standard 0101.04. These energy levels were then applied to a three-dimensional Human Torso Finite Element Model (HTFEM) with soft armor vest. An examination will be made of tissue stresses to determine the effects of the increased kinetic energy levels on the probability of injury. A clay finite element model (CFEM) was created with a material model that required nonlinear properties for clay. To determine these properties empirically, the results from the CFEM were matched with experimental drop tests. A soft armor vest was modeled over the clay to create a vest over clay block finite element model (VCFEM) and empirical methods were again used to obtain material properties for the vest from experimental ballistic testing. Once the properties for the vest and clay had been obtained, the kinetic energy required to produce a 44-mm deformation in the VCFEM was determined through ballistic testing. The resulting kinetic energy was then used in the HTFEM to evaluate the probability of BABT. The VCFEM, with determined clay and vest material properties, was exercised with the equivalent of a 9-mm (8-gm) projectile at various impact velocities. The 44-mm clay deformation was produced with a velocity of 785 m/s. This impact condition (9-mm projectile at 785 m/s) was used in ballistic exercises of the HTFEM, which was modeled with high-strain rate human tissue properties for the organs. The impact zones were over the sternum anterior to T6 and over the liver. The principal stresses in both soft and hard tissue at both locations exceeded the tissue tensile strength. This study indicates that although NIJ standard 0101.04 may be a good guide to soft armor failure, it may not be as good a guide in BABT, especially at large projectile kinetic energies. Further studies, both numerical and experimental, are needed to assist in predicting injury using the NIJ standard.

SU-E-J-203: Investigation of 1.5T Magnetic Field Dose Effects On Organs of Different Density

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, H; Rubinstein, A; Ibbott, G

2015-06-15

Purpose: For the combined 1.5T/6MV MRI-linac system, the perpendicular magnetic field to the radiation beam results in altered radiation dose distributions. This Monte Carlo study investigates the change in dose at interfaces for common organs neighboring soft tissue. Methods: MCNP6 was used to simulate the effects of a 1.5T magnetic field when irradiating tissues with a 6 MV beam. The geometries used in this study were not necessarily anatomically representative in size in order to directly compare quantitative dose effects for each tissue at the same depths. For this purpose, a 512 cm{sup 3} cubic material was positioned at themore » center of a 2744 cm{sup 3} cubic soft tissue material phantom. The following tissue materials and their densities were used in this study: lung (0.296 g/cm{sup 3}), fat (0.95), spinal cord (1.038), soft tissue (1.04), muscle (1.05), eye (1.076), trabecular bone (1.40), and cortical bone (1.85). Results: The addition of a 1.5T magnetic field caused dose changes of +46.5%, +2.4%, −0.9%, −0.8%, −1.5%, −6.5%, and −8.8% at the entrance interface between soft tissue and lung, fat, spinal cord, muscle, eye, trabecular bone, and cortical bone tissues respectively. Dose changes of −39.4%, −4.1%, −0.8%, −0.8%, +0.5%, +6.7%, and +10.9% were observed at the second interface between the same tissues respectively and soft tissue. On average, the build-up distance was reduced by 0.6 cm, and a dose increase of 62.7% was observed at the exit interface between soft tissue and air of the entire phantom. Conclusion: The greatest changes in dose were observed at interfaces containing lung and bone tissues. Due to the prevalence and proximity of bony anatomy to soft tissues throughout the human body, these results encourage further examination of these tissues with anatomically representative geometries using multiple beam configurations for safe treatment using the MRI-linac system.« less

Absorbed Dose and Dose Equivalent Calculations for Modeling Effective Dose

NASA Technical Reports Server (NTRS)

Welton, Andrew; Lee, Kerry

2010-01-01

While in orbit, Astronauts are exposed to a much higher dose of ionizing radiation than when on the ground. It is important to model how shielding designs on spacecraft reduce radiation effective dose pre-flight, and determine whether or not a danger to humans is presented. However, in order to calculate effective dose, dose equivalent calculations are needed. Dose equivalent takes into account an absorbed dose of radiation and the biological effectiveness of ionizing radiation. This is important in preventing long-term, stochastic radiation effects in humans spending time in space. Monte carlo simulations run with the particle transport code FLUKA, give absorbed and equivalent dose data for relevant shielding. The shielding geometry used in the dose calculations is a layered slab design, consisting of aluminum, polyethylene, and water. Water is used to simulate the soft tissues that compose the human body. The results obtained will provide information on how the shielding performs with many thicknesses of each material in the slab. This allows them to be directly applicable to modern spacecraft shielding geometries.

Standardized 3D Bioprinting of Soft Tissue Models with Human Primary Cells.

PubMed

Rimann, Markus; Bono, Epifania; Annaheim, Helene; Bleisch, Matthias; Graf-Hausner, Ursula

2016-08-01

Cells grown in 3D are more physiologically relevant than cells cultured in 2D. To use 3D models in substance testing and regenerative medicine, reproducibility and standardization are important. Bioprinting offers not only automated standardizable processes but also the production of complex tissue-like structures in an additive manner. We developed an all-in-one bioprinting solution to produce soft tissue models. The holistic approach included (1) a bioprinter in a sterile environment, (2) a light-induced bioink polymerization unit, (3) a user-friendly software, (4) the capability to print in standard labware for high-throughput screening, (5) cell-compatible inkjet-based printheads, (6) a cell-compatible ready-to-use BioInk, and (7) standard operating procedures. In a proof-of-concept study, skin as a reference soft tissue model was printed. To produce dermal equivalents, primary human dermal fibroblasts were printed in alternating layers with BioInk and cultured for up to 7 weeks. During long-term cultures, the models were remodeled and fully populated with viable and spreaded fibroblasts. Primary human dermal keratinocytes were seeded on top of dermal equivalents, and epidermis-like structures were formed as verified with hematoxylin and eosin staining and immunostaining. However, a fully stratified epidermis was not achieved. Nevertheless, this is one of the first reports of an integrative bioprinting strategy for industrial routine application. © 2015 Society for Laboratory Automation and Screening.

Scale-up of nature’s tissue weaving algorithms to engineer advanced functional materials

NASA Astrophysics Data System (ADS)

Ng, Joanna L.; Knothe, Lillian E.; Whan, Renee M.; Knothe, Ulf; Tate, Melissa L. Knothe

2017-01-01

We are literally the stuff from which our tissue fabrics and their fibers are woven and spun. The arrangement of collagen, elastin and other structural proteins in space and time embodies our tissues and organs with amazing resilience and multifunctional smart properties. For example, the periosteum, a soft tissue sleeve that envelops all nonarticular bony surfaces of the body, comprises an inherently “smart” material that gives hard bones added strength under high impact loads. Yet a paucity of scalable bottom-up approaches stymies the harnessing of smart tissues’ biological, mechanical and organizational detail to create advanced functional materials. Here, a novel approach is established to scale up the multidimensional fiber patterns of natural soft tissue weaves for rapid prototyping of advanced functional materials. First second harmonic generation and two-photon excitation microscopy is used to map the microscopic three-dimensional (3D) alignment, composition and distribution of the collagen and elastin fibers of periosteum, the soft tissue sheath bounding all nonarticular bone surfaces in our bodies. Then, using engineering rendering software to scale up this natural tissue fabric, as well as multidimensional weaving algorithms, macroscopic tissue prototypes are created using a computer-controlled jacquard loom. The capacity to prototype scaled up architectures of natural fabrics provides a new avenue to create advanced functional materials.

X-ray phase contrast imaging of the breast: Analysis of tissue simulating materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vedantham, Srinivasan; Karellas, Andrew

Purpose: Phase contrast imaging, particularly of the breast, is being actively investigated. The purpose of this work is to investigate the x-ray phase contrast properties of breast tissues and commonly used breast tissue substitutes or phantom materials with an aim of determining the phantom materials best representative of breast tissues. Methods: Elemental compositions of breast tissues including adipose, fibroglandular, and skin were used to determine the refractive index, n= 1 -{delta}+i {beta}. The real part of the refractive index, specifically the refractive index decrement ({delta}), over the energy range of 5-50 keV were determined using XOP software (version 2.3, Europeanmore » Synchrotron Radiation Facility, France). Calcium oxalate and calcium hydroxyapatite were considered to represent the material compositions of microcalcifications in vivo. Nineteen tissue substitutes were considered as possible candidates to represent adipose tissue, fibroglandular tissue and skin, and four phantom materials were considered as possible candidates to represent microcalcifications. For each material, either the molecular formula, if available, or the elemental composition based on weight fraction, was used to determine {delta}. At each x-ray photon energy, the absolute percent difference in {delta} between the breast tissue and the substitute material was determined, from which three candidates were selected. From these candidate tissue substitutes, the material that minimized the absolute percent difference in linear attenuation coefficient {mu}, and hence {beta}, was considered to be best representative of that breast tissue. Results: Over the energy range of 5-50 keV, while the {delta} of CB3 and fibroglandular tissue-equivalent material were within 1% of that of fibroglandular tissue, the {mu} of fibroglandular tissue-equivalent material better approximated the fibroglandular tissue. While the {delta} of BR10 and adipose tissue-equivalent material were within 1% of that of adipose tissue, the tissue-equivalent material better approximated the adipose tissue in terms of {mu}. Polymethyl methacrylate, a commonly used tissue substitute, exhibited {delta} greater than fibroglandular tissue by {approx}12%. The A-150 plastic closely approximated the skin. Several materials exhibited {delta} between that of adipose and fibroglandular tissue. However, there was an energy-dependent mismatch in terms of equivalent fibroglandular weight fraction between {delta} and {mu} for these materials. For microcalcifications, aluminum and calcium carbonate were observed to straddle the {delta} and {mu} of calcium oxalate and calcium hydroxyapatite. Aluminum oxide, commonly used to represent microcalcifications in the American College of Radiology recommended phantoms for accreditation exhibited {delta} greater than calcium hydroxyapatite by {approx}23%. Conclusions: A breast phantom comprising A-150 plastic to represent the skin, commercially available adipose and fibroglandular tissue-equivalent formulations to represent adipose and fibroglandular tissue, respectively, was found to be best suited for x-ray phase-sensitive imaging of the breast. Calcium carbonate or aluminum can be used to represent microcalcifications.« less

X-ray phase contrast imaging of the breast: Analysis of tissue simulating materials1

PubMed Central

Vedantham, Srinivasan; Karellas, Andrew

2013-01-01

Purpose: Phase contrast imaging, particularly of the breast, is being actively investigated. The purpose of this work is to investigate the x-ray phase contrast properties of breast tissues and commonly used breast tissue substitutes or phantom materials with an aim of determining the phantom materials best representative of breast tissues. Methods: Elemental compositions of breast tissues including adipose, fibroglandular, and skin were used to determine the refractive index, n = 1 − δ + i β. The real part of the refractive index, specifically the refractive index decrement (δ), over the energy range of 5–50 keV were determined using XOP software (version 2.3, European Synchrotron Radiation Facility, France). Calcium oxalate and calcium hydroxyapatite were considered to represent the material compositions of microcalcifications in vivo. Nineteen tissue substitutes were considered as possible candidates to represent adipose tissue, fibroglandular tissue and skin, and four phantom materials were considered as possible candidates to represent microcalcifications. For each material, either the molecular formula, if available, or the elemental composition based on weight fraction, was used to determine δ. At each x-ray photon energy, the absolute percent difference in δ between the breast tissue and the substitute material was determined, from which three candidates were selected. From these candidate tissue substitutes, the material that minimized the absolute percent difference in linear attenuation coefficient μ, and hence β, was considered to be best representative of that breast tissue. Results: Over the energy range of 5–50 keV, while the δ of CB3 and fibroglandular tissue-equivalent material were within 1% of that of fibroglandular tissue, the μ of fibroglandular tissue-equivalent material better approximated the fibroglandular tissue. While the δ of BR10 and adipose tissue-equivalent material were within 1% of that of adipose tissue, the tissue-equivalent material better approximated the adipose tissue in terms of μ. Polymethyl methacrylate, a commonly used tissue substitute, exhibited δ greater than fibroglandular tissue by ∼12%. The A-150 plastic closely approximated the skin. Several materials exhibited δ between that of adipose and fibroglandular tissue. However, there was an energy-dependent mismatch in terms of equivalent fibroglandular weight fraction between δ and μ for these materials. For microcalcifications, aluminum and calcium carbonate were observed to straddle the δ and μ of calcium oxalate and calcium hydroxyapatite. Aluminum oxide, commonly used to represent microcalcifications in the American College of Radiology recommended phantoms for accreditation exhibited δ greater than calcium hydroxyapatite by ∼23%. Conclusions: A breast phantom comprising A-150 plastic to represent the skin, commercially available adipose and fibroglandular tissue-equivalent formulations to represent adipose and fibroglandular tissue, respectively, was found to be best suited for x-ray phase-sensitive imaging of the breast. Calcium carbonate or aluminum can be used to represent microcalcifications. PMID:23556900

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lujano, C; Hernandez, N; Keith, T

Purpose: To describe the proton phantoms that IROC Houston uses to approve and credential proton institutions to participate in NCI-sponsored clinical trials. Methods: Photon phantoms cannot necessarily be used for proton measurements because protons react differently than photons in some plastics. As such plastics that are tissue equivalent for protons were identified. Another required alteration is to ensure that the film dosimeters are housed in the phantom with no air gap to avoid proton streaming. Proton-equivalent plastics/materials used include RMI Solid Water, Techron HPV, blue water, RANDO soft tissue material, balsa wood, compressed cork and polyethylene. Institutions wishing to bemore » approved or credentialed request a phantom and are prioritized for delivery. At the institution, the phantom is imaged, a treatment plan is developed, positioned on the treatment couch and the treatment is delivered. The phantom is returned and the measured dose distributions are compared to the institution’s electronically submitted treatment plan dosimetry data. Results: IROC Houston has developed an extensive proton phantom approval/credentialing program consisting of five different phantoms designs: head, prostate, lung, liver and spine. The phantoms are made with proton equivalent plastics that have HU and relative stopping powers similar (within 5%) of human tissues. They also have imageable targets, avoidance structures, and heterogeneities. TLD and radiochromic film are contained in the target structures. There have been 13 head, 33 prostate, 18 lung, 2 liver and 16 spine irradiations with either passive scatter, or scanned proton beams. The pass rates have been: 100%, 69.7%, 72.2%, 50%, and 81.3%, respectively. Conclusion: IROC Houston has responded to the recent surge in proton facilities by developing a family of anthropomorphic phantoms that are able to be used for remote audits of proton beams. Work supported by PHS grant CA10953 and CA081647.« less

Ultrasound elastography as a tool for imaging guidance during prostatectomy: Initial experience

PubMed Central

Fleming, Ioana Nicolaescu; Kut, Carmen; Macura, Katarzyna J.; Su, Li-Ming; Rivaz, Hassan; Schneider, Caitlin; Hamper, Ulrike; Lotan, Tamara; Taylor, Russ; Hager, Gregory; Boctor, Emad

2012-01-01

Summary Background During laparoscopic or robotic assisted laparoscopic prostatectomy, the surgeon lacks tactile feedback which can help him tailor the size of the excision. Ultrasound elastography (USE) is an emerging imaging technology which maps the stiffness of tissue. In the paper we are evaluating USE as a palpation equivalent tool for intraoperative image guided robotic assisted laparoscopic prostatectomy. Material/Methods Two studies were performed: 1) A laparoscopic ultrasound probe was used in a comparative study of manual palpation versus USE in detecting tumor surrogates in synthetic and ex-vivo tissue phantoms; N=25 participants (students) were asked to provide the presence, size and depth of these simulated lesions, and 2) A standard ultrasound probe was used for the evaluation of USE on ex-vivo human prostate specimens (N=10 lesions in N=6 specimens) to differentiate hard versus soft lesions with pathology correlation. Results were validated by pathology findings, and also by in-vivo and ex-vivo MR imaging correlation. Results In the comparative study, USE displayed higher accuracy and specificity in tumor detection (sensitivity=84%, specificity=74%). Tumor diameters and depths were better estimated using USE versus with manual palpation. USE also proved consistent in identification of lesions in ex-vivo prostate specimens; hard and soft, malignant and benign, central and peripheral. Conclusions USE is a strong candidate for assisting surgeons by providing palpation equivalent evaluation of the tumor location, boundaries and extra-capsular extension. The results encourage us to pursue further testing in the robotic laparoscopic environment. PMID:23111738

Elastic Cherenkov effects in transversely isotropic soft materials-I: Theoretical analysis, simulations and inverse method

NASA Astrophysics Data System (ADS)

Li, Guo-Yang; Zheng, Yang; Liu, Yanlin; Destrade, Michel; Cao, Yanping

2016-11-01

A body force concentrated at a point and moving at a high speed can induce shear-wave Mach cones in dusty-plasma crystals or soft materials, as observed experimentally and named the elastic Cherenkov effect (ECE). The ECE in soft materials forms the basis of the supersonic shear imaging (SSI) technique, an ultrasound-based dynamic elastography method applied in clinics in recent years. Previous studies on the ECE in soft materials have focused on isotropic material models. In this paper, we investigate the existence and key features of the ECE in anisotropic soft media, by using both theoretical analysis and finite element (FE) simulations, and we apply the results to the non-invasive and non-destructive characterization of biological soft tissues. We also theoretically study the characteristics of the shear waves induced in a deformed hyperelastic anisotropic soft material by a source moving with high speed, considering that contact between the ultrasound probe and the soft tissue may lead to finite deformation. On the basis of our theoretical analysis and numerical simulations, we propose an inverse approach to infer both the anisotropic and hyperelastic parameters of incompressible transversely isotropic (TI) soft materials. Finally, we investigate the properties of the solutions to the inverse problem by deriving the condition numbers in analytical form and performing numerical experiments. In Part II of the paper, both ex vivo and in vivo experiments are conducted to demonstrate the applicability of the inverse method in practical use.

Soft Tissue Augmentation Using Silk Gels: An In Vitro and In Vivo Study

PubMed Central

Etienne, Olivier; Schneider, Aurore; Kluge, Jonathan A.; Bellemin-Laponnaz, Claire; Polidori, Camille; Leisk, Gary G.; Kaplan, David L.; Garlick, Jonathan A.; Egles, Christophe

2010-01-01

Background Restoration of a three-dimensional shape with soft tissue augmentation is a challenge for surgical reconstruction and esthetic improvement of intraoral mucosa and perioral skin tissues. A connective tissue graft or free gingival graft, classically used for such indications, requires a donor site, which may lead to various clinical complications. Methods In this article, a new three-dimensional scaffold made of silk fibroin that could be of great interest for these indications was studied. Mechanical tests were conducted to characterize the physical properties of the materials. The biocompatibility of such scaffolds was positively assessed in vitro using a combination of immunostaining, 5-bromo-2′-deoxyuridine proliferation assays, and histologic staining. Finally, the shaped material was grafted subcutaneously in nude mice for a long-time implantation study. Results Human fibroblasts embedded in this material had a survival rate up to 68.4% and were able to proliferate and synthesize proteins. One month after subcutaneous implantation, the three-dimensional soft tissue augmentation was stable, and histologic analysis revealed revascularization of the area through the biomaterial. A mild inflammatory reaction disappeared after 12 weeks. Conclusion The results indicate that silk-gel material was able to create a lasting three-dimensional soft tissue augmentation and is a promising biomaterial for periodontal and maxillofacial therapies, either as a scaffold for cells or alone as a biomaterial. PMID:19905955

Nonwoven-Based Gelatin/Polycaprolactone Membrane Proves Suitability in a Preclinical Assessment for Treatment of Soft Tissue Defects

PubMed Central

Schulz, Simon; Angarano, Marco; Fabritius, Martin; Mülhaupt, Rolf; Dard, Michel; Obrecht, Marcel; Tomakidi, Pascal

2014-01-01

Standard preclinical assessments in vitro often have limitations regarding their transferability to human beings, mainly evoked by their nonhuman and tissue-different/nontissue-specific source. Here, we aimed at employing tissue-authentic simple and complex interactive fibroblast-epithelial cell systems and their in vivo-relevant biomarkers for preclinical in vitro assessment of nonwoven-based gelatin/polycaprolactone membranes (NBMs) for treatment of soft tissue defects. NBMs were composed of electrospun gelatin and polycaprolactone nanofiber nonwovens. Scanning electron microscopy in conjunction with actin/focal contact integrin fluorescence revealed successful adhesion and proper morphogenesis of keratinocytes and fibroblasts, along with cells' derived extracellular matrix deposits. The “feel-good factor” of cells under study on the NBM was substantiated by forming a confluent connective tissue entity, which was concomitant with a stratified epithelial equivalent. Immunohistochemistry proved tissue authenticity over time by abundance of the biomarker vimentin in the connective tissue entity, and chronological increase of keratins KRT1/10 and involucrin expression in epithelial equivalents. Suitability of the novel NBM as wound dressing was evidenced by an almost completion of epithelial wound closure in a pilot mini-pig study, after a surgical intervention-caused gingival dehiscence. In summary, preclinical assessment by tissue-authentic cell systems and the animal pilot study revealed the NBM as an encouraging therapeutic medical device for prospective clinical applications. PMID:24494668

MO-F-CAMPUS-I-03: Tissue Equivalent Material Phantom to Test and Optimize Coherent Scatter Imaging for Tumor Classification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Albanese, K; Morris, R; Lakshmanan, M

Purpose: To accurately model different breast geometries using a tissue equivalent phantom, and to classify these tissues in a coherent x-ray scatter imaging system. Methods: A breast phantom has been designed to assess the capability of coded aperture coherent x-ray scatter imaging system to classify different types of breast tissue (adipose, fibroglandular, tumor). The tissue-equivalent phantom was modeled as a hollow plastic cylinder containing multiple cylindrical and spherical inserts that can be positioned, rearranged, or removed to model different breast geometries. Each enclosure can be filled with a tissue-equivalent material and excised human tumors. In this study, beef and lard,more » placed inside 2-mm diameter plastic Nalgene containers, were used as surrogates for fibroglandular and adipose tissue, respectively. The phantom was imaged at 125 kVp, 40 mA for 10 seconds each with a 1-mm pencil beam. The raw data were reconstructed using a model-based reconstruction algorithm and yielded the location and form factor, or momentum transfer (q) spectrum of the materials that were imaged. The measured material form factors were then compared to the ground truth measurements acquired by x-ray diffraction (XRD) imaging. Results: The tissue equivalent phantom was found to accurately model different types of breast tissue by qualitatively comparing our measured form factors to those of adipose and fibroglandular tissue from literature. Our imaging system has been able to define the location and composition of the various materials in the phantom. Conclusion: This work introduces a new tissue equivalent phantom for testing and optimization of our coherent scatter imaging system for material classification. In future studies, the phantom will enable the use of a variety of materials including excised human tissue specimens in evaluating and optimizing our imaging system using pencil- and fan-beam geometries. United States Department of Homeland Security Duke University Medical Center - Department of Radiology Carl E Ravin Advanced Imaging Laboratories Duke University Medical Physics Graduate Program.« less

Methodological questions of creating tissue-equivalent phantoms

NASA Technical Reports Server (NTRS)

Kolodkin, A. V.; Popov, V. I.; Sychkov, M. A.; Nikl, I.; Erdei, M.; Eyben, O.

1974-01-01

On the basis of analysis and generalization of literature data, the composition of tissue equivalent plastic was justified, parameters of a standard man were determined, plaster and metal forms were created for casting dummies, and an experimental model was produced from tissue equivalent material.

Containment-enhanced Ho:YAG photofragmentation of soft tissues

NASA Astrophysics Data System (ADS)

Christens-Barry, William A.; Guarnieri, Michael; Carson, Benjamin S.

1998-01-01

Laser surgery of soft tissue can exploit the power of brief, intense pulses of light to cause localized disruption of tissue with minimal effect upon surrounding tissue. In particular, studies of Ho:YAG laser surgery have shown that the effects of cavitation upon tissues and bone depend upon the physical composition of structures in the vicinity of the surgical site. For photofragmentation of occluding structures within catheters and other implant devices, it is possible to exploit the particular geometry of the catheter to amplify the effects of photofragmentation beyond those seen in bulk tissue. A Ho:YAG laser was used to photofragment occlusive material (tissue and tissue analogs) contained in glass capillary tubing and catheter tubing of the kind used in ventricular shunt implants for the management of hydrocephalus. Occluded catheters obtained from patient explants were also employed. Selection of operational parameters used in photoablation and photofragmentation of soft tissue must consider the physical composition and geometry of the treatment site. In the present case, containment of the soft tissue within relatively inelastic catheters dramatically alters the extent of photofragmentation relative to bulk (unconstrained) material. Our results indicate that the disruptive effect of cavitation bubbles is increased in catheters, due to the rapid displacement of material by cavitation bubbles comparable in size to the inner diameter of the catheter. The cylindrical geometry of the catheter lumen may additionally influence the propagation of acoustic shock waves that result from the collapse of the condensing cavitation bubbles.

Determination of shielding requirements for mammography.

PubMed

Okunade, Akintunde Akangbe; Ademoroti, Olalekan Albert

2004-05-01

Shielding requirements for mammography when considerations are to be given to attenuation by compression paddle, breast tissue, grid and image receptor (intervening materials) has been investigated. By matching of the attenuation and hardening properties, comparisons are made between shielding afforded by breast tissue materials (water, Lucite and 50%-50% adipose-glandular tissue) and some materials considered for shielding diagnostic x-ray beams, namely lead, steel and gypsum wallboard. Results show that significant differences exist between the thickness required to produce equal attenuation and that required to produce equal hardening of a given incident beam. While attenuation equivalent thickness produces equal exposure, it does not produce equal hardening. For shielding purposes, equivalence in exposure reduction without equivalence in penetrating power of an emerging beam does not amount to equivalence in shielding affordable by two different materials. Presented are models and results of sample calculations of additional shielding requirements apart from that provided by intervening materials. The shielding requirements for the integrated beam emerging from intervening materials are different from those for the integrated beam emerging from materials (lead/steel/gypsum wallboard) with attenuation equivalent thicknesses of these intervening materials.

A biphasic model for bleeding in soft tissue

NASA Astrophysics Data System (ADS)

Chang, Yi-Jui; Chong, Kwitae; Eldredge, Jeff D.; Teran, Joseph; Benharash, Peyman; Dutson, Erik

2017-11-01

The modeling of blood passing through soft tissues in the body is important for medical applications. The current study aims to capture the effect of tissue swelling and the transport of blood under bleeding or hemorrhaging conditions. The soft tissue is considered as a non-static poro-hyperelastic material with liquid-filled voids. A biphasic formulation effectively, a generalization of Darcy's law-is utilized, treating the phases as occupying fractions of the same volume. The interaction between phases is captured through a Stokes-like friction force on their relative velocities and a pressure that penalizes deviations from volume fractions summing to unity. The soft tissue is modeled as a hyperelastic material with a typical J-shaped stress-strain curve, while blood is considered as a Newtonian fluid. The method of Smoothed Particle Hydrodynamics is used to discretize the conservation equations based on the ease of treating free surfaces in the liquid. Simulations of swelling under acute hemorrhage and of draining under gravity and compression will be demonstrated. Ongoing progress in modeling of organ tissues under injuries and surgical conditions will be discussed.

Non-integer viscoelastic constitutive law to model soft biological tissues to in-vivo indentation.

PubMed

Demirci, Nagehan; Tönük, Ergin

2014-01-01

During the last decades, derivatives and integrals of non-integer orders are being more commonly used for the description of constitutive behavior of various viscoelastic materials including soft biological tissues. Compared to integer order constitutive relations, non-integer order viscoelastic material models of soft biological tissues are capable of capturing a wider range of viscoelastic behavior obtained from experiments. Although integer order models may yield comparably accurate results, non-integer order material models have less number of parameters to be identified in addition to description of an intermediate material that can monotonically and continuously be adjusted in between an ideal elastic solid and an ideal viscous fluid. In this work, starting with some preliminaries on non-integer (fractional) calculus, the "spring-pot", (intermediate mechanical element between a solid and a fluid), non-integer order three element (Zener) solid model, finally a user-defined large strain non-integer order viscoelastic constitutive model was constructed to be used in finite element simulations. Using the constitutive equation developed, by utilizing inverse finite element method and in vivo indentation experiments, soft tissue material identification was performed. The results indicate that material coefficients obtained from relaxation experiments, when optimized with creep experimental data could simulate relaxation, creep and cyclic loading and unloading experiments accurately. Non-integer calculus viscoelastic constitutive models, having physical interpretation and modeling experimental data accurately is a good alternative to classical phenomenological viscoelastic constitutive equations.

Soft network composite materials with deterministic and bio-inspired designs

PubMed Central

Jang, Kyung-In; Chung, Ha Uk; Xu, Sheng; Lee, Chi Hwan; Luan, Haiwen; Jeong, Jaewoong; Cheng, Huanyu; Kim, Gwang-Tae; Han, Sang Youn; Lee, Jung Woo; Kim, Jeonghyun; Cho, Moongee; Miao, Fuxing; Yang, Yiyuan; Jung, Han Na; Flavin, Matthew; Liu, Howard; Kong, Gil Woo; Yu, Ki Jun; Rhee, Sang Il; Chung, Jeahoon; Kim, Byunggik; Kwak, Jean Won; Yun, Myoung Hee; Kim, Jin Young; Song, Young Min; Paik, Ungyu; Zhang, Yihui; Huang, Yonggang; Rogers, John A.

2015-01-01

Hard and soft structural composites found in biology provide inspiration for the design of advanced synthetic materials. Many examples of bio-inspired hard materials can be found in the literature; far less attention has been devoted to soft systems. Here we introduce deterministic routes to low-modulus thin film materials with stress/strain responses that can be tailored precisely to match the non-linear properties of biological tissues, with application opportunities that range from soft biomedical devices to constructs for tissue engineering. The approach combines a low-modulus matrix with an open, stretchable network as a structural reinforcement that can yield classes of composites with a wide range of desired mechanical responses, including anisotropic, spatially heterogeneous, hierarchical and self-similar designs. Demonstrative application examples in thin, skin-mounted electrophysiological sensors with mechanics precisely matched to the human epidermis and in soft, hydrogel-based vehicles for triggered drug release suggest their broad potential uses in biomedical devices. PMID:25782446

Long-term follow-up on soft and hard tissue levels following guided bone regeneration treatment in combination with a xenogeneic filling material: a 5-year prospective clinical study.

PubMed

Dahlin, C; Simion, M; Hatano, N

2010-12-01

In the present prospective study, bone augmentation by guided bone regeneration (GBR) in combination with bovine hydroxyapatite (BHA) as filling material was evaluated with regard to soft and hard tissue stability over time. Implant survival, radiologic bone level (marginal bone level [MBL]), and clinical soft tissue parameters (marginal soft tissue level [MSTL]) were observed. Twenty patients received a total of 41 implants (Brånemark System, Nobel Biocare, Göteborg, Sweden) in conjunction with GBR treatment. The end point of the study was after 5 years following implant placement. The cumulative implant survival rate was 97.5% corresponding to one implant failure. The radiologic evaluation of the MBL demonstrated a crestal bone height above the level of the fixture head. The bone height decreased from -3.51 to -2.38 mm (p < .001). The MSTL was -1.52 mm at baseline and -1.15 mm at the 5-year follow-up (p < .04) demonstrating a stable submucosal crown margin throughout the study period. GBR treatment in combination with a xenogeneic filling material (BHA) is a viable treatment option in order to maintain stable hard and soft tissue levels in conjunction with augmentative procedure related to oral implant treatment. © 2009, Copyright the Authors. Journal Compilation © 2010, Wiley Periodicals, Inc.

Free flap reconstructions of tibial fractures complicated after internal fixation.

PubMed

Nieminen, H; Kuokkanen, H; Tukiainen, E; Asko-Seljavaara, S

1995-04-01

The cases of 15 patients are presented where microvascular soft-tissue reconstructions became necessary after internal fixation of tibial fractures. Primarily, seven of the fractures were closed. Eleven fractures had originally been treated by open reduction and internal fixation using plates and screws, and four by intramedullary nailing. All of the patients suffered from postoperative complications leading to exposure of the bone or fixation material. The internal fixation material was removed and radical revision of dead and infected tissue was carried out in all cases. Soft tissue reconstruction was performed using a free microvascular muscle flap (11 latissimus dorsi, three rectus abdominis, and one gracilis). In eight cases the nonunion of the fracture indicated external fixation. The microvascular reconstruction was successful in all 15 patients. In one case the recurrence of deep infection finally indicated a below-knee amputation. In another case, chronic infection with fistulation recurred postoperatively. After a mean follow-up of 26 months the soft tissue coverage was good in all the remaining 13 cases. All the fractures united. Microvascular free muscle flap reconstruction of the leg is regarded as a reliable method for salvaging legs with large soft-tissue defects or defects in the distal leg. If after internal fixation of the tibial fracture the osteosynthesis material or fracture is exposed, reconstruction of the soft-tissue can successfully be performed by free flap transfer. By radical revision, external fixation, bone grafting, and a free flap the healing of the fracture can be achieved.

Design of radial phononic crystal using annular soft material with low-frequency resonant elastic structures

NASA Astrophysics Data System (ADS)

Gao, Nansha; Wu, Jiu Hui; Yu, Lie; Xin, Hang

2016-10-01

Using FEM, we theoretically study the vibration properties of radial phononic crystal (RPC) with annular soft material. The band structures, transmission spectra, and displacement fields of eigenmode are given to estimate the starting and cut-off frequency of band gaps. Numerical calculation results show that RPC with annular soft material can yield low-frequency band gaps below 350 Hz. Annular soft material decreases equivalent stiffness of the whole structure effectively, and makes corresponding band gaps move to the lower frequency range. Physical mechanism behind band gaps is the coupling effect between long or traveling wave in plate matrix and the vibrations of corrugations. By changing geometrical dimensions of plate thickness e, the length of silicone rubber h2, and the corrugation width b, we can control the location and width of the first band gap. These research conclusions of RPC structure with annular soft material can potentially be applied to optimize band gaps, generate filters, and design acoustic devices.

Hyaluronic acid fillers with cohesive polydensified matrix for soft-tissue augmentation and rejuvenation: a literature review

PubMed Central

Prasetyo, Adri D; Prager, Welf; Rubin, Mark G; Moretti, Ernesto A; Nikolis, Andreas

2016-01-01

Background Cohesive monophasic polydensified fillers show unique viscoelastic properties and variable density of hyaluronic acid, allowing for a homogeneous tissue integration and distribution of the material. Objective The aim of this paper was to review the clinical data regarding the performance, tolerability, and safety of the Belotero® fillers for soft-tissue augmentation and rejuvenation. Methods A literature search was performed up until May 31, 2015 to identify all relevant articles on Belotero® fillers (Basic/Balance, Hydro, Soft, Intense, Volume) and equivalent products (Esthélis®, Mesolis®, Fortélis®, Modélis®). Results This comprehensive review included 26 papers. Findings from three randomized controlled trials showed a greater reduction in nasolabial fold severity with Belotero® Basic/Balance than with collagen (at 8, 12, 16, and 24 weeks, n=118) and Restylane® (at 4 weeks, n=40), and higher patient satisfaction with Belotero® Intense than with Perlane® (at 2 weeks, n=20). With Belotero® Basic/Balance, an improvement of at least 1 point on the severity scale can be expected in ~80% of patients 1–6 months after injection, with an effect still visible at 8–12 months. Positive findings were also reported with Belotero® Volume (no reduction in hyaluronic acid volume at 12 months, as demonstrated by magnetic resonance imaging), Soft (improvement in the esthetic outcomes when used in a sequential approach), and Hydro (improvement in skin appearance in all patients). The most common adverse effects were mild-to-moderate erythema, edema, and hematoma, most of which were temporary. There were no reports of Tyndall effect, nodules, granulomas, or tissue necrosis. Conclusion Clinical evidence indicates sustainable esthetic effects, good safety profile, and long-term tolerability of the Belotero® fillers, particularly Belotero® Basic/Balance and Intense. PMID:27660479

Multiaxial mechanical properties and constitutive modeling of human adipose tissue: a basis for preoperative simulations in plastic and reconstructive surgery.

PubMed

Sommer, Gerhard; Eder, Maximilian; Kovacs, Laszlo; Pathak, Heramb; Bonitz, Lars; Mueller, Christoph; Regitnig, Peter; Holzapfel, Gerhard A

2013-11-01

A preoperative simulation of soft tissue deformations during plastic and reconstructive surgery is desirable to support the surgeon's planning and to improve surgical outcomes. The current development of constitutive adipose tissue models, for the implementation in multilayer computational frameworks for the simulation of human soft tissue deformations, has proved difficult because knowledge of the required mechanical parameters of fat tissue is limited. Therefore, for the first time, human abdominal adipose tissues were mechanically investigated by biaxial tensile and triaxial shear tests. The results of this study suggest that human abdominal adipose tissues under quasi-static and dynamic multiaxial loadings can be characterized as a nonlinear, anisotropic and viscoelastic soft biological material. The nonlinear and anisotropic features are consequences of the material's collagenous microstructure. The aligned collagenous septa observed in histological investigations causes the anisotropy of the tissue. A hyperelastic model used in this study was appropriate to represent the quasi-static multiaxial mechanical behavior of fat tissue. The constitutive parameters are intended to serve as a basis for soft tissue simulations using the finite element method, which is an apparent method for obtaining promising results in the field of plastic and reconstructive surgery. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

High strain-rate soft material characterization via inertial cavitation

NASA Astrophysics Data System (ADS)

Estrada, Jonathan B.; Barajas, Carlos; Henann, David L.; Johnsen, Eric; Franck, Christian

2018-03-01

Mechanical characterization of soft materials at high strain-rates is challenging due to their high compliance, slow wave speeds, and non-linear viscoelasticity. Yet, knowledge of their material behavior is paramount across a spectrum of biological and engineering applications from minimizing tissue damage in ultrasound and laser surgeries to diagnosing and mitigating impact injuries. To address this significant experimental hurdle and the need to accurately measure the viscoelastic properties of soft materials at high strain-rates (103-108 s-1), we present a minimally invasive, local 3D microrheology technique based on inertial microcavitation. By combining high-speed time-lapse imaging with an appropriate theoretical cavitation framework, we demonstrate that this technique has the capability to accurately determine the general viscoelastic material properties of soft matter as compliant as a few kilopascals. Similar to commercial characterization algorithms, we provide the user with significant flexibility in evaluating several constitutive laws to determine the most appropriate physical model for the material under investigation. Given its straightforward implementation into most current microscopy setups, we anticipate that this technique can be easily adopted by anyone interested in characterizing soft material properties at high loading rates including hydrogels, tissues and various polymeric specimens.

SU-F-T-220: Validation of Hounsfield Unit-To-Stopping Power Ratio Calibration Used for Dose Calculation in Proton Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Polf, J; Chung, H; Langen, K

Purpose: To validate the stoichiometric calibration of the Hounsfield Unit (HU) to Stopping Power Ratio (SPR) calibration used to commission a commercial treatment planning system (TPS) for proton radiotherapy dose calculation. Methods and Materials: The water equivalent thickness (WET) of several individual pig tissues (lung, fat, muscle, liver, intestine, rib, femur), mixed tissue samples (muscle/rib, ice/femur, rib/air cavity/muscle), and an intact pig head were measured with a multi-layer ionization chamber (MLIC). A CT scan of each sample was obtained and imported into a commercial TPS. The WET calculated by the TPS for each tissue sample was compared to the measuredmore » WET value to determine the accuracy of the HU-to-SPR calibration curve used by the TPS to calculate dose. Results: The WET values calculated by the TPS showed good agreement (< 2.0%) with the measured values for bone and all soft tissues except fat (3.1% difference). For the mixed tissue samples and the intact pig head measurements, the difference in the TPS and measured WET values all agreed to within 3.5%. In addition, SPR values were calculated from the measured WET of each tissue, and compared to SPR values of reference tissues from ICRU 46 used to generate the HU-to-SPR calibration for the TPS. Conclusion: For clinical scenarios where the beam passes through multiple tissue types and its path is dominated by soft tissues, we believe using an uncertainty of 3.5% of the planned beam range is acceptable to account for uncertainties in the TPS WET determination.« less

Influence of Four Different Abutment Materials and the Adhesive Joint of Two-Piece Abutments on Cervical Implant Bone and Soft Tissue.

PubMed

Mehl, Christian; Gassling, Volker; Schultz-Langerhans, Stephan; Açil, Yahya; Bähr, Telse; Wiltfang, Jörg; Kern, Matthias

The main aim of this study was to evaluate the influence of four different abutment materials and the adhesive joint of two-piece abutments on the cervical implant bone and soft tissue. Sixty-four titanium implants (Camlog Conelog; 4.3 ± 9 mm) were placed bone level into the edentulous arches of four minipigs. Four different types of abutments were placed at implant exposure: zirconium dioxide, lithium disilicate, and titanium bonded to a titanium luting base with resin cement; one-piece titanium abutments served as the control. The animals were sacrificed 6 months after implant exposure, and the bone-to-implant contact (BIC) area, sulcus depth, the length of the junctional epithelium and the connective tissue, the biologic width, and first cervical BIC-implant shoulder distance were measured using histomorphometry and light and fluorescence microscopy. Overall, 14 implants were lost (22%). At exposure, the implant shoulder-bone distance was 0.6 ± 0.7 mm. Six months later, the bone loss was 2.1 ± 1.2 mm measured histomorphometrically. There was a significant difference between the two measurements (P ≤ .0001). No significant influence could be found between any of the abutment materials with regard to bone loss or soft tissue anatomy (P > .05), with the exception of zirconium dioxide and onepiece titanium abutments when measuring the length of the junctional epithelium (P ≤ .01). The maxilla provided significantly more soft tissue and less bone loss compared with the mandible (P ≤ .02). All tested abutment materials and techniques seem to be comparable with regard to soft tissue properties and the cervical bone level.

Direct microCT imaging of non-mineralized connective tissues at high resolution.

PubMed

Naveh, Gili R S; Brumfeld, Vlad; Dean, Mason; Shahar, Ron; Weiner, Steve

2014-01-01

The 3D imaging of soft tissues in their native state is challenging, especially when high resolution is required. An X-ray-based microCT is, to date, the best choice for high resolution 3D imaging of soft tissues. However, since X-ray attenuation of soft tissues is very low, contrasting enhancement using different staining materials is needed. The staining procedure, which also usually involves tissue fixation, causes unwanted and to some extent unknown tissue alterations. Here, we demonstrate that a method that enables 3D imaging of soft tissues without fixing and staining using an X-ray-based bench-top microCT can be applied to a variety of different tissues. With the sample mounted in a custom-made loading device inside a humidity chamber, we obtained soft tissue contrast and generated 3D images of fresh, soft tissues with a resolution of 1 micron voxel size. We identified three critical conditions which make it possible to image soft tissues: humidified environment, mechanical stabilization of the sample and phase enhancement. We demonstrate the capability of the technique using different specimens: an intervertebral disc, the non-mineralized growth plate, stingray tessellated radials (calcified cartilage) and the collagenous network of the periodontal ligament. Since the scanned specimen is fresh an interesting advantage of this technique is the ability to scan a specimen under load and track the changes of the different structures. This method offers a unique opportunity for obtaining valuable insights into 3D structure-function relationships of soft tissues.

Theoretical and experimental characterization of novel water-equivalent plastics in clinical high-energy carbon-ion beams.

PubMed

Lourenço, A; Wellock, N; Thomas, R; Homer, M; Bouchard, H; Kanai, T; MacDougall, N; Royle, G; Palmans, H

2016-11-07

Water-equivalent plastics are frequently used in dosimetry for experimental simplicity. This work evaluates the water-equivalence of novel water-equivalent plastics specifically designed for light-ion beams, as well as commercially available plastics in a clinical high-energy carbon-ion beam. A plastic- to-water conversion factor [Formula: see text] was established to derive absorbed dose to water in a water phantom from ionization chamber readings performed in a plastic phantom. Three trial plastic materials with varying atomic compositions were produced and experimentally characterized in a high-energy carbon-ion beam. Measurements were performed with a Roos ionization chamber, using a broad un-modulated beam of 11  ×  11 cm 2 , to measure the plastic-to-water conversion factor for the novel materials. The experimental results were compared with Monte Carlo simulations. Commercially available plastics were also simulated for comparison with the plastics tested experimentally, with particular attention to the influence of nuclear interaction cross sections. The measured [Formula: see text] correction increased gradually from 0% at the surface to 0.7% at a depth near the Bragg peak for one of the plastics prepared in this work, while for the other two plastics a maximum correction of 0.8%-1.3% was found. Average differences between experimental and numerical simulations were 0.2%. Monte Carlo results showed that for polyethylene, polystyrene, Rando phantom soft tissue and A-150, the correction increased from 0% to 2.5%-4.0% with depth, while for PMMA it increased to 2%. Water-equivalent plastics such as, Plastic Water, RMI-457, Gammex 457-CTG, WT1 and Virtual Water, gave similar results where maximum corrections were of the order of 2%. Considering the results from Monte Carlo simulations, one of the novel plastics was found to be superior in comparison with the plastic materials currently used in dosimetry, demonstrating that it is feasible to tailor plastic materials to be water-equivalent for carbon ions specifically.

Prevalence of Soft Tissue Calcifications in CBCT Images of Mandibular Region

PubMed Central

Khojastepour, Leila; Haghnegahdar, Abdolaziz; Sayar, Hamed

2017-01-01

Statement of the Problem: Most of the soft tissue calcifications within the head and neck region might not be accompanied by clinical symptoms but may indicate some pathological conditions. Purpose: The aim of this research was to determine the prevalence of soft tissue calcifications in cone beam computed tomography (CBCT) images of mandibular region. Materials and Method: In this cross sectional study the CBCT images of 602 patients including 294 men and 308 women with mean age 41.38±15.18 years were evaluated regarding the presence, anatomical location; type (single or multiple) and size of soft tissue calcification in mandibular region. All CBCT images were acquired by NewTom VGi scanner. Odds ratio and chi-square tests were used for data analysis and p< 0.05 was considered to be statistically significant. Results: 156 out of 602 patients had at least one soft tissue calcification in their mandibular region (25.9%. of studied population with mean age 51.7±18.03 years). Men showed significantly higher rate of soft tissue calcification than women (30.3% vs. 21.8%). Soft tissue calcification was predominantly seen at posterior region of the mandible (88%) and most of them were single (60.7%). The prevalence of soft tissue calcification increased with age. Most of the detected soft tissue calcifications were smaller than 3mm (90%). Conclusion: Soft tissue calcifications in mandibular area were a relatively common finding especially in posterior region and more likely to happen in men and in older age group. PMID:28620632

Estimation of identification limit for a small-type OSL dosimeter on the medical images by measurement of X-ray spectra.

PubMed

Takegami, Kazuki; Hayashi, Hiroaki; Okino, Hiroki; Kimoto, Natsumi; Maehata, Itsumi; Kanazawa, Yuki; Okazaki, Tohru; Hashizume, Takuya; Kobayashi, Ikuo

2016-07-01

Our aim in this study is to derive an identification limit on a dosimeter for not disturbing a medical image when patients wear a small-type optically stimulated luminescence (OSL) dosimeter on their bodies during X-ray diagnostic imaging. For evaluation of the detection limit based on an analysis of X-ray spectra, we propose a new quantitative identification method. We performed experiments for which we used diagnostic X-ray equipment, a soft-tissue-equivalent phantom (1-20 cm), and a CdTe X-ray spectrometer assuming one pixel of the X-ray imaging detector. Then, with the following two experimental settings, corresponding X-ray spectra were measured with 40-120 kVp and 0.5-1000 mAs at a source-to-detector distance of 100 cm: (1) X-rays penetrating a soft-tissue-equivalent phantom with the OSL dosimeter attached directly on the phantom, and (2) X-rays penetrating only the soft-tissue-equivalent phantom. Next, the energy fluence and errors in the fluence were calculated from the spectra. When the energy fluence with errors concerning these two experimental conditions was estimated to be indistinctive, we defined the condition as the OSL dosimeter not being identified on the X-ray image. Based on our analysis, we determined the identification limit of the dosimeter. We then compared our results with those for the general irradiation conditions used in clinics. We found that the OSL dosimeter could not be identified under the irradiation conditions of abdominal and chest radiography, namely, one can apply the OSL dosimeter to measurement of the exposure dose in the irradiation field of X-rays without disturbing medical images.

Development of dopant-free conductive bioelastomers

PubMed Central

Xu, Cancan; Huang, Yihui; Yepez, Gerardo; Wei, Zi; Liu, Fuqiang; Bugarin, Alejandro; Tang, Liping; Hong, Yi

2016-01-01

Conductive biodegradable materials are of great interest for various biomedical applications, such as tissue repair and bioelectronics. They generally consist of multiple components, including biodegradable polymer/non-degradable conductive polymer/dopant, biodegradable conductive polymer/dopant or biodegradable polymer/non-degradable inorganic additives. The dopants or additives induce material instability that can be complex and possibly toxic. Material softness and elasticity are also highly expected for soft tissue repair and soft electronics. To address these concerns, we designed a unicomponent dopant-free conductive polyurethane elastomer (DCPU) by chemically linking biodegradable segments, conductive segments, and dopant molecules into one polymer chain. The DCPU films which had robust mechanical properties with high elasticity and conductivity can be degraded enzymatically and by hydrolysis. It exhibited great electrical stability in physiological environment with charge. Mouse 3T3 fibroblasts survived and proliferated on these films exhibiting good cytocompatibility. Polymer degradation products were non-toxic. DCPU could also be processed into a porous scaffold and in an in vivo subcutaneous implantation model, exhibited good tissue compatibility with extensive cell infiltration over 2 weeks. Such biodegradable DCPU with good flexibility and elasticity, processability, and electrical stability may find broad applications for tissue repair and soft/stretchable/wearable bioelectronics. PMID:27686216

Standardization of Code on Dental Procedures

DTIC Science & Technology

1992-02-13

oral hard and soft tissues using a periodontal probe, mirror, and explorer, and bitewing, panoramic, or other radiographs as...of living tissue or inert material into periodontal osseous defects to regenerate new periodontal attachment (bone, periodontal ligament, and cementum...Simple (up to 5 cm). Repair and/or suturing of simple to moderately complicated wounds of facial and/or oral soft tissues . 7211 1.8 Repair

Controlled molecular self-assembly of complex three-dimensional structures in soft materials

PubMed Central

Huang, Changjin; Quinn, David; Suresh, Subra

2018-01-01

Many applications in tissue engineering, flexible electronics, and soft robotics call for approaches that are capable of producing complex 3D architectures in soft materials. Here we present a method using molecular self-assembly to generate hydrogel-based 3D architectures that resembles the appealing features of the bottom-up process in morphogenesis of living tissues. Our strategy effectively utilizes the three essential components dictating living tissue morphogenesis to produce complex 3D architectures: modulation of local chemistry, material transport, and mechanics, which can be engineered by controlling the local distribution of polymerization inhibitor (i.e., oxygen), diffusion of monomers/cross-linkers through the porous structures of cross-linked polymer network, and mechanical constraints, respectively. We show that oxygen plays a role in hydrogel polymerization which is mechanistically similar to the role of growth factors in tissue growth, and the continued growth of hydrogel enabled by diffusion of monomers/cross-linkers into the porous hydrogel similar to the mechanisms of tissue growth enabled by material transport. The capability and versatility of our strategy are demonstrated through biomimetics of tissue morphogenesis for both plants and animals, and its application to generate other complex 3D architectures. Our technique opens avenues to studying many growth phenomena found in nature and generating complex 3D structures to benefit diverse applications. PMID:29255037

The use of platelet-rich fibrin as a hemostatic material in oral soft tissues.

PubMed

de Almeida Barros Mourão, Carlos Fernando; Calasans-Maia, Mônica Diuana; de Mello Machado, Rafael Coutinho; de Brito Resende, Rodrigo Figueiredo; Alves, Gutemberg Gomes

2018-06-26

The control of postoperative bleeding represents one of the main intercurrent events associated with soft tissue surgical procedures in the oral cavity. In this context, platelet-rich fibrin (PRF) membranes are materials with great potential for optimizing soft tissue healing and induction of hemostasis. This interventional case series describes the treatment of 10 patients with excisional biopsy of benign oral cavity lesions, following a screening sequence at the surgery clinic of a Brazilian dental school between the years of 2015 and 2017. After treatment with PRF, patients presented mean time for postoperative hemostasis of 10.3 ± 2.5 s, requiring the average use of three membranes to cover the surgical area. The results suggest that the use of platelet-rich fibrin membranes may represent a feasible alternative hemostatic material for the treatment of oral lesions.

Changes of the peri-implant soft tissue thickness after grafting with a collagen matrix

PubMed Central

Zafiropoulos, Gregory-George; Deli, Giorgio; Hoffmann, Oliver; John, Gordon

2016-01-01

Background: The aim of this study was to determine the treatment outcome of the use of a porcine monolayer collagen matrix (mCM) to increase soft-tissue volume as a part of implant site development. Materials and Methods: Implants were placed in single sites in 27 patients. In the test group, mCM was used for soft-tissue augmentation. No graft was placed in the control group. Soft-tissue thickness (STTh) was measured at the time of surgery (T0) and 6 months postoperatively (T1) at two sites (STTh 1, 1 mm below the gingival margin; STTh 2, 3 mm below the mucogingival margin). Results: Significant increases (P < 0.001) in STTh (STTh 1 = 1.06 mm, 117%; STTh 2 = 0.89 mm, 81%) were observed in the test group. Biopsy results showed angiogenesis and mature connective tissue covered by keratinized epithelium. Conclusions: Within the limitations of this study, it could be concluded that mCM leads to a significant increase of peri-implant soft-tissue thickness, with good histological integration and replacement by soft tissue and may serve as an alternative to connective tissue grafting. PMID:28298828

Accuracy of three-dimensional soft tissue prediction for Le Fort I osteotomy using Dolphin 3D software: a pilot study.

PubMed

Resnick, C M; Dang, R R; Glick, S J; Padwa, B L

2017-03-01

Three-dimensional (3D) soft tissue prediction is replacing two-dimensional analysis in planning for orthognathic surgery. The accuracy of different computational models to predict soft tissue changes in 3D, however, is unclear. A retrospective pilot study was implemented to assess the accuracy of Dolphin 3D software in making these predictions. Seven patients who had a single-segment Le Fort I osteotomy and had preoperative (T 0 ) and >6-month postoperative (T 1 ) cone beam computed tomography (CBCT) scans and 3D photographs were included. The actual skeletal change was determined by subtracting the T 0 from the T 1 CBCT. 3D photographs were overlaid onto the T 0 CBCT and virtual skeletal movements equivalent to the achieved repositioning were applied using Dolphin 3D planner. A 3D soft tissue prediction (T P ) was generated and differences between the T P and T 1 images (error) were measured at 14 points and at the nasolabial angle. A mean linear prediction error of 2.91±2.16mm was found. The mean error at the nasolabial angle was 8.1±5.6°. In conclusion, the ability to accurately predict 3D soft tissue changes after Le Fort I osteotomy using Dolphin 3D software is limited. Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Effects of selected materials and geometries on the beta dose equivalent rate in a tissue equivalent phantom immersed in infinite clouds of 133Xe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Piltingsrud, H.V.; Gels, G.L.

1986-06-01

Most calculations of dose equivalent (D.E.) rates at 70-micron tissue depths in tissue equivalent (T.E.) phantoms from infinite clouds (radius exceeds maximum beta range in air) of /sup 133/Xe do not consider the possible effects of clothing overlays. Consequently, a series of measurements were made using a 1-mm-thick plastic scintillation detector assembly mounted in a tissue equivalent (T.E.) phantom with an overlay of 70 micron of T.E. material. This assembly was placed in an infinite cloud containing a known concentration of /sup 133/Xe. Material samples were placed at selected distances from the detector phantom, both individually and in various combinations.more » Pulse-height spectra resulting from beta radiations were converted to relative D.E. rates at a 70-micron tissue depth. The relative D.E. rates were reduced from values with no clothing cover by as little as 45% when placing a single thin nylon cloth 1 cm from the phantom, to 94% for a T-shirt material plus wool material plus denim placed 1/2, 1 and 3 cm, respectively, from the phantom. The results indicate that even loosely fitting clothing can have an important effect on reducing the D.E. rate. Close-fitting clothing appears to provide better protection.« less

Miniature soft robots — road to the clinic

NASA Astrophysics Data System (ADS)

Sitti, Metin

2018-06-01

Soft small robots offer the opportunity to non-invasively access human tissue to perform medical operations and deliver drugs; however, challenges in materials design, biocompatibility and function control remain to be overcome for soft robots to reach the clinic.

Application of laser scanning confocal microscopy in the soft tissue exquisite structure for 3D scan

PubMed Central

Zhang, Zhaoqiang; Ibrahim, Mohamed; Fu, Yang; Wu, Xujia; Ren, Fei; Chen, Lei

2018-01-01

Three-dimensional (3D) printing is a new developing technology for printing individualized materials swiftly and precisely in the field of biological medicine (especially tissue-engineered materials). Prior to printing, it is necessary to scan the structure of the natural biological tissue, then construct the 3D printing digital model through optimizing the scanned data. By searching the literatures, magazines at home and abroad, this article reviewed the current status, main processes and matters needing attention of confocal laser scanning microscope (LSCM) in the application of soft tissue fine structure 3D scanning, empathizing the significance of LSCM in this field. PMID:29755838

Sci-Thur AM: YIS – 07: Optimizing dual-energy x-ray parameters using a single filter for both high and low-energy images to enhance soft-tissue imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bowman, Wesley; Sattarivand, Mike

Objective: To optimize dual-energy parameters of ExacTrac stereoscopic x-ray imaging system for lung SBRT patients Methods: Simulated spectra and a lung phantom were used to optimize filter material, thickness, kVps, and weighting factors to obtain bone subtracted dual-energy images. Spektr simulations were used to identify material in the atomic number (Z) range [3–83] based on a metric defined to separate spectrums of high and low energies. Both energies used the same filter due to time constraints of image acquisition in lung SBRT imaging. A lung phantom containing bone, soft tissue, and a tumor mimicking material was imaged with filter thicknessesmore » range [0–1] mm and kVp range [60–140]. A cost function based on contrast-to-noise-ratio of bone, soft tissue, and tumor, as well as image noise content, was defined to optimize filter thickness and kVp. Using the optimized parameters, dual-energy images of anthropomorphic Rando phantom were acquired and evaluated for bone subtraction. Imaging dose was measured with dual-energy technique using tin filtering. Results: Tin was the material of choice providing the best energy separation, non-toxicity, and non-reactiveness. The best soft-tissue-only image in the lung phantom was obtained using 0.3 mm tin and [140, 80] kVp pair. Dual-energy images of the Rando phantom had noticeable bone elimination when compared to no filtration. Dose was lower with tin filtering compared to no filtration. Conclusions: Dual-energy soft-tissue imaging is feasible using ExacTrac stereoscopic imaging system utilizing a single tin filter for both high and low energies and optimized acquisition parameters.« less

Intrasocket reactive soft tissue for primary closure after augmentation of extraction sites with severe bone loss before implant placement.

PubMed

Mardinger, Ofer; Chaushu, Gavriel; Ghelfan, Oded; Nissan, Joseph

2009-06-01

The normal bone resorption after tooth extraction can be significantly aggravated in the case of pre-existing severe bone loss and chronic infection. Bone augmentation procedures have been proposed, but they require adequate closure of soft tissues. We propose the use of intrasocket reactive tissue to cover extraction sites augmented by bovine bone mineral graft to promote the success of the graft procedure. The study included 24 patients with severe bone loss and chronic pathology in 27 sites. The intrasocket reactive soft tissue was elevated from the bony walls in a subperiosteal plane. Porous bovine or allograft bone mineral was placed in the extraction site without membranes, and the intrasocket reactive soft tissue was sutured over the grafting material to seal the coronal portion of the socket. Twenty-seven implants were placed 6 months after bone augmentation. Healing progressed uneventfully. Postoperative morbidity was minimal. There was no leakage or infection of the grafting material. The mean time to implant placement was 7.8 months. Supplemental augmentation was not needed. There were no implant failures. Follow-up ranged from 6 to 36 months (mean, 15 months). All implants were rehabilitated with fixed prostheses. Intrasocket reactive soft tissue can be used predictably to obtain primary closure of augmented extraction sites with severe bone loss with minimal postoperative morbidity.

Biological effectiveness of nuclear fragments produced by high-energy protons interacting in tissues near the bone- soft tissue interface

NASA Astrophysics Data System (ADS)

Shavers, Mark Randall

1999-12-01

High-energy protons in the galactic cosmic rays (GCR)-or generated by nuclear interactions of GCR heavy-ions with material-are capable of penetrating great thicknesses of shielding to irradiate humans in spacecraft or in lunar or Martian habitats. As protons interact with the nuclei of the elemental constituents of soft tissue and bone, low energy nuclei-target fragments-are emitted into the cells responsible for bone development and maintenance and for hematopoiesis. Leukemogenesis is the principal endpoint of concern because it is the most likely deleterious effect, and it has a short latency period and comparatively low survival rate, although other myelo- proliferative disorders and osteosarcoma also may be induced. A one-dimensional proton-target fragment transport model was used to calculate the energy spectra of fragments produced in bone and soft tissue, and present in marrow cavities at distances from a bone interface. In terms of dose equivalent, the target fragments are as significant as the incident protons. An average radiation quality factor was found to be between 1.8 and 2.6. Biological response to the highly non- uniform energy deposition of the target fragments is such that an alternative approach to conventional predictive risk assessment is needed. Alternative procedures are presented. In vitro cell response and relative biological effectiveness were calculated from the radial dose distribution of each fragment produced by 1-GeV protons using parameters of a modified Ion-Gamma- Kill (IGK) model of radiation action. The modelled endpoints were survival of C3H10t 1/2 and V79 cells, neoplastic transformation of C3H10t1/2 cells, and mutation of the X-linked hypoxanthine phosphoribosyltransferase (HPRT) locus in V79 cells. The dose equivalent and cell responses increased by 10% or less near the interface. Since RBE increases with decreasing dose in the IGK model, comparisons with quality factors were made at dose levels 0.01 <= D [Gy] <= 2. Applying average quality factors derived herein to GCR exposures results in a <= 5% increase of in average quality. Calculated RBEs indicate that accepted quality factors for high-energy protons may be too low due to the relatively high effectiveness of the low-charged target fragments. Derived RBEs for target fragments increase the calculated biological effectiveness of GCR by 20% to 180%.

Fatigue Damage of Collagenous Tissues: Experiment, Modeling and Simulation Studies

PubMed Central

Martin, Caitlin; Sun, Wei

2017-01-01

Mechanical fatigue damage is a critical issue for soft tissues and tissue-derived materials, particularly for musculoskeletal and cardiovascular applications; yet, our understanding of the fatigue damage process is incomplete. Soft tissue fatigue experiments are often difficult and time-consuming to perform, which has hindered progress in this area. However, the recent development of soft-tissue fatigue-damage constitutive models has enabled simulation-based fatigue analyses of tissues under various conditions. Computational simulations facilitate highly controlled and quantitative analyses to study the distinct effects of various loading conditions and design features on tissue durability; thus, they are advantageous over complex fatigue experiments. Although significant work to calibrate the constitutive models from fatigue experiments and to validate predictability remains, further development in these areas will add to our knowledge of soft-tissue fatigue damage and will facilitate the design of durable treatments and devices. In this review, the experimental, modeling, and simulation efforts to study collagenous tissue fatigue damage are summarized and critically assessed. PMID:25955007

Calculation of Dose, Dose Equivalent, and Relative Biological Effectiveness for High Charge and Energy Ion Beams

NASA Technical Reports Server (NTRS)

Wilson, J. W.; Reginatto, M.; Hajnal, F.; Chun, S. Y.

1995-01-01

The Green's function for the transport of ions of high charge and energy is utilized with a nuclear fragmentation database to evaluate dose, dose equivalent, and RBE for C3H1OT1/2 cell survival and neoplastic transformation as a function of depth in soft tissue. Such evaluations are useful to estimates of biological risk for high altitude aircraft, space operations, accelerator operations, and biomedical applications.

Calculation of dose, dose equivalent, and relative biological effectiveness for high charge and energy ion beams

NASA Technical Reports Server (NTRS)

Wilson, J. W.; Chun, S. Y.; Reginatto, M.; Hajnal, F.

1995-01-01

The Green's function for the transport of ions of high charge and energy is utilized with a nuclear fragmentation database to evaluate dose, dose equivalent, and RBE for C3H10T1/2 cell survival and neo-plastic transformation as function of depth in soft tissue. Such evaluations are useful to estimates of biological risk for high altitude aircraft, space operations, accelerator operations, and biomedical application.

On the importance of 3D, geometrically accurate, and subject-specific finite element analysis for evaluation of in-vivo soft tissue loads.

PubMed

Moerman, Kevin M; van Vijven, Marc; Solis, Leandro R; van Haaften, Eline E; Loenen, Arjan C Y; Mushahwar, Vivian K; Oomens, Cees W J

2017-04-01

Pressure ulcers are a type of local soft tissue injury due to sustained mechanical loading and remain a common issue in patient care. People with spinal cord injury (SCI) are especially at risk of pressure ulcers due to impaired mobility and sensory perception. The development of load improving support structures relies on realistic tissue load evaluation e.g. using finite element analysis (FEA). FEA requires realistic subject-specific mechanical properties and geometries. This study focuses on the effect of geometry. MRI is used for the creation of geometrically accurate models of the human buttock for three able-bodied volunteers and three volunteers with SCI. The effect of geometry on observed internal tissue deformations for each subject is studied by comparing FEA findings for equivalent loading conditions. The large variations found between subjects confirms the importance of subject-specific FEA.

Esthetic soft tissue management for teeth and implants.

PubMed

Fu, Jia-Hui; Su, Chuan-Yi; Wang, Hom-Lay

2012-09-01

Can newly introduced graft materials be successfully used in soft tissue augmentation around teeth and dental implants? An electronic search on the PubMed database for English articles published before March 31, 2012, was performed using the following key words: "root coverage," "soft tissue graft," "periodontal plastic surgery," "subepithelial connective graft (SCTG)," "acellular dermal matrix (ADM)," "guided tissue regeneration based root coverage (GTRC)," "recession defects," "mucogingival defects," "collagen matrix," "living cellular construct (LCC)," "mucograft," and "biologic agents." Literature featuring new soft tissue graft materials, such as ADM, collagen matrix, GTRC, and biologic agents, were included. Data showed (1) allogeneic grafts were comparable to SCTG in terms of mean complete root coverage (CRC), mean root coverage (RC), and mean amount of keratinized tissue (KT) gain; (2) xenogeneic collagen matrix was as comparable to SCTG in terms of mean amount of KT gain around teeth and dental implants but inferior in achieving RC; (3) GTRC was inferior to SCTG in terms of mean CRC and mean RC; (4) LCC was inferior to free gingival graft in terms of mean amount of KT gain but was superior in esthetics and patient satisfaction; and (5) adjunctive use of biologic agents did not exert a significant effect on mean CRC, mean RC, and mean amount of KT gain. Although these new materials do not surpass the gold standard (SCTG), they do provide improved patient satisfaction and esthetics, are available in abundance, and lead to reduced postoperative discomfort and surgical time. Copyright © 2012 Elsevier Inc. All rights reserved.

Biomedical applications of soft robotics

NASA Astrophysics Data System (ADS)

Cianchetti, Matteo; Laschi, Cecilia; Menciassi, Arianna; Dario, Paolo

2018-06-01

Soft robotics enables the design of soft machines and devices at different scales. The compliance and mechanical properties of soft robots make them especially interesting for medical applications. Depending on the level of interaction with humans, different levels of biocompatibility and biomimicry are required for soft materials used in robots. In this Review, we investigate soft robots for biomedical applications, including soft tools for surgery, diagnosis and drug delivery, wearable and assistive devices, prostheses, artificial organs and tissue-mimicking active simulators for training and biomechanical studies. We highlight challenges regarding durability and reliability, and examine traditional and novel soft and active materials as well as different actuation strategies. Finally, we discuss future approaches and applications in the field.

Development of a dosimeter for distributed body organs

NASA Technical Reports Server (NTRS)

Khandelwal, G. S.

1976-01-01

Calculational methods for estimation of dose from external proton exposure of aribtrary convex bodies is briefly reviewed and all of the necessary information for the estimation of dose in soft tissue is presented. Special emphasis is on retaining the effects of nuclear reaction especially in relation to the dose equivalent.

TAKING THE LONG VIEW TOWARDS THE LONG WAR. Equipping General Purpose Force Leaders with Soft Power Tools for Irregular Warfare

DTIC Science & Technology

2009-02-12

equivalent to usual printing or typescript . Can read either representations of familiar formulaic verbal exchanges or simple language containing only...read simple, authentic written material in a form equivalent to usual printing or typescript on subjects within a familiar context. Able to read with

Controlled molecular self-assembly of complex three-dimensional structures in soft materials.

PubMed

Huang, Changjin; Quinn, David; Suresh, Subra; Hsia, K Jimmy

2018-01-02

Many applications in tissue engineering, flexible electronics, and soft robotics call for approaches that are capable of producing complex 3D architectures in soft materials. Here we present a method using molecular self-assembly to generate hydrogel-based 3D architectures that resembles the appealing features of the bottom-up process in morphogenesis of living tissues. Our strategy effectively utilizes the three essential components dictating living tissue morphogenesis to produce complex 3D architectures: modulation of local chemistry, material transport, and mechanics, which can be engineered by controlling the local distribution of polymerization inhibitor (i.e., oxygen), diffusion of monomers/cross-linkers through the porous structures of cross-linked polymer network, and mechanical constraints, respectively. We show that oxygen plays a role in hydrogel polymerization which is mechanistically similar to the role of growth factors in tissue growth, and the continued growth of hydrogel enabled by diffusion of monomers/cross-linkers into the porous hydrogel similar to the mechanisms of tissue growth enabled by material transport. The capability and versatility of our strategy are demonstrated through biomimetics of tissue morphogenesis for both plants and animals, and its application to generate other complex 3D architectures. Our technique opens avenues to studying many growth phenomena found in nature and generating complex 3D structures to benefit diverse applications. Copyright © 2017 the Author(s). Published by PNAS.

Histomorphometrical analysis following augmentation of infected extraction sites exhibiting severe bone loss and primarily closed by intrasocket reactive soft tissue.

PubMed

Mardinger, Ofer; Vered, Marilena; Chaushu, Gavriel; Nissan, Joseph

2012-06-01

Intrasocket reactive soft tissue can be used for primary closure during augmentation of infected extraction sites exhibiting severe bone loss prior to implant placement. The present study evaluated the histological characteristics of the initially used intrasocket reactive soft tissue, the overlying soft tissue, and the histomorphometry of the newly formed bone during implant placement. Thirty-six consecutive patients (43 sites) were included in the study. Extraction sites demonstrating extensive bone loss on preoperative periapical and panoramic radiographs served as inclusion criteria. Forty-three implants were inserted after a healing period of 6 months. Porous bovine xenograft bone mineral was used as a single bone substitute. The intrasocket reactive soft tissue was sutured over the grafting material to seal the coronal portion of the socket. Biopsies of the intrasocket reactive soft tissue at augmentation, healed mucosa, and bone cores at implant placement were retrieved and evaluated. The intrasocket reactive soft tissue demonstrated features compatible with granulation tissue and long junctional epithelium. The mucosal samples at implant placement demonstrated histopathological characteristics of keratinized mucosa with no residual elements of granulation tissue. Histomorphometrically, the mean composition of the bone cores was - vital bone 40 ± 19% (13.7-74.8%); bone substitute 25.7 ± 13% (0.6-51%); connective tissue 34.3 ± 15% (13.8-71.9%). Intrasocket reactive soft tissue used for primary closure following ridge augmentation is composed of granulation tissue and long junctional epithelium. At implant placement, clinical and histological results demonstrate its replacement by keratinized gingiva. The histomorphometrical results reveal considerable bone formation. Fresh extraction sites of hopeless teeth demonstrating chronic infection and severe bone loss may be grafted simultaneously with their removal. © 2010 Wiley Periodicals, Inc.

Photoactivated Composite Biomaterial for Soft Tissue Restoration in Rodents and in Humans

PubMed Central

Nahas, Zayna; Reid, Branden; Coburn, Jeannine M.; Axelman, Joyce; Chae, Jemin J.; Guo, Qiongyu; Trow, Robert; Thomas, Andrew; Hou, Zhipeng; Lichtsteiner, Serge; Sutton, Damon; Matheson, Christine; Walker, Patricia; David, Nathaniel; Mori, Susumu; Taube, Janis M.; Elisseeff, Jennifer H.

2015-01-01

Soft tissue reconstruction often requires multiple surgical procedures that can result in scars and disfiguration. Facial soft tissue reconstruction represents a clinical challenge because even subtle deformities can severely affect an individual’s social and psychological function. We therefore developed a biosynthetic soft tissue replacement composed of poly(ethylene glycol) (PEG) and hyaluronic acid (HA) that can be injected and photocrosslinked in situ with transdermal light exposure. Modulating the ratio of synthetic to biological polymer allowed us to tune implant elasticity and volume persistence. In a small-animal model, implanted photocrosslinked PEG-HA showed a dose-dependent relationship between increasing PEG concentration and enhanced implant volume persistence. In direct comparison with commercial HA injections, the PEG-HA implants maintained significantly greater average volumes and heights. Reversibility of the implant volume was achieved with hyaluronidase injection. Pilot clinical testing in human patients confirmed the feasibility of the transdermal photocrosslinking approach for implantation in abdomen soft tissue, although an inflammatory response was observed surrounding some of the materials. PMID:21795587

Spot-scanning proton therapy for malignant soft tissue tumors in childhood: First experiences at the Paul Scherrer Institute

DOE Office of Scientific and Technical Information (OSTI.GOV)

Timmermann, Beate; Schuck, Andreas; Niggli, Felix

2007-02-01

Purpose: Radiotherapy plays a major role in the treatment strategy of childhood sarcomas. Consequences of treatment are likely to affect the survivor's quality of life significantly. We investigated the feasibility of spot-scanning proton therapy (PT) for soft tissue tumors in childhood. Methods and Materials: Sixteen children with soft tissue sarcomas were included. Median age at PT was 3.3 years. In 10 children the tumor histology was embryonal rhabdomyosarcoma. All tumors were located in the head or neck, parameningeal, or paraspinal, or pelvic region. In the majority of children, the tumor was initially unresectable (Intergroup Rhabdomyosarcoma Study [IRS] Group III inmore » 75%). In 50% of children the tumors exceeded 5 cm. Fourteen children had chemotherapy before and during PT. Median total dose of radiotherapy was 50 cobalt Gray equivalent (CGE). All 16 children were treated with spot-scanning proton therapy at the Paul Scherrer Institute, and in 3 children the PT was intensity-modulated (IMPT). Results: After median follow-up of 1.5 years, local control was achieved in 12 children. Four children failed locally, 1 at the border of the radiation field and 3 within the field. All 4 children died of tumor recurrence. All 4 showed unfavorable characteristic either of site or histopathology of the tumor. Acute toxicity was low, with Grade 3 or 4 side effects according to Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer (RTOG/EORTC) criteria occurring in the bone marrow only. Conclusions: Proton therapy was feasible and well tolerated. Early local control rates are comparable to those being achieved after conventional radiotherapy. For investigations on late effect, longer follow-up is needed.« less

Multi-scale modelling of rubber-like materials and soft tissues: an appraisal

PubMed Central

Puglisi, G.

2016-01-01

We survey, in a partial way, multi-scale approaches for the modelling of rubber-like and soft tissues and compare them with classical macroscopic phenomenological models. Our aim is to show how it is possible to obtain practical mathematical models for the mechanical behaviour of these materials incorporating mesoscopic (network scale) information. Multi-scale approaches are crucial for the theoretical comprehension and prediction of the complex mechanical response of these materials. Moreover, such models are fundamental in the perspective of the design, through manipulation at the micro- and nano-scales, of new polymeric and bioinspired materials with exceptional macroscopic properties. PMID:27118927

Bioglass® 45S5-based composites for bone tissue engineering and functional applications.

PubMed

Rizwan, M; Hamdi, M; Basirun, W J

2017-11-01

Bioglass® 45S5 (BG) has an outstanding ability to bond with bones and soft tissues, but its application as a load-bearing scaffold material is restricted due to its inherent brittleness. BG-based composites combine the amazing biological and bioactive characteristics of BG with structural and functional features of other materials. This article reviews the composites of Bioglass ® in combination with metals, ceramics and polymers for a wide range of potential applications from bone scaffolds to nerve regeneration. Bioglass ® also possesses angiogenic and antibacterial properties in addition to its very high bioactivity; hence, composite materials developed for these applications are also discussed. BG-based composites with polymer matrices have been developed for a wide variety of soft tissue engineering. This review focuses on the research that suggests the suitability of BG-based composites as a scaffold material for hard and soft tissues engineering. Composite production techniques have a direct influence on the bioactivity and mechanical behavior of scaffolds. A detailed discussion of the bioactivity, in vitro and in vivo biocompatibility and biodegradation is presented as a function of materials and its processing techniques. Finally, an outlook for future research is also proposed. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3197-3223, 2017. © 2017 Wiley Periodicals, Inc.

Estimation of the viscous properties of skin and subcutaneous tissue in uniaxial stress relaxation tests.

PubMed

Wu, John Z; Cutlip, Robert G; Welcome, Daniel; Dong, Ren G

2006-01-01

Knowledge of viscoelastic properties of soft tissues is essential for the finite element modelling of the stress/strain distributions in finger-pad during vibratory loading, which is important in exploring the mechanism of hand-arm vibration syndrome. In conventional procedures, skin and subcutaneous tissue have to be separated for testing the viscoelastic properties. In this study, a novel method has been proposed to simultaneously determine the viscoelastic properties of skin and subcutaneous tissue in uniaxial stress relaxation tests. A mathematical approach has been derived to obtain the creep and relaxation characteristics of skin and subcutaneous tissue using uniaxial stress relaxation data of skin/subcutaneous composite specimens. The micro-structures of collagen fiber networks in the soft tissue, which underline the tissue mechanical characteristics, will be intact in the proposed method. Therefore, the viscoelastic properties of soft tissues obtained using the proposed method would be more physiologically relevant than those obtained using the conventional method. The proposed approach has been utilized to measure the viscoelastic properties of soft tissues of pig. The relaxation curves of pig skin and subcutaneous tissue obtained in the current study agree well with those in literature. Using the proposed approach, reliable material properties of soft tissues can be obtained in a cost- and time-efficient manner, which simultaneously improves the physiological relevance.

Use of methylnaltrexone to induce laxation in acutely injured patients with burns and necrotizing soft-tissue infections.

PubMed

Hewitt, Kelly; Lin, Hsin; Faraklas, Iris; Morris, Stephen; Cochran, Amalia; Saffle, Jeffrey

2014-01-01

The routine use of high-dose opioids for analgesia in patients with acute burns and soft-tissue injuries often leads to the development of opioid-induced constipation. The opioid antagonist methylnaltrexone (MLTX) reverses narcotic-related ileus without affecting systemic pain treatment. The authors' burn center developed a bowel protocol that included administration of MLTX for relief of opioid-induced constipation after other methods failed. The authors performed a retrospective review of patients with acute burns or necrotizing soft-tissue infections, who had been given subcutaneous MLTX to induce laxation. All patients who received MLTX were included and all administrations of the drug were included in the analysis. The primary outcome examined was time to laxation from drug administration. Forty-eight patients received MLTX a total of 112 times. Six patients were admitted with soft-tissue injuries and the rest suffered burns with an average TBSA of 17%. The median patient age was 41 years and the majority (75%) were men. Administration of a single dose of MLTX resulted in laxation within 4 hours in 38% of cases, and within 24 hours in 68%. Patients given MLTX received an average of 174 mg morphine equivalents daily for pain control. MLTX was given after an average of 52 hours since the last bowel movement. As this experience has evolved, it has been incorporated into an organized bowel protocol, which includes MLTX administration after other laxatives have failed. MLTX is an effective laxation agent in patients with burn and soft-tissue injuries, who have failed conventional agents.

Checklist and Scoring System for the Assessment of Soft Tissue Preservation in CT Examinations of Human Mummies.

PubMed

Panzer, Stephanie; Mc Coy, Mark R; Hitzl, Wolfgang; Piombino-Mascali, Dario; Jankauskas, Rimantas; Zink, Albert R; Augat, Peter

2015-01-01

The purpose of this study was to develop a checklist for standardized assessment of soft tissue preservation in human mummies based on whole-body computed tomography examinations, and to add a scoring system to facilitate quantitative comparison of mummies. Computed tomography examinations of 23 mummies from the Capuchin Catacombs of Palermo, Sicily (17 adults, 6 children; 17 anthropogenically and 6 naturally mummified) and 7 mummies from the crypt of the Dominican Church of the Holy Spirit of Vilnius, Lithuania (5 adults, 2 children; all naturally mummified) were used to develop the checklist following previously published guidelines. The scoring system was developed by assigning equal scores for checkpoints with equivalent quality. The checklist was evaluated by intra- and inter-observer reliability. The finalized checklist was applied to compare the groups of anthropogenically and naturally mummified bodies. The finalized checklist contains 97 checkpoints and was divided into two main categories, "A. Soft Tissues of Head and Musculoskeletal System" and "B. Organs and Organ Systems", each including various subcategories. The complete checklist had an intra-observer reliability of 98% and an inter-observer reliability of 93%. Statistical comparison revealed significantly higher values in anthropogenically compared to naturally mummified bodies for the total score and for three subcategories. In conclusion, the developed checklist allows for a standardized assessment and documentation of soft tissue preservation in whole-body computed tomography examinations of human mummies. The scoring system facilitates a quantitative comparison of the soft tissue preservation status between single mummies or mummy collections.

Common Soft Tissue Musculoskeletal Pain Disorders.

PubMed

Hubbard, Matthew J; Hildebrand, Bernard A; Battafarano, Monica M; Battafarano, Daniel F

2018-06-01

Soft tissue musculoskeletal pain disorders are common in the primary care setting. Early recognition and diagnosis of these syndromes minimizes patient pain and disability. This article gives a brief overview of the most common soft tissue musculoskeletal pain syndromes. The authors used a regional approach to organize the material, as providers will encounter these syndromes with complaints of pain referring to an anatomic location. The covered disorders include myofascial pain syndrome, rotator cuff tendinopathy, bicipital tendinopathy, subacromial bursitis, olecranon bursitis, epicondylitis, De Quervain disease, trigger finger, trochanteric bursitis, knee bursitis, pes anserine bursitis, Baker cyst, plantar fasciitis, and Achilles tendinopathy. Published by Elsevier Inc.

Evaluation of sample holders designed for long-lasting X-ray micro-tomographic scans of ex-vivo soft tissue samples

NASA Astrophysics Data System (ADS)

Dudak, J.; Zemlicka, J.; Krejci, F.; Karch, J.; Patzelt, M.; Zach, P.; Sykora, V.; Mrzilkova, J.

2016-03-01

X-ray microradiography and microtomography are imaging techniques with increasing applicability in the field of biomedical and preclinical research. Application of hybrid pixel detector Timepix enables to obtain very high contrast of low attenuating materials such as soft biological tissue. However X-ray imaging of ex-vivo soft tissue samples is a difficult task due to its structural instability. Ex-vivo biological tissue is prone to fast drying-out which is connected with undesired changes of sample size and shape producing later on artefacts within the tomographic reconstruction. In this work we present the optimization of our Timepix equipped micro-CT system aiming to maintain soft tissue sample in stable condition. Thanks to the suggested approach higher contrast of tomographic reconstructions can be achieved while also large samples that require detector scanning can be easily measured.

New Platforms for Characterization of Biological Material Failure and Resilience Properties

NASA Astrophysics Data System (ADS)

Brown, Katherine; Butler, Benjamin J.; Nguyen, Thuy-Tien N.; Sorry, David; Williams, Alun; Proud, William G.

2017-06-01

Obtaining information about the material responses of viscoelastic soft matter, such as polymers and foams has, required adaptation of techniques traditionally used with hard condensed matter. More recently it has been recognized that understanding the strain-rate behavior of natural and synthetic soft biological materials poses even greater challenges for materials research due their heterogeneous composition and structural complexity. Expanding fundamental knowledge about how these classes of biomaterials function under different loading regimes is of considerable interest in both fundamental and applied research. A comparative overview of methods, developed in our laboratory or elsewhere, for determining material responses of cells and soft tissues over a wide range of strain rates (quasi-static to blast loading) will be presented. Examples will illustrate how data are obtained for studying material responses of cells and tissues. Strengths and weaknesses of current approaches will be discussed, with particular emphasis on challenges associated with the development of realistic experimental and computational models for trauma and other disease indications.

Optical characterization of tissue mimicking phantoms by a vertical double integrating sphere system

NASA Astrophysics Data System (ADS)

Han, Yilin; Jia, Qiumin; Shen, Shuwei; Liu, Guangli; Guo, Yuwei; Zhou, Ximing; Chu, Jiaru; Zhao, Gang; Dong, Erbao; Allen, David W.; Lemaillet, Paul; Xu, Ronald

2016-03-01

Accurate characterization of absorption and scattering properties for biologic tissue and tissue-simulating materials enables 3D printing of traceable tissue-simulating phantoms for medical spectral device calibration and standardized medical optical imaging. Conventional double integrating sphere systems have several limitations and are suboptimal for optical characterization of liquid and soft materials used in 3D printing. We propose a vertical double integrating sphere system and the associated reconstruction algorithms for optical characterization of phantom materials that simulate different human tissue components. The system characterizes absorption and scattering properties of liquid and solid phantom materials in an operating wavelength range from 400 nm to 1100 nm. Absorption and scattering properties of the phantoms are adjusted by adding titanium dioxide powder and India ink, respectively. Different material compositions are added in the phantoms and characterized by the vertical double integrating sphere system in order to simulate the human tissue properties. Our test results suggest that the vertical integrating sphere system is able to characterize optical properties of tissue-simulating phantoms without precipitation effect of the liquid samples or wrinkling effect of the soft phantoms during the optical measurement.

Soft tissue grafting to improve implant esthetics

PubMed Central

Kassab, Moawia M

2010-01-01

Dental implants are becoming the treatment of choice to replace missing teeth, especially if the adjacent teeth are free of restorations. When minimal bone width is present, implant placement becomes a challenge and often resulting in recession and dehiscence around the implant that leads to subsequent gingival recession. To correct such defect, the author turned to soft tissue autografting and allografting to correct a buccal dehiscence around tooth #24 after a malpositioned implant placed by a different surgeon. A 25-year-old woman presented with the chief complaint of gingival recession and exposure of implant threads around tooth #24. The patient received three soft tissue grafting procedures to augment the gingival tissue. The first surgery included a connective tissue graft to increase the width of the keratinized gingival tissue. The second surgery included the use of autografting (connective tissue graft) to coronally position the soft tissue and achieve implant coverage. The third and final surgery included the use of allografting material Alloderm to increase and mask the implant from showing through the gingiva. Healing period was uneventful for the patient. After three surgical procedures, it appears that soft tissue grafting has increased the width and height of the gingiva surrounding the implant. The accomplished thickness of gingival tissue appeared to mask the showing of implant threads through the gingival tissue and allowed for achieving the desired esthetic that the patient desired. The aim of the study is to present a clinical case with soft tissue grafting procedures. PMID:23662087

Real-time, haptics-enabled simulator for probing ex vivo liver tissue.

PubMed

Lister, Kevin; Gao, Zhan; Desai, Jaydev P

2009-01-01

The advent of complex surgical procedures has driven the need for realistic surgical training simulators. Comprehensive simulators that provide realistic visual and haptic feedback during surgical tasks are required to familiarize surgeons with the procedures they are to perform. Complex organ geometry inherent to biological tissues and intricate material properties drive the need for finite element methods to assure accurate tissue displacement and force calculations. Advances in real-time finite element methods have not reached the state where they are applicable to soft tissue surgical simulation. Therefore a real-time, haptics-enabled simulator for probing of soft tissue has been developed which utilizes preprocessed finite element data (derived from accurate constitutive model of the soft-tissue obtained from carefully collected experimental data) to accurately replicate the probing task in real-time.

SU-E-T-353: Verification of Water Equivalent Thickness (WET) and Water Equivalent Spreadness (WES) of Proton Beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Demez, N; Lee, T; Keppel, Cynthia

Purpose: To verify calculated water equivalent thickness (WET) and water equivalent spreadness (WES) in various tissue equivalent media for proton therapy Methods: Water equivalent thicknesses (WET) of tissue equivalent materials have been calculated using the Bragg-Kleeman rule. Lateral spreadness and fluence reduction of proton beams both in those media were calculated using proton loss model (PLM) algorithm. In addition, we calculated lateral spreadness ratios with respect to that in water at the same WET depth and so the WES was defined. The WETs of those media for different proton beam energies were measured using MLIC (Multi-Layered Ionization Chamber). Also, fluencemore » and field sizes in those materials of various thicknesses were measured with ionization chambers and films Results: Calculated WETs are in agreement with measured WETs within 0.5%. We found that water equivalent spreadness (WES) is constant and the fluence and field size measurements verify that fluence can be estimated using the concept of WES. Conclusions: Calculation of WET based on the Bragg-Kleeman rule as well as the constant WES of proton beams for tissue equivalent phantoms can be used to predict fluence and field sizes at the depths of interest both in tissue equivalent media accurately for clinically available protonenergies.« less

A randomized comparative prospective study of platelet-rich plasma, platelet-rich fibrin, and hydroxyapatite as a graft material for mandibular third molar extraction socket healing

PubMed Central

Dutta, Shubha Ranjan; Passi, Deepak; Singh, Purnima; Sharma, Sarang; Singh, Mahinder; Srivastava, Dhirendra

2016-01-01

Aim: The purpose of this study was to compare the efficacy of platelet-rich plasma (PRP), platelet-rich fibrin (PRF), and hydroxyapatite (HA) for reduction of pain and swelling, absence of dry socket, soft tissue healing, and bone regeneration after mandibular third molar extraction in human patients. Materials and Methods: Forty patients requiring extraction of mandibular third molars were randomly grouped as control, PRP, PRF, and HA-treated. The patients were assessed for postoperative pain, swelling, dry socket, and soft tissue healing on the 3rd, 7th, and 14th day of postoperative periods depending on the standard methods. Radiological assessment of the extraction site was done at 1, 2, and 6 months interval to compare the change in bone density in the sockets in control and treated patients. Results: Pain and swelling were less on PRP and PRF site when compared to HA and control site. PRP and PRF site showed better soft tissue healing when compared to HA and control site. Radiographic assessment showed comparatively lesser bone density values in PRP, PRF, and control site at 1, 2, and 6 months than HA site. Conclusion: Our study showed that PRP and PRF are better graft materials than HA regarding pain, swelling, dry socket, and soft tissue healing. Bone regeneration is induced promptly by HA as compared to other graft materials. However, a more elaborate study with a larger number of clinical cases is very much essential to be more conclusive regarding the efficacy of the graft materials. PMID:28163478

Incorporation of a Theranostic "Two-Tone" Luminescent Silver Complex into Biocompatible Agar Hydrogel Composite for the Eradication of ESKAPE Pathogens in a Skin and Soft Tissue Infection Model.

PubMed

Pinto, Miguel N; Martinez-Gonzalez, Jorge; Chakraborty, Indranil; Mascharak, Pradip K

2018-06-04

Microbial invasion and colonization of the skin and underlying soft tissues are among the most common types of infections, becoming increasingly prevalent in hospital settings. Systemic antibiotic chemotherapies are now extremely limited due to emergence of drug-resistant Gram-positive and multidrug-resistant Gram-negative bacterial strains. Topical administration of antimicrobials provides an effective route for the treatment of skin and soft tissue infections (SSTIs). Therefore, the development of new and effective materials for the delivery of these agents is of paramount importance. Silver is a broad-spectrum antibiotic used for the treatment and prevention of infections since ancient times. However, the high reactivity of silver cation (Ag + ) makes its incorporation into delivery materials quite challenging. Herein we report a novel soft agar hydrogel composite for the delivery of Ag + into infected wound sites. This material incorporates a Ag(I) complex [Ag 2 (DSX) 2 (NO 3 ) 2 ] (1; DSX = 5-(dimethylamino)- N, N-bis(pyridin-2-ylmethyl) naphthalene-1-sulfonamide) that exhibits a change in fluorescence upon Ag + release and qualitatively indicates the end point of silver delivery. The antibacterial efficacy of the material was tested against several bacterial strains in an SSTI model. The complex 1-agar composite proved effective at eradicating the pathogens responsible for the majority of SSTIs. The theranostic (therapeutic/diagnostic) properties coupled with its stability, softness, ease of application, and removal make this material an attractive silver-delivery vehicle for the treatment and prevention of SSTIs.

Elastomeric and soft conducting microwires for implantable neural interfaces

PubMed Central

Kolarcik, Christi L.; Luebben, Silvia D.; Sapp, Shawn A.; Hanner, Jenna; Snyder, Noah; Kozai, Takashi D.Y.; Chang, Emily; Nabity, James A.; Nabity, Shawn T.; Lagenaur, Carl F.; Cui, X. Tracy

2015-01-01

Current designs for microelectrodes used for interfacing with the nervous system elicit a characteristic inflammatory response that leads to scar tissue encapsulation, electrical insulation of the electrode from the tissue and ultimately failure. Traditionally, relatively stiff materials like tungsten and silicon are employed which have mechanical properties several orders of magnitude different from neural tissue. This mechanical mismatch is thought to be a major cause of chronic inflammation and degeneration around the device. In an effort to minimize the disparity between neural interface devices and the brain, novel soft electrodes consisting of elastomers and intrinsically conducting polymers were fabricated. The physical, mechanical and electrochemical properties of these materials were extensively characterized to identify the formulations with the optimal combination of parameters including Young’s modulus, elongation at break, ultimate tensile strength, conductivity, impedance and surface charge injection. Our final electrode has a Young’s modulus of 974 kPa which is five orders of magnitude lower than tungsten and significantly lower than other polymer-based neural electrode materials. In vitro cell culture experiments demonstrated the favorable interaction between these soft materials and neurons, astrocytes and microglia, with higher neuronal attachment and a two-fold reduction in inflammatory microglia attachment on soft devices compared to stiff controls. Surface immobilization of neuronal adhesion proteins on these microwires further improved the cellular response. Finally, in vivo electrophysiology demonstrated the functionality of the elastomeric electrodes in recording single unit activity in the rodent visual cortex. The results presented provide initial evidence in support of the use of soft materials in neural interface applications. PMID:25993261

Checklist and Scoring System for the Assessment of Soft Tissue Preservation in CT Examinations of Human Mummies: Application to the Tyrolean Iceman.

PubMed

Panzer, Stephanie; Pernter, Patrizia; Piombino-Mascali, Dario; Jankauskas, Rimantas; Zesch, Stephanie; Rosendahl, Wilfried; Hotz, Gerhard; Zink, Albert R

2017-12-01

Purpose  Soft tissues make a skeleton into a mummy and they allow for a diagnosis beyond osteology. Following the approach of structured reporting in clinical radiology, a recently developed checklist was used to evaluate the soft tissue preservation status of the Tyrolean Iceman using computed tomography (CT). The purpose of this study was to apply the "Checklist and Scoring System for the Assessment of Soft Tissue Preservation in CT Examinations of Human Mummies" to the Tyrolean Iceman, and to compare the Iceman's soft tissue preservation score to the scores calculated for other mummies. Materials and Methods  A whole-body (CT) (SOMATOM Definition Flash, Siemens, Forchheim, Germany) consisting of five scans, performed in January 2013 in the Department of Radiodiagnostics, Central Hospital, Bolzano, was used (slice thickness 0.6 mm; kilovolt ranging from 80 to 140). For standardized evaluation the "CT Checklist and Scoring System for the Assessment of Soft Tissue Preservation in Human Mummies" was used. Results  All checkpoints under category "A. Soft Tissues of Head and Musculoskeletal System" and more than half in category "B. Organs and Organ Systems" were observed. The scoring system accounted for a total score of 153 (out of 200). The comparison of the scores between the Iceman and three mummy collections from Vilnius, Lithuania, and Palermo, Sicily, as well as one Egyptian mummy resulted in overall higher soft tissue preservation scores for the Iceman. Conclusion  Application of the checklist allowed for standardized assessment and documentation of the Iceman's soft tissue preservation status. The scoring system allowed for a quantitative comparison between the Iceman and other mummies. The Iceman showed remarkable soft tissue preservation. Key Points   · The approach of structured reporting can be transferred to paleoradiology.. · The checklist allowed for standardized soft tissue assessment and documentation.. · The scoring system facilitated a quantitative comparison among mummies.. · Based on CT, the Tyrolean Iceman demonstrated remarkable soft tissue preservation.. Citation Format · Panzer S, Pernter P, Piombino-Mascali D et al. Checklist and Scoring System for the Assessment of Soft Tissue Preservation in CT Examinations of Human Mummies: Application to the Tyrolean Iceman. Fortschr Röntgenstr 2017; 189: 1152 - 1160. © Georg Thieme Verlag KG Stuttgart · New York.

Effects of heat transfer and energy absorption in the ablation of biological tissues by pulsetrain-burst (>100 MHz) ultrafast laser processing

NASA Astrophysics Data System (ADS)

Forrester, Paul; Bol, Kieran; Lilge, Lothar; Marjoribanks, Robin

2006-09-01

Energy absorption and heat transfer are important factors for regulating the effects of ablation of biological tissues. Heat transfer to surrounding material may be desirable when ablating hard tissue, such as teeth or bone, since melting can produce helpful material modifications. However, when ablating soft tissue it is important to minimize heat transfer to avoid damage to healthy tissue - for example, in eye refractive surgery (e.g., Lasik), nanosecond pulses produce gross absorption and heating in tissue, leading to shockwaves, which kill and thin the non-replicating epithelial cells on the inside of the cornea; ultrafast pulses are recognized to reduce this effect. Using a laser system that delivers 1ps pulses in 10μs pulsetrains at 133MHz we have studied a range of heat- and energy-transfer effects on hard and soft tissue. We describe the ablation of tooth dentin and enamel under various conditions to determine the ablation rate and chemical changes that occur. Furthermore, we characterize the impact of pulsetrain-burst treatment of collagen-based tissue to determine more efficient methods of energy transfer to soft tissues. By studying the optical science of laser tissue interaction we hope to be able to make qualitative improvements to medical treatments using lasers.

The effect of zirconia or titanium as abutment material on soft peri-implant tissues: a systematic review and meta-analysis.

PubMed

Linkevicius, Tomas; Vaitelis, Julius

2015-09-01

The objective of this review was to analyze research with regard to the effect of zirconia or titanium as abutment material on soft peri-implant tissues. Clinical studies were selected via electronic and hand searches in English language journals until December 1, 2014. Only randomized clinical trials (RCTs) and prospective controlled clinical trials (CCTs) showing direct comparison between zirconia (Zr) and titanium (Ti) abutments in the same patient were considered. The outcome measures were (1) soft tissue color, (2) soft tissue recession, (3) peri-implant probing, (4) bleeding on probing, (5) esthetic indexes, (6) patient-reported outcome, (7) marginal bone level, and (8) biological complications. Nine relevant studies (11 papers) were identified: 4 RCTs and 5 CCTs. Due to heterogeneity in the study design, statistical methods, and reported results, a meta-analysis of the data was feasible only for soft tissue color. The outcome was found to be significantly superior for Zr abutments. For the other outcome measures, a qualitative analysis of the selected articles was performed. The studies did not show any statistically significant differences between Zr and Ti abutments on soft tissue recession, probing depths, bleeding on probing, marginal bone level, and patient-reported outcome. One study reported significantly higher pink esthetic score (PES) scores at Zr implants with Zr abutments, compared to metal implants and Ti abutments. Overall, the research does not support any obvious advantage of Ti or Zr abutments over each other. However, there is a significant tendency in Zr abutments evoking better color response of peri-implant mucosa and superior esthetic outcome measured by PES score. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Optimizing dual-energy x-ray parameters for the ExacTrac clinical stereoscopic imaging system to enhance soft-tissue imaging.

PubMed

Bowman, Wesley A; Robar, James L; Sattarivand, Mike

2017-03-01

Stereoscopic x-ray image guided radiotherapy for lung tumors is often hindered by bone overlap and limited soft-tissue contrast. This study aims to evaluate the feasibility of dual-energy imaging techniques and to optimize parameters of the ExacTrac stereoscopic imaging system to enhance soft-tissue imaging for application to lung stereotactic body radiation therapy. Simulated spectra and a physical lung phantom were used to optimize filter material, thickness, tube potentials, and weighting factors to obtain bone subtracted dual-energy images. Spektr simulations were used to identify material in the atomic number range (3-83) based on a metric defined to separate spectra of high and low-energies. Both energies used the same filter due to time constraints of imaging in the presence of respiratory motion. The lung phantom contained bone, soft tissue, and tumor mimicking materials, and it was imaged with a filter thickness in the range of (0-0.7) mm and a kVp range of (60-80) for low energy and (120,140) for high energy. Optimal dual-energy weighting factors were obtained when the bone to soft-tissue contrast-to-noise ratio (CNR) was minimized. Optimal filter thickness and tube potential were achieved by maximizing tumor-to-background CNR. Using the optimized parameters, dual-energy images of an anthropomorphic Rando phantom with a spherical tumor mimicking material inserted in his lung were acquired and evaluated for bone subtraction and tumor contrast. Imaging dose was measured using the dual-energy technique with and without beam filtration and matched to that of a clinical conventional single energy technique. Tin was the material of choice for beam filtering providing the best energy separation, non-toxicity, and non-reactiveness. The best soft-tissue-weighted image in the lung phantom was obtained using 0.2 mm tin and (140, 60) kVp pair. Dual-energy images of the Rando phantom with the tin filter had noticeable improvement in bone elimination, tumor contrast, and noise content when compared to dual-energy imaging with no filtration. The surface dose was 0.52 mGy per each stereoscopic view for both clinical single energy technique and the dual-energy technique in both cases of with and without the tin filter. Dual-energy soft-tissue imaging is feasible without additional imaging dose using the ExacTrac stereoscopic imaging system with optimized acquisition parameters and no beam filtration. Addition of a single tin filter for both the high and low energies has noticeable improvements on dual-energy imaging with optimized parameters. Clinical implementation of a dual-energy technique on ExacTrac stereoscopic imaging could improve lung tumor visibility. © 2017 American Association of Physicists in Medicine.

Soft tissue fillers for adipose tissue regeneration: From hydrogel development toward clinical applications.

PubMed

Van Nieuwenhove, I; Tytgat, L; Ryx, M; Blondeel, P; Stillaert, F; Thienpont, H; Ottevaere, H; Dubruel, P; Van Vlierberghe, S

2017-11-01

There is a clear and urgent clinical need to develop soft tissue fillers that outperform the materials currently used for adipose tissue reconstruction. Recently, extensive research has been performed within this field of adipose tissue engineering as the commercially available products and the currently existing techniques are concomitant with several disadvantages. Commercial products are highly expensive and associated with an imposing need for repeated injections. Lipofilling or free fat transfer has an unpredictable outcome with respect to cell survival and potential resorption of the fat grafts. Therefore, researchers are predominantly investigating two challenging adipose tissue engineering strategies: in situ injectable materials and porous 3D printed scaffolds. The present work provides an overview of current research encompassing synthetic, biopolymer-based and extracellular matrix-derived materials with a clear focus on emerging fabrication technologies and developments realized throughout the last decade. Moreover, clinical relevance of the most promising materials will be discussed, together with potential concerns associated with their application in the clinic. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Reliability and validity of quantifying absolute muscle hardness using ultrasound elastography.

PubMed

Chino, Kentaro; Akagi, Ryota; Dohi, Michiko; Fukashiro, Senshi; Takahashi, Hideyuki

2012-01-01

Muscle hardness is a mechanical property that represents transverse muscle stiffness. A quantitative method that uses ultrasound elastography for quantifying absolute human muscle hardness has been previously devised; however, its reliability and validity have not been completely verified. This study aimed to verify the reliability and validity of this quantitative method. The Young's moduli of seven tissue-mimicking materials (in vitro; Young's modulus range, 20-80 kPa; increments of 10 kPa) and the human medial gastrocnemius muscle (in vivo) were quantified using ultrasound elastography. On the basis of the strain/Young's modulus ratio of two reference materials, one hard and one soft (Young's moduli of 7 and 30 kPa, respectively), the Young's moduli of the tissue-mimicking materials and medial gastrocnemius muscle were calculated. The intra- and inter-investigator reliability of the method was confirmed on the basis of acceptably low coefficient of variations (≤6.9%) and substantially high intraclass correlation coefficients (≥0.77) obtained from all measurements. The correlation coefficient between the Young's moduli of the tissue-mimicking materials obtained using a mechanical method and ultrasound elastography was 0.996, which was equivalent to values previously obtained using magnetic resonance elastography. The Young's moduli of the medial gastrocnemius muscle obtained using ultrasound elastography were within the range of values previously obtained using magnetic resonance elastography. The reliability and validity of the quantitative method for measuring absolute muscle hardness using ultrasound elastography were thus verified.

Reliability and Validity of Quantifying Absolute Muscle Hardness Using Ultrasound Elastography

PubMed Central

Chino, Kentaro; Akagi, Ryota; Dohi, Michiko; Fukashiro, Senshi; Takahashi, Hideyuki

2012-01-01

Muscle hardness is a mechanical property that represents transverse muscle stiffness. A quantitative method that uses ultrasound elastography for quantifying absolute human muscle hardness has been previously devised; however, its reliability and validity have not been completely verified. This study aimed to verify the reliability and validity of this quantitative method. The Young’s moduli of seven tissue-mimicking materials (in vitro; Young’s modulus range, 20–80 kPa; increments of 10 kPa) and the human medial gastrocnemius muscle (in vivo) were quantified using ultrasound elastography. On the basis of the strain/Young’s modulus ratio of two reference materials, one hard and one soft (Young’s moduli of 7 and 30 kPa, respectively), the Young’s moduli of the tissue-mimicking materials and medial gastrocnemius muscle were calculated. The intra- and inter-investigator reliability of the method was confirmed on the basis of acceptably low coefficient of variations (≤6.9%) and substantially high intraclass correlation coefficients (≥0.77) obtained from all measurements. The correlation coefficient between the Young’s moduli of the tissue-mimicking materials obtained using a mechanical method and ultrasound elastography was 0.996, which was equivalent to values previously obtained using magnetic resonance elastography. The Young’s moduli of the medial gastrocnemius muscle obtained using ultrasound elastography were within the range of values previously obtained using magnetic resonance elastography. The reliability and validity of the quantitative method for measuring absolute muscle hardness using ultrasound elastography were thus verified. PMID:23029231

A novel bioprinting method and system for forming hybrid tissue engineering constructs.

PubMed

Shanjani, Y; Pan, C C; Elomaa, L; Yang, Y

2015-12-18

Three dimensional (3D) bioprinting is a promising approach to form tissue engineering constructs (TECs) via positioning biomaterials, growth factors, and cells with controlled spatial distribution due to its layer-by-layer manufacturing nature. Hybrid TECs composed of relatively rigid porous scaffolds for structural and mechanical integrity and soft hydrogels for cell- and growth factor-loading have a tremendous potential to tissue regeneration under mechanical loading. However, despite excessive progress in the field, the current 3D bioprinting techniques and systems fall short in integration of such soft and rigid multifunctional components. Here we present a novel 3D hybrid bioprinting technology (Hybprinter) and its capability enabling integration of soft and rigid components for TECs. Hybprinter employs digital light processing-based stereolithography (DLP-SLA) and molten material extrusion techniques for soft and rigid materials, respectively. In this study, poly-ethylene glycol diacrylate (PEGDA) and poly-(ε-caprolactone) (PCL) were used as a model material for soft hydrogel and rigid scaffold, respectively. It was shown that geometrical accuracy, swelling ratio and mechanical properties of the hydrogel component can be tailored by DLP-SLA module. We have demonstrated the printability of variety of complex hybrid construct designs using Hybprinter technology and characterized the mechanical properties and functionality of such constructs. The compressive mechanical stiffness of a hybrid construct (90% hydrogel) was significantly higher than hydrogel itself (∼6 MPa versus 100 kPa). In addition, viability of cells incorporated within the bioprinted hybrid constructs was determined approximately 90%. Furthermore, a functionality of a hybrid construct composed of porous scaffold with an embedded hydrogel conduit was characterized for vascularized tissue engineering applications. High material diffusion and high cell viability in about 2.5 mm distance surrounding the conduit indicated that culture media effectively diffused through the conduit and fed the cells. The results suggest that the developed technology is potent to form functional TECs composed of rigid and soft biomaterials.

On the Use of Machine Learning Techniques for the Mechanical Characterization of Soft Biological Tissues.

PubMed

Cilla, M; Pérez-Rey, I; Martínez, M A; Peña, Estefania; Martínez, Javier

2018-06-23

Motivated by the search for new strategies for fitting a material model, a new approach is explored in the present work. The use of numerical and complex algorithms based on machine learning techniques such as support vector machines for regression, bagged decision trees and artificial neural networks is proposed for solving the parameter identification of constitutive laws for soft biological tissues. First, the mathematical tools were trained with analytical uniaxial data (circumferential and longitudinal directions) as inputs, and their corresponding material parameters of the Gasser, Ogden and Holzapfel strain energy function as outputs. The train and test errors show great efficiency during the training process in finding correlations between inputs and outputs; besides, the correlation coefficients were very close to 1. Second, the tool was validated with unseen observations of analytical circumferential and longitudinal uniaxial data. The results show an excellent agreement between the prediction of the material parameters of the SEF and the analytical curves. Finally, data from real circumferential and longitudinal uniaxial tests on different cardiovascular tissues were fitted, thus the material model of these tissues was predicted. We found that the method was able to consistently identify model parameters, and we believe that the use of these numerical tools could lead to an improvement in the characterization of soft biological tissues. This article is protected by copyright. All rights reserved.

Dynamic impact indentation of hydrated biological tissues and tissue surrogate gels

NASA Astrophysics Data System (ADS)

Ilke Kalcioglu, Z.; Qu, Meng; Strawhecker, Kenneth E.; Shazly, Tarek; Edelman, Elazer; VanLandingham, Mark R.; Smith, James F.; Van Vliet, Krystyn J.

2011-03-01

For both materials engineering research and applied biomedicine, a growing need exists to quantify mechanical behaviour of tissues under defined hydration and loading conditions. In particular, characterisation under dynamic contact-loading conditions can enable quantitative predictions of deformation due to high rate 'impact' events typical of industrial accidents and ballistic insults. The impact indentation responses were examined of both hydrated tissues and candidate tissue surrogate materials. The goals of this work were to determine the mechanical response of fully hydrated soft tissues under defined dynamic loading conditions, and to identify design principles by which synthetic, air-stable polymers could mimic those responses. Soft tissues from two organs (liver and heart), a commercially available tissue surrogate gel (Perma-Gel™) and three styrenic block copolymer gels were investigated. Impact indentation enabled quantification of resistance to penetration and energy dissipative constants under the rates and energy densities of interest for tissue surrogate applications. These analyses indicated that the energy dissipation capacity under dynamic impact increased with increasing diblock concentration in the styrenic gels. Under the impact rates employed (2 mm/s to 20 mm/s, corresponding to approximate strain energy densities from 0.4 kJ/m3 to 20 kJ/m3), the energy dissipation capacities of fully hydrated soft tissues were ultimately well matched by a 50/50 triblock/diblock composition that is stable in ambient environments. More generally, the methodologies detailed here facilitate further optimisation of impact energy dissipation capacity of polymer-based tissue surrogate materials, either in air or in fluids.

Hindfoot containment orthosis for management of bone and soft-tissue defects of the heel.

PubMed

Johnson, Jeffrey E; Rudzki, Jonas R; Janisse, Erick; Janisse, Dennis J; Valdez, Ray R; Hanel, Douglas P; Gould, John S

2005-03-01

Bone, soft-tissue, and nerve deficits of the weightbearing surface of the foot are frequent sequelae from foot trauma or diabetes mellitus and present challenging treatment issues. Injury to the specialized, shock-absorbing, heel-pad tissue containing spirally arranged fat chambers is particularly difficult to manage. Appropriate footwear modifications and shoe inserts for protection of this skin are essential to the long-term management of bone and soft-tissue defects of the heel. This study evaluated the performance of a new custom total contact foot orthosis (Hindfoot Containment Orthosis, HCO) which was designed to contain the soft tissues of the heel, reduce shear forces, redistribute weightbearing load, and accommodate bone or soft-tissue deformity of the heel. Twenty-two patients treated with HCO were retrospectively reviewed. Followup averaged 26 months. The effectiveness of the orthosis was assessed by how well the integrity of the soft tissue was maintained (e.g. the number of ulcerations since dispensing the orthosis), the number of refabrications of the orthosis that were required, and whether or not revision surgery was required. Ten patients had superficial ulcerations. No patient required revision surgery. A total of 62 refabrications of the orthoses in 22 patients were required over a 2-year period. Overall results were good in 17 (77%) patients, fair in four (18%), and poor in one. The HCO is effective for preservation of soft-tissue integrity of the heel pad after bony or soft-tissue injury. Important factors in achieving success with the HCO are patient compliance and periodic monitoring for refabrication of the orthosis to accommodate skeletal growth, change in foot size or shape, and compression or wear of insert materials.

Theoretical and experimental characterization of novel water-equivalent plastics in clinical high-energy carbon-ion beams

NASA Astrophysics Data System (ADS)

Lourenço, A.; Wellock, N.; Thomas, R.; Homer, M.; Bouchard, H.; Kanai, T.; MacDougall, N.; Royle, G.; Palmans, H.

2016-11-01

Water-equivalent plastics are frequently used in dosimetry for experimental simplicity. This work evaluates the water-equivalence of novel water-equivalent plastics specifically designed for light-ion beams, as well as commercially available plastics in a clinical high-energy carbon-ion beam. A plastic- to-water conversion factor {{H}\\text{pl,w}} was established to derive absorbed dose to water in a water phantom from ionization chamber readings performed in a plastic phantom. Three trial plastic materials with varying atomic compositions were produced and experimentally characterized in a high-energy carbon-ion beam. Measurements were performed with a Roos ionization chamber, using a broad un-modulated beam of 11  ×  11 cm2, to measure the plastic-to-water conversion factor for the novel materials. The experimental results were compared with Monte Carlo simulations. Commercially available plastics were also simulated for comparison with the plastics tested experimentally, with particular attention to the influence of nuclear interaction cross sections. The measured H\\text{pl,w}\\exp correction increased gradually from 0% at the surface to 0.7% at a depth near the Bragg peak for one of the plastics prepared in this work, while for the other two plastics a maximum correction of 0.8%-1.3% was found. Average differences between experimental and numerical simulations were 0.2%. Monte Carlo results showed that for polyethylene, polystyrene, Rando phantom soft tissue and A-150, the correction increased from 0% to 2.5%-4.0% with depth, while for PMMA it increased to 2%. Water-equivalent plastics such as, Plastic Water, RMI-457, Gammex 457-CTG, WT1 and Virtual Water, gave similar results where maximum corrections were of the order of 2%. Considering the results from Monte Carlo simulations, one of the novel plastics was found to be superior in comparison with the plastic materials currently used in dosimetry, demonstrating that it is feasible to tailor plastic materials to be water-equivalent for carbon ions specifically.

Wrinkling pattern evolution of cylindrical biological tissues with differential growth.

PubMed

Jia, Fei; Li, Bo; Cao, Yan-Ping; Xie, Wei-Hua; Feng, Xi-Qiao

2015-01-01

Three-dimensional surface wrinkling of soft cylindrical tissues induced by differential growth is explored. Differential volumetric growth can cause their morphological stability, leading to the formation of hexagonal and labyrinth wrinkles. During postbuckling, multiple bifurcations and morphological transitions may occur as a consequence of continuous growth in the surface layer. The physical mechanisms underpinning the morphological evolution are examined from the viewpoint of energy. Surface curvature is found to play a regulatory role in the pattern evolution. This study may not only help understand the morphogenesis of soft biological tissues, but also inspire novel routes for creating desired surface patterns of soft materials.

Advances in bionanomaterials for bone tissue engineering.

PubMed

Scott, Timothy G; Blackburn, Gary; Ashley, Michael; Bayer, Ilker S; Ghosh, Anindya; Biris, Alexandru S; Biswas, Abhijit

2013-01-01

Bone is a specialized form of connective tissue that forms the skeleton of the body and is built at the nano and microscale levels as a multi-component composite material consisting of a hard inorganic phase (minerals) in an elastic, dense organic network. Mimicking bone structure and its properties present an important frontier in the fields of nanotechnology, materials science and bone tissue engineering, given the complex morphology of this tissue. There has been a growing interest in developing artificial bone-mimetic nanomaterials with controllable mineral content, nanostructure, chemistry for bone, cartilage tissue engineering and substitutes. This review describes recent advances in bionanomaterials for bone tissue engineering including developments in soft tissue engineering. The significance and basic process of bone tissue engineering along with different bionanomaterial bone scaffolds made of nanocomposites and nanostructured biopolymers/bioceramics and the prerequisite biomechanical functions are described. It also covers latest developments in soft-tissue reconstruction and replacement. Finally, perspectives on the future direction in nanotechnology-enabled bone tissue engineering are presented.

Biological characterization of soft tissue sarcomas.

PubMed

Hayashi, Takuma; Horiuchi, Akiko; Sano, Kenji; Kanai, Yae; Yaegashi, Nobuo; Aburatani, Hiroyuki; Konishi, Ikuo

2015-12-01

Soft tissue sarcomas are neoplastic malignancies that typically arise in tissues of mesenchymal origin. The identification of novel molecular mechanisms leading to mesenchymal transformation and the establishment of new therapies and diagnostic biomarker has been hampered by several critical factors. First, malignant soft tissue sarcomas are rarely observed in the clinic with fewer than 15,000 newly cases diagnosed each year in the United States. Another complicating factor is that soft tissue sarcomas are extremely heterogeneous as they arise in a multitude of tissues from many different cell lineages. The scarcity of clinical materials coupled with its inherent heterogeneity creates a challenging experimental environment for clinicians and scientists. Faced with these challenges, there has been extremely limited advancement in clinical treatment options available to patients as compared to other malignant tumours. In order to glean insight into the pathobiology of soft tissue sarcomas, scientists are now using mouse models whose genomes have been specifically tailored to carry gene deletions, gene amplifications, and somatic mutations commonly observed in human soft tissue sarcomas. The use of these model organisms has been successful in increasing our knowledge and understanding of how alterations in relevant oncogenic and/or tumour suppressive signal cascades, i.e., interferon-γ (IFN-γ), tumour protein 53 (TP53) and/or retinoblastoma (RB) pathway directly impact sarcomagenesis. It is the goal of many in the physiological community that the use of several mouse models will serve as powerful in vivo tools for further understanding of sarcomagenesis and potentially identify new diagnostic biomarker and therapeutic strategies against human soft tissue sarcomas.

Evidence-based alternatives for autogenous grafts around teeth: outcomes, attachment, and stability.

PubMed

McGuire, Michael K

2014-06-01

Although the use of autogenous harvested tissues has proven to be the gold standard for soft tissue augmentation procedures involving root coverage or generation of keratinized tissue, harvest site morbidity and limited supply have prompted clinicians to seek graft alternatives. Using a hierarchy of evidence, the author reviews both clinical and patient-reported results for harvest graft substitutes and, considering his own research experience, reviews autogenous graft substitute outcomes, attachment, and stability over time. Overall, when the goal is keratinized-tissue generation, living cellular constructs and xenogeneic collagen matrices have provided acceptable clinical results, but with better esthetics and patient preference than autogenous free gingival grafts. For root coverage therapy, enamel matrix derivatives, platelet-derived growth factors, and xenogeneic collagen matrices have provided acceptable results with equivalent esthetics to autogenous connective tissue grafts, while also being preferred by patients. Longterm results for enamel matrix derivatives, platelet-derived growth factors, and xenogeneic collagen matrices indicate root coverage can be maintained over time. In the author's hands, xenogeneic collagen matrices have been the only harvest graft alternatives that can be used either covered or uncovered by soft tissue.

Parameter identification of hyperelastic material properties of the heel pad based on an analytical contact mechanics model of a spherical indentation.

PubMed

Suzuki, Ryo; Ito, Kohta; Lee, Taeyong; Ogihara, Naomichi

2017-01-01

Accurate identification of the material properties of the plantar soft tissue is important for computer-aided analysis of foot pathologies and design of therapeutic footwear interventions based on subject-specific models of the foot. However, parameter identification of the hyperelastic material properties of plantar soft tissues usually requires an inverse finite element analysis due to the lack of a practical contact model of the indentation test. In the present study, we derive an analytical contact model of a spherical indentation test in order to directly estimate the material properties of the plantar soft tissue. Force-displacement curves of the heel pads are obtained through an indentation experiment. The experimental data are fit to the analytical stress-strain solution of the spherical indentation in order to obtain the parameters. A spherical indentation approach successfully predicted the non-linear material properties of the heel pad without iterative finite element calculation. The force-displacement curve obtained in the present study was found to be situated lower than those identified in previous studies. The proposed framework for identifying the hyperelastic material parameters may facilitate the development of subject-specific FE modeling of the foot for possible clinical and ergonomic applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

Measuring soft tissue material properties using stereovision and indentation: a proof-of-concept study

NASA Astrophysics Data System (ADS)

Ji, Songbai; Fan, Xiaoyao; Hartov, Alex; Roberts, David W.; Paulsen, Keith D.

2013-03-01

Accurate measurement of soft tissue material properties is critical for characterizing its biomechanical behaviors but can be challenging especially for the human brain. Recently, we have applied stereovision to track motion of the exposed cortical surface noninvasively for patients undergoing open skull neurosurgical operations. In this paper, we conduct a proof-of-concept study to evaluate the feasibility of the technique in measuring material properties of soft tissue in vivo using a tofu phantom. A block of soft tofu was prepared with black pepper randomly sprinkled on the top surface to provide texture to facilitate image-based displacement mapping. A disk-shaped indenter made of high-density tungsten was placed on the top surface to induce deformation through its weight. Stereoscopic images were acquired before and after indentation using a pair of stereovision cameras mounted on a surgical microscope with its optical path perpendicular to the imaging surface. Rectified left camera images obtained from stereovision reconstructions were then co-registered using optical flow motion tracking from which a 2D surface displacement field around the indenter disk was derived. A corresponding finite element model of the tofu was created subjected to the indenter weight and a hyperelastic material model was chosen to account for large deformation around the intender edges. By successively assigning different shear stiffness constant, computed tofu surface deformation was obtained, and an optimal shear stiffness was obtained that matched the model-derived surface displacements with those measured from the images. The resulting quasi-static, long-term shear stiffness for the tofu was 1.04 k Pa, similar to that reported in the literature. We show that the stereovision and free-weight indentation techniques coupled with an FE model are feasible for in vivo measurement of the human brain material properties, and it may also be feasible for other soft tissues.

Imunohistological aspects of the tissue around dental implants

NASA Astrophysics Data System (ADS)

Nimigean, Victor; Nimigean, Vanda R.; Sǎlǎvǎstru, Dan I.; Moraru, Simona; BuÅ£incu, Lavinia; Ivaşcu, Roxana V.; Poll, Alexandru

2016-03-01

Objectives: study of soft and hard tissues around implants. Material and methods: For the immunohistochemical and histological study of the implant/soft tissue interface, we examined pieces of peri-implant mucosa harvested from 35 patients. The implant/bone interface was assessed using histologic and histomorphometric examination of hard tissues around unloaded, early loaded or delayed loaded dental implants with pre-established design, with a sandblasted and acid-etched surface, placed both in extraction sockets, or after bone healing following tooth removal. This study was performed on 9 common race dogs. Results: The histological study of the implant/soft tissue interface showed regenerative modifications and moderate chronic subepithelial inflammatory reactions. Immunohistochemical evaluation of the soft tissue biopsies revealed the presence of specific immunocompetent cells and proteins of the matrix metalloproteinase (MMP) expression. Bone-implants contacts were more obvious in the apical half of the implants and at the edges of the threads, than between them. A mature, lamelliform bone containing lacunae with osteocytes and lack of connective tissue were noticed around implants that were late placed and loaded. The new-formed bone was also abundant in the crestal zone, not only in the apical part of the implants. Conclusions: A thorough understanding of the microstructure of dental implant/soft and hard tissue interface will improve the longevity of osseointegrated implants.

A teaching phantom for sonographers.

PubMed

Zagzebski, J A; Madsen, E L; Frank, G R

1991-01-01

An anthropomorphic torso section phantom is described that is intended for use during initial stages of ultrasonographer training. The phantom represents a section of the upper abdomen, with simulated ribs, liver, kidney with fat pad, gallbladder, aorta, and bowel gas. Positioned in the liver are ten simulated soft tissue masses, which produce a variety of typical echographic patterns. All simulated soft tissue components are formed of tissue-mimicking materials that match their corresponding tissue counterparts in terms of speed of sound, ultrasonic attenuation, and density. Construction details are presented and examples of images are shown.

Augmenting endogenous repair of soft tissues with nanofibre scaffolds

PubMed Central

Snelling, Sarah; Dakin, Stephanie; Carr, Andrew

2018-01-01

As our ability to engineer nanoscale materials has developed we can now influence endogenous cellular processes with increasing precision. Consequently, the use of biomaterials to induce and guide the repair and regeneration of tissues is a rapidly developing area. This review focuses on soft tissue engineering, it will discuss the types of biomaterial scaffolds available before exploring physical, chemical and biological modifications to synthetic scaffolds. We will consider how these properties, in combination, can provide a precise design process, with the potential to meet the requirements of the injured and diseased soft tissue niche. Finally, we frame our discussions within clinical trial design and the regulatory framework, the consideration of which is fundamental to the successful translation of new biomaterials. PMID:29695606

Casting materials and their application in research and teaching.

PubMed

Haenssgen, Kati; Makanya, Andrew N; Djonov, Valentin

2014-04-01

From a biological point of view, casting refers to filling of anatomical and/or pathological spaces with extraneous material that reproduces a three-dimensional replica of the space. Casting may be accompanied by additional procedures such as corrosion, in which the soft tissue is digested out, leaving a clean cast, or the material may be mixed with radiopaque substances to allow x-ray photography or micro computed topography (µCT) scanning. Alternatively, clearing of the surrounding soft tissue increases transparency and allows visualization of the casted cavities. Combination of casting with tissue fixation allows anatomical dissection and didactic surgical procedures on the tissue. Casting materials fall into three categories namely, aqueous substances (India ink, Prussian blue ink), pliable materials (gelatins, latex, and silicone rubber), or hard materials (methyl methacrylates, polyurethanes, polyesters, and epoxy resins). Casting has proved invaluable in both teaching and research and many phenomenal biological processes have been discovered through casting. The choice of a particular material depends inter alia on the targeted use and the intended subsequent investigative procedures, such as dissection, microscopy, or µCT. The casting material needs to be pliable where anatomical and surgical manipulations are intended, and capillary-passable for ultrastructural investigations.

An improved parameter estimation and comparison for soft tissue constitutive models containing an exponential function.

PubMed

Aggarwal, Ankush

2017-08-01

Motivated by the well-known result that stiffness of soft tissue is proportional to the stress, many of the constitutive laws for soft tissues contain an exponential function. In this work, we analyze properties of the exponential function and how it affects the estimation and comparison of elastic parameters for soft tissues. In particular, we find that as a consequence of the exponential function there are lines of high covariance in the elastic parameter space. As a result, one can have widely varying mechanical parameters defining the tissue stiffness but similar effective stress-strain responses. Drawing from elementary algebra, we propose simple changes in the norm and the parameter space, which significantly improve the convergence of parameter estimation and robustness in the presence of noise. More importantly, we demonstrate that these changes improve the conditioning of the problem and provide a more robust solution in the case of heterogeneous material by reducing the chances of getting trapped in a local minima. Based upon the new insight, we also propose a transformed parameter space which will allow for rational parameter comparison and avoid misleading conclusions regarding soft tissue mechanics.

A randomized comparative prospective study of platelet-rich plasma, platelet-rich fibrin, and hydroxyapatite as a graft material for mandibular third molar extraction socket healing.

PubMed

Dutta, Shubha Ranjan; Passi, Deepak; Singh, Purnima; Sharma, Sarang; Singh, Mahinder; Srivastava, Dhirendra

2016-01-01

The purpose of this study was to compare the efficacy of platelet-rich plasma (PRP), platelet-rich fibrin (PRF), and hydroxyapatite (HA) for reduction of pain and swelling, absence of dry socket, soft tissue healing, and bone regeneration after mandibular third molar extraction in human patients. Forty patients requiring extraction of mandibular third molars were randomly grouped as control, PRP, PRF, and HA-treated. The patients were assessed for postoperative pain, swelling, dry socket, and soft tissue healing on the 3 rd , 7 th , and 14 th day of postoperative periods depending on the standard methods. Radiological assessment of the extraction site was done at 1, 2, and 6 months interval to compare the change in bone density in the sockets in control and treated patients. Pain and swelling were less on PRP and PRF site when compared to HA and control site. PRP and PRF site showed better soft tissue healing when compared to HA and control site. Radiographic assessment showed comparatively lesser bone density values in PRP, PRF, and control site at 1, 2, and 6 months than HA site. Our study showed that PRP and PRF are better graft materials than HA regarding pain, swelling, dry socket, and soft tissue healing. Bone regeneration is induced promptly by HA as compared to other graft materials. However, a more elaborate study with a larger number of clinical cases is very much essential to be more conclusive regarding the efficacy of the graft materials.

A multi-physics model for ultrasonically activated soft tissue.

PubMed

Suvranu De, Rahul

2017-02-01

A multi-physics model has been developed to investigate the effects of cellular level mechanisms on the thermomechanical response of ultrasonically activated soft tissue. Cellular level cavitation effects have been incorporated in the tissue level continuum model to accurately determine the thermodynamic states such as temperature and pressure. A viscoelastic material model is assumed for the macromechanical response of the tissue. The cavitation model based equation-of-state provides the additional pressure arising from evaporation of intracellular and cellular water by absorbing heat due to structural and viscoelastic heating in the tissue, and temperature to the continuum level thermomechanical model. The thermomechanical response of soft tissue is studied for the operational range of frequencies of oscillations and applied loads for typical ultrasonically activated surgical instruments. The model is shown to capture characteristics of ultrasonically activated soft tissue deformation and temperature evolution. At the cellular level, evaporation of water below the boiling temperature under ambient conditions is indicative of protein denaturation around the temperature threshold for coagulation of tissues. Further, with increasing operating frequency (or loading), the temperature rises faster leading to rapid evaporation of tissue cavity water, which may lead to accelerated protein denaturation and coagulation.

Sugary interfaces mitigate contact damage where stiff meets soft

PubMed Central

Yoo, Hee Young; Iordachescu, Mihaela; Huang, Jun; Hennebert, Elise; Kim, Sangsik; Rho, Sangchul; Foo, Mathias; Flammang, Patrick; Zeng, Hongbo; Hwang, Daehee; Waite, J. Herbert; Hwang, Dong Soo

2016-01-01

The byssal threads of the fan shell Atrina pectinata are non-living functional materials intimately associated with living tissue, which provide an intriguing paradigm of bionic interface for robust load-bearing device. An interfacial load-bearing protein (A. pectinata foot protein-1, apfp-1) with L-3,4-dihydroxyphenylalanine (DOPA)-containing and mannose-binding domains has been characterized from Atrina's foot. apfp-1 was localized at the interface between stiff byssus and the soft tissue by immunochemical staining and confocal Raman imaging, implying that apfp-1 is an interfacial linker between the byssus and soft tissue, that is, the DOPA-containing domain interacts with itself and other byssal proteins via Fe3+–DOPA complexes, and the mannose-binding domain interacts with the soft tissue and cell membranes. Both DOPA- and sugar-mediated bindings are reversible and robust under wet conditions. This work shows the combination of DOPA and sugar chemistry at asymmetric interfaces is unprecedented and highly relevant to bionic interface design for tissue engineering and bionic devices. PMID:27305949

Sugary interfaces mitigate contact damage where stiff meets soft

NASA Astrophysics Data System (ADS)

Yoo, Hee Young; Iordachescu, Mihaela; Huang, Jun; Hennebert, Elise; Kim, Sangsik; Rho, Sangchul; Foo, Mathias; Flammang, Patrick; Zeng, Hongbo; Hwang, Daehee; Waite, J. Herbert; Hwang, Dong Soo

2016-06-01

The byssal threads of the fan shell Atrina pectinata are non-living functional materials intimately associated with living tissue, which provide an intriguing paradigm of bionic interface for robust load-bearing device. An interfacial load-bearing protein (A. pectinata foot protein-1, apfp-1) with L-3,4-dihydroxyphenylalanine (DOPA)-containing and mannose-binding domains has been characterized from Atrina's foot. apfp-1 was localized at the interface between stiff byssus and the soft tissue by immunochemical staining and confocal Raman imaging, implying that apfp-1 is an interfacial linker between the byssus and soft tissue, that is, the DOPA-containing domain interacts with itself and other byssal proteins via Fe3+-DOPA complexes, and the mannose-binding domain interacts with the soft tissue and cell membranes. Both DOPA- and sugar-mediated bindings are reversible and robust under wet conditions. This work shows the combination of DOPA and sugar chemistry at asymmetric interfaces is unprecedented and highly relevant to bionic interface design for tissue engineering and bionic devices.

U.S. Army Institute of Dental Research Annual Progress Report, Fiscal Year 1982 (1 October 1981-30 September 1982)

DTIC Science & Technology

1982-10-01

WOUND HEALING PRINCIPAL INVESTIGA TOR: COL STEPHEN G. WOODYARD, DC Evaluation of Citric Acid Enhancement of Oral Soft Tissue Healing on Previously Denuded...Craniofacial Tissues . 3S162775A825 CCMBAT MAXILLOFACIAL INJURY. AA,AB,AC,AD Oral and Maxillofacial Sciences. iA OE 6022 Preventive" Dentistry Measures of...Biodegradable Materials For the Treatment of 46 Fractures and Soft Tissue Wounds in the Military Situation. 3462734A875 MEDICAL DEFENSE AGAINST CHEMICAL AGENTS

Cubical Mass-Spring Model design based on a tensile deformation test and nonlinear material model.

PubMed

San-Vicente, Gaizka; Aguinaga, Iker; Tomás Celigüeta, Juan

2012-02-01

Mass-Spring Models (MSMs) are used to simulate the mechanical behavior of deformable bodies such as soft tissues in medical applications. Although they are fast to compute, they lack accuracy and their design remains still a great challenge. The major difficulties in building realistic MSMs lie on the spring stiffness estimation and the topology identification. In this work, the mechanical behavior of MSMs under tensile loads is analyzed before studying the spring stiffness estimation. In particular, the performed qualitative and quantitative analysis of the behavior of cubical MSMs shows that they have a nonlinear response similar to hyperelastic material models. According to this behavior, a new method for spring stiffness estimation valid for linear and nonlinear material models is proposed. This method adjusts the stress-strain and compressibility curves to a given reference behavior. The accuracy of the MSMs designed with this method is tested taking as reference some soft-tissue simulations based on nonlinear Finite Element Method (FEM). The obtained results show that MSMs can be designed to realistically model the behavior of hyperelastic materials such as soft tissues and can become an interesting alternative to other approaches such as nonlinear FEM.

Calculated organ doses using Monte Carlo simulations in a reference male phantom undergoing HDR brachytherapy applied to localized prostate carcinoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Candela-Juan, Cristian; Perez-Calatayud, Jose; Ballester, Facundo

Purpose: The aim of this study was to obtain equivalent doses in radiosensitive organs (aside from the bladder and rectum) when applying high-dose-rate (HDR) brachytherapy to a localized prostate carcinoma using {sup 60}Co or {sup 192}Ir sources. These data are compared with results in a water phantom and with expected values in an infinite water medium. A comparison with reported values from proton therapy and intensity-modulated radiation therapy (IMRT) is also provided. Methods: Monte Carlo simulations in Geant4 were performed using a voxelized phantom described in International Commission on Radiological Protection (ICRP) Publication 110, which reproduces masses and shapes frommore » an adult reference man defined in ICRP Publication 89. Point sources of {sup 60}Co or {sup 192}Ir with photon energy spectra corresponding to those exiting their capsules were placed in the center of the prostate, and equivalent doses per clinical absorbed dose in this target organ were obtained in several radiosensitive organs. Values were corrected to account for clinical circumstances with the source located at various positions with differing dwell times throughout the prostate. This was repeated for a homogeneous water phantom. Results: For the nearest organs considered (bladder, rectum, testes, small intestine, and colon), equivalent doses given by {sup 60}Co source were smaller (8%-19%) than from {sup 192}Ir. However, as the distance increases, the more penetrating gamma rays produced by {sup 60}Co deliver higher organ equivalent doses. The overall result is that effective dose per clinical absorbed dose from a {sup 60}Co source (11.1 mSv/Gy) is lower than from a {sup 192}Ir source (13.2 mSv/Gy). On the other hand, equivalent doses were the same in the tissue and the homogeneous water phantom for those soft tissues closer to the prostate than about 30 cm. As the distance increased, the differences of photoelectric effect in water and soft tissue, and appearance of other materials such as air, bone, or lungs, produced variations between both phantoms which were at most 35% in the considered organ equivalent doses. Finally, effective doses per clinical absorbed dose from IMRT and proton therapy were comparable to those from both brachytherapy sources, with brachytherapy being advantageous over external beam radiation therapy for the furthest organs. Conclusions: A database of organ equivalent doses when applying HDR brachytherapy to the prostate with either {sup 60}Co or {sup 192}Ir is provided. According to physical considerations, {sup 192}Ir is dosimetrically advantageous over {sup 60}Co sources at large distances, but not in the closest organs. Damage to distant healthy organs per clinical absorbed dose is lower with brachytherapy than with IMRT or protons, although the overall effective dose per Gy given to the prostate seems very similar. Given that there are several possible fractionation schemes, which result in different total amounts of therapeutic absorbed dose, advantage of a radiation treatment (according to equivalent dose to healthy organs) is treatment and facility dependent.« less

Design, fabrication and control of soft robots.

PubMed

Rus, Daniela; Tolley, Michael T

2015-05-28

Conventionally, engineers have employed rigid materials to fabricate precise, predictable robotic systems, which are easily modelled as rigid members connected at discrete joints. Natural systems, however, often match or exceed the performance of robotic systems with deformable bodies. Cephalopods, for example, achieve amazing feats of manipulation and locomotion without a skeleton; even vertebrates such as humans achieve dynamic gaits by storing elastic energy in their compliant bones and soft tissues. Inspired by nature, engineers have begun to explore the design and control of soft-bodied robots composed of compliant materials. This Review discusses recent developments in the emerging field of soft robotics.

A rate insensitive linear viscoelastic model for soft tissues

PubMed Central

Zhang, Wei; Chen, Henry Y.; Kassab, Ghassan S.

2012-01-01

It is well known that many biological soft tissues behave as viscoelastic materials with hysteresis curves being nearly independent of strain rate when loading frequency is varied over a large range. In this work, the rate insensitive feature of biological materials is taken into account by a generalized Maxwell model. To minimize the number of model parameters, it is assumed that the characteristic frequencies of Maxwell elements form a geometric series. As a result, the model is characterized by five material constants: μ0, τ, m, ρ and β, where μ0 is the relaxed elastic modulus, τ the characteristic relaxation time, m the number of Maxwell elements, ρ the gap between characteristic frequencies, and β = μ1/μ0 with μ1 being the elastic modulus of the Maxwell body that has relaxation time τ. The physical basis of the model is motivated by the microstructural architecture of typical soft tissues. The novel model shows excellent fit of relaxation data on the canine aorta and captures the salient features of vascular viscoelasticity with significantly fewer model parameters. PMID:17512585

Micromechanics and constitutive modeling of connective soft tissues.

PubMed

Fallah, A; Ahmadian, M T; Firozbakhsh, K; Aghdam, M M

2016-07-01

In this paper, a micromechanical model for connective soft tissues based on the available histological evidences is developed. The proposed model constituents i.e. collagen fibers and ground matrix are considered as hyperelastic materials. The matrix material is assumed to be isotropic Neo-Hookean while the collagen fibers are considered to be transversely isotropic hyperelastic. In order to take into account the effects of tissue structure in lower scales on the macroscopic behavior of tissue, a strain energy density function (SEDF) is developed for collagen fibers based on tissue hierarchical structure. Macroscopic response and properties of tissue are obtained using the numerical homogenization method with the help of ABAQUS software. The periodic boundary conditions and the proposed constitutive models are implemented into ABAQUS using the DISP and the UMAT subroutines, respectively. The existence of the solution and stable material behavior of proposed constitutive model for collagen fibers are investigated based on the poly-convexity condition. Results of the presented micromechanics model for connective tissues are compared and validated with available experimental data. Effects of geometrical and material parameters variation at microscale on macroscopic mechanical behavior of tissues are investigated. The results show that decrease in collagen content of the connective tissues like the tendon due to diseases leads 20% more stretch than healthy tissue under the same load which can results in connective tissue malfunction and hypermobility in joints. Copyright © 2016 Elsevier Ltd. All rights reserved.

Estimating zero strain states of very soft tissue under gravity loading using digital image correlation⋆,⋆⋆,★

PubMed Central

Gao, Zhan; Desai, Jaydev P.

2009-01-01

This paper presents several experimental techniques and concepts in the process of measuring mechanical properties of very soft tissue in an ex vivo tensile test. Gravitational body force on very soft tissue causes pre-compression and results in a non-uniform initial deformation. The global Digital Image Correlation technique is used to measure the full field deformation behavior of liver tissue in uniaxial tension testing. A maximum stretching band is observed in the incremental strain field when a region of tissue passes from compression and enters a state of tension. A new method for estimating the zero strain state is proposed: the zero strain position is close to, but ahead of the position of the maximum stretching band, or in other words, the tangent of a nominal stress-stretch curve reaches minimum at λ ≳ 1. The approach, to identify zero strain by using maximum incremental strain, can be implemented in other types of image-based soft tissue analysis. The experimental results of ten samples from seven porcine livers are presented and material parameters for the Ogden model fit are obtained. The finite element simulation based on the fitted model confirms the effect of gravity on the deformation of very soft tissue and validates our approach. PMID:20015676

Using Digital Image Correlation to Characterize Local Strains on Vascular Tissue Specimens.

PubMed

Zhou, Boran; Ravindran, Suraj; Ferdous, Jahid; Kidane, Addis; Sutton, Michael A; Shazly, Tarek

2016-01-24

Characterization of the mechanical behavior of biological and engineered soft tissues is a central component of fundamental biomedical research and product development. Stress-strain relationships are typically obtained from mechanical testing data to enable comparative assessment among samples and in some cases identification of constitutive mechanical properties. However, errors may be introduced through the use of average strain measures, as significant heterogeneity in the strain field may result from geometrical non-uniformity of the sample and stress concentrations induced by mounting/gripping of soft tissues within the test system. When strain field heterogeneity is significant, accurate assessment of the sample mechanical response requires measurement of local strains. This study demonstrates a novel biomechanical testing protocol for calculating local surface strains using a mechanical testing device coupled with a high resolution camera and a digital image correlation technique. A series of sample surface images are acquired and then analyzed to quantify the local surface strain of a vascular tissue specimen subjected to ramped uniaxial loading. This approach can improve accuracy in experimental vascular biomechanics and has potential for broader use among other native soft tissues, engineered soft tissues, and soft hydrogel/polymeric materials. In the video, we demonstrate how to set up the system components and perform a complete experiment on native vascular tissue.

Use of a porcine collagen matrix as an alternative to autogenous tissue for grafting oral soft tissue defects.

PubMed

Herford, Alan S; Akin, Lee; Cicciu, Marco; Maiorana, Carlo; Boyne, Philip J

2010-07-01

Soft tissue grafting is often required to correct intraoral mucosal deficiencies. Autogenous grafts have disadvantages including an additional harvest site with its associated pain and morbidity and, sometimes, poor quality and limited amount of the graft. Porcine collagen matrices have the potential to be helpful for grafting of soft tissue defects. Thirty consecutive patients underwent intraoral grafting to re-create missing soft tissue. Defects ranged in size from 50 to 900 mm(2). Porcine collagen matrices were used to reconstruct missing tissue. Indications included preprosthetic (22), followed by tumor removal (5), trauma (2), and release of cheek ankylosis (1). The primary efficacy parameters evaluated were the degree of lateral and/or alveolar extension and the evaluation of re-epithelialization and shrinkage of the grafted area. Overall, the percentage of shrinkage of the graft was 14% (range, 5%-20%). The amount of soft tissue extension averaged 3.4 mm (range, 2-10 mm). The secondary efficacy parameters included hemostatic effect, pain evaluation, pain and discomfort, and clinical evaluation of the grafted site. All patients reported minimal pain and swelling associated with the grafted area. No infections were noted. This porcine collagen matrix provides a biocompatible surgical material as an alternative to an autogenous transplant, thus obviating the need to harvest soft tissue autogenous grafts from other areas of the oral cavity. Copyright 2010 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Soft Material-Enabled, Flexible Hybrid Electronics for Medicine, Healthcare, and Human-Machine Interfaces

PubMed Central

Herbert, Robert; Kim, Jong-Hoon; Kim, Yun Soung; Lee, Hye Moon

2018-01-01

Flexible hybrid electronics (FHE), designed in wearable and implantable configurations, have enormous applications in advanced healthcare, rapid disease diagnostics, and persistent human-machine interfaces. Soft, contoured geometries and time-dynamic deformation of the targeted tissues require high flexibility and stretchability of the integrated bioelectronics. Recent progress in developing and engineering soft materials has provided a unique opportunity to design various types of mechanically compliant and deformable systems. Here, we summarize the required properties of soft materials and their characteristics for configuring sensing and substrate components in wearable and implantable devices and systems. Details of functionality and sensitivity of the recently developed FHE are discussed with the application areas in medicine, healthcare, and machine interactions. This review concludes with a discussion on limitations of current materials, key requirements for next generation materials, and new application areas. PMID:29364861

Soft Material-Enabled, Flexible Hybrid Electronics for Medicine, Healthcare, and Human-Machine Interfaces.

PubMed

Herbert, Robert; Kim, Jong-Hoon; Kim, Yun Soung; Lee, Hye Moon; Yeo, Woon-Hong

2018-01-24

Flexible hybrid electronics (FHE), designed in wearable and implantable configurations, have enormous applications in advanced healthcare, rapid disease diagnostics, and persistent human-machine interfaces. Soft, contoured geometries and time-dynamic deformation of the targeted tissues require high flexibility and stretchability of the integrated bioelectronics. Recent progress in developing and engineering soft materials has provided a unique opportunity to design various types of mechanically compliant and deformable systems. Here, we summarize the required properties of soft materials and their characteristics for configuring sensing and substrate components in wearable and implantable devices and systems. Details of functionality and sensitivity of the recently developed FHE are discussed with the application areas in medicine, healthcare, and machine interactions. This review concludes with a discussion on limitations of current materials, key requirements for next generation materials, and new application areas.

Preliminary research on dual-energy X-ray phase-contrast imaging

NASA Astrophysics Data System (ADS)

Han, Hua-Jie; Wang, Sheng-Hao; Gao, Kun; Wang, Zhi-Li; Zhang, Can; Yang, Meng; Zhang, Kai; Zhu, Pei-Ping

2016-04-01

Dual-energy X-ray absorptiometry (DEXA) has been widely applied to measure the bone mineral density (BMD) and soft-tissue composition of the human body. However, the use of DEXA is greatly limited for low-Z materials such as soft tissues due to their weak absorption, while X-ray phase-contrast imaging (XPCI) shows significantly improved contrast in comparison with the conventional standard absorption-based X-ray imaging for soft tissues. In this paper, we propose a novel X-ray phase-contrast method to measure the area density of low-Z materials, including a single-energy method and a dual-energy method. The single-energy method is for the area density calculation of one low-Z material, while the dual-energy method aims to calculate the area densities of two low-Z materials simultaneously. Comparing the experimental and simulation results with the theoretical ones, the new method proves to have the potential to replace DEXA in area density measurement. The new method sets the prerequisites for a future precise and low-dose area density calculation method for low-Z materials. Supported by Major State Basic Research Development Program (2012CB825800), Science Fund for Creative Research Groups (11321503) and National Natural Science Foundation of China (11179004, 10979055, 11205189, 11205157)

Restrained shrinkage cracking of cementitious composites containing soft PCM inclusions: A paste (matrix) controlled response

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wei, Zhenhua; Falzone, Gabriel; Das, Sumanta

The addition of phase change materials (PCMs) has been proposed as a way to mitigate thermal cracking in cementitious materials. However, the addition of PCMs, i.e., soft inclusions, degrades the compressive strength of cementitious composites. From a strength-of-materials viewpoint, such reductions in strength are suspected to increase the tendency of cementitious materials containing PCMs to crack under load (e.g., volume instability-induced stresses resulting from thermal and/or hygral deformations). Based on detailed assessments of free and restrained shrinkage, elastic modulus, and tensile strength, this study shows that the addition of PCMs does not alter the cracking sensitivity of the material. Inmore » fact, the addition of PCMs (or other soft inclusions) enhances the cracking resistance as compared to a plain cement paste or composites containing equivalent dosages of (stiff) quartz inclusions. This is because composites containing soft inclusions demonstrate benefits resulting from crack blunting and deflection, and improved stress relaxation. As a result, although the tensile stress at failure remains similar, the time to failure (i.e., macroscopic cracking) of PCM-containing composites is considerably extended. More generally, the outcomes indicate that dosages of soft(er) inclusions, and the resulting decrease in compressive strength does not amplify the cracking risk of cementitious composites.« less

Synthetic diamond devices for radio-oncology applications

NASA Astrophysics Data System (ADS)

Descamps, C.; Tromson, D.; Mer, C.; Nesládek, M.; Bergonzo, P.; Benabdesselam, M.

2006-09-01

Diamond exhibits a range of outstanding properties that make it a material of interest for radiation detection and particularly in the field of dosimetry applications. In fact, its crystallographic structure makes it chemically inert and radiation hard. Moreover, its atomic number (carbon Z = 6) close to the equivalent effective atomic number of human soft tissues (Z = 7.4) and of water (reference material in radiotherapy) enables a direct evaluation of the deposited dose without requiring corrections for material nature or energy. Finally, as a bio-compatible material, it can be sterilised, and it is non-toxic thus giving strong advantages for medical uses. Natural diamonds are expensive, rare and their use implies a severe gem selection to fabricate reproducible and reliable devices. The emergence of synthetic samples from the chemical vapour deposition (CVD) technique offers new possibilities in the fabrication of ionisation chamber for the particular field of radiotherapy. Previous studies have shown that defect levels present in material clearly influence the device response under irradiation. Therefore, in order to optimise dosimetric characteristics needed in radiotherapy applications, various low and precisely nitrogen concentrations were incorporated in the material during growth. Influence of these incorporations on ionisation chamber response under medical cobalt irradiator is presented in this paper.

Quantitative diagnostics of soft tissue through viscoelastic characterization using time-based instrumented palpation.

PubMed

Palacio-Torralba, Javier; Hammer, Steven; Good, Daniel W; Alan McNeill, S; Stewart, Grant D; Reuben, Robert L; Chen, Yuhang

2015-01-01

Although palpation has been successfully employed for centuries to assess soft tissue quality, it is a subjective test, and is therefore qualitative and depends on the experience of the practitioner. To reproduce what the medical practitioner feels needs more than a simple quasi-static stiffness measurement. This paper assesses the capacity of dynamic mechanical palpation to measure the changes in viscoelastic properties that soft tissue can exhibit under certain pathological conditions. A diagnostic framework is proposed to measure elastic and viscous behaviors simultaneously using a reduced set of viscoelastic parameters, giving a reliable index for quantitative assessment of tissue quality. The approach is illustrated on prostate models reconstructed from prostate MRI scans. The examples show that the change in viscoelastic time constant between healthy and cancerous tissue is a key index for quantitative diagnostics using point probing. The method is not limited to any particular tissue or material and is therefore useful for tissue where defining a unique time constant is not trivial. The proposed framework of quantitative assessment could become a useful tool in clinical diagnostics for soft tissue. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Synchronous Measuring Techniques in Parallel to MRE: Study of Pressure, Pre-Tension, and Surface Dynamics

NASA Astrophysics Data System (ADS)

Brinker, Spencer Thomas

The contents of this dissertation include investigations in Magnetic Resonance Elastography (MRE) using a preclinical 9.4 Tesla small animal Magnetic Resonance Imaging (MRI) system along with synthetic materials that mimic the mechanical properties of soft human tissue. MRE is used for studying the mechanical behavior of soft tissue particularly applicable to medical applications. Wave motion induced by a mechanical driver is measured with MRI to acquire internal displacement fields over time and space within a material media. Complex shear modulus of the media is calculated from the response of mechanical wave transmission through the material. Changes in soft tissue stiffness is associated with disease progression and thus, is why assessing tissue mechanical properties with MRE has powerful diagnostic potential due to the noninvasive procedure of MRI. The experiments performed in this dissertation used elastic phantoms and specimens to observe the influence of pre-stress on MRE derived mechanical properties while additional mechanical measurements from other related material testing methods were synchronously collected alongside MRI scanning. An organ simulating phantom was used to explore changes in MRE stiffness in response to gas and liquid cyclic pressure loading. MRE stiffness increased with pressure and hysteresis was observed in cyclic pressure loading. The results suggest MRE is applicable to pressure related disease assessment. In addition, an interconnected porosity pressure phantom was constructed for future porous media investigations. A custom system was also built to demonstrate concurrent tensile testing during MRE for investigating homogeneous soft material media undergoing pre-tension. Stiffness increased with uniaxial tensile stress and strain. The tension and stiffness relationship explored can be related to the stress analysis of voluntary muscle. The results also offer prospective experimental strategies for community wide standards on MRE calibration methods. Lastly, a novel platform was developed for synchronous acquisition of Scanning Laser Doppler Vibrometry (SLDV) and MRE for examining surface wave dynamics related to internal media wave propagation in soft material experiencing sinusoidal mechanical excitation. The results indicate that optical displacement measurements of media on the surface are similar in nature to internal displacement measured from MRE. It is concluded that optical and MRI based elastography yield similar values of complex shear modulus.

Role of structural anisotropy of biological tissues in poroelastic wave propagation

PubMed Central

Cardoso, Luis; Cowin, Stephen C.

2011-01-01

Ultrasound waves have a broad range of clinical applications as a non-destructive testing approach in imaging and in the diagnoses of medical conditions. Generally, biological tissues are modeled as an homogenized equivalent medium with an apparent density through which a single wave propagates. Only the first wave arriving at the ultrasound probe is used for the measurement of the speed of sound. However, the existence of a second wave in tissues such as cancellous bone has been reported and its existence is an unequivocal signature of Biot type poroelastic media. To account for the fact that ultrasound is sensitive to microarchitecture as well as density, a fabric-dependent anisotropic poroelastic ultrasound (PEU) propagation theory was recently developed. Key to this development was the inclusion of the fabric tensor - a quantitative stereological measure of the degree of structural anisotropy of bone - into the linear poroelasticity theory. In the present study, this framework is extended to the propagation of waves in several soft and hard tissues. It was found that collagen fibers in soft tissues and the mineralized matrix in hard tissues are responsible for the anisotropy of the solid tissue constituent through the fabric tensor in the model. PMID:22162897

A composites-based hyperelastic constitutive model for soft tissue with application to the human annulus fibrosus

NASA Astrophysics Data System (ADS)

Guo, Z. Y.; Peng, X. Q.; Moran, B.

2006-09-01

This paper presents a composites-based hyperelastic constitutive model for soft tissue. Well organized soft tissue is treated as a composite in which the matrix material is embedded with a single family of aligned fibers. The fiber is modeled as a generalized neo-Hookean material in which the stiffness depends on fiber stretch. The deformation gradient is decomposed multiplicatively into two parts: a uniaxial deformation along the fiber direction and a subsequent shear deformation. This permits the fiber-matrix interaction caused by inhomogeneous deformation to be estimated by using effective properties from conventional composites theory based on small strain linear elasticity and suitably generalized to the present large deformation case. A transversely isotropic hyperelastic model is proposed to describe the mechanical behavior of fiber-reinforced soft tissue. This model is then applied to the human annulus fibrosus. Because of the layered anatomical structure of the annulus fibrosus, an orthotropic hyperelastic model of the annulus fibrosus is developed. Simulations show that the model reproduces the stress-strain response of the human annulus fibrosus accurately. We also show that the expression for the fiber-matrix shear interaction energy used in a previous phenomenological model is compatible with that derived in the present paper.

A device for characterising the mechanical properties of the plantar soft tissue of the foot.

PubMed

Parker, D; Cooper, G; Pearson, S; Crofts, G; Howard, D; Busby, P; Nester, C

2015-11-01

The plantar soft tissue is a highly functional viscoelastic structure involved in transferring load to the human body during walking. A Soft Tissue Response Imaging Device was developed to apply a vertical compression to the plantar soft tissue whilst measuring the mechanical response via a combined load cell and ultrasound imaging arrangement. Accuracy of motion compared to input profiles; validation of the response measured for standard materials in compression; variability of force and displacement measures for consecutive compressive cycles; and implementation in vivo with five healthy participants. Static displacement displayed average error of 0.04 mm (range of 15 mm), and static load displayed average error of 0.15 N (range of 250 N). Validation tests showed acceptable agreement compared to a Houndsfield tensometer for both displacement (CMC > 0.99 RMSE > 0.18 mm) and load (CMC > 0.95 RMSE < 4.86 N). Device motion was highly repeatable for bench-top tests (ICC = 0.99) and participant trials (CMC = 1.00). Soft tissue response was found repeatable for intra (CMC > 0.98) and inter trials (CMC > 0.70). The device has been shown to be capable of implementing complex loading patterns similar to gait, and of capturing the compressive response of the plantar soft tissue for a range of loading conditions in vivo. Copyright © 2015. Published by Elsevier Ltd.

Development of crosslinked methylcellulose hydrogels for soft tissue augmentation using an ammonium persulfate-ascorbic acid redox system.

PubMed

Gold, Gittel T; Varma, Devika M; Taub, Peter J; Nicoll, Steven B

2015-12-10

Hydrogels composed of methylcellulose are candidate materials for soft tissue reconstruction. Although photocrosslinked methylcellulose hydrogels have shown promise for such applications, gels crosslinked using reduction-oxidation (redox) initiators may be more clinically viable. In this study, methylcellulose modified with functional methacrylate groups was polymerized using an ammonium persulfate (APS)-ascorbic acid (AA) redox initiation system to produce injectable hydrogels with tunable properties. By varying macromer concentration from 2% to 4% (w/v), the equilibrium moduli of the hydrogels ranged from 1.47 ± 0.33 to 5.31 ± 0.71 kPa, on par with human adipose tissue. Gelation time was found to conform to the ISO standard for injectable materials. Cellulase treatment resulted in complete degradation of the hydrogels within 24h, providing a reversible corrective feature. Co-culture with human dermal fibroblasts confirmed the cytocompatibility of the gels based on DNA measurements and Live/Dead imaging. Taken together, this evidence indicates that APS-AA redox-polymerized methylcellulose hydrogels possess properties beneficial for use as soft tissue fillers. Copyright © 2015 Elsevier Ltd. All rights reserved.

A method for subject-specific modelling and optimisation of the cushioning properties of insole materials used in diabetic footwear.

PubMed

Chatzistergos, Panagiotis E; Naemi, Roozbeh; Chockalingam, Nachiappan

2015-06-01

This study aims to develop a numerical method that can be used to investigate the cushioning properties of different insole materials on a subject-specific basis. Diabetic footwear and orthotic insoles play an important role for the reduction of plantar pressure in people with diabetes (type-2). Despite that, little information exists about their optimum cushioning properties. A new in-vivo measurement based computational procedure was developed which entails the generation of 2D subject-specific finite element models of the heel pad based on ultrasound indentation. These models are used to inverse engineer the material properties of the heel pad and simulate the contact between plantar soft tissue and a flat insole. After its validation this modelling procedure was utilised to investigate the importance of plantar soft tissue stiffness, thickness and loading for the correct selection of insole material. The results indicated that heel pad stiffness and thickness influence plantar pressure but not the optimum insole properties. On the other hand loading appears to significantly influence the optimum insole material properties. These results indicate that parameters that affect the loading of the plantar soft tissues such as body mass or a person's level of physical activity should be carefully considered during insole material selection. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

Modeling Soft Tissue Damage and Failure Using a Combined Particle/Continuum Approach.

PubMed

Rausch, M K; Karniadakis, G E; Humphrey, J D

2017-02-01

Biological soft tissues experience damage and failure as a result of injury, disease, or simply age; examples include torn ligaments and arterial dissections. Given the complexity of tissue geometry and material behavior, computational models are often essential for studying both damage and failure. Yet, because of the need to account for discontinuous phenomena such as crazing, tearing, and rupturing, continuum methods are limited. Therefore, we model soft tissue damage and failure using a particle/continuum approach. Specifically, we combine continuum damage theory with Smoothed Particle Hydrodynamics (SPH). Because SPH is a meshless particle method, and particle connectivity is determined solely through a neighbor list, discontinuities can be readily modeled by modifying this list. We show, for the first time, that an anisotropic hyperelastic constitutive model commonly employed for modeling soft tissue can be conveniently implemented within a SPH framework and that SPH results show excellent agreement with analytical solutions for uniaxial and biaxial extension as well as finite element solutions for clamped uniaxial extension in 2D and 3D. We further develop a simple algorithm that automatically detects damaged particles and disconnects the spatial domain along rupture lines in 2D and rupture surfaces in 3D. We demonstrate the utility of this approach by simulating damage and failure under clamped uniaxial extension and in a peeling experiment of virtual soft tissue samples. In conclusion, SPH in combination with continuum damage theory may provide an accurate and efficient framework for modeling damage and failure in soft tissues.

Modeling Soft Tissue Damage and Failure Using a Combined Particle/Continuum Approach

PubMed Central

Rausch, M. K.; Karniadakis, G. E.; Humphrey, J. D.

2016-01-01

Biological soft tissues experience damage and failure as a result of injury, disease, or simply age; examples include torn ligaments and arterial dissections. Given the complexity of tissue geometry and material behavior, computational models are often essential for studying both damage and failure. Yet, because of the need to account for discontinuous phenomena such as crazing, tearing, and rupturing, continuum methods are limited. Therefore, we model soft tissue damage and failure using a particle/continuum approach. Specifically, we combine continuum damage theory with Smoothed Particle Hydrodynamics (SPH). Because SPH is a meshless particle method, and particle connectivity is determined solely through a neighbor list, discontinuities can be readily modeled by modifying this list. We show, for the first time, that an anisotropic hyperelastic constitutive model commonly employed for modeling soft tissue can be conveniently implemented within a SPH framework and that SPH results show excellent agreement with analytical solutions for uniaxial and biaxial extension as well as finite element solutions for clamped uniaxial extension in 2D and 3D. We further develop a simple algorithm that automatically detects damaged particles and disconnects the spatial domain along rupture lines in 2D and rupture surfaces in 3D. We demonstrate the utility of this approach by simulating damage and failure under clamped uniaxial extension and in a peeling experiment of virtual soft tissue samples. In conclusion, SPH in combination with continuum damage theory may provide an accurate and efficient framework for modeling damage and failure in soft tissues. PMID:27538848

Influence of Abutment Color and Mucosal Thickness on Soft Tissue Color.

PubMed

Ferrari, Marco; Carrabba, Michele; Vichi, Alessandro; Goracci, Cecilia; Cagidiaco, Maria Crysanti

Zirconia (ZrO₂) and titanium nitride (TiN) implant abutments were introduced mainly for esthetic purposes, as titanium's gray color can be visible through mucosal tissues. This study was aimed at assessing whether ZrO₂ and TiN abutments could achieve better esthetics in comparison with titanium (Ti) abutments, regarding the appearance of soft tissues. Ninety patients were included in the study. Each patient was provided with an implant (OsseoSpeed, Dentsply Implant System). A two-stage surgical technique was performed. Six months later, surgical reentry was performed. After 1 week, provisional restorations were screwed onto the implants. After 8 weeks, implant-level impressions were taken and soft tissue thickness was recorded, ranking thin (≤ 2 mm) or thick (≥ 2 mm). Patients were randomly allocated to three experimental groups, based on abutment type: (1) Ti, (2) TiN, and (3) ZrO₂. After 15 weeks, the final restorations were delivered. The mucosal area referring to each abutment was measured for color using a clinical spectrophotometer (Easyshade, VITA); color measurements of the contralateral areas referring to natural teeth were performed at the same time. The data were collected using the Commission Internationale de l'Eclairage (CIE) L*a*b* color system, and ΔE was calculated between peri-implant and contralateral soft tissues. A critical threshold of ΔE = 3.7 was selected. The chi-square test was used to identify statistically significant differences in ΔE between thin and thick mucosal tissues and among the abutment types. Three patients were lost at follow-up. No statistically significant differences were noticed as to the abutment type (P = .966). Statistically significant differences in ΔE were recorded between thick and thin peri-implant soft tissues (P < .001). Only 2 out of 64 patients with thick soft tissues showed a ΔE higher than 3.7: 1 in the TiN group and 1 in the ZrO₂ group. All the patients with thin soft tissues reported color changes that exceeded the critical threshold. The different abutment materials showed comparable results in terms of influence on soft tissue color. Regarding peri-implant soft tissue thickness, the influence of the tested abutments on soft tissue color became clinically relevant for values ≤ 2 mm.

Evidence for explosive chromospheric evaporation in a solar flare observed with SMM

NASA Technical Reports Server (NTRS)

Zarro, D. M.; Saba, J. L. R.; Strong, K. T.; Canfield, R. C.; Metcalf, T.

1986-01-01

SMM soft X-ray data and Sacramento Peak Observatory H-alpha observations are combined in a study of the impulsive phase of a solar flare. A blue asymmetry, indicative of upflow motions, was observed in the coronal Ca XIX line during the soft X-ray rise phase. H-alpha redshifts, indicative of downward motions, were observed simultaneously in bright flare kernels during the period of hard X-ray emission. It is shown that, to within observational errors, the impulsive phase momentum transported by the upflowing soft X-ray plasma is equivalent to that of the downward moving chromospheric material.

Polyacylurethanes as Novel Degradable Cell Carrier Materials for Tissue Engineering

PubMed Central

Jovanovic, Danijela; Roukes, Frans V.; Löber, Andrea; Engels, Gerwin E.; van Oeveren, Willem; van Seijen, Xavier J. Gallego; van Luyn, Marja J.A.; Harmsen, Martin C.; Schouten, Arend Jan

2011-01-01

Polycaprolactone (PCL) polyester and segmented aliphatic polyester urethanes based on PCL soft segment have been thoroughly investigated as biodegradable scaffolds for tissue engineering. Although proven beneficial as long term implants, these materials degrade very slowly and are therefore not suitable in applications in which scaffold support is needed for a shorter time. A recently developed class of polyacylurethanes (PAUs) is expected to fulfill such requirements. Our aim was to assess in vitro the degradation of PAUs and evaluate their suitability as temporary scaffold materials to support soft tissue repair. With both a mass loss of 2.5–3.0% and a decrease in molar mass of approx. 35% over a period of 80 days, PAUs were shown to degrade via both bulk and surface erosion mechanisms. Fourier Transform Infra Red (FTIR) spectroscopy was successfully applied to study the extent of PAUs microphase separation during in vitro degradation. The microphase separated morphology of PAU1000 (molar mass of the oligocaprolactone soft segment = 1000 g/mol) provided this polymer with mechano-physical characteristics that would render it a suitable material for constructs and devices. PAU1000 exhibited excellent haemocompatibility in vitro. In addition, PAU1000 supported both adhesion and proliferation of vascular endothelial cells and this could be further enhanced by pre-coating of PAU1000 with fibronectin (Fn). The contact angle of PAU1000 decreased both with in vitro degradation and by incubation in biological fluids. In endothelial cell culture medium the contact angle reached 60°, which is optimal for cell adhesion. Taken together, these results support the application of PAU1000 in the field of soft tissue repair as a temporary degradable scaffold. PMID:28824103

Biomimetic 3D tissue printing for soft tissue regeneration.

PubMed

Pati, Falguni; Ha, Dong-Heon; Jang, Jinah; Han, Hyun Ho; Rhie, Jong-Won; Cho, Dong-Woo

2015-09-01

Engineered adipose tissue constructs that are capable of reconstructing soft tissue with adequate volume would be worthwhile in plastic and reconstructive surgery. Tissue printing offers the possibility of fabricating anatomically relevant tissue constructs by delivering suitable matrix materials and living cells. Here, we devise a biomimetic approach for printing adipose tissue constructs employing decellularized adipose tissue (DAT) matrix bioink encapsulating human adipose tissue-derived mesenchymal stem cells (hASCs). We designed and printed precisely-defined and flexible dome-shaped structures with engineered porosity using DAT bioink that facilitated high cell viability over 2 weeks and induced expression of standard adipogenic genes without any supplemented adipogenic factors. The printed DAT constructs expressed adipogenic genes more intensely than did non-printed DAT gel. To evaluate the efficacy of our printed tissue constructs for adipose tissue regeneration, we implanted them subcutaneously in mice. The constructs did not induce chronic inflammation or cytotoxicity postimplantation, but supported positive tissue infiltration, constructive tissue remodeling, and adipose tissue formation. This study demonstrates that direct printing of spatially on-demand customized tissue analogs is a promising approach to soft tissue regeneration. Copyright © 2015 Elsevier Ltd. All rights reserved.

A strain-hardening bi-power law for the nonlinear behaviour of biological soft tissues.

PubMed

Nicolle, S; Vezin, P; Palierne, J-F

2010-03-22

Biological soft tissues exhibit a strongly nonlinear viscoelastic behaviour. Among parenchymous tissues, kidney and liver remain less studied than brain, and a first goal of this study is to report additional material properties of kidney and liver tissues in oscillatory shear and constant shear rate tests. Results show that the liver tissue is more compliant but more strain hardening than kidney. A wealth of multi-parameter mathematical models has been proposed for describing the mechanical behaviour of soft tissues. A second purpose of this work is to develop a new constitutive law capable of predicting our experimental data in the both linear and nonlinear viscoelastic regime with as few parameters as possible. We propose a nonlinear strain-hardening fractional derivative model in which six parameters allow fitting the viscoelastic behaviour of kidney and liver tissues for strains ranging from 0.01 to 1 and strain rates from 0.0151 s(-1) to 0.7s(-1). Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Implantation of preadipocyte-loaded hyaluronic acid-based scaffolds into nude mice to evaluate potential for soft tissue engineering.

PubMed

Hemmrich, Karsten; von Heimburg, Dennis; Rendchen, Raoul; Di Bartolo, Chiara; Milella, Eva; Pallua, Norbert

2005-12-01

The reconstruction of soft tissue defects following extensive deep burns or tumor resections remains an unresolved problem in plastic and reconstructive surgery since adequate implant materials are still not available. Preadipocytes, immature precursor cells found between mature adipocytes in adipose tissue, are a potential material for soft tissue engineering since they can proliferate and differentiate into adipose tissue after transplantation. In previous studies, we identified hyaluronan benzyl ester (HYAFF 11) sponges to be promising carrier matrices. This study now evaluates, in vitro and in vivo, a new sponge architecture with pores of 400 microm either made of plain HYAFF 11 or HYAFF 11 coated with the extracellular matrix glycosaminoglycan hyaluronic acid. Human preadipocytes were isolated, seeded onto carriers and implanted into nude athymic mice. Explants harvested after 3, 8, and 12 weeks were examined for macroscopical appearance, thickness, weight, pore structure, histology, and immunohistochemistry. Compared to previous studies, we found better penetration of cells into both types of scaffolds, with more extensive formation of new vessels throughout the construct but with only minor adipose tissue. Our encouraging results contribute towards a better seeded and vascularised scaffold but also show that the enhancement of adipogenic conversion of preadipocytes remains a major task for further in vivo experiments.

Soft and hard tissues healing at immediate transmucosal implants placed into molar extraction sites with collagen membrane uncovered: a 12-month prospective study.

PubMed

Cafiero, Carlo; Marenzi, Gaetano; Blasi, Andrea; Siciliano, Vincenzo Iorio; Nicolò, Michele; Sammartino, Gilberto

2013-10-01

To assess soft and hard tissues healing at immediate transmucosal implants placed into maxillary molar region with collagen membranes uncovered. Twenty subjects received 20 immediate transmucosal implants placed in maxillary molar extraction sockets. Periimplant marginal defects were treated according to the principles of guided bone regeneration by means of deproteinized bovine bone mineral particles in conjunction with collagen membrane. Flaps were repositioned and sutured, allowing nonsubmerged, transmucosal soft tissues healing. The collagen membranes adapted around implant neck were uncovered. No implants were lost during the 1-year observation period yielding a survival rate of 100%. No postsurgical wound healing complications were observed. No degranulation of grafting material was reported. The results of this 12-month prospective study showed that the exposure of collagen membrane at time of the flap suturing does not represent a limitation for the soft and hard tissues healing at immediate transmucosal implants placed into maxillary molar extraction sites.

Performance of a plastic-wrapped composting system for biosecure emergency disposal of disease-related swine mortalities.

PubMed

Glanville, Thomas D; Ahn, Heekwon; Akdeniz, Neslihan; Crawford, Benjamin P; Koziel, Jacek A

2016-02-01

A passively-ventilated plastic-wrapped composting system initially developed for biosecure disposal of poultry mortalities caused by avian influenza was adapted and tested to assess its potential as an emergency disposal option for disease-related swine mortalities. Fresh air was supplied through perforated plastic tubing routed through the base of the compost pile. The combined air inlet and top vent area is ⩽∼1% of the gas exchange surface of a conventional uncovered windrow. Parameters evaluated included: (1) spatial and temporal variations in matrix moisture content (m.c.), leachate production, and matrix O2 concentrations; (2) extent of soft tissue decomposition; and (3) internal temperature and the success rate in achieving USEPA time/temperature (T) criteria for pathogen reduction. Six envelope materials (wood shavings, corn silage, ground cornstalks, ground oat straw, ground soybean straw, or ground alfalfa hay) and two initial m.c.'s (15-30% w.b. for materials stored indoors, and 45-65% w.b. to simulate materials exposed to precipitation) were tested to determine their effect on performance parameters (1-3). Results of triple-replicated field trials showed that the composting system did not accumulate moisture despite the 150kg carcass water load (65% of 225kg total carcass mass) released during decomposition. Mean compost m.c. in the carcass layer declined by ∼7 percentage points during 8-week trials, and a leachate accumulation was rare. Matrix O2 concentrations for all materials other than silage were ⩾10% using the equivalent of 2m inlet/vent spacing. In silage O2 dropped below 5% in some cases even when 0.5m inlet/vent spacing was used. Eight week soft tissue decomposition ranged from 87% in cornstalks to 72% in silage. Success rates for achievement of USEPA Class B time/temperature criteria ranged from 91% for silage to 33-57% for other materials. Companion laboratory biodegradation studies suggest that Class B success rates can be improved by slightly increasing envelope material m.c. Moistening initially dry (15% m.c.) envelope materials to 35% m.c. nearly doubled their heat production potential, boosting it to levels ⩾silage. The 'contradictory' silage test results showing high temperatures paired with slow soft tissue degradation are likely due to this material's high density, low gas permeability and low water vapor loss. While slow decomposition typically suggests low microbial activity and heat production, it does not rule out high internal temperatures if the heat produced is conserved. Occasional short-term odor releases during the first 2weeks of composting were associated with top-to-bottom gas flow which is contrary to the typical bottom-to-top flow typically observed in conventional compost piles. In cases where biosecurity concerns are paramount, results of this study show the plastic-wrapped passively-ventilated composting method to have good potential for above-ground swine mortality disposal. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mimicking biological stress-strain behaviour with synthetic elastomers

NASA Astrophysics Data System (ADS)

Vatankhah-Varnosfaderani, Mohammad; Daniel, William F. M.; Everhart, Matthew H.; Pandya, Ashish A.; Liang, Heyi; Matyjaszewski, Krzysztof; Dobrynin, Andrey V.; Sheiko, Sergei S.

2017-09-01

Despite the versatility of synthetic chemistry, certain combinations of mechanical softness, strength, and toughness can be difficult to achieve in a single material. These combinations are, however, commonplace in biological tissues, and are therefore needed for applications such as medical implants, tissue engineering, soft robotics, and wearable electronics. Present materials synthesis strategies are predominantly Edisonian, involving the empirical mixing of assorted monomers, crosslinking schemes, and occluded swelling agents, but this approach yields limited property control. Here we present a general strategy for mimicking the mechanical behaviour of biological materials by precisely encoding their stress-strain curves in solvent-free brush- and comb-like polymer networks (elastomers). The code consists of three independent architectural parameters—network strand length, side-chain length and grafting density. Using prototypical poly(dimethylsiloxane) elastomers, we illustrate how this parametric triplet enables the replication of the strain-stiffening characteristics of jellyfish, lung, and arterial tissues.

Synthesis and characterization of cycloaliphatic hydrophilic polyurethanes, modified with l-ascorbic acid, as materials for soft tissue regeneration.

PubMed

Kucinska-Lipka, J; Gubanska, I; Strankowski, M; Cieśliński, H; Filipowicz, N; Janik, H

2017-06-01

In this paper we described synthesis and characteristic of obtained hydrophilic polyurethanes (PURs) modified with ascorbic acid (commonly known as vitamin C). Such materials may find an application in the biomedical field, for example in the regenerative medicine of soft tissues, according to ascorbic acid wide influence on tissue regeneration Flora (2009), Szymańska-Pasternak et al. (2011), Taikarimi and Ibrahim (2011), Myrvik and Volk (1954), Li et al. (2001), Cursino et al. (2005) . Hydrophilic PURs were obtained with the use of amorphous α,ω-dihydroxy(ethylene-butylene adipate) (dHEBA) polyol, 1,4-butanediol (BDO) chain extender and aliphatic 4,4'-methylenebis(cyclohexyl isocyanate) (HMDI). HMDI was chosen as a nontoxic diisocyanate, suitable for biomedical PUR synthesis. Modification with l-ascorbic acid (AA) was performed to improve obtained PUR materials biocompatibility. Chemical structure of obtained PURs was provided and confirmed by Fourier transform infrared spectroscopy (FTIR) and Proton nuclear magnetic resonance spectroscopy ( 1 HNMR). Differential scanning calorimetry (DSC) was used to indicate the influence of ascorbic acid modification on such parameters as glass transition temperature, melting temperature and melting enthalpies of obtained materials. To determine how these materials may potentially behave, after implementation in tissue, degradation behavior of obtained PURs in various chemical environments, which were represented by canola oil, saline solution, distilled water and phosphate buffered saline (PBS) was estimated. The influence of AA on hydrophilic-hydrophobic character of obtained PURs was established by contact angle study. This experiment revealed that ascorbic acid significantly improves hydrophilicity of obtained PUR materials and the same cause that they are more suitable candidates for biomedical applications. Good hemocompatibility characteristic of studied PUR materials was confirmed by the hemocompatibility test with human blood. Microbiological tests were carried out to indicate the microbiological sensitivity of obtained PURs. Results of performed studies showed that obtained AA-modified PUR materials may find an application in soft tissue regeneration. Copyright © 2017 Elsevier B.V. All rights reserved.

Surgical Removal of Neglected Soft Tissue Foreign Bodies by Needle-Guided Technique

PubMed Central

Ebrahimi, Ali; Radmanesh, Mohammad; Rabiei, Sohrab; kavoussi, Hossein

2013-01-01

Introduction: The phenomenon of neglected foreign bodies is a significant cause of morbidity in soft tissue injuries and may present to dermatologists as delayed wound healing, localized cellulitis and inflammation, abscess formation, or foreign body sensation. Localization and removal of neglected soft tissue foreign bodies (STFBs) is complex due to possible inflammation, indurations, granulated tissue, and fibrotic scar. This paper describes a simple method for the quick localization and (surgical) removal of neglected STFBs using two 23-gauge needles without ultrasonographic or fluoroscopic guidance. Materials and Methods: A technique based on the use of two 23-gauge needles was used in 41 neglected STFBs in order to achieve proper localization and fixation of foreign bodies during surgery. Results: Surgical removal was successful in 38 of 41 neglected STFBs (ranging from 2–13mm in diameter). Conclusion: The cross-needle-guided technique is an office-based procedure that allows the successful surgical removal of STFBs using minimal soft tissue exploration and dissection via proper localization, fixation, and propulsion of the foreign body toward the surface of the skin. PMID:24303416

Electron Density Calibration for Radiotherapy Treatment Planning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Herrera-Martinez, F.; Rodriguez-Villafuerte, M.; Martinez-Davalos, A.

2006-09-08

Computed tomography (CT) images are used as basic input data for most modern radiosurgery treatment planning systems (TPS). CT data not only provide anatomic information to delineate target volumes, but also allow the introduction of corrections for tissue inhomogeneities into dose calculations during the treatment planning procedure. These corrections involve the determination of a relationship between tissue electron density ({rho}e) and their corresponding Hounsfield Units (HU). In this work, an elemental analysis of different commercial tissue equivalent materials using Scanning Electron Microscopy was carried out to characterize their chemical composition. The tissue equivalent materials were chosen to ensure a largemore » range of {rho}e to be included in the CT scanner calibration. A phantom was designed and constructed with these materials to simulate the size of a human head.« less

Bone formation in mono cortical mandibular critical size defects after augmentation with two synthetic nanostructured and one xenogenous hydroxyapatite bone substitute - in vivo animal study.

PubMed

Dau, Michael; Kämmerer, Peer W; Henkel, Kai-Olaf; Gerber, Thomas; Frerich, Bernhard; Gundlach, Karsten K H

2016-05-01

Healing characteristics as well as level of tissue integration and degradation of two different nanostructured hydroxyapatite bone substitute materials (BSM) in comparison with a deproteinized hydroxyapatite bovine BSM were evaluated in an in vivo animal experiment. In the posterior mandible of 18 minipigs, bilateral mono cortical critical size bone defects were created. Randomized augmentation procedures with NanoBone(®) (NHA1), Ostim(®) (NHA2) or Bio-Oss(®) (DBBM) were conducted (each material n = 12). Samples were analyzed after five (each material n = 6) and 8 months (each material n = 6). Defect healing, formation of soft tissue and bone as well as the amount of remaining respective BSM were quantified both macro- and microscopically. For NHA2, the residual bone defect after 5 weeks was significantly less compared to NHA1 or DBBM. There was no difference in residual BSM between NHA1 and DBBM, but the amount in NHA2 was significantly lower. NHA2 also showed the least amount of soft tissue and the highest amount of new bone after 5 weeks. Eight months after implantation, no significant differences in the amount of residual bone defects, in soft tissue or in bone formation were detected between the groups. Again, NHA2 showed significant less residual material than NHA1 and DBBM. We observed non-significant differences in the biological hard tissue response of NHA1 and DBBM. The water-soluble NHA2 initially induced an increased amount of new bone but was highly compressed which may have a negative effect in less stable augmentations of the jaw. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

ON THE BIOMECHANICAL FUNCTION OF SCAFFOLDS FOR ENGINEERING LOAD BEARING SOFT TISSUES

PubMed Central

Stella, John A.; D’Amore, Antonio; Wagner, William R.; Sacks, Michael S.

2010-01-01

Replacement or regeneration of load bearing soft tissues has long been the impetus for the development bioactive materials. While maturing, current efforts continue to be confounded by our lack of understanding of the intricate multi-scale hierarchical arrangements and interactions typically found in native tissues. The current state of the art in biomaterial processing enables a degree of controllable microstructure that can be used for the development of model systems to deduce fundamental biological implications of matrix morphologies on cell function. Furthermore, the development of computational frameworks which allow for the simulation of experimentally derived observations represents a positive departure from what has mostly been an empirically driven field, enabling a deeper understanding of the highly complex biological mechanisms we wish to ultimately emulate. Ongoing research is actively pursuing new materials and processing methods to control material structure down to the micro-scale to sustain or improve cell viability, guide tissue growth, and provide mechanical integrity all while exhibiting the capacity to degrade in a controlled manner. The purpose of this review is not to focus solely on material processing but to assess the ability of these techniques to produce mechanically sound tissue surrogates, highlight the unique structural characteristics produced in these materials, and discuss how this translates to distinct macroscopic biomechanical behaviors. PMID:20060509

Socket Preservation using Enzyme-treated Equine Bone Granules and an Equine Collagen Matrix: A Case Report with Histological and Histomorphometrical Assessment.

PubMed

Leonida, Alessandro; Todeschini, Giovanni; Lomartire, Giovanni; Cinci, Lorenzo; Pieri, Laura

2016-11-01

To histologically assess the effectiveness of a socket-preservation technique using enzyme-treated equine bone granules as a bone-graft material in combination with an equine collagen matrix as a scaffold for soft-tissue regeneration. Enzyme-treated equine bone granules and equine collagen matrix recently have been developed to help overcome alveolar bone deficiencies that develop in the wake of edentulism. The patient had one mandibular molar extracted and the socket grafted with equine bone granules. The graft was covered with the equine collagen matrix, placed in a double layer. No flap was prepared, and the gingival margins were stabilized with a single stitch, leaving the matrix partially exposed and the site to heal by secondary intention. The adjacent molar was extracted 1 month later, and that socket was left to heal by secondary intention without any further treatment. Three months after each surgery, an implant was placed and a biopsy was collected. The two biopsies underwent histological processing and qualitative evaluation. Histomorphometric analysis was also performed to calculate the percentage of newly formed bone (NFB) in the two cores. Healing at both sites was uneventful, and no inflammation or other adverse reactions were observed in the samples. Soft-tissue healing by secondary intention appeared to occur faster at the grafted site. The corresponding core showed a marked separation between soft and hard tissue that was not observed in the core from the nongrafted site, where soft-tissue hypertrophy could be observed. Newly formed bone at the grafted and nongrafted sites was not significantly different (27.2 ± 7.1 and 29.4 ± 6.2% respectively, p = 0.45). The surgical technique employed in this case appeared to facilitate postextraction soft-tissue healing by second intention and simplify soft-tissue management. Using a collagen-based matrix to cover a postextraction grafted site may facilitate second intention soft-tissue healing and proper soft-tissue growth.

Characterization of Cement Particles Found in Peri-implantitis-Affected Human Biopsy Specimens.

PubMed

Burbano, Maria; Wilson, Thomas G; Valderrama, Pilar; Blansett, Jonathan; Wadhwani, Chandur P K; Choudhary, Pankaj K; Rodriguez, Lucas C; Rodrigues, Danieli C

2015-01-01

Peri-implantitis is a disease characterized by soft tissue inflammation and continued loss of supporting bone, which can result in implant failure. Peri-implantitis is a multifactorial disease, and one of its triggering factors may be the presence of excess cement in the soft tissues surrounding an implant. This descriptive study evaluated the composition of foreign particles from 36 human biopsy specimens with 19 specimens selected for analysis. The biopsy specimens were obtained from soft tissues affected by peri-implantitis around cement-retained implant crowns and compared with the elemental composition of commercial luting cement. Nineteen biopsy specimens were chosen for the comparison, and five test cements (TempBond, Telio, Premier Implant Cement, Intermediate Restorative Material, and Relyx) were analyzed using scanning electron microscopy equipped with energy dispersive x-ray spectroscopy. This enabled the identification of the chemical composition of foreign particles embedded in the tissue specimens and the composition of the five cements. Statistical analysis was conducted using classification trees to pair the particles present in each specimen with the known cements. The particles in each biopsy specimen could be associated with one of the commercial cements with a level of probability ranging between .79 and 1. TempBond particles were found in one biopsy specimen, Telio particles in seven, Premier Implant Cement particles in four, Relyx particles in four, and Intermediate Restorative Material particles in three. Particles found in human soft tissue biopsy specimens around implants affected by peri-implant disease were associated with five commercially available dental cements.

Medical ultrasound: imaging of soft tissue strain and elasticity

PubMed Central

Wells, Peter N. T.; Liang, Hai-Dong

2011-01-01

After X-radiography, ultrasound is now the most common of all the medical imaging technologies. For millennia, manual palpation has been used to assist in diagnosis, but it is subjective and restricted to larger and more superficial structures. Following an introduction to the subject of elasticity, the elasticity of biological soft tissues is discussed and published data are presented. The basic physical principles of pulse-echo and Doppler ultrasonic techniques are explained. The history of ultrasonic imaging of soft tissue strain and elasticity is summarized, together with a brief critique of previously published reviews. The relevant techniques—low-frequency vibration, step, freehand and physiological displacement, and radiation force (displacement, impulse, shear wave and acoustic emission)—are described. Tissue-mimicking materials are indispensible for the assessment of these techniques and their characteristics are reported. Emerging clinical applications in breast disease, cardiology, dermatology, gastroenterology, gynaecology, minimally invasive surgery, musculoskeletal studies, radiotherapy, tissue engineering, urology and vascular disease are critically discussed. It is concluded that ultrasonic imaging of soft tissue strain and elasticity is now sufficiently well developed to have clinical utility. The potential for further research is examined and it is anticipated that the technology will become a powerful mainstream investigative tool. PMID:21680780

Comprehensive analysis of proton range uncertainties related to patient stopping-power-ratio estimation using the stoichiometric calibration

PubMed Central

Yang, M; Zhu, X R; Park, PC; Titt, Uwe; Mohan, R; Virshup, G; Clayton, J; Dong, L

2012-01-01

The purpose of this study was to analyze factors affecting proton stopping-power-ratio (SPR) estimations and range uncertainties in proton therapy planning using the standard stoichiometric calibration. The SPR uncertainties were grouped into five categories according to their origins and then estimated based on previously published reports or measurements. For the first time, the impact of tissue composition variations on SPR estimation was assessed and the uncertainty estimates of each category were determined for low-density (lung), soft, and high-density (bone) tissues. A composite, 95th percentile water-equivalent-thickness uncertainty was calculated from multiple beam directions in 15 patients with various types of cancer undergoing proton therapy. The SPR uncertainties (1σ) were quite different (ranging from 1.6% to 5.0%) in different tissue groups, although the final combined uncertainty (95th percentile) for different treatment sites was fairly consistent at 3.0–3.4%, primarily because soft tissue is the dominant tissue type in human body. The dominant contributing factor for uncertainties in soft tissues was the degeneracy of Hounsfield Numbers in the presence of tissue composition variations. To reduce the overall uncertainties in SPR estimation, the use of dual-energy computed tomography is suggested. The values recommended in this study based on typical treatment sites and a small group of patients roughly agree with the commonly referenced value (3.5%) used for margin design. By using tissue-specific range uncertainties, one could estimate the beam-specific range margin by accounting for different types and amounts of tissues along a beam, which may allow for customization of range uncertainty for each beam direction. PMID:22678123

Longitudinal nonlinear wave propagation through soft tissue.

PubMed

Valdez, M; Balachandran, B

2013-04-01

In this paper, wave propagation through soft tissue is investigated. A primary aim of this investigation is to gain a fundamental understanding of the influence of soft tissue nonlinear material properties on the propagation characteristics of stress waves generated by transient loadings. Here, for computational modeling purposes, the soft tissue is modeled as a nonlinear visco-hyperelastic material, the geometry is assumed to be one-dimensional rod geometry, and uniaxial propagation of longitudinal waves is considered. By using the linearized model, a basic understanding of the characteristics of wave propagation is developed through the dispersion relation and in terms of the propagation speed and attenuation. In addition, it is illustrated as to how the linear system can be used to predict brain tissue material parameters through the use of available experimental ultrasonic attenuation curves. Furthermore, frequency thresholds for wave propagation along internal structures, such as axons in the white matter of the brain, are obtained through the linear analysis. With the nonlinear material model, the authors analyze cases in which one of the ends of the rods is fixed and the other end is subjected to a loading. Two variants of the nonlinear model are analyzed and the associated predictions are compared with the predictions of the corresponding linear model. The numerical results illustrate that one of the imprints of the nonlinearity on the wave propagation phenomenon is the steepening of the wave front, leading to jump-like variations in the stress wave profiles. This phenomenon is a consequence of the dependence of the local wave speed on the local deformation of the material. As per the predictions of the nonlinear material model, compressive waves in the structure travel faster than tensile waves. Furthermore, it is found that wave pulses with large amplitudes and small elapsed times are attenuated over shorter spans. This feature is due to the elevated strain-rates introduced at the end of the structure where the load is applied. In addition, it is shown that when steep wave fronts are generated in the nonlinear viscoelastic material, energy dissipation is focused in those wave fronts implying deposition of energy in a highly localized region of the material. Novel mechanisms for brain tissue damage are proposed based on the results obtained. The first mechanism is related to the dissipation of energy at steep wave fronts, while the second one is related to the interaction of steep wave fronts with axons encountered on its way through the structure. Copyright © 2013 Elsevier Ltd. All rights reserved.

On the Rule of Mixtures for Predicting Stress-Softening and Residual Strain Effects in Biological Tissues and Biocompatible Materials

PubMed Central

Elías-Zúñiga, Alex; Baylón, Karen; Ferrer, Inés; Serenó, Lídia; Garcia-Romeu, Maria Luisa; Bagudanch, Isabel; Grabalosa, Jordi; Pérez-Recio, Tania; Martínez-Romero, Oscar; Ortega-Lara, Wendy; Elizalde, Luis Ernesto

2014-01-01

In this work, we use the rule of mixtures to develop an equivalent material model in which the total strain energy density is split into the isotropic part related to the matrix component and the anisotropic energy contribution related to the fiber effects. For the isotropic energy part, we select the amended non-Gaussian strain energy density model, while the energy fiber effects are added by considering the equivalent anisotropic volumetric fraction contribution, as well as the isotropized representation form of the eight-chain energy model that accounts for the material anisotropic effects. Furthermore, our proposed material model uses a phenomenological non-monotonous softening function that predicts stress softening effects and has an energy term, derived from the pseudo-elasticity theory, that accounts for residual strain deformations. The model’s theoretical predictions are compared with experimental data collected from human vaginal tissues, mice skin, poly(glycolide-co-caprolactone) (PGC25 3-0) and polypropylene suture materials and tracheal and brain human tissues. In all cases examined here, our equivalent material model closely follows stress-softening and residual strain effects exhibited by experimental data. PMID:28788466

On the Rule of Mixtures for Predicting Stress-Softening and Residual Strain Effects in Biological Tissues and Biocompatible Materials.

PubMed

Elías-Zúñiga, Alex; Baylón, Karen; Ferrer, Inés; Serenó, Lídia; García-Romeu, Maria Luisa; Bagudanch, Isabel; Grabalosa, Jordi; Pérez-Recio, Tania; Martínez-Romero, Oscar; Ortega-Lara, Wendy; Elizalde, Luis Ernesto

2014-01-16

In this work, we use the rule of mixtures to develop an equivalent material model in which the total strain energy density is split into the isotropic part related to the matrix component and the anisotropic energy contribution related to the fiber effects. For the isotropic energy part, we select the amended non-Gaussian strain energy density model, while the energy fiber effects are added by considering the equivalent anisotropic volumetric fraction contribution, as well as the isotropized representation form of the eight-chain energy model that accounts for the material anisotropic effects. Furthermore, our proposed material model uses a phenomenological non-monotonous softening function that predicts stress softening effects and has an energy term, derived from the pseudo-elasticity theory, that accounts for residual strain deformations. The model's theoretical predictions are compared with experimental data collected from human vaginal tissues, mice skin, poly(glycolide-co-caprolactone) (PGC25 3-0) and polypropylene suture materials and tracheal and brain human tissues. In all cases examined here, our equivalent material model closely follows stress-softening and residual strain effects exhibited by experimental data.

Toward quantitative estimation of material properties with dynamic mode atomic force microscopy: a comparative study.

PubMed

Ghosal, Sayan; Gannepalli, Anil; Salapaka, Murti

2017-08-11

In this article, we explore methods that enable estimation of material properties with the dynamic mode atomic force microscopy suitable for soft matter investigation. The article presents the viewpoint of casting the system, comprising of a flexure probe interacting with the sample, as an equivalent cantilever system and compares a steady-state analysis based method with a recursive estimation technique for determining the parameters of the equivalent cantilever system in real time. The steady-state analysis of the equivalent cantilever model, which has been implicitly assumed in studies on material property determination, is validated analytically and experimentally. We show that the steady-state based technique yields results that quantitatively agree with the recursive method in the domain of its validity. The steady-state technique is considerably simpler to implement, however, slower compared to the recursive technique. The parameters of the equivalent system are utilized to interpret storage and dissipative properties of the sample. Finally, the article identifies key pitfalls that need to be avoided toward the quantitative estimation of material properties.

3D printing of soft robotic systems

NASA Astrophysics Data System (ADS)

Wallin, T. J.; Pikul, J.; Shepherd, R. F.

2018-06-01

Soft robots are capable of mimicking the complex motion of animals. Soft robotic systems are defined by their compliance, which allows for continuous and often responsive localized deformation. These features make soft robots especially interesting for integration with human tissues, for example, the implementation of biomedical devices, and for robotic performance in harsh or uncertain environments, for example, exploration in confined spaces or locomotion on uneven terrain. Advances in soft materials and additive manufacturing technologies have enabled the design of soft robots with sophisticated capabilities, such as jumping, complex 3D movements, gripping and releasing. In this Review, we examine the essential soft material properties for different elements of soft robots, highlighting the most relevant polymer systems. Advantages and limitations of different additive manufacturing processes, including 3D printing, fused deposition modelling, direct ink writing, selective laser sintering, inkjet printing and stereolithography, are discussed, and the different techniques are investigated for their application in soft robotic fabrication. Finally, we explore integrated robotic systems and give an outlook for the future of the field and remaining challenges.

Comparison of platelet rich plasma and synthetic graft material for bone regeneration after third molar extraction.

PubMed

Nathani, Dipesh B; Sequeira, Joyce; Rao, B H Sripathi

2015-01-01

To compare the efficacy of Platelet rich plasma and synthetic graft material for bone regeneration after bilateral third molar extraction. This study was conducted in 10 patients visiting the outpatient department of Oral & Maxillofacial Surgery, Yenepoya Dental College & Hospital. Patients requiring extraction of bilateral mandibular third molars were taken for the study. Following extraction, PRP (Platelet Rich Plasma) was placed in one extraction socket and synthetic graft material in form granules [combination of Hydroxyapatite (HA) and Bioactive glass (BG)] in another extraction socket. The patients were assessed for postoperative pain and soft tissue healing. Radiological assessment of the extraction site was done at 8, 12 and 16 weeks interval to compare the change in bone density in both the sockets. Pain was less on PRP site when compared to HA site. Soft tissue evaluation done using gingival healing index given by Landry et al showed better healing on PRP site when compared to HA site. The evaluation of bone density by radiological assessment showed the grey level values calculated at 4 months at the PRP site were comparatively higher than HA site. The study showed that the platelet rich plasma is a better graft material than synthetic graft material in terms of soft tissue and bone healing. However a more elaborate study with a larger number of clinical cases is very much essential to be more conclusive regarding the efficacy of both the materials.

Collecting and Storing Tissue, Blood, and Bone Marrow Samples From Patients With Rhabdomyosarcoma or Other Soft Tissue Sarcoma

ClinicalTrials.gov

2017-12-11

Adult Rhabdomyosarcoma; Childhood Desmoplastic Small Round Cell Tumor; Chordoma; Desmoid Tumor; Metastatic Childhood Soft Tissue Sarcoma; Nonmetastatic Childhood Soft Tissue Sarcoma; Previously Treated Childhood Rhabdomyosarcoma; Previously Untreated Childhood Rhabdomyosarcoma; Recurrent Adult Soft Tissue Sarcoma; Recurrent Childhood Rhabdomyosarcoma; Recurrent Childhood Soft Tissue Sarcoma; Stage I Adult Soft Tissue Sarcoma; Stage II Adult Soft Tissue Sarcoma; Stage III Adult Soft Tissue Sarcoma; Stage IV Adult Soft Tissue Sarcoma

Evaluating the accuracy of the XVI dual registration tool compared with manual soft tissue matching to localise tumour volumes for post-prostatectomy patients receiving radiotherapy.

PubMed

Campbell, Amelia; Owen, Rebecca; Brown, Elizabeth; Pryor, David; Bernard, Anne; Lehman, Margot

2015-08-01

Cone beam computerised tomography (CBCT) enables soft tissue visualisation to optimise matching in the post-prostatectomy setting, but is associated with inter-observer variability. This study assessed the accuracy and consistency of automated soft tissue localisation using XVI's dual registration tool (DRT). Sixty CBCT images from ten post-prostatectomy patients were matched using: (i) the DRT and (ii) manual soft tissue registration by six radiation therapists (RTs). Shifts in the three Cartesian planes were recorded. The accuracy of the match was determined by comparing shifts to matches performed by two genitourinary radiation oncologists (ROs). A Bland-Altman method was used to assess the 95% levels of agreement (LoA). A clinical threshold of 3 mm was used to define equivalence between methods of matching. The 95% LoA between DRT-ROs in the superior/inferior, left/right and anterior/posterior directions were -2.21 to +3.18 mm, -0.77 to +0.84 mm, and -1.52 to +4.12 mm, respectively. The 95% LoA between RTs-ROs in the superior/inferior, left/right and anterior/posterior directions were -1.89 to +1.86 mm, -0.71 to +0.62 mm and -2.8 to +3.43 mm, respectively. Five DRT CBCT matches (8.33%) were outside the 3-mm threshold, all in the setting of bladder underfilling or rectal gas. The mean time for manual matching was 82 versus 65 s for DRT. XVI's DRT is comparable with RTs manually matching soft tissue on CBCT. The DRT can minimise RT inter-observer variability; however, involuntary bladder and rectal filling can influence the tools accuracy, highlighting the need for RT evaluation of the DRT match. © 2015 The Royal Australian and New Zealand College of Radiologists.

Vascularized interpositional periosteal connective tissue flap: A modern approach to augment soft tissue

PubMed Central

Agarwal, Chitra; Deora, Savita; Abraham, Dennis; Gaba, Rohini; Kumar, Baron Tarun; Kudva, Praveen

2015-01-01

Context: Nowadays esthetics plays an important role in dentistry along with function of the prosthesis. Various soft tissue augmentation procedures are available to correct the ridge defects in the anterior region. The newer technique, vascularized interpositional periosteal connective tissue (VIP-CT) flap has been introduced, which has the potential to augment predictable amount of tissue and has many benefits when compared to other techniques. Aim: The study was designed to determine the efficacy of the VIP-CT flap in augmenting the ridge defect. Materials and Methods: Ten patients with Class III (Seibert's) ridge defects were treated with VIP-CT flap technique before fabricating fixed partial denture. Height and width of the ridge defects were measured before and after the procedure. Subsequent follow-up was done every 3 months for 1-year. Statistical Analysis Used: Paired t-test was performed to detect the significance of the procedure. Results: The surgical site healed uneventfully. The predictable amount of soft tissue augmentation had been achieved with the procedure. The increase in height and width of the ridge was statistically highly significant. Conclusion: The VIP-CT flap technique was effective in augmenting the soft tissue in esthetic area that remained stable over a long period. PMID:25810597

A review of cutting mechanics and modeling techniques for biological materials.

PubMed

Takabi, Behrouz; Tai, Bruce L

2017-07-01

This paper presents a comprehensive survey on the modeling of tissue cutting, including both soft tissue and bone cutting processes. In order to achieve higher accuracy in tissue cutting, as a critical process in surgical operations, the meticulous modeling of such processes is important in particular for surgical tool development and analysis. This review paper is focused on the mechanical concepts and modeling techniques utilized to simulate tissue cutting such as cutting forces and chip morphology. These models are presented in two major categories, namely soft tissue cutting and bone cutting. Fracture toughness is commonly used to describe tissue cutting while Johnson-Cook material model is often adopted for bone cutting in conjunction with finite element analysis (FEA). In each section, the most recent mathematical and computational models are summarized. The differences and similarities among these models, challenges, novel techniques, and recommendations for future work are discussed along with each section. This review is aimed to provide a broad and in-depth vision of the methods suitable for tissue and bone cutting simulations. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

Tissue mimicking materials for dental ultrasound

PubMed Central

Singh, Rahul S.; Culjat, Martin O.; Grundfest, Warren S.; Brown, Elliott R.; White, Shane N.

2008-01-01

While acoustic tissue mimicking materials have been explored for a variety of soft and hard biological tissues, no dental hard tissue mimicking materials have been characterized. Tooth phantoms are necessary to better understand acoustic phenomenology within the tooth environment and to accelerate the advancement of dental ultrasound imaging systems. In this study, soda lime glass and dental composite were explored as surrogates for human enamel and dentin, respectively, in terms of compressional velocity, attenuation, and acoustic impedance. The results suggest that a tooth phantom consisting of glass and composite can effectively mimic the acoustic behavior of a natural human tooth. PMID:18396919

Soft bioelectronics using nanomaterials

NASA Astrophysics Data System (ADS)

Lee, Hyunjae; Kim, Dae-Hyeong

2016-09-01

Recently, soft bioelectronics has attracted significant attention because of its potential applications in biointegrated healthcare devices and minimally invasive surgical tools. Mechanical mismatch between conventional electronic/optoelectronic devices and soft human tissues/organs, however, causes many challenges in materials and device designs of bio-integrated devices. Intrinsically soft hybrid materials comprising twodimensional nanomaterials are utilized to solve these issues. In this paper, we describe soft bioelectronic devices based on graphene synthesized by a chemical vapor deposition process. These devices have unique advantages over rigid electronics, particularly in biomedical applications. The functionalized graphene is hybridized with other nanomaterials and fabricated into high-performance sensors and actuators toward wearable and minimally invasive healthcare devices. Integrated bioelectronic systems constructed using these devices solve pending issues in clinical medicine while providing new opportunities in personalized healthcare.

Sinus Floor Elevation and Augmentation Using Synthetic Nanocrystalline and Nanoporous Hydroxyapatite Bone Substitute Materials: Preliminary Histologic Results.

PubMed

Belouka, Sofia-Maria; Strietzel, Frank Peter

To compare the tissue composition of augmented sites after using two different synthetic bone substitute materials, nanocrystalline and nanoporous hydroxyapatite (HA), for sinus floor elevation and augmentation. Forty-four patients received 88 titanium screw implants (Camlog Promote plus) of 4.3-mm diameter and 11- or 13-mm length, placed simultaneously during sinus floor elevation and augmentation. Nanocrystalline (Ostim) or nanoporous (NanoBone) HA were used exclusively. Bone substitute materials and implant lengths were allocated by randomization. Bone biopsy specimens were obtained from the former area of the lateral access window at implant exposure during healing abutment placement after 6 months. Biopsy specimens were prepared and examined histologically and histomorphometrically. All implants were osseointegrated at the time of exposure. Clinically and histologically, no signs of inflammation in the augmented sites were present. The histomorphometric analysis of 44 biopsy specimens revealed 31.8% ± 11.6% newly formed bone for sites augmented with nanocrystalline HA and 34.6% ± 9.2% for nanoporous HA (P = .467). The proportion of remaining bone substitute material was 28.4% ± 18.6% and 30% ± 13%, respectively (P = .453). The proportion of soft tissue within the biopsy specimens was 39.9% ± 11.1% and 35.4% ± 6.8%, respectively (P = .064). No significant differences were found between the area fractions of bone, bone substitute material, and soft tissue concerning the bone substitute material utilized. Within the present study, both synthetic bone substitute materials, nanocrystalline and nanoporous HA, were found to support bone formation in sinus floor elevation and augmentation procedures by osteoconductivity. They were not completely resorbed after 6 months. The amounts of newly formed bone, soft tissue, and bone substitute material remnants were found to be similar, indicating that both materials are likewise suitable for sinus floor elevation and augmentation procedures.

Resonant acoustic spectroscopy of soft tissues using embedded magnetomotive nanotransducers and optical coherence tomography

PubMed Central

Oldenburg, Amy L

2010-01-01

We present a new method for performing dynamic elastography of soft tissue samples. By sensing nanoscale displacements with optical coherence tomography, a chirped, modulated force is applied to acquire the mechanical spectrum of a tissue sample within a few seconds. This modulated force is applied via magnetic nanoparticles, named ‘nanotransducers’, which are diffused into the tissue, and which contribute negligible inertia to the soft tissue mechanical system. Using this novel system, we observed that excised tissues exhibit mechanical resonance modes which are well described by a linear damped harmonic oscillator. Results are validated by using cylindrical tissue phantoms of agarose in which resonant frequencies (30–400 Hz) are consistent with longitudinal modes and the sample boundary conditions. We furthermore show that the Young’s modulus can be computed from their measured resonance frequencies, analogous to resonant ultrasound spectroscopy for stiff material analysis. Using this new technique, named magnetomotive resonant acoustic spectroscopy (MRAS), we monitored the relative stiffening of an excised rat liver during a chemical fixation process. PMID:20124653

Isolated Limb Perfusion of Melphalan With or Without Tumor Necrosis Factor in Treating Patients With Soft Tissue Sarcoma of the Arm or Leg

ClinicalTrials.gov

2012-03-14

Stage IVB Adult Soft Tissue Sarcoma; Stage IIB Adult Soft Tissue Sarcoma; Stage IIC Adult Soft Tissue Sarcoma; Recurrent Adult Soft Tissue Sarcoma; Stage IVA Adult Soft Tissue Sarcoma; Stage III Adult Soft Tissue Sarcoma

Research on Equivalent Tests of Dynamics of On-orbit Soft Contact Technology Based on On-Orbit Experiment Data

NASA Astrophysics Data System (ADS)

Yang, F.; Dong, Z. H.; Ye, X.

2018-05-01

Currently, space robots have been become a very important means of space on-orbit maintenance and support. Many countries are taking deep research and experiment on this. Because space operation attitude is very complicated, it is difficult to model them in research lab. This paper builds up a complete equivalent experiment framework according to the requirement of proposed space soft-contact technology. Also, this paper carries out flexible multi-body dynamics parameters verification for on-orbit soft-contact mechanism, which combines on-orbit experiment data, the built soft-contact mechanism equivalent model and flexible multi-body dynamics equivalent model that is based on KANE equation. The experiment results approve the correctness of the built on-orbit soft-contact flexible multi-body dynamics.

A discrete mechanics framework for real time virtual surgical simulations with application to virtual laparoscopic nephrectomy.

PubMed

Zhou, Xiangmin; Zhang, Nan; Sha, Desong; Shen, Yunhe; Tamma, Kumar K; Sweet, Robert

2009-01-01

The inability to render realistic soft-tissue behavior in real time has remained a barrier to face and content aspects of validity for many virtual reality surgical training systems. Biophysically based models are not only suitable for training purposes but also for patient-specific clinical applications, physiological modeling and surgical planning. When considering the existing approaches for modeling soft tissue for virtual reality surgical simulation, the computer graphics-based approach lacks predictive capability; the mass-spring model (MSM) based approach lacks biophysically realistic soft-tissue dynamic behavior; and the finite element method (FEM) approaches fail to meet the real-time requirement. The present development stems from physics fundamental thermodynamic first law; for a space discrete dynamic system directly formulates the space discrete but time continuous governing equation with embedded material constitutive relation and results in a discrete mechanics framework which possesses a unique balance between the computational efforts and the physically realistic soft-tissue dynamic behavior. We describe the development of the discrete mechanics framework with focused attention towards a virtual laparoscopic nephrectomy application.

The experimental and numerical investigation of pistol bullet penetrating soft tissue simulant.

PubMed

Wang, Yongjuan; Shi, Xiaoning; Chen, Aijun; Xu, Cheng

2015-04-01

Gelatin, a representative simulant for soft tissue of the human body, was used to study the effects of 9 mm pistol bullet's penetration. The behavior of a bullet penetrating gelatin was quantified by the temporary cavity sizes in ballistic gelatin and the pressure values of bullet's impact. A numerical simulation model of a bullet penetrating the soft tissue simulant gelatin was built using the finite element method (FEM). The model was validated by the comparison between the numerical results and the experimental results. During a bullet penetrating ballistic gelatin, four stages were clearly observed in both the experiment and the numerical simulation: a smooth attenuation stage, a rolling stage, a full penetration stage, and a stage of expansion and contraction. The cavity evolution, equivalent stress field and the strain field in gelatin were analyzed by numerical simulation. Moreover, the effects of the bullet's impact velocities and angles of incidence on the temporary cavity in gelatin, its velocity attenuation, and its rolling angle were investigated, as well as the bullet's resistance and energy variation. The physical process and the interactive mechanism during a pistol bullet penetrating gelatin were comprehensively revealed. This may be significant for research in wound ballistics. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

TH-AB-209-12: Tissue Equivalent Phantom with Excised Human Tissue for Assessing Clinical Capabilities of Coherent Scatter Imaging Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Albanese, K; Morris, R; Spencer, J

Purpose: Previously we reported the development of anthropomorphic tissue-equivalent scatter phantoms of the human breast. Here we present the first results from the scatter imaging of the tissue equivalent breast phantoms for breast cancer diagnosis. Methods: A breast phantom was designed to assess the capability of coded aperture coherent x-ray scatter imaging to classify different types of breast tissue (adipose, fibroglandular, tumor). The phantom geometry was obtained from a prone breast geometry scanned on a dedicated breast CT system. The phantom was 3D printed using the segmented DICOM breast CT data. The 3D breast phantom was filled with lard (asmore » a surrogate for adipose tissue) and scanned in different geometries alongside excised human breast tissues (obtained from lumpectomy and mastectomy procedures). The raw data were reconstructed using a model-based reconstruction algorithm and yielded the location and form factor (i.e., momentum transfer (q) spectrum) of the materials that were imaged. The measured material form factors were then compared to the ground truth measurements acquired by x-ray diffraction (XRD) imaging. Results: Our scatter imaging system was able to define the location and composition of the various materials and tissues within the phantom. Cancerous breast tissue was detected and classified through automated spectral matching and an 86% correlation threshold. The total scan time for the sample was approximately 10 minutes and approaches workflow times for clinical use in intra-operative or other diagnostic tasks. Conclusion: This work demonstrates the first results from an anthropomorphic tissue equivalent scatter phantom to characterize a coherent scatter imaging system. The functionality of the system shows promise in applications such as intra-operative margin detection or virtual biopsy in the diagnosis of breast cancer. Future work includes using additional patient-derived tissues (e.g., human fat), and modeling additional organs (e.g., lung).« less

The Dermal Apron Technique for Immediate Implant Socket Management: A Novel Technique.

PubMed

Levin, Barry P

2016-01-01

With immediate implant placement and provisionalization (IIP) in the esthetic zone, measures to counter hard and soft tissue loss are frequently necessary. To reduce the morbidity associated with bone and connective tissue procurement, various exogenous materials are utilized. The "Dermal Apron Technique" presented in this article demonstrates the use of a composite bone particulate (allograft/xenograft) plus a dermal allograft, adapted around screw-retained temporary crowns and secured within a subperiosteal pouch. The purpose is to augment the thickness of peri-implant mucosa for the purpose of preserving ridge dimensions and preventing mucosal recession. Controlled studies are required to further support its use. Clinical significance: Soft tissue health and harmony are critical for successful implant therapy in the esthetic regions of the dentition. Often, autogenous soft tissue grafts are used to augment peri-implant soft tissues. The Dermal Apron Technique is a method, that in specific situations, obviates the need for autogenous grafting. This reduces treatment time and morbidity associated with procurement of these grafts. The Dermal Apron Technique is used simultaneous with immediate placement and provisionalization and can improve long-term esthetic outcomes for patients. © 2016 Wiley Periodicals, Inc.

A finite nonlinear hyper-viscoelastic model for soft biological tissues.

PubMed

Panda, Satish Kumar; Buist, Martin Lindsay

2018-03-01

Soft tissues exhibit highly nonlinear rate and time-dependent stress-strain behaviour. Strain and strain rate dependencies are often modelled using a hyperelastic model and a discrete (standard linear solid) or continuous spectrum (quasi-linear) viscoelastic model, respectively. However, these models are unable to properly capture the materials characteristics because hyperelastic models are unsuited for time-dependent events, whereas the common viscoelastic models are insufficient for the nonlinear and finite strain viscoelastic tissue responses. The convolution integral based models can demonstrate a finite viscoelastic response; however, their derivations are not consistent with the laws of thermodynamics. The aim of this work was to develop a three-dimensional finite hyper-viscoelastic model for soft tissues using a thermodynamically consistent approach. In addition, a nonlinear function, dependent on strain and strain rate, was adopted to capture the nonlinear variation of viscosity during a loading process. To demonstrate the efficacy and versatility of this approach, the model was used to recreate the experimental results performed on different types of soft tissues. In all the cases, the simulation results were well matched (R 2 ⩾0.99) with the experimental data. Copyright © 2018 Elsevier Ltd. All rights reserved.

On the biomechanical function of scaffolds for engineering load-bearing soft tissues.

PubMed

Stella, John A; D'Amore, Antonio; Wagner, William R; Sacks, Michael S

2010-07-01

Replacement or regeneration of load-bearing soft tissues has long been the impetus for the development of bioactive materials. While maturing, current efforts continue to be confounded by our lack of understanding of the intricate multi-scale hierarchical arrangements and interactions typically found in native tissues. The current state of the art in biomaterial processing enables a degree of controllable microstructure that can be used for the development of model systems to deduce fundamental biological implications of matrix morphologies on cell function. Furthermore, the development of computational frameworks which allow for the simulation of experimentally derived observations represents a positive departure from what has mostly been an empirically driven field, enabling a deeper understanding of the highly complex biological mechanisms we wish to ultimately emulate. Ongoing research is actively pursuing new materials and processing methods to control material structure down to the micro-scale to sustain or improve cell viability, guide tissue growth, and provide mechanical integrity, all while exhibiting the capacity to degrade in a controlled manner. The purpose of this review is not to focus solely on material processing but to assess the ability of these techniques to produce mechanically sound tissue surrogates, highlight the unique structural characteristics produced in these materials, and discuss how this translates to distinct macroscopic biomechanical behaviors. Copyright 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Micromechanics and constitutive models for soft active materials with phase evolution

NASA Astrophysics Data System (ADS)

Wang, Binglian

Soft active materials, such as shape memory polymers, liquid crystal elastomers, soft tissues, gels etc., are materials that can deform largely in response to external stimuli. Micromechanics analysis of heterogeneous materials based on finite element method is a typically numerical way to study the thermal-mechanical behaviors of soft active materials with phase evolution. While the constitutive models that can precisely describe the stress and strain fields of materials in the process of phase evolution can not be found in the databases of some commercial finite element analysis (FEA) tools such as ANSYS or Abaqus, even the specific constitutive behavior for each individual phase either the new formed one or the original one has already been well-known. So developing a computationally efficient and general three dimensional (3D) thermal-mechanical constitutive model for soft active materials with phase evolution which can be implemented into FEA is eagerly demanded. This paper first solved this problem theoretically by recording the deformation history of each individual phase in the phase evolution process, and adopted the idea of effectiveness by regarding all the new formed phase as an effective phase with an effective deformation to make this theory computationally efficient. A user material subroutine (UMAT) code based on this theoretical constitutive model has been finished in this work which can be added into the material database in Abaqus or ANSYS and can be easily used for most soft active materials with phase evolution. Model validation also has been done through comparison between micromechanical FEA and experiments on a particular composite material, shape memory elastomeric composite (SMEC) which consisted of an elastomeric matrix and the crystallizable fibre. Results show that the micromechanics and the constitutive models developed in this paper for soft active materials with phase evolution are completely relied on.

Reinforcement of mono- and bi-layer poly(ethylene glycol) hydrogels with a fibrous collagen scaffold

PubMed Central

Kinneberg, K. R. C.; Nelson, A.; Stender, M.; Aziz, A. H.; Mozdzen, L. C.; Harley, B. A. C.; Bryant, S. J.; Ferguson, V. L.

2015-01-01

Biomaterial-based tissue engineering strategies hold great promise for osteochondral tissue repair. Yet significant challenges remain in joining highly dissimilar materials to achieve a biomimetic, mechanically robust design for repairing interfaces between soft tissue and bone. This study sought to improve interfacial properties and function in a bilayer, multi-phase hydrogel interpenetrated with a fibrous collagen scaffold. ‘Soft’ 10% (w/w) and ‘stiff’ 30% (w/w) PEGDM was formed into mono- or bilayer hydrogels possessing a sharp diffusional interface. Hydrogels were evaluated as single- (hydrogel only) or multi-phase (hydrogel+fibrous scaffold penetrating throughout the stiff layer and extending >500μm into the soft layer). Including a fibrous scaffold into both soft and stiff single-phase hydrogels significantly increased tangent modulus and toughness and decreased lateral expansion under compressive loading. In multi-phase hydrogels, finite element simulations predict substantially reduced stress and strain gradients across the soft—stiff hydrogel interface. When combining two low moduli constituent material, composites theory poorly predicts the observed, large modulus increases. These results suggest material structure associated with the fibrous scaffold penetrating within the PEG hydrogel as the major contributor to improved properties and function – the hydrogel bore compressive loads and the 3D fibrous scaffold was loaded in tension thus resisting lateral expansion. PMID:26001970

Evaluation of Light-Activated Provisional Resin Materials for Periodontal Soft Tissue Management

PubMed Central

Jun, Soo-Kyung; Lee, Hae-Hyoung

2016-01-01

The purpose of this study was to determine mechanical properties using a compressive test with cylinder specimen (h = 6 mm and ϕ = 4 mm) as well as cytotoxicity using elutes from disk specimen (ϕ = 10 mm and h = 2 mm) against human gingival fibroblasts and oral keratinocytes with light-activated provisional resin materials (Revotek LC and Luxatemp Solar) compared to chemically activated counterpart (Snap, Trim II, and Jet). Significantly increased compressive strength (210~280 MPa) was detected in light-activated products compared to chemically activated ones (20~65 MPa, P < 0.05) and similar compressive modulus was detected in both types (0.8~1.5 and 0.5~1.3 GPa). Simultaneously, the light-activated products showed less adverse effects on the periodontal soft tissue cells in any polymerization stage compared to the chemically activated products. Particularly, chemically activated products had significantly greater adverse effects during the “polymerizing” phase compared to those that were “already set” (P < 0.05), as shown in confocal microscopic images of live and dead cells. In conclusion, light-activated provisional resin materials have better mechanical properties as well as biocompatibility against two tested types of oral cells compared to the chemically activated counterpart, which are considered as more beneficial choice for periodontal soft tissue management. PMID:27672651

Evaluation of Light-Activated Provisional Resin Materials for Periodontal Soft Tissue Management.

PubMed

Jun, Soo-Kyung; Lee, Hae-Hyoung; Lee, Jung-Hwan

The purpose of this study was to determine mechanical properties using a compressive test with cylinder specimen ( h = 6 mm and ϕ = 4 mm) as well as cytotoxicity using elutes from disk specimen ( ϕ = 10 mm and h = 2 mm) against human gingival fibroblasts and oral keratinocytes with light-activated provisional resin materials (Revotek LC and Luxatemp Solar) compared to chemically activated counterpart (Snap, Trim II, and Jet). Significantly increased compressive strength (210~280 MPa) was detected in light-activated products compared to chemically activated ones (20~65 MPa, P < 0.05) and similar compressive modulus was detected in both types (0.8~1.5 and 0.5~1.3 GPa). Simultaneously, the light-activated products showed less adverse effects on the periodontal soft tissue cells in any polymerization stage compared to the chemically activated products. Particularly, chemically activated products had significantly greater adverse effects during the "polymerizing" phase compared to those that were "already set" ( P < 0.05), as shown in confocal microscopic images of live and dead cells. In conclusion, light-activated provisional resin materials have better mechanical properties as well as biocompatibility against two tested types of oral cells compared to the chemically activated counterpart, which are considered as more beneficial choice for periodontal soft tissue management.

Study on biphasic material model and mechanical analysis of knee joint cartilage

NASA Astrophysics Data System (ADS)

Nakatani, A.; Sakashita, A.

2008-02-01

A material model of articular cartilage is formulated, and fundamental problems are analyzed. The soft tissue is assumed to comprise two phases: solid and fluid. The biphasic theory proposed by Spilker and Suh (1990) to deal with such materials is reviewed, and some new additional analyses are carried out on the basis of this theory. Assuming the elasticity for the solid phase and introducing the pressure, which is defined by the product of the volume change and penalty coefficient, it is shown that the viscoelastic property of the soft tissue can be reproduced. A preferable solution is obtained for the solid phase by using the reduction integral, even if a high-order interpolation function is used. However, the high-order element cannot satisfactorily capture the velocity distribution of fluids. The pressure distribution is studied by assuming the change in the surface characteristics of the cartilage tissue with the progress of osteoarthritis. The pressure is strongly related to the lubrication conditions, i.e., perfect lubrication, perfect adhesion, and partial adhesion.

Supersoft lithography: Candy-based fabrication of soft silicone microstructures

PubMed Central

Moraes, Christopher; Labuz, Joseph M.; Shao, Yue; Fu, Jianping; Takayama, Shuichi

2015-01-01

We designed a fabrication technique able to replicate microstructures in soft silicone materials (E < 1 kPa). Sugar-based ‘hard candy’ recipes from the confectionery industry were modified to be compatible with silicone processing conditions, and used as templates for replica molding. Microstructures fabricated in soft silicones can then be easily released by dissolving the template in water. We anticipate that this technique will be of particular importance in replicating physiologically soft, microstructured environments for cell culture, and demonstrate a first application in which intrinsically soft microstructures are used to measure forces generated by fibroblast-laden contractile tissues. PMID:26245893

Supersoft lithography: candy-based fabrication of soft silicone microstructures.

PubMed

Moraes, Christopher; Labuz, Joseph M; Shao, Yue; Fu, Jianping; Takayama, Shuichi

2015-01-01

We designed a fabrication technique able to replicate microstructures in soft silicone materials (E < 1 kPa). Sugar-based 'hard candy' recipes from the confectionery industry were modified to be compatible with silicone processing conditions, and used as templates for replica molding. Microstructures fabricated in soft silicones can then be easily released by dissolving the template in water. We anticipate that this technique will be of particular importance in replicating physiologically soft, microstructured environments for cell culture, and demonstrate a first application in which intrinsically soft microstructures are used to measure forces generated by fibroblast-laden contractile tissues.

Novel three-dimensional autologous tissue-engineered vaginal tissues using the self-assembly technique.

PubMed

Orabi, Hazem; Saba, Ingrid; Rousseau, Alexandre; Bolduc, Stéphane

2017-02-01

Many diseases necessitate the substitution of vaginal tissues. Current replacement therapies are associated with many complications. In this study, we aimed to create bioengineered neovaginas with the self-assembly technique using autologous vaginal epithelial (VE) and vaginal stromal (VS) cells without the use of exogenous materials and to document the survival and incorporation of these grafts into the tissues of nude female mice. Epithelial and stromal cells were isolated from vaginal biopsies. Stromal cells were driven to form collagen sheets, 3 of which were superimposed to form vaginal stromas. VE cells were seeded on top of these stromas and allowed to mature in an air-liquid interface. The vaginal equivalents were implanted subcutaneously in female nude mice, which were sacrificed after 1 and 2 weeks after surgery. The in vitro and animal-retrieved equivalents were assessed using histologic, functional, and mechanical evaluations. Vaginal equivalents could be handled easily. VE cells formed a well-differentiated epithelial layer with a continuous basement membrane. The equivalent matrix was composed of collagen I and III and elastin. The epithelium, basement membrane, and stroma were comparable to those of native vaginal tissues. The implanted equivalents formed mature vaginal epithelium and matrix that were integrated into the mice tissues. Using the self-assembly technique, in vitro vaginal tissues were created with many functional and biological similarities to native vagina without any foreign material. They formed functional vaginal tissues after in vivo animal implantation. It is appropriate for vaginal substitution and disease modeling for infectious studies, vaginal applicants, and drug testing. Copyright © 2016 Elsevier Inc. All rights reserved.

MCNP modelling of the wall effects observed in tissue-equivalent proportional counters.

PubMed

Hoff, J L; Townsend, L W

2002-01-01

Tissue-equivalent proportional counters (TEPCs) utilise tissue-equivalent materials to depict homogeneous microscopic volumes of human tissue. Although both the walls and gas simulate the same medium, they respond to radiation differently. Density differences between the two materials cause distortions, or wall effects, in measurements, with the most dominant effect caused by delta rays. This study uses a Monte Carlo transport code, MCNP, to simulate the transport of secondary electrons within a TEPC. The Rudd model, a singly differential cross section with no dependence on electron direction, is used to describe the energy spectrum obtained by the impact of two iron beams on water. Based on the models used in this study, a wall-less TEPC had a higher lineal energy (keV.micron-1) as a function of impact parameter than a solid-wall TEPC for the iron beams under consideration. An important conclusion of this study is that MCNP has the ability to model the wall effects observed in TEPCs.

Tissue Equivalent Phantom Design for Characterization of a Coherent Scatter X-ray Imaging System

NASA Astrophysics Data System (ADS)

Albanese, Kathryn Elizabeth

Scatter in medical imaging is typically cast off as image-related noise that detracts from meaningful diagnosis. It is therefore typically rejected or removed from medical images. However, it has been found that every material, including cancerous tissue, has a unique X-ray coherent scatter signature that can be used to identify the material or tissue. Such scatter-based tissue-identification provides the advantage of locating and identifying particular materials over conventional anatomical imaging through X-ray radiography. A coded aperture X-ray coherent scatter spectral imaging system has been developed in our group to classify different tissue types based on their unique scatter signatures. Previous experiments using our prototype have demonstrated that the depth-resolved coherent scatter spectral imaging system (CACSSI) can discriminate healthy and cancerous tissue present in the path of a non-destructive x-ray beam. A key to the successful optimization of CACSSI as a clinical imaging method is to obtain anatomically accurate phantoms of the human body. This thesis describes the development and fabrication of 3D printed anatomical scatter phantoms of the breast and lung. The purpose of this work is to accurately model different breast geometries using a tissue equivalent phantom, and to classify these tissues in a coherent x-ray scatter imaging system. Tissue-equivalent anatomical phantoms were designed to assess the capability of the CACSSI system to classify different types of breast tissue (adipose, fibroglandular, malignant). These phantoms were 3D printed based on DICOM data obtained from CT scans of prone breasts. The phantoms were tested through comparison of measured scatter signatures with those of adipose and fibroglandular tissue from literature. Tumors in the phantom were modeled using a variety of biological tissue including actual surgically excised benign and malignant tissue specimens. Lung based phantoms have also been printed for future testing. Our imaging system has been able to define the location and composition of the various materials in the phantom. These phantoms were used to characterize the CACSSI system in terms of beam width and imaging technique. The result of this work showed accurate modeling and characterization of the phantoms through comparison of the tissue-equivalent form factors to those from literature. The physical construction of the phantoms, based on actual patient anatomy, was validated using mammography and computed tomography to visually compare the clinical images to those of actual patient anatomy.

Mechanics of ultrasound elastography

PubMed Central

Li, Guo-Yang

2017-01-01

Ultrasound elastography enables in vivo measurement of the mechanical properties of living soft tissues in a non-destructive and non-invasive manner and has attracted considerable interest for clinical use in recent years. Continuum mechanics plays an essential role in understanding and improving ultrasound-based elastography methods and is the main focus of this review. In particular, the mechanics theories involved in both static and dynamic elastography methods are surveyed. They may help understand the challenges in and opportunities for the practical applications of various ultrasound elastography methods to characterize the linear elastic, viscoelastic, anisotropic elastic and hyperelastic properties of both bulk and thin-walled soft materials, especially the in vivo characterization of biological soft tissues. PMID:28413350

Histopathological Diagnostic Discrepancies in Soft Tissue Tumours Referred to a Specialist Centre: Reassessment in the Era of Ancillary Molecular Diagnosis

PubMed Central

Thway, Khin; Mubako, Taka

2014-01-01

Introduction. Soft tissue tumour pathology is a highly specialised area of surgical pathology, but soft tissue neoplasms can occur at virtually all sites and are therefore encountered by a wide population of surgical pathologists. Potential sarcomas require referral to specialist centres for review by pathologists who see a large number of soft tissue lesions and where appropriate ancillary investigations can be performed. We have previously assessed the types of diagnostic discrepancies between referring and final diagnosis for soft tissue lesions referred to our tertiary centre. We now reaudit this 6 years later, assessing changes in discrepancy patterns, particularly in relation to the now widespread use of ancillary molecular diagnostic techniques which were not prevalent in our original study. Materials and Methods. We compared the sarcoma unit's histopathology reports with referring reports on 348 specimens from 286 patients with suspected or proven soft tissue tumours in a one-year period. Results. Diagnostic agreement was seen in 250 cases (71.8%), with 57 (16.4%) major and 41 (11.8%) minor discrepancies. There were 23 cases of benign/malignant discrepancies (23.5% of all discrepancies). 50 ancillary molecular tests were performed, 33 for aiding diagnosis and 17 mutational analyses for gastrointestinal stromal tumour to guide therapy. Findings from ancillary techniques contributed to 3 major and 4 minor discrepancies. While the results were broadly similar to those of the previous study, there was an increase in frequency of major discrepancies. Conclusion. Six years following our previous study and notably now in an era of widespread ancillary molecular diagnosis, the overall discrepancy rate between referral and tertiary centre diagnosis remains similar, but there is an increase in frequency of major discrepancies likely to alter patient management. A possible reason for the increase in major discrepancies is the increasing lack of exposure to soft tissue cases in nonspecialist centres in a time of subspecialisation. The findings support the national guidelines in which all suspected soft tissue tumour pathology specimens should be referred to a specialist sarcoma unit. PMID:25165418

Histopathological diagnostic discrepancies in soft tissue tumours referred to a specialist centre: reassessment in the era of ancillary molecular diagnosis.

PubMed

Thway, Khin; Wang, Jayson; Mubako, Taka; Fisher, Cyril

2014-01-01

Introduction. Soft tissue tumour pathology is a highly specialised area of surgical pathology, but soft tissue neoplasms can occur at virtually all sites and are therefore encountered by a wide population of surgical pathologists. Potential sarcomas require referral to specialist centres for review by pathologists who see a large number of soft tissue lesions and where appropriate ancillary investigations can be performed. We have previously assessed the types of diagnostic discrepancies between referring and final diagnosis for soft tissue lesions referred to our tertiary centre. We now reaudit this 6 years later, assessing changes in discrepancy patterns, particularly in relation to the now widespread use of ancillary molecular diagnostic techniques which were not prevalent in our original study. Materials and Methods. We compared the sarcoma unit's histopathology reports with referring reports on 348 specimens from 286 patients with suspected or proven soft tissue tumours in a one-year period. Results. Diagnostic agreement was seen in 250 cases (71.8%), with 57 (16.4%) major and 41 (11.8%) minor discrepancies. There were 23 cases of benign/malignant discrepancies (23.5% of all discrepancies). 50 ancillary molecular tests were performed, 33 for aiding diagnosis and 17 mutational analyses for gastrointestinal stromal tumour to guide therapy. Findings from ancillary techniques contributed to 3 major and 4 minor discrepancies. While the results were broadly similar to those of the previous study, there was an increase in frequency of major discrepancies. Conclusion. Six years following our previous study and notably now in an era of widespread ancillary molecular diagnosis, the overall discrepancy rate between referral and tertiary centre diagnosis remains similar, but there is an increase in frequency of major discrepancies likely to alter patient management. A possible reason for the increase in major discrepancies is the increasing lack of exposure to soft tissue cases in nonspecialist centres in a time of subspecialisation. The findings support the national guidelines in which all suspected soft tissue tumour pathology specimens should be referred to a specialist sarcoma unit.

SU-E-I-44: Some Preliminary Analysis of Angular Distribution of X-Ray Scattered On Soft Tissues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ganezer, K; Krmar, M; Cvejic, Z

2015-06-15

Purpose: The angular distribution of x-radiation scattered at small angles (up to 16 degrees) from several different animal soft tissue (skin, fat, muscle, retina, etc) were measured using standard equipment devoted to study of crystal structure which provides excellent geometry conditions of measurements. showed measurable differences for different tissues. In the simplest possible case when measured samples do not differ in structure (different concentration solutions) it can be seen that intensity of scattered radiation is decreasing function of the concentration and the peak of the maximum of scattering distribution depends on the concentration as well. Methods: An x-ray scattering profilemore » usually consists of sharp diffraction peak; however some properties of the spatial profiles of scattered radiation as intensity, the peak position, height, area, FWHM, the ratio of peak heights, etc. Results: The data contained measurable differences for different tissues. In the simplest possible case when measured samples do not differ in structure (different concentration solutions) it can be seen that intensity of scattered radiation is decreasing function of the concentration and the peak of the maximum of scattering distribution depends on the concentration as well. Measurements of different samples in the very preliminary phase showed that simple biological material used in study showed slightly different scattering pattern, especially at higher angles (around 10degrees). Intensity of radiation scattered from same tissue type is very dependent on water content and several more parameters. Conclusion: This preliminary study using animal soft tissues on the angular distributions of scattered x-rays suggests that angular distributions of X-rays scattered off of soft tissues might be useful in distinguishing healthy tissue from malignant soft tissue.« less

Manipulation of mechanical compliance of elastomeric PGS by incorporation of halloysite nanotubes for soft tissue engineering applications.

PubMed

Chen, Qi-Zhi; Liang, Shu-Ling; Wang, Jiang; Simon, George P

2011-11-01

Poly (glycerol sebacate) (PGS) is a promising elastomer for use in soft tissue engineering. However, it is difficult to achieve with PGS a satisfactory balance of mechanical compliance and degradation rate that meet the requirements of soft tissue engineering. In this work, we have synthesised a new PGS nanocomposite system filled with halloysite nanotubes, and mechanical properties, as well as related chemical characters, of the nanocomposites were investigated. It was found that the addition of nanotubular halloysite did not compromise the extensibility of material, compared with the pure PGS counterpart; instead the elongation at rupture was increased from 110 (in the pure PGS) to 225% (in the 20 wt% composite). Second, Young's modulus and resilience of 3-5 wt% composites were ∼0.8 MPa and >94% respectively, remaining close to the level of pure PGS which is desired for applications in soft tissue engineering. Third, an important feature of the 1-5 wt% composites was their stable mechanical properties over an extended period, which could allow the provision of reliable mechanical support to damaged tissues during the lag phase of the healing process. Finally, the in vitro study indicated that the addition of halloysite slowed down the degradation rate of the composites. In conclusion, the good compliance, enhanced stretchability, stable mechanical behavior over an extended period, and reduced degradation rates make the 3-5 wt% composites promising candidates for application in soft tissue engineering. Copyright © 2011 Elsevier Ltd. All rights reserved.

How to characterize a nonlinear elastic material? A review on nonlinear constitutive parameters in isotropic finite elasticity

PubMed Central

2017-01-01

The mechanical response of a homogeneous isotropic linearly elastic material can be fully characterized by two physical constants, the Young’s modulus and the Poisson’s ratio, which can be derived by simple tensile experiments. Any other linear elastic parameter can be obtained from these two constants. By contrast, the physical responses of nonlinear elastic materials are generally described by parameters which are scalar functions of the deformation, and their particular choice is not always clear. Here, we review in a unified theoretical framework several nonlinear constitutive parameters, including the stretch modulus, the shear modulus and the Poisson function, that are defined for homogeneous isotropic hyperelastic materials and are measurable under axial or shear experimental tests. These parameters represent changes in the material properties as the deformation progresses, and can be identified with their linear equivalent when the deformations are small. Universal relations between certain of these parameters are further established, and then used to quantify nonlinear elastic responses in several hyperelastic models for rubber, soft tissue and foams. The general parameters identified here can also be viewed as a flexible basis for coupling elastic responses in multi-scale processes, where an open challenge is the transfer of meaningful information between scales. PMID:29225507

SU-E-T-283: Dose Perturbations Near Heterogeneity Junctions for Modulated-Scanning Protons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deng, Y; Li, Y; Sheng, Y

2015-06-15

Purpose: To compare calculated and measured doses near heterogeneity junctions of tissue-substitute materials for modulated-scanning protons. Methods: Three heterogeneous phantoms were configured using slabs of various plastics to simulate lung, fat, soft-tissue (polystyrene), and bone with known relative linear stopping powers (RLSPs). Each phantom consisted of soft-tissue and a single heterogeneity of a 5 or 10 cm thickness of a non-soft-tissue material. CT images were loaded into a Syngo treatment planning system and each material contoured and assigned its RLSP. Planning target volumes (PTVs) were drawn such that a beam would partially traverse the heterogeneity and partially only soft-tissue. Lateralmore » profiles were measured using EDR2 films at a minimum of six depths between the phantom surface and the depth corresponding to the beam range. Absolute doses were measured inside and distal to the PTV in all phantoms using either a parallel plate or thimble chamber. Additional dose measurements were made between two lung slabs. Results: Profiles measured by film generally agreed with calculations except for depths distal to lung and fat junctions. Measured lateral penumbras for depths at the distal junction of lung were found to be wider than calculated ones. Compared with calculated doses, measured doses in the PTVs were 5.19% and 2.51% lower for lung and fat respectively but for bone were 0.2% higher. Measured doses for depths distal to the PTV were up to 29.65% and 10.58% higher for lung and fat, respectively but 6.30% lower for bone. Conclusion: The low measured doses in the PTVs for lung and fat might be due to underestimation of lateral scattering of protons. The higher measured doses distal to the PTV for the lung and fat are a Result of a shortened calculated beam range whereas the higher dose distal to the bone junction is within uncertainties.« less

[The effect of composition and structure of radiological equivalent materials on radiological equivalent].

PubMed

Wang, Y; Lin, D; Fu, T

1997-03-01

Morphology of inorganic material powders before and after being treated by ultrafine crush was observed by transformite electron microscope. The length and diameter of granules were measured. Polymers inorganic material powders before and after being treated by ultrafine crush were used for preparing radiological equivalent materials. Blending compatibility of inorganic meterials with polymer materials was observed by scanning electron microscope. CT values of tissue equivalent materials were measured by X-ray CT. Distribution of inorganic materials was examined. The compactness of materials was determined by the water absorbed method. The elastic module of materials was measured by laser speckle interferementry method. The results showed that the inorganic material powders treated by the ultrafine crush blent well with polymer and the distribution of these powders in the polymer was homogeneous. The equivalent errors of linear attenuation coefficients and CT values of equivalent materials were small. Their elastic modules increased one order of magnitude from 6.028 x 10(2) kg/cm2 to 9.753 x 10(3) kg/cm2. In addition, the rod inorganic material powders having rod granule blent easily with polymer. The present study provides a theoretical guidance and experimental basis for the design and synthesis of radiological equivalent materials.

Release of metal in vivo from stressed and nonstressed maxillofacial fracture plates and screws.

PubMed

Matthew, I R; Frame, J W

2000-07-01

To analyze the release of metal into the adjacent tissues from stressed and nonstressed titanium and stainless steel miniplates and screws. Two miniplates were inserted into the cranial vaults of 12 beagle dogs while they were under general endotracheal anesthesia. One miniplate was shaped to fit the curvature of the skull (control). Another miniplate, made of the same material, was bent in a curve until the midpoint was raised 3 mm above the ends. Screws were inserted and tightened until the plate conformed to the skull curvature, creating stresses in the system. Four animals (2 each, having titanium or stainless steel plates and screws) were killed after 4, 12, and 24 weeks. Metallosis of adjacent soft tissues was assessed qualitatively. Miniplates and screws were removed, and adjacent soft tissue and bone was excised. Titanium, iron, chromium, nickel, and aluminum levels were assayed by ultraviolet/visible light and atomic absorption spectrophotometry. Nonparametric statistical methods were used for data analysis. There was no clear relationship between pigmentation of soft tissue adjacent to the miniplates and screws and the concentrations of metal present. The data did not demonstrate any consistent differences in the concentrations of metallic elements next to stressed and nonstressed (control) miniplates and screws of either material. Stresses arising through poor contouring of miniplates do not appear to influence the extent of release of metal into the adjacent tissues.

A repeated-measures analysis of the effects of soft tissues on wrist range of motion in the extant phylogenetic bracket of dinosaurs: Implications for the functional origins of an automatic wrist folding mechanism in Crocodilia.

PubMed

Hutson, Joel David; Hutson, Kelda Nadine

2014-07-01

A recent study hypothesized that avian-like wrist folding in quadrupedal dinosaurs could have aided their distinctive style of locomotion with semi-pronated and therefore medially facing palms. However, soft tissues that automatically guide avian wrist folding rarely fossilize, and automatic wrist folding of unknown function in extant crocodilians has not been used to test this hypothesis. Therefore, an investigation of the relative contributions of soft tissues to wrist range of motion (ROM) in the extant phylogenetic bracket of dinosaurs, and the quadrupedal function of crocodilian wrist folding, could inform these questions. Here, we repeatedly measured wrist ROM in degrees through fully fleshed, skinned, minus muscles/tendons, minus ligaments, and skeletonized stages in the American alligator Alligator mississippiensis and the ostrich Struthio camelus. The effects of dissection treatment and observer were statistically significant for alligator wrist folding and ostrich wrist flexion, but not ostrich wrist folding. Final skeletonized wrist folding ROM was higher than (ostrich) or equivalent to (alligator) initial fully fleshed ROM, while final ROM was lower than initial ROM for ostrich wrist flexion. These findings suggest that, unlike the hinge/ball and socket-type elbow and shoulder joints in these archosaurs, ROM within gliding/planar diarthrotic joints is more restricted to the extent of articular surfaces. The alligator data indicate that the crocodilian wrist mechanism functions to automatically lock their semi-pronated palms into a rigid column, which supports the hypothesis that this palmar orientation necessitated soft tissue stiffening mechanisms in certain dinosaurs, although ROM-restricted articulations argue against the presence of an extensive automatic mechanism. Anat Rec, 297:1228-1249, 2014. © 2014 Wiley Periodicals, Inc. © 2014 Wiley Periodicals, Inc.

Motorcyclists and pillion passengers with open lower-limb fractures: a study using TARN data 2007-2014.

PubMed

Hay-David, Agc; Stacey, T; Pallister, I

2018-03-01

Introduction We aimed to identify population demographics of motorcyclists and pillion passengers with isolated open lower-limb fractures, to ascertain the impact of the revised 2009 British Orthopaedic Association/British Association of Plastic Reconstructive and Aesthetic Surgeons joint standards for the management of open fractures of the lower limb (BOAST 4), in terms of time to skeletal stabilisation and soft-tissue coverage, and to observe any impact on patient movement. Methods Retrospective cohort data was collected by the Trauma Audit and Research Network (TARN). A longitudinal analysis was performed between two timeframes in England (pre-and post-BOAST 4 revision): 2007-2009 and 2010-2014. Results A total of 1564 motorcyclists and 64 pillion passengers were identified. Of these, 93% (1521/1628) were male. The median age for males was 30.5 years and 36.7 years for females. There was a statistically significant difference in the number of patients who underwent skeletal stabilisation (49% vs 65%, P < 0.0001), the time from injury to skeletal stabilisation (7.33 hours vs 14.3 hours, P < 0.0001) and the proportion receiving soft-tissue coverage (26% vs 43%, P < 0.0001). There was no difference in the time from injury to soft-tissue coverage (62.3 hours vs 63.7 hours, P = 0.726). The number of patients taken directly to a major trauma centre (or its equivalent) increased between the two timeframes (12.5% vs, 41%, P < 0.001). Conclusions Since the 2009 BOAST 4 revision, there has been no difference in the time taken from injury to soft-tissue coverage but the time from injury to skeletal stabilisation is longer. There has also been an increase in patient movement to centres offering joint orthopaedic and plastic care.

Linezolid versus Vancomycin in Treatment of Complicated Skin and Soft Tissue Infections

PubMed Central

Weigelt, John; Itani, Kamal; Stevens, Dennis; Lau, William; Dryden, Matthew; Knirsch, Charles

2005-01-01

Skin and soft tissue infections (SSTIs) are a common cause of morbidity in both the community and the hospital. An SSTI is classified as complicated if the infection has spread to the deeper soft tissues, if surgical intervention is necessary, or if the patient has a comorbid condition hindering treatment response (e.g., diabetes mellitus or human immunodeficiency virus). The purpose of this study was to compare linezolid to vancomycin in the treatment of suspected or proven methicillin-resistant gram-positive complicated SSTIs (CSSTIs) requiring hospitalization. This was a randomized, open-label, comparator-controlled, multicenter, multinational study that included patients with suspected or proven methicillin-resistant Staphylococcus aureus (MRSA) infections that involved substantial areas of skin or deeper soft tissues, such as cellulitis, abscesses, infected ulcers, or burns (<10% of total body surface area). Patients were randomized (1:1) to receive linezolid (600 mg) every 12 h either intravenously (i.v.) or orally or vancomycin (1 g) every 12 h i.v. In the intent-to-treat population, 92.2% and 88.5% of patients treated with linezolid and vancomycin, respectively, were clinically cured at the test-of-cure (TOC) visit (P = 0.057). Linezolid outcomes (124/140 patients or 88.6%) were superior to vancomycin outcomes (97/145 patients or 66.9%) at the TOC visit for patients with MRSA infections (P < 0.001). Drug-related adverse events were reported in similar numbers in both the linezolid and the vancomycin arms of the trial. The results of this study demonstrate that linezolid therapy is well tolerated, equivalent to vancomycin in treating CSSTIs, and superior to vancomycin in the treatment of CSSTIs due to MRSA. PMID:15917519

The versatile subepithelial connective tissue graft: a literature update.

PubMed

Karthikeyan, B V; Khanna, Divya; Chowdhary, Kamedh Yashawant; Prabhuji, M Lv

2016-01-01

Harmony between hard and soft tissue morphologies is essential for form, function, and a good esthetic outlook. Replacement grafts for correction of soft tissue defects around the teeth have become important to periodontal plastic and implant surgical procedures. Among a multitude of surgical techniques and graft materials reported in literature, the subepithelial connective tissue graft (SCTG) has gained wide popularity and acceptance. The purpose of this article is to acquaint clinicians with the current understanding of the versatile SCTG. Key factors associated with graft harvesting as well as applications, limitations, and complications of SCTGs are discussed. This connective tissue has shown excellent short- and long-term stability, is easily available, and is economical to use. The SCTG should be considered as an alternative in all periodontal reconstruction surgeries.

Stretchable conducting materials with multi-scale hierarchical structures for biomedical applications

NASA Astrophysics Data System (ADS)

Kim, Hyun; Shim, Bong Sup

2014-08-01

Electrogenetic tissues in human body such as central and peripheral nerve systems, muscular and cardiomuscular systems are soft and stretchable materials. However, most of the artificial materials, interfacing with those conductive tissues, such as neural electrodes and cardiac pacemakers, have stiff mechanical properties. The rather contradictory properties between natural and artificial materials usually cause critical incompatibility problems in implanting bodymachine interfaces for wide ranges of biomedical devices. Thus, we developed a stretchable and electrically conductive material with complex hierarchical structures; multi-scale microstructures and nanostructural electrical pathways. For biomedical purposes, an implantable polycaprolactone (PCL) membrane was coated by molecularly controlled layer-bylayer (LBL) assembly of single-walled carbon nanotubes (SWNTs) or poly(3,4-ethylenedioxythiophene) (PEDOT). The soft PCL membrane with asymmetric micro- and nano-pores provides elastic properties, while conductive SWNT or PEDOT coating preserves stable electrical conductivity even in a fully stretched state. This electrical conductivity enhanced ionic cell transmission and cell-to-cell interactions as well as electrical cellular stimulation on the membrane. Our novel stretchable conducting materials will overcome long-lasting challenges for bioelectronic applications by significantly reducing mechanical property gaps between tissues and artificial materials and by providing 3D interconnected electro-active pathways which can be available even at a fully stretched state.

Modeling of anisotropic wound healing

NASA Astrophysics Data System (ADS)

Valero, C.; Javierre, E.; García-Aznar, J. M.; Gómez-Benito, M. J.; Menzel, A.

2015-06-01

Biological soft tissues exhibit non-linear complex properties, the quantification of which presents a challenge. Nevertheless, these properties, such as skin anisotropy, highly influence different processes that occur in soft tissues, for instance wound healing, and thus its correct identification and quantification is crucial to understand them. Experimental and computational works are required in order to find the most precise model to replicate the tissues' properties. In this work, we present a wound healing model focused on the proliferative stage that includes angiogenesis and wound contraction in three dimensions and which relies on the accurate representation of the mechanical behavior of the skin. Thus, an anisotropic hyperelastic model has been considered to analyze the effect of collagen fibers on the healing evolution of an ellipsoidal wound. The implemented model accounts for the contribution of the ground matrix and two mechanically equivalent families of fibers. Simulation results show the evolution of the cellular and chemical species in the wound and the wound volume evolution. Moreover, the local strain directions depend on the relative wound orientation with respect to the fibers.

Computational model of soft tissues in the human upper airway.

PubMed

Pelteret, J-P V; Reddy, B D

2012-01-01

This paper presents a three-dimensional finite element model of the tongue and surrounding soft tissues with potential application to the study of sleep apnoea and of linguistics and speech therapy. The anatomical data was obtained from the Visible Human Project, and the underlying histological data was also extracted and incorporated into the model. Hyperelastic constitutive models were used to describe the material behaviour, and material incompressibility was accounted for. An active Hill three-element muscle model was used to represent the muscular tissue of the tongue. The neural stimulus for each muscle group was determined through the use of a genetic algorithm-based neural control model. The fundamental behaviour of the tongue under gravitational and breathing-induced loading is investigated. It is demonstrated that, when a time-dependent loading is applied to the tongue, the neural model is able to control the position of the tongue and produce a physiologically realistic response for the genioglossus.

A mechano-acoustic indentor system for in vivo measurement of nonlinear elastic properties of soft tissue.

PubMed

Koo, Terry K; Cohen, Jeffrey H; Zheng, Yongping

2011-11-01

Soft tissue exhibits nonlinear stress-strain behavior under compression. Characterizing its nonlinear elasticity may aid detection, diagnosis, and treatment of soft tissue abnormality. The purposes of this study were to develop a rate-controlled Mechano-Acoustic Indentor System and a corresponding finite element optimization method to extract nonlinear elastic parameters of soft tissue and evaluate its test-retest reliability. An indentor system using a linear actuator to drive a force-sensitive probe with a tip-mounted ultrasound transducer was developed. Twenty independent sites at the upper lateral quadrant of the buttock from 11 asymptomatic subjects (7 men and 4 women from a chiropractic college) were indented at 6% per second for 3 sessions, each consisting of 5 trials. Tissue thickness, force at 25% deformation, and area under the load-deformation curve from 0% to 25% deformation were calculated. Optimized hyperelastic parameters of the soft tissue were calculated with a finite element model using a first-order Ogden material model. Load-deformation response on a standardized block was then simulated, and the corresponding area and force parameters were calculated. Between-trials repeatability and test-retest reliability of each parameter were evaluated using coefficients of variation and intraclass correlation coefficients, respectively. Load-deformation responses were highly reproducible under repeated measurements. Coefficients of variation of tissue thickness, area under the load-deformation curve from 0% to 25% deformation, and force at 25% deformation averaged 0.51%, 2.31%, and 2.23%, respectively. Intraclass correlation coefficients ranged between 0.959 and 0.999, indicating excellent test-retest reliability. The automated Mechano-Acoustic Indentor System and its corresponding optimization technique offers a viable technology to make in vivo measurement of the nonlinear elastic properties of soft tissue. This technology showed excellent between-trials repeatability and test-retest reliability with potential to quantify the effects of a wide variety of manual therapy techniques on the soft tissue elastic properties. Copyright © 2011 National University of Health Sciences. Published by Mosby, Inc. All rights reserved.

Talimogene Laherparepvec and Radiation Therapy in Treating Patients With Newly Diagnosed Soft Tissue Sarcoma That Can Be Removed by Surgery

ClinicalTrials.gov

2018-05-23

FNCLCC Sarcoma Grade 2; FNCLCC Sarcoma Grade 3; Leiomyosarcoma; Liposarcoma; Stage I Soft Tissue Sarcoma AJCC v7; Stage IA Soft Tissue Sarcoma AJCC v7; Stage IB Soft Tissue Sarcoma AJCC v7; Stage II Soft Tissue Sarcoma AJCC v7; Stage IIA Soft Tissue Sarcoma AJCC v7; Stage IIB Soft Tissue Sarcoma AJCC v7; Undifferentiated Pleomorphic Sarcoma

Diagnostic value of MRI signs in differentiating Ewing sarcoma from osteomyelitis.

PubMed

Kasalak, Ömer; Overbosch, Jelle; Adams, Hugo Ja; Dammann, Amelie; Dierckx, Rudi Ajo; Jutte, Paul C; Kwee, Thomas C

2018-01-01

Background The value of magnetic resonance imaging (MRI) signs in differentiating Ewing sarcoma from osteomyelitis has not be thoroughly investigated. Purpose To investigate the value of various MRI signs in differentiating Ewing sarcoma from osteomyelitis. Material and Methods Forty-one patients who underwent MRI because of a bone lesion of unknown nature with a differential diagnosis that included both Ewing sarcoma and osteomyelitis were included. Two observers assessed several MRI signs, including the transition zone of the bone lesion, the presence of a soft-tissue mass, intramedullary and extramedullary fat globules, and the penumbra sign. Results Diagnostic accuracies for discriminating Ewing sarcoma from osteomyelitis were 82.4% and 79.4% for the presence of a soft-tissue mass, and 64.7% and 58.8% for a sharp transition zone of the bone lesion, for readers 1 and 2 respectively. Inter-observer agreement with regard to the presence of a soft-tissue mass and the transition zone of the bone lesion were moderate (κ = 0.470) and fair (κ = 0.307), respectively. Areas under the receiver operating characteristic curve of the diameter of the soft-tissue mass (if present) were 0.829 and 0.833, for readers 1 and 2 respectively. Mean inter-observer difference in soft-tissue mass diameter measurement ± limits of agreement was 35.0 ± 75.0 mm. Diagnostic accuracies of all other MRI signs were all < 50%. Conclusion Presence and size of a soft-tissue mass, and sharpness of the transition zone, are useful MRI signs to differentiate Ewing sarcoma from osteomyelitis, but inter-observer agreement is relatively low. Other MRI signs are of no value in this setting.

Efficacy of soft tissue augmentation around dental implants and in partially edentulous areas: a systematic review.

PubMed

Thoma, Daniel S; Buranawat, Borvornwut; Hämmerle, Christoph H F; Held, Ulrike; Jung, Ronald E

2014-04-01

To review the dental literature in terms of efficacy of soft tissue augmentation procedures around dental implants and in partially edentulous sites. A Medline search was performed for human studies augmenting keratinized mucosa (KM) and soft tissue volume around implants and in partially edentulous areas. Due to heterogeneity in between the studies, no meta-analyses could be performed. Nine (KM) and eleven (volume) studies met the inclusion criteria. An apically positioned flap/vestibuloplasty (APF/V) plus a graft material [free gingival graft (FGG)/subepithelial connective tissue graft (SCTG)/collagen matrix (CM)] resulted in an increase of keratinized tissue (1.4-3.3 mm). Statistically significantly better outcomes were obtained for APF/V plus FGG/SCTG compared with controls (APF/V alone; no treatment) (p < 0.05). For surgery time and patient morbidity, statistically significantly more favourable outcomes were reported for CM compared to SCTGs (p < 0.05) in two randomized controlled clinical trials (RCTs), even though rendering less keratinized tissue. SCTGs were the best-documented method for gain of soft tissue volume at implant sites and partially edentulous sites. Aesthetically at immediate implant sites, better papilla fill and higher marginal mucosal levels were obtained using SCTGs compared to non-grafted sites. An APF/V plus FGG/SCTG was the best-documented and most successful method to increase the width of KM. APF/V plus CM demonstrated less gain in KM, but also less patient morbidity and surgery time compared to APF/V plus SCTG based on two RCTs. Autogenous grafts (SCTG) rendered an increase in soft tissue thickness and better aesthetics compared to non-grafted sites. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Boundary Electron and Beta Dosimetry-Quantification of the Effects of Dissimilar Media on Absorbed Dose

NASA Astrophysics Data System (ADS)

Nunes, Josane C.

1991-02-01

This work quantifies the changes effected in electron absorbed dose to a soft-tissue equivalent medium when part of this medium is replaced by a material that is not soft -tissue equivalent. That is, heterogeneous dosimetry is addressed. Radionuclides which emit beta particles are the electron sources of primary interest. They are used in brachytherapy and in nuclear medicine: for example, beta -ray applicators made with strontium-90 are employed in certain ophthalmic treatments and iodine-131 is used to test thyroid function. More recent medical procedures under development and which involve beta radionuclides include radioimmunotherapy and radiation synovectomy; the first is a cancer modality and the second deals with the treatment of rheumatoid arthritis. In addition, the possibility of skin surface contamination exists whenever there is handling of radioactive material. Determination of absorbed doses in the examples of the preceding paragraph requires considering boundaries of interfaces. Whilst the Monte Carlo method can be applied to boundary calculations, for routine work such as in clinical situations, or in other circumstances where doses need to be determined quickly, analytical dosimetry would be invaluable. Unfortunately, few analytical methods for boundary beta dosimetry exist. Furthermore, the accuracy of results from both Monte Carlo and analytical methods has to be assessed. Although restricted to one radionuclide, phosphorus -32, the experimental data obtained in this work serve several purposes, one of which is to provide standards against which calculated results can be tested. The experimental data also contribute to the relatively sparse set of published boundary dosimetry data. At the same time, they may be useful in developing analytical boundary dosimetry methodology. The first application of the experimental data is demonstrated. Results from two Monte Carlo codes and two analytical methods, which were developed elsewhere, are compared with experimental data. Monte Carlo results compare satisfactory with experimental results for the boundaries considered. The agreement with experimental results for air interfaces is of particular interest because of discrepancies reported previously by another investigator who used data obtained from a different experimental technique. Results from one of the analytical methods differ significantly from the experimental data obtained here. The second analytical method provided data which approximate experimental results to within 30%. This is encouraging but it remains to be determined whether this method performs equally well for other source energies.

A Biomechanical Comparison of Allograft Tendons for Ligament Reconstruction.

PubMed

Palmer, Jeremiah E; Russell, Joseph P; Grieshober, Jason; Iacangelo, Abigail; Ellison, Benjamin A; Lease, T Dylan; Kim, Hyunchul; Henn, R Frank; Hsieh, Adam H

2017-03-01

Allograft tendons are frequently used for ligament reconstruction about the knee, but they entail availability and cost challenges. The identification of other tissues that demonstrate equivalent performance to preferred tendons would improve limitations. Hypothesis/Purpose: We compared the biomechanical properties of 4 soft tissue allograft tendons: tibialis anterior (TA), tibialis posterior (TP), peroneus longus (PL), and semitendinosus (ST). We hypothesized that allograft properties would be similar when standardized by the looped diameter. Controlled laboratory study. This study consisted of 2 arms evaluating large and small looped-diameter grafts: experiment A consisted of TA, TP, and PL tendons (n = 47 each) with larger looped diameters of 9.0 to 9.5 mm, and experiment B consisted of TA, TP, PL, and ST tendons (n = 53 each) with smaller looped diameters of 7.0 to 7.5 mm. Each specimen underwent mechanical testing to measure the modulus of elasticity (E), ultimate tensile force (UTF), maximal elongation at failure, ultimate tensile stress (UTS), and ultimate tensile strain (UTε). Experiment A: No significant differences were noted among tendons for UTF, maximal elongation at failure, and UTϵ. UTS was significantly higher for the PL (54 MPa) compared with the TA (44 MPa) and TP (43 MPa) tendons. E was significantly higher for the PL (501 MPa) compared with the TP (416 MPa) tendons. Equivalence testing showed that the TP and PL tendon properties were equivalent or superior to those of the TA tendons for all outcomes. Experiment B: All groups exhibited a similar E. UTF was again highest in the PL tendons (2294 N) but was significantly different from only the ST tendons (1915 N). UTϵ was significantly higher for the ST (0.22) compared with the TA (0.19) and TP (0.19) tendons. Equivalence testing showed that the TA, TP, and PL tendon properties were equivalent or superior to those of the ST tendons. Compared with TA tendons, TP and PL tendons of a given looped diameter exhibited noninferior initial biomechanical strength and stiffness characteristics. ST tendons were mostly similar to TA tendons but exhibited a significantly higher elongation/UTϵ and smaller cross-sectional area. For smaller looped-diameter grafts, all tissues were noninferior to ST tendons. In contrast to previous findings, PL tendons proved to be equally strong. The results of this study should encourage surgeons to use these soft tissue allografts interchangeably, which is important as the number of ligament reconstructions performed with allografts continues to rise.

Sorafenib in Treating Patients With Soft Tissue Sarcomas (Extremity Sarcoma Closed to Entry as of 5/30/07)

ClinicalTrials.gov

2014-04-01

Metastatic Ewing Sarcoma/Peripheral Primitive Neuroectodermal Tumor; Metastatic Osteosarcoma; Recurrent Adult Soft Tissue Sarcoma; Recurrent Ewing Sarcoma/Peripheral Primitive Neuroectodermal Tumor; Recurrent Osteosarcoma; Stage I Adult Soft Tissue Sarcoma; Stage II Adult Soft Tissue Sarcoma; Stage III Adult Soft Tissue Sarcoma; Stage IV Adult Soft Tissue Sarcoma

Simulation of medical Q-switch flash-pumped Er:YAG laser

NASA Astrophysics Data System (ADS)

-Yan-lin, Wang; Huang-Chuyun; Yao-Yucheng; Xiaolin, Zou

2011-01-01

Er: YAG laser, the wavelength is 2940nm, can be absorbed strongly by water. The absorption coefficient is as high as 13000 cm-1. As the water strong absorption, Erbium laser can bring shallow penetration depth and smaller surrounding tissue injury in most soft tissue and hard tissue. At the same time, the interaction between 2940nm radiation and biological tissue saturated with water is equivalent to instantaneous heating within limited volume, thus resulting in the phenomenon of micro-explosion to removal organization. Different parameters can be set up to cut enamel, dentin, caries and soft tissue. For the development and optimization of laser system, it is a practical choice to use laser modeling to predict the influence of various parameters for laser performance. Aim at the status of low Erbium laser output power, flash-pumped Er: YAG laser performance was simulated to obtain optical output in theory. the rate equation model was obtained and used to predict the change of population densities in various manifolds and use the technology of Q-switch the simulate laser output for different design parameters and results showed that Er: YAG laser output energy can achieve the maximum average output power of 9.8W under the given parameters. The model can be used to find the potential laser systems that meet application requirements.

TU-F-CAMPUS-T-02: Risk Assessment of Scattered Neutrons for a Fetus From Proton Therapy of a Brain Tumor During Pregnancy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geng, C; Nanjing University of Aeronautics and Astronautics, Nanjing; Moteabbed, M

Purpose: To determine the scattered neutron dose and the resulting risk for a fetus from proton therapy for brain tumors during pregnancy. Methods: Using the Monte Carlo platform TOPAS, the ICRP reference parameters based anthropomorphic pregnancy phantoms for three stages (3-, 6-, 9-month) were applied to evaluate the scattered neutron dose and dose equivalent. To calculate the dose equivalent, organ specific linear energy transfer (LET) based quality factor was used. Treatment plans from both passive scattering (PS) and pencil beam scanning (PBS) methods were considered in this study. Results: For pencil beam scanning, the neutron dose equivalent in the softmore » tissue of the fetus increases from 1.53x10−{sup 3} to 2.84x10−{sup 3} mSv per treatment Gy with increasing stage of gestation. This is due to scattered neutrons from the patient as the main contaminant source in PBS and a decrease in distance between the soft tissue of the fetus and GTV with increasing stage of gestation. For passive scattering, neutron dose equivalent to the soft tissue of the fetus shows a decrease from 0.17 to 0.13 mSv per treatment Gy in different stages, while the dose to the brain shows little difference around 0.18 mSv per treatment Gy because scattered neutrons from the treatment head contribute predominantly in passive scattering. Conclusion: The results show that the neutron dose to the fetus assuming a prescribed dose of 52.2 Gy is negligible for PBS, and is comparable to the scattered dose (0–10 mSv) from a head and neck CT scan for PS. It can be concluded that the dose to fetus is far lower than the thresholds of malformation, SMR and lethal death. The excess relative risk of childhood cancer induction would be increased by 0.48 and 0.103 using the Oxford Survey of Childhood Cancers and Japanese atomic model, respectively. Changran Geng is supported by the Chinese Scholarship Council (CSC) and the National Natural Science Foundation of China (Grant No. 11475087)« less

Spectral optimization for micro-CT.

PubMed

Hupfer, Martin; Nowak, Tristan; Brauweiler, Robert; Eisa, Fabian; Kalender, Willi A

2012-06-01

To optimize micro-CT protocols with respect to x-ray spectra and thereby reduce radiation dose at unimpaired image quality. Simulations were performed to assess image contrast, noise, and radiation dose for different imaging tasks. The figure of merit used to determine the optimal spectrum was the dose-weighted contrast-to-noise ratio (CNRD). Both optimal photon energy and tube voltage were considered. Three different types of filtration were investigated for polychromatic x-ray spectra: 0.5 mm Al, 3.0 mm Al, and 0.2 mm Cu. Phantoms consisted of water cylinders of 20, 32, and 50 mm in diameter with a central insert of 9 mm which was filled with different contrast materials: an iodine-based contrast medium (CM) to mimic contrast-enhanced (CE) imaging, hydroxyapatite to mimic bone structures, and water with reduced density to mimic soft tissue contrast. Validation measurements were conducted on a commercially available micro-CT scanner using phantoms consisting of water-equivalent plastics. Measurements on a mouse cadaver were performed to assess potential artifacts like beam hardening and to further validate simulation results. The optimal photon energy for CE imaging was found at 34 keV. For bone imaging, optimal energies were 17, 20, and 23 keV for the 20, 32, and 50 mm phantom, respectively. For density differences, optimal energies varied between 18 and 50 keV for the 20 and 50 mm phantom, respectively. For the 32 mm phantom and density differences, CNRD was found to be constant within 2.5% for the energy range of 21-60 keV. For polychromatic spectra and CMs, optimal settings were 50 kV with 0.2 mm Cu filtration, allowing for a dose reduction of 58% compared to the optimal setting for 0.5 mm Al filtration. For bone imaging, optimal tube voltages were below 35 kV. For soft tissue imaging, optimal tube settings strongly depended on phantom size. For 20 mm, low voltages were preferred. For 32 mm, CNRD was found to be almost independent of tube voltage. For 50 mm, voltages larger than 50 kV were preferred. For all three phantom sizes stronger filtration led to notable dose reduction for soft tissue imaging. Validation measurements were found to match simulations well, with deviations being less than 10%. Mouse measurements confirmed simulation results. Optimal photon energies and tube settings strongly depend on both phantom size and imaging task at hand. For in vivo CE imaging and density differences, strong filtration and voltages of 50-65 kV showed good overall results. For soft tissue imaging of animals the size of a rat or larger, voltages higher than 65 kV allow to greatly reduce scan times while maintaining dose efficiency. For imaging of bone structures, usage of only minimum filtration and low tube voltages of 40 kV and below allow exploiting the high contrast of bone at very low energies. Therefore, a combination of two filtrations could prove beneficial for micro-CT: a soft filtration allowing for bone imaging at low voltages, and a variable stronger filtration (e.g., 0.2 mm Cu) for soft tissue and contrast-enhanced imaging. © 2012 American Association of Physicists in Medicine.

Influence of soft ferromagnetic substrate on magneto-elastic behavior in a superconducting coated conductor strip

NASA Astrophysics Data System (ADS)

He, An; Xue, Cun; Yong, Huadong; Zhou, Youhe

2013-11-01

Ferromagnetic materials will affect not only the electromagnetic response but also the mechanical behaviors of coated conductors. The influence of soft ferromagnetic substrate on magneto-elastic behavior in a superconductor/ferromagnetic (SC/FM) bilayer exposed to a transverse magnetic field is investigated theoretically. The ferromagnetic substrate is regarded as ideal soft magnets with high permeability and small magnetic hysteresis. Due to the composite structure of SC/FM hybrids, magneto-elastic behavior will be subjected to combined effect of equivalent force and flexural moment. Analytical expressions for internal stress and strain components are derived by virtue of a two-dimensional elasticity analysis. It is worth pointing out that the y component of strain has much larger positive value during field ascent, which may result in the delamitation at the interface. Irreversible magnetostrictive behaviors are observed both along x direction and along y direction. For the thickness dependence of magnetostriction, the flexural moment dominates when the SC thickness is small while the equivalent force plays a critical role at higher SC thickness.

Soft-tissue facial characteristics of attractive Chinese men compared to normal men

PubMed Central

Wu, Feng; Li, Junfang; He, Hong; Huang, Na; Tang, Youchao; Wang, Yuanqing

2015-01-01

Objective: To compare the facial characteristics of attractive Chinese men with those of reference men. Materials and Methods: The three-dimensional coordinates of 50 facial landmarks were collected in 40 healthy reference men and in 40 “attractive” men, soft tissue facial angles, distances, areas, and volumes were computed and compared using analysis of variance. Results: When compared with reference men, attractive men shared several similar facial characteristics: relatively large forehead, reduced mandible, and rounded face. They had a more acute soft tissue profile, an increased upper facial width and middle facial depth, larger mouth, and more voluminous lips than reference men. Conclusions: Attractive men had several facial characteristics suggesting babyness. Nonetheless, each group of men was characterized by a different development of these features. Esthetic reference values can be a useful tool for clinicians, but should always consider the characteristics of individual faces. PMID:26221357

Alginate nanobeads interspersed fibrin network as in situ forming hydrogel for soft tissue engineering.

PubMed

Deepthi, S; Jayakumar, R

2018-06-01

Hydrogels are a class of materials that has the property of injectability and in situ gel formation. This property of hydrogels is manipulated in this study to develop a biomimetic bioresorbable injectable system of alginate nanobeads interspersed in fibrin network. Alginate nanobeads developed by calcium cross-linking yielded a size of 200-500 nm. The alginate nanobeads fibrin hydrogel was formed using dual syringe apparatus. Characterization of the in situ injectable hydrogel was done by SEM, FTIR and Rheometer. The developed hydrogel showed mechanical strength of 19 kPa which provides the suitable compliance for soft tissue engineering. Cytocompatibility studies using human umbilical cord blood derived mesenchymal stem cells showed good attachment, proliferation and infiltration within the hydrogel similar to fibrin gel. The developed in situ forming hydrogel could be a suitable delivery carrier of stem cells for soft tissue regeneration.

The global mechanical properties and multi-scale failure mechanics of heterogeneous human stratum corneum.

PubMed

Liu, X; Cleary, J; German, G K

2016-10-01

The outermost layer of skin, or stratum corneum, regulates water loss and protects underlying living tissue from environmental pathogens and insults. With cracking, chapping or the formation of exudative lesions, this functionality is lost. While stratum corneum exhibits well defined global mechanical properties, macroscopic mechanical testing techniques used to measure them ignore the structural heterogeneity of the tissue and cannot provide any mechanistic insight into tissue fracture. As such, a mechanistic understanding of failure in this soft tissue is lacking. This insight is critical to predicting fracture risk associated with age or disease. In this study, we first quantify previously unreported global mechanical properties of isolated stratum corneum including the Poisson's ratio and mechanical toughness. African American breast stratum corneum is used for all assessments. We show these parameters are highly dependent on the ambient humidity to which samples are equilibrated. A multi-scale investigation assessing the influence of structural heterogeneities on the microscale nucleation and propagation of cracks is then performed. At the mesoscale, spatially resolved equivalent strain fields within uniaxially stretched stratum corneum samples exhibit a striking heterogeneity, with localized peaks correlating closely with crack nucleation sites. Subsequent crack propagation pathways follow inherent topographical features in the tissue and lengthen with increased tissue hydration. At the microscale, intact corneocytes and polygonal shaped voids at crack interfaces highlight that cracks propagate in superficial cell layers primarily along intercellular junctions. Cellular fracture does occur however, but is uncommon. Human stratum corneum protects the body against harmful environmental pathogens and insults. Upon mechanical failure, this barrier function is lost. Previous studies characterizing the mechanics of stratum corneum have used macroscopic testing equipment designed for homogenous materials. Such measurements ignore the tissue's rich topography and heterogeneous structure, and cannot describe the underlying mechanistic process of tissue failure. For the first time, we establish a mechanistic insight into the failure mechanics of soft heterogeneous tissues by investigating how cracks nucleate and propagate in stratum corneum. We further quantify previously unreported values of the tissue's Poisson's ratio and toughness, and their dramatic variation with ambient humidity. To date, skin models examining drug delivery, wound healing, and ageing continue to estimate these parameters. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Abutment Material Effect on Peri-implant Soft Tissue Color and Perceived Esthetics.

PubMed

Kim, Aram; Campbell, Stephen D; Viana, Marlos A G; Knoernschild, Kent L

2016-12-01

The purpose of this study was to evaluate the effect of implant abutment material on peri-implant soft tissue color using intraoral spectrophotometric analysis and to compare the clinical outcomes with patient and clinician perception and satisfaction. Thirty patients and four prosthodontic faculty members participated. Abutments were zirconia, gold-hued titanium, and titanium. Peri-implant mucosa color of a single anterior implant restoration was compared to the patient's control tooth. Spectrophotometric analysis using SpectroShade TM Micro data determined the color difference (ΔE, ΔL*, Δa*, Δb*) between the midfacial peri-implant soft tissue for each abutment material and the marginal gingiva of the control tooth. Color difference values of the abutment groups were compared using ANOVA (α = 0.05). Patient and clinician satisfaction surveys were also conducted using a color-correcting light source. The results of each patient and clinician survey question were compared using chi-square analysis (α = 0.05). Pearson correlation analyses identified the relationship between the total color difference (ΔE) and the patient/clinician perception and satisfaction, as well as between ΔE and tissue thickness. Zirconia abutments displayed significantly smaller spectrophotometric gingival color difference (ΔE) compared to titanium and gold-hued titanium abutments (respectively, 3.98 ± 0.99; 7.22 ± 3.31; 5.65 ± 2.11; p < 0.05). Among ΔL*, Δa*, and Δb*, only Δa* (red-green spectrum) showed significant difference between groups. There was no significant correlation between measured soft tissue thickness and ΔE, but thick gingival phenotype, determined by a probe test, demonstrated a smaller ΔE than thin phenotype (4.82 ± 1.49; 6.41 ± 3.27; p = 0.097). There was no statistical difference in patient or clinician satisfaction among abutment materials, and no correlation between ΔE and the patient and clinician satisfaction. Patient satisfaction was significantly higher than clinician, and patient-perceived differences were lower than clinicians' (p < 0.01). Clinicians' satisfaction was higher for gingival (pink) esthetics than crown (white) esthetics (p < 0.05). Peri-implant mucosa with zirconia abutments demonstrated significantly lower mean color difference compared to titanium or gold-hued titanium abutments as measured spectrophotometrically; however, no statistical difference in patient or clinician perception/satisfaction among abutment materials was demonstrated. Patients were significantly more satisfied than clinicians. © 2015 by the American College of Prosthodontists.

Super stretchable electroactive elastomer formation driven by aniline trimer self-assembly

PubMed Central

Chen, Jing; Guo, Baolin; Eyster, Thomas W.; Ma, Peter X.

2015-01-01

Biomedical electroactive elastomers with a modulus similar to that of soft tissues are highly desirable for muscle, nerve, and other soft tissue replacement or regeneration, but have rarely been reported. In this work, superiorly stretchable electroactive polyurethane-urea elastomers were designed based on poly(lactide), poly(ethylene glycol), and aniline trimer (AT). A strain at break higher than 1600% and a modulus close to soft tissues was achieved from these copolymers. The mechanisms of super stretchability of the copolymer were systematically investigated. Crystallinity, chemical cross-linking, ionic cross-linking and hard domain formation were examined using differential scanning calorimetry (DSC), X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS), nuclear magnetic resonance (NMR) measurements and transmission electron microscopy (TEM). The sphere-like hard domains self-assembled from AT segments were found to provide the crucial physical interactions needed for the novel super elastic material formation. These super stretchable copolymers were blended with conductive fillers such as polyaniline nanofibers and nanosized carbon black to achieve a high electric conductivity of 0.1 S/cm while maintaining an excellent stretchability and a modulus similar to that of soft tissues (lower than 10 MPa). PMID:26692638

Soft mechanical metamaterials with unusual swelling behavior and tunable stress-strain curves

PubMed Central

Guo, Xiaogang; Wu, Jun

2018-01-01

Soft adaptable materials that change their shapes, volumes, and properties in response to changes under ambient conditions have important applications in tissue engineering, soft robotics, biosensing, and flexible displays. Upon water absorption, most existing soft materials, such as hydrogels, show a positive volume change, corresponding to a positive swelling. By contrast, the negative swelling represents a relatively unusual phenomenon that does not exist in most natural materials. The development of material systems capable of large or anisotropic negative swelling remains a challenge. We combine analytic modeling, finite element analyses, and experiments to design a type of soft mechanical metamaterials that can achieve large effective negative swelling ratios and tunable stress-strain curves, with desired isotropic/anisotropic features. This material system exploits horseshoe-shaped composite microstructures of hydrogel and passive materials as the building blocks, which extend into a periodic network, following the lattice constructions. The building block structure leverages a sandwiched configuration to convert the hydraulic swelling deformations of hydrogel into bending deformations, thereby resulting in an effective shrinkage (up to around −47% linear strain) of the entire network. By introducing spatially heterogeneous designs, we demonstrated a range of unusual, anisotropic swelling responses, including those with expansion in one direction and, simultaneously, shrinkage along the perpendicular direction. The design approach, as validated by experiments, allows the determination of tailored microstructure geometries to yield desired length/area changes. These design concepts expand the capabilities of existing soft materials and hold promising potential for applications in a diverse range of areas.

Observation, Radiation Therapy, Combination Chemotherapy, and/or Surgery in Treating Young Patients With Soft Tissue Sarcoma

ClinicalTrials.gov

2017-09-07

Adult Alveolar Soft-part Sarcoma; Adult Angiosarcoma; Adult Epithelioid Sarcoma; Adult Extraskeletal Chondrosarcoma; Adult Extraskeletal Osteosarcoma; Adult Fibrosarcoma; Adult Leiomyosarcoma; Adult Liposarcoma; Adult Malignant Fibrous Histiocytoma; Adult Malignant Hemangiopericytoma; Adult Malignant Mesenchymoma; Adult Neurofibrosarcoma; Adult Synovial Sarcoma; Childhood Alveolar Soft-part Sarcoma; Childhood Angiosarcoma; Childhood Epithelioid Sarcoma; Childhood Fibrosarcoma; Childhood Leiomyosarcoma; Childhood Liposarcoma; Childhood Malignant Mesenchymoma; Childhood Neurofibrosarcoma; Childhood Synovial Sarcoma; Dermatofibrosarcoma Protuberans; Metastatic Childhood Soft Tissue Sarcoma; Nonmetastatic Childhood Soft Tissue Sarcoma; Stage I Adult Soft Tissue Sarcoma; Stage II Adult Soft Tissue Sarcoma; Stage III Adult Soft Tissue Sarcoma; Stage IV Adult Soft Tissue Sarcoma

Method for Fabricating Soft Tissue Implants with Microscopic Surface Roughness

NASA Technical Reports Server (NTRS)

Banks, Bruce A. (Inventor); Rutledge, Sharon K. (Inventor)

1999-01-01

A method for fabricating soft tissue implants using a mold. The cavity surface of an initially untextured mold. made of an organic material such as epoxy. is given a thin film coating of material that has pinholes and is resistant to atomic particle bombardment. The mold cavity surface is then subjected to atomic particle bombardment, such as when placed in an isotropic atomic oxygen environment. Microscopic depressions in the mold cavity surface are created at the pinhole sites on the thin film coating. The thin film coating is removed and the mold is then used to cast the soft tissue implant. The thin film coating having pinholes may be created by chilling the mold below the dew point such that water vapor condenses upon it; distributing particles, that can partially dissolve and become attached to the mold cavity surface, onto the mold cavity surface; removing the layer of condensate, such as by evaporation; applying the thin film coating over the entire mold surface; and, finally removing the particles, such as by dissolving or brushing it off. Pinholes are created in the thin film coating at the sites previously occupied by the particles.

Development and characterization of a rapid polymerizing collagen for soft tissue augmentation.

PubMed

Devore, Dale; Zhu, Jiaxun; Brooks, Robert; McCrate, Rebecca Rone; Grant, David A; Grant, Sheila A

2016-03-01

A liquid collagen has been developed that fibrilizes upon injection. Rapid polymerizing collagen (RPC) is a type I porcine collagen that undergoes fibrillization upon interaction with ionic solutions, such as physiological solutions. The ability to inject liquid collagen would be beneficial for many soft tissue augmentation applications. In this study, RPC was synthesized and characterized as a possible dermal filler. Transmission electron microscopy, ion induced RPC fibrillogenesis tests, collagenase resistance assay, and injection force studies were performed to assess RPC's physicochemical properties. An in vivo study was performed which consisted of a 1-, 3-, and 6-month study where RPC was injected into the ears of miniature swine. The results demonstrated that the liquid RPC requires low injection force (<7 N); fibrillogenesis and banding of collagen occurs when RPC is injected into ionic solutions, and RPC has enhanced resistance to collagenase breakdown. The in vivo study demonstrated long-term biocompatibility with low irritation scores. In conclusion RPC possesses many of the desirable properties of a soft tissue augmentation material. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 758-767, 2016. © 2015 The authors journal of biomedical materials research part a published by wiley periodicals, inc.

An electromechanical based deformable model for soft tissue simulation.

PubMed

Zhong, Yongmin; Shirinzadeh, Bijan; Smith, Julian; Gu, Chengfan

2009-11-01

Soft tissue deformation is of great importance to surgery simulation. Although a significant amount of research efforts have been dedicated to simulating the behaviours of soft tissues, modelling of soft tissue deformation is still a challenging problem. This paper presents a new deformable model for simulation of soft tissue deformation from the electromechanical viewpoint of soft tissues. Soft tissue deformation is formulated as a reaction-diffusion process coupled with a mechanical load. The mechanical load applied to a soft tissue to cause a deformation is incorporated into the reaction-diffusion system, and consequently distributed among mass points of the soft tissue. Reaction-diffusion of mechanical load and non-rigid mechanics of motion are combined to govern the simulation dynamics of soft tissue deformation. An improved reaction-diffusion model is developed to describe the distribution of the mechanical load in soft tissues. A three-layer artificial cellular neural network is constructed to solve the reaction-diffusion model for real-time simulation of soft tissue deformation. A gradient based method is established to derive internal forces from the distribution of the mechanical load. Integration with a haptic device has also been achieved to simulate soft tissue deformation with haptic feedback. The proposed methodology does not only predict the typical behaviours of living tissues, but it also accepts both local and large-range deformations. It also accommodates isotropic, anisotropic and inhomogeneous deformations by simple modification of diffusion coefficients.

Imaging of rare appendicular non-acral soft-tissue chondromas in adults with histopathologic correlation.

PubMed

Nouh, Mohamed Ragab; Amr, Hanan Abd El-Aziz; Ali, Rola H

2018-06-01

Background Soft-tissue chondroma (STC) is a rare benign soft tissue tumor that arises primarily in acral extra-skeletal locations. Occasionally, STCs may arise in more proximal non-acral locations, accompanied by non-classic features that label them as indeterminate lesions and pose diagnostic challenge for both radiologists and pathologists alike. Purpose To explicate the potential of diagnostic imaging in the identification and characterization of appendicular non-acral STCs with emphasis on their morphologic magnetic resonance imaging (MRI) enhancement. Material and Methods Our clinical database records were searched for patients with histologically proven primary soft-tissue chondroid lesions over a five-year period. Two musculoskeletal (MSK) trained radiologists evaluated the imaging studies and an MSK pathologist revised the pathological findings. Results The study included six cases of appendicular non-acral STCs (mean age = 40.5 years). The mean size of the tumors was 5.6 cm, with four localized to the knee region, one in the thigh, and one in the sternoclavicular region. All cases showed high signal intensity matrix with low-signal intensity septa on T2-weighted MRI and post-contrast marginal/septal enhancement. The lesions were lobulated and lacked host tissue reaction except for one showing subjacent mild soft-tissue edema. Histologically, the cases lacked overt features of malignancy although one was originally misdiagnosed as chondrosarcoma. Conclusion Non-acral STCs are benign cartilaginous tumors that may pose a diagnostic challenge, both radiologically and pathologically. Collaborative imaging and pathologic workup is needed for better characterization of non-aggression of these lesions, and to avoid diagnostic pitfalls and unnecessary radical resections.

Outcomes of single organism peritonitis in peritoneal dialysis: gram negatives versus gram positives in the Network 9 Peritonitis Study.

PubMed

Bunke, C M; Brier, M E; Golper, T A

1997-08-01

The use of the "peritonitis rate" in the management of patients undergoing peritoneal dialysis is assuming importance in comparing the prowess of facilities, care givers and new innovations. For this to be a meaningful outcome measure, the type of infection (causative pathogen) must have less clinical significance than the number of infections during a time interval. The natural history of Staphylococcus aureus, pseudomonas, and fungal peritonitis would not support that the outcome of an episode of peritonitis is independent of the causative pathogen. Could this concern be extended to other more frequently occurring pathogens? To address this, the Network 9 Peritonitis Study identified 530 episodes of single organism peritonitis caused by a gram positive organism and 136 episodes caused by a single non-pseudomonal gram negative (NPGN) pathogen. Coincidental soft tissue infections (exit site or tunnel) occurred equally in both groups. Outcomes of peritonitis were analyzed by organism classification and by presence or absence of a soft tissue infection. NPGN peritonitis was associated with significantly more frequent catheter loss, hospitalization, and technique failure and was less likely to resolve regardless of the presence or absence of a soft tissue infection. Hospitalization and death tended to occur more frequently with enterococcal peritonitis than with other gram positive peritonitis. The outcomes in the NPGN peritonitis group were significantly worse (resolution, catheter loss, hospitalization, technique failure) compared to coagulase negative staphylococcal or S. aureus peritonitis, regardless of the presence or absence of a coincidental soft tissue infection. Furthermore, for the first time, the poor outcomes of gram negative peritonitis are shown to be independent of pseudomonas or polymicrobial involvement or soft tissue infections. The gram negative organism appears to be the important factor. In addition, the outcome of peritonitis caused by S. aureus is worse than that of other staphylococci. Thus, it is clear that all peritonitis episodes cannot be considered equivalent in terms of outcome. The concept of peritonitis rate is only meaningful when specific organisms are considered.

Why we should care about soft tissue interfaces when applying ultrasonic diathermy: an experimental and computer simulation study.

PubMed

Omena, Thaís Pionório; Fontes-Pereira, Aldo José; Costa, Rejane Medeiros; Simões, Ricardo Jorge; von Krüger, Marco Antônio; Pereira, Wagner Coelho de Albuquerque

2017-01-01

One goal of therapeutic ultrasound is enabling heat generation in tissue. Ultrasound application protocols typically neglect these processes of absorption and backscatter/reflection at the skin/fat, fat/muscle, and muscle/bone interfaces. The aim of this study was to investigate the heating process at interfaces close to the transducer and the bone with the aid of computer simulation and tissue-mimicking materials (phantoms). The experimental setup consists of physiotherapeutic ultrasound equipment for irradiation, two layers of soft tissue-mimicking material, and one with and one without an additional layer of bone-mimicking material. Thermocouple monitoring is used in both cases. A computational model is used with the experimental parameters in a COMSOL® software platform. The experimental results show significant temperature rise (42 °C) at 10 mm depth, regardless of bone layer presence, diverging 3 °C from the simulated values. The probable causes are thermocouple and transducer heating and interface reverberations. There was no statistical difference in the experimental results with and without the cortical bone for the central thermocouple of the first interface [ t (38) = -1.52; 95% CI = -0.85, 0.12; p  = 14]. Temperature rise (>6 °C) close to the bone layer was lower than predicted (>21 °C), possibly because without the bone layer, thermocouples at 30 mm make contact with the water bath and convection intensifies heat loss; this factor was omitted in the simulation model. This work suggests that more attention should be given to soft tissue layer interfaces in ultrasound therapeutic procedures even in the absence of a close bone layer.

Diode laser soft-tissue surgery: advancements aimed at consistent cutting, improved clinical outcomes.

PubMed

Romanos, Georgios E

2013-01-01

Laser dentistry and soft-tissue surgery, in particular, have become widely adopted in recent years. Significant cost reductions for dental lasers and the increasing popularity of CADCAM, among other factors, have contributed to a substantial increase in the installed base of dental lasers, especially soft-tissue lasers. New development in soft-tissue surgery, based on the modern understanding of laser-tissue interactions and contact soft-tissue surgery mechanisms, will bring a higher quality and consistency level to laser soft-tissue surgery. Recently introduced diode-laser technology enables enhanced control of side effects that result from tissue overheating and may improve soft-tissue surgical outcomes.

Surgical Management and Reconstruction Training (SMART) Course for International Orthopedic Surgeons.

PubMed

Wu, Hao-Hua; Patel, Kushal R; Caldwell, Amber M; Coughlin, R Richard; Hansen, Scott L; Carey, Joseph N

The burden of complex orthopedic trauma in low- and middle-income countries (LMICs) is exacerbated by soft-tissue injuries, which can often lead to amputations. This study's purpose was to create and evaluate the Surgical Management and Reconstruction Training (SMART) course to help orthopedic surgeons from LMICs manage soft-tissue defects and reduce the rate of amputations. In this prospective observational study, orthopedic surgeons from LMICs were recruited to attend a 2-day SMART course taught by plastic surgery faculty in San Francisco. Before the course, participants were asked to assess the burden of soft-tissue injury and amputation encountered at their respective sites of practice. A survey was then given immediately and 1-year postcourse to evaluate the quality of instructional materials and the course's effect in reducing the burden of amputation, respectively. Fifty-one practicing orthopedic surgeons from 25 countries attended the course. No participant reported previously attempting a flap reconstruction procedure to treat a soft-tissue defect. Before the course, participants cumulatively reported 580-970 amputations performed annually as a result of soft-tissue defects. Immediately after the course, participants rated the quality and effectiveness of training materials to be a mean of ≥4.4 on a Likert scale of 5 (Excellent) in all 14 instructional criteria. Of the 34 (66.7%) orthopedic surgeons who completed the 1-year postcourse survey, 34 (100%, P < 0.01) reported performing flaps learned at the course to treat soft-tissue defects. Flap procedures prevented 116 patients from undergoing amputation; 554 (93.3%) of the cumulative 594 flaps performed by participants 1 year after the course were reported to be successful. Ninety-seven percent of course participants taught flap reconstruction techniques to colleagues or residents, and a self-reported estimate of 28 other surgeons undertook flap reconstruction as a result of information dissemination by 1 year postcourse. The SMART Course can give orthopedic surgeons in LMICs the skills and knowledge to successfully perform flaps, reducing the self-reported incidence of amputations. Course participants were able to disseminate flap reconstructive techniques to colleagues at their home institution. While this course offers a collaborative, sustainable approach to reduce global surgical disparities in amputation, future investigation into the viability of teaching the SMART course in LMICs is warranted. Copyright © 2016. Published by Elsevier Inc.

Elastic-viscoplastic modeling of soft biological tissues using a mixed finite element formulation based on the relative deformation gradient.

PubMed

Weickenmeier, J; Jabareen, M

2014-11-01

The characteristic highly nonlinear, time-dependent, and often inelastic material response of soft biological tissues can be expressed in a set of elastic-viscoplastic constitutive equations. The specific elastic-viscoplastic model for soft tissues proposed by Rubin and Bodner (2002) is generalized with respect to the constitutive equations for the scalar quantity of the rate of inelasticity and the hardening parameter in order to represent a general framework for elastic-viscoplastic models. A strongly objective integration scheme and a new mixed finite element formulation were developed based on the introduction of the relative deformation gradient-the deformation mapping between the last converged and current configurations. The numerical implementation of both the generalized framework and the specific Rubin and Bodner model is presented. As an example of a challenging application of the new model equations, the mechanical response of facial skin tissue is characterized through an experimental campaign based on the suction method. The measurement data are used for the identification of a suitable set of model parameters that well represents the experimentally observed tissue behavior. Two different measurement protocols were defined to address specific tissue properties with respect to the instantaneous tissue response, inelasticity, and tissue recovery. Copyright © 2014 John Wiley & Sons, Ltd.

Division of Chinese soft-shelled turtle intestine with molecular markers is slightly different from the morphological and histological observation.

PubMed

Zhang, Zuobing; Song, Ruxin; Xing, Xiao; Wang, Lan; Niu, Cuijuan

2018-01-01

The Chinese soft-shelled turtle (Pelodiscus sinensis) is a commercially important species in Asian countries. Knowledge of its nutritional requirements and physiology is essential for determining the appropriate content of the feed for this animal. However, the lack of functional characterization of the intestine of this turtle limits the understanding of its absorption and utilization of nutritional materials. To solve this problem, this work utilized anatomical and histological methods to characterize 9 segments sampled along the anterior-posterior axis of the intestine. Furthermore, 9 genes, which have been well documented in the intestine division of mammals and fish, were employed to functionally characterize the 9 sampled segments. Our results suggest that regions covering from the starting site to S3 (position at 29.9% of the total length from the starting of the intestine) are the equivalent of mammalian dedumonen, and those covering S4 (40.2%) and S5 (65.4%), posterior to S8 (92.7%), are the equivalent of the mammalian ileum and the large intestine, respectively. As to the region spaning S6 (81.3%) and S7 (87.3%), its functional equivalent (small intestine or large intestine) may be variable and depends on the functional genes. This molecular characterization in relation to the division of the intestine of Chinese soft-shelled turtle may contribute to the understanding of the nutritional physiology of the turtle, and promote Chinese soft-shelled turtle production. © 2017 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

Percentage depth dose evaluation in heterogeneous media using thermoluminescent dosimetry

PubMed Central

da Rosa, L.A.R.; Campos, L.T.; Alves, V.G.L.; Batista, D.V.S.; Facure, A.

2010-01-01

The purpose of this study is to investigate the influence of lung heterogeneity inside a soft tissue phantom on percentage depth dose (PDD). PDD curves were obtained experimentally using LiF:Mg,Ti (TLD‐100) thermoluminescent detectors and applying Eclipse treatment planning system algorithms Batho, modified Batho (M‐Batho or BMod), equivalent TAR (E‐TAR or EQTAR), and anisotropic analytical algorithm (AAA) for a 15 MV photon beam and field sizes of 1×1,2×2,5×5, and 10×10cm2. Monte Carlo simulations were performed using the DOSRZnrc user code of EGSnrc. The experimental results agree with Monte Carlo simulations for all irradiation field sizes. Comparisons with Monte Carlo calculations show that the AAA algorithm provides the best simulations of PDD curves for all field sizes investigated. However, even this algorithm cannot accurately predict PDD values in the lung for field sizes of 1×1 and 2×2cm2. An overdosage in the lung of about 40% and 20% is calculated by the AAA algorithm close to the interface soft tissue/lung for 1×1 and 2×2cm2 field sizes, respectively. It was demonstrated that differences of 100% between Monte Carlo results and the algorithms Batho, modified Batho, and equivalent TAR responses may exist inside the lung region for the 1×1cm2 field. PACS number: 87.55.kd

Acoustic micro-tapping for non-contact 4D imaging of tissue elasticity.

PubMed

Ambroziński, Łukasz; Song, Shaozhen; Yoon, Soon Joon; Pelivanov, Ivan; Li, David; Gao, Liang; Shen, Tueng T; Wang, Ruikang K; O'Donnell, Matthew

2016-12-23

Elastography plays a key role in characterizing soft media such as biological tissue. Although this technology has found widespread use in both clinical diagnostics and basic science research, nearly all methods require direct physical contact with the object of interest and can even be invasive. For a number of applications, such as diagnostic measurements on the anterior segment of the eye, physical contact is not desired and may even be prohibited. Here we present a fundamentally new approach to dynamic elastography using non-contact mechanical stimulation of soft media with precise spatial and temporal shaping. We call it acoustic micro-tapping (AμT) because it employs focused, air-coupled ultrasound to induce significant mechanical displacement at the boundary of a soft material using reflection-based radiation force. Combining it with high-speed, four-dimensional (three space dimensions plus time) phase-sensitive optical coherence tomography creates a non-contact tool for high-resolution and quantitative dynamic elastography of soft tissue at near real-time imaging rates. The overall approach is demonstrated in ex-vivo porcine cornea.

Acoustic micro-tapping for non-contact 4D imaging of tissue elasticity

PubMed Central

Ambroziński, Łukasz; Song, Shaozhen; Yoon, Soon Joon; Pelivanov, Ivan; Li, David; Gao, Liang; Shen, Tueng T.; Wang, Ruikang K.; O’Donnell, Matthew

2016-01-01

Elastography plays a key role in characterizing soft media such as biological tissue. Although this technology has found widespread use in both clinical diagnostics and basic science research, nearly all methods require direct physical contact with the object of interest and can even be invasive. For a number of applications, such as diagnostic measurements on the anterior segment of the eye, physical contact is not desired and may even be prohibited. Here we present a fundamentally new approach to dynamic elastography using non-contact mechanical stimulation of soft media with precise spatial and temporal shaping. We call it acoustic micro-tapping (AμT) because it employs focused, air-coupled ultrasound to induce significant mechanical displacement at the boundary of a soft material using reflection-based radiation force. Combining it with high-speed, four-dimensional (three space dimensions plus time) phase-sensitive optical coherence tomography creates a non-contact tool for high-resolution and quantitative dynamic elastography of soft tissue at near real-time imaging rates. The overall approach is demonstrated in ex-vivo porcine cornea. PMID:28008920

Acoustic micro-tapping for non-contact 4D imaging of tissue elasticity

NASA Astrophysics Data System (ADS)

Ambroziński, Łukasz; Song, Shaozhen; Yoon, Soon Joon; Pelivanov, Ivan; Li, David; Gao, Liang; Shen, Tueng T.; Wang, Ruikang K.; O'Donnell, Matthew

2016-12-01

Elastography plays a key role in characterizing soft media such as biological tissue. Although this technology has found widespread use in both clinical diagnostics and basic science research, nearly all methods require direct physical contact with the object of interest and can even be invasive. For a number of applications, such as diagnostic measurements on the anterior segment of the eye, physical contact is not desired and may even be prohibited. Here we present a fundamentally new approach to dynamic elastography using non-contact mechanical stimulation of soft media with precise spatial and temporal shaping. We call it acoustic micro-tapping (AμT) because it employs focused, air-coupled ultrasound to induce significant mechanical displacement at the boundary of a soft material using reflection-based radiation force. Combining it with high-speed, four-dimensional (three space dimensions plus time) phase-sensitive optical coherence tomography creates a non-contact tool for high-resolution and quantitative dynamic elastography of soft tissue at near real-time imaging rates. The overall approach is demonstrated in ex-vivo porcine cornea.

Heterogeneous Deformable Modeling of Bio-Tissues and Haptic Force Rendering for Bio-Object Modeling

NASA Astrophysics Data System (ADS)

Lin, Shiyong; Lee, Yuan-Shin; Narayan, Roger J.

This paper presents a novel technique for modeling soft biological tissues as well as the development of an innovative interface for bio-manufacturing and medical applications. Heterogeneous deformable models may be used to represent the actual internal structures of deformable biological objects, which possess multiple components and nonuniform material properties. Both heterogeneous deformable object modeling and accurate haptic rendering can greatly enhance the realism and fidelity of virtual reality environments. In this paper, a tri-ray node snapping algorithm is proposed to generate a volumetric heterogeneous deformable model from a set of object interface surfaces between different materials. A constrained local static integration method is presented for simulating deformation and accurate force feedback based on the material properties of a heterogeneous structure. Biological soft tissue modeling is used as an example to demonstrate the proposed techniques. By integrating the heterogeneous deformable model into a virtual environment, users can both observe different materials inside a deformable object as well as interact with it by touching the deformable object using a haptic device. The presented techniques can be used for surgical simulation, bio-product design, bio-manufacturing, and medical applications.

SU-E-T-130: Dosimetric Evaluation of Tissue Equivalent Gel Dosimeter Using Saccharide in Radiotherapy System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cho, Y; Lee, D; Jung, H

2014-06-01

Purpose: In this study, the dose responses of the MAGIC gel with various concentrations and type of saccharide are examined to clarify the roles of mono and disaccharide in the polymerization process. Then we focused on the tissue equivalence and dose sensitivity of MAGIC gel dosimeters. Methods: The gel is composed of HPLC, 8% gelatin, 2 × 10-3 M L-ascorbic acid, 1.8 × 10-2 M hydroquinone, 8 × 10-5 M copper(II)sulfate and 9% methacrylic acid, new polymer gels are synthesized by adding glucose(monosaccharide), sucrose(disaccharide) and urea in the concentration range of 5∼35%. For irradiation of the gel, cesium-137 gamma-ray irradiatormore » was used, radiation dose was delivered from 5∼50 Gy. MRI images of the gel were acquired by using a 3.0 T MRI system. Results: When saccharide and urea were added, the O/C, O/N and C/N ratios agreed with those of soft tissue with 1.7%. The dose-response of glucose and sucrose gel have slope-to-intercept ratio of 0.044 and 0.283 respectively. The slope-to-ratio is one important determinant of gel sensitivity. R-square values of glucose and sucrose gel dosimeters were 0.984 and 0.994 respectively. Moreover when urea were added, the slope-to-intercept ratio is 0.044 and 0.073 respectively. R-square values of mono and disaccharide gel were 0.973 and 0.989 respectively. When a saccharide is added into the MAGIC gel dosimeter, dose sensitivity is increased. However when urea were added, dose sensitivity is slightly decreased. Conclusion: In this study, it was possible to obtain the following conclusions by looking at the dose response characteristics after adding mono-, di-saccharide and urea to a MAGIC gel dosimeter. Saccharide was a tendency of increasing dose sensitivity with disaccharide. Sa.ccharide is cost effective, safe, soft tissue equivalent, and can be used under various experimental conditions, making it a suitable dosimeter for some radiotherapy applications.« less

Biology of soft tissue wound healing and regeneration--consensus report of Group 1 of the 10th European Workshop on Periodontology.

PubMed

Hämmerle, Christoph H F; Giannobile, William V

2014-04-01

The scope of this consensus was to review the biological processes of soft tissue wound healing in the oral cavity and to histologically evaluate soft tissue healing in clinical and pre-clinical models. To review the current knowledge regarding the biological processes of soft tissue wound healing at teeth, implants and on the edentulous ridge. Furthermore, to review soft tissue wound healing at these sites, when using barrier membranes, growth and differentiation factors and soft tissue substitutes. Searches of the literature with respect to recessions at teeth and soft tissue deficiencies at implants, augmentation of the area of keratinized tissue and soft tissue volume were conducted. The available evidence was collected, categorized and summarized. Oral mucosal and skin wound healing follow a similar pattern of the four phases of haemostasis, inflammation, proliferation and maturation/matrix remodelling. The soft connective tissue determines the characteristics of the overlaying oral epithelium. Within 7-14 days, epithelial healing of surgical wounds at teeth is completed. Soft tissue healing following surgery at implants requires 6-8 weeks for maturation. The resulting tissue resembles scar tissue. Well-designed pre-clinical studies providing histological data have been reported describing soft tissue wound healing, when using barrier membranes, growth and differentiation factors and soft tissue substitutes. Few controlled clinical studies with low numbers of patients are available for some of the treatments reviewed at teeth. Whereas, histological new attachment has been demonstrated in pre-clinical studies resulting from some of the treatments reviewed, human histological data commonly report a lack of new attachment but rather long junctional epithelial attachment and connective tissue adhesion. Regarding soft tissue healing at implants human data are very scarce. Oral soft tissue healing at teeth, implants and the edentulous ridge follows the same phases as skin wound healing. Histological studies in humans have not reported new attachment formation at teeth for the indications studied. Human histological data of soft tissue wound healing at implants are limited. The use of barriers membranes, growth and differentiation factors and soft tissue substitutes for the treatment of localized gingival/mucosal recessions, insufficient amount of keratinized tissue and insufficient soft tissue volume is at a developing stage. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Chameleon-like elastomers with molecularly encoded strain-adaptive stiffening and coloration

NASA Astrophysics Data System (ADS)

Vatankhah-Varnosfaderani, Mohammad; Keith, Andrew N.; Cong, Yidan; Liang, Heyi; Rosenthal, Martin; Sztucki, Michael; Clair, Charles; Magonov, Sergei; Ivanov, Dimitri A.; Dobrynin, Andrey V.; Sheiko, Sergei S.

2018-03-01

Active camouflage is widely recognized as a soft-tissue feature, and yet the ability to integrate adaptive coloration and tissuelike mechanical properties into synthetic materials remains elusive. We provide a solution to this problem by uniting these functions in moldable elastomers through the self-assembly of linear-bottlebrush-linear triblock copolymers. Microphase separation of the architecturally distinct blocks results in physically cross-linked networks that display vibrant color, extreme softness, and intense strain stiffening on par with that of skin tissue. Each of these functional properties is regulated by the structure of one macromolecule, without the need for chemical cross-linking or additives. These materials remain stable under conditions characteristic of internal bodily environments and under ambient conditions, neither swelling in bodily fluids nor drying when exposed to air.

Pyogenic granuloma associated with periodontal abscess and bone loss - A rare case report

PubMed Central

Panseriya, Bhrugesh J.; Hungund, Shital

2011-01-01

A diverse group of the pathologic process can produce the enlargement of soft tissues in the oral cavity and often present a diagnostic challenge. This soft tissue enlargement may represent a variation of the normal anatomic structure, inflammatory reaction, cyst, neoplasm, and developmental anomalies. A group of reactive hyperplasias, which develop in response to chronic recurring tissue injury that stimulates an excessive tissue repair response. The pyogenic granuloma (PG) is a reactive enlargement that is an inflammatory response to local irritation such as calculus, a fractured tooth, rough dental restoration, and foreign materials or hormonal (pregnancy tumor) and rarely associated with bone loss. This paper presents a rare case of PG associated with periodontal abscess and bone loss in a 30-year-old male. PMID:22090773

Pyogenic granuloma associated with periodontal abscess and bone loss - A rare case report.

PubMed

Panseriya, Bhrugesh J; Hungund, Shital

2011-07-01

A diverse group of the pathologic process can produce the enlargement of soft tissues in the oral cavity and often present a diagnostic challenge. This soft tissue enlargement may represent a variation of the normal anatomic structure, inflammatory reaction, cyst, neoplasm, and developmental anomalies. A group of reactive hyperplasias, which develop in response to chronic recurring tissue injury that stimulates an excessive tissue repair response. The pyogenic granuloma (PG) is a reactive enlargement that is an inflammatory response to local irritation such as calculus, a fractured tooth, rough dental restoration, and foreign materials or hormonal (pregnancy tumor) and rarely associated with bone loss. This paper presents a rare case of PG associated with periodontal abscess and bone loss in a 30-year-old male.

Clinical Outcomes of Comparing Soft Tissue Alternatives to Free Gingival Graft: A Systematic Review and Meta-Analysis
.

PubMed

Dragan, Irina F; Hotlzman, Lucrezia Paterno; Karimbux, Nadeem Y; Morin, Rebecca A; Bassir, Seyed Hossein

2017-12-01

This systematic review and meta-analysis aimed to compare clinical outcomes and width of keratinized tissue (KT) around teeth, following the soft tissue alter- natives and free gingival graft (FGG) procedures. The specific graft materials that were explored were extracellular matrix membrane, bilayer collagen membrane, living cellular construct, and acellular dermal matrix. Four different databases were queried to identify human controlled clinical trials and randomized controlled clinical trials that fulfilled the eligibility criteria. Relevant studies were identified by 3 independent reviewers, compiling the results of the electronic and handsearches. Studies identified through electronic and handsearches were reviewed by title, abstract, and full text using Covidence Software. Primary outcome in the present study was change in the width of KT. Results of the included studies were pooled to estimate the effect size, expressed as weighted mean differences and 95% confidence interval. A random-effects model was used to perform the meta-analyses. Six hundred thirty-eight articles were screened by title, 55 articles were screened by abstracts, and 34 full-text articles were reviewed. Data on quantitative changes in width of KT were provided in 7 studies. Quantitative analyses revealed a significant difference in changes in width of KT between patients treated with soft tissue alternatives and patients treated with FGGs (P < .001). The weighted mean difference of changes in the width of KT was 21.39 (95% confidence interval: 21.82 to 20.96; heterogeneity I 5 70.89%), indicating patients who were treated with soft tissue alternatives gained 1.39 mm less KT width compared with the patients who received free gingival graft. Based on the clinical outcomes, the results of this systematic review and meta-analysis showed that soft tissue alternatives result in an increased width of KT. Patients in the soft tissue alternatives group obtained 1.39 mm less KT compared with those in the FGGs group. Copyright © 2017 Elsevier Inc. All rights reserved.

A new laser reflectance system capable of measuring changing cross-sectional area of soft tissues during tensile testing.

PubMed

Pokhai, Gabriel G; Oliver, Michele L; Gordon, Karen D

2009-09-01

Determination of the biomechanical properties of soft tissues such as tendons and ligaments is dependent on the accurate measurement of their cross-sectional area (CSA). Measurement methods, which involve contact with the specimen, are problematic because soft tissues are easily deformed. Noncontact measurement methods are preferable in this regard, but may experience difficulty in dealing with the complex cross-sectional shapes and glistening surfaces seen in soft tissues. Additionally, existing CSA measurement systems are separated from the materials testing machine, resulting in the inability to measure CSA during testing. Furthermore, CSA measurements are usually made in a different orientation, and with a different preload, prior to testing. To overcome these problems, a noncontact laser reflectance system (LRS) was developed. Designed to fit in an Instron 8872 servohydraulic test machine, the system measures CSA by orbiting a laser transducer in a circular path around a soft tissue specimen held by tissue clamps. CSA measurements can be conducted before and during tensile testing. The system was validated using machined metallic specimens of various shapes and sizes, as well as different sizes of bovine tendons. The metallic specimens could be measured to within 4% accuracy, and the tendons to within an average error of 4.3%. Statistical analyses showed no significant differences between the measurements of the LRS and those of the casting method, an established measurement technique. The LRS was successfully used to measure the changing CSA of bovine tendons during uniaxial tensile testing. The LRS developed in this work represents a simple, quick, and accurate way of reconstructing complex cross-sectional profiles and calculating cross-sectional areas. In addition, the LRS represents the first system capable of automatically measuring changing CSA of soft tissues during tensile testing, facilitating the calculation of more accurate biomechanical properties.

Computer modeling of the combined effects of perfusion, electrical conductivity, and thermal conductivity on tissue heating patterns in radiofrequency tumor ablation.

PubMed

Ahmed, Muneeb; Liu, Zhengjun; Humphries, Stanley; Goldberg, S Nahum

2008-11-01

To use an established computer simulation model of radiofrequency (RF) ablation to characterize the combined effects of varying perfusion, and electrical and thermal conductivity on RF heating. Two-compartment computer simulation of RF heating using 2-D and 3-D finite element analysis (ETherm) was performed in three phases (n = 88 matrices, 144 data points each). In each phase, RF application was systematically modeled on a clinically relevant template of application parameters (i.e., varying tumor and surrounding tissue perfusion: 0-5 kg/m(3)-s) for internally cooled 3 cm single and 2.5 cm cluster electrodes for tumor diameters ranging from 2-5 cm, and RF application times (6-20 min). In the first phase, outer thermal conductivity was changed to reflect three common clinical scenarios: soft tissue, fat, and ascites (0.5, 0.23, and 0.7 W/m- degrees C, respectively). In the second phase, electrical conductivity was changed to reflect different tumor electrical conductivities (0.5 and 4.0 S/m, representing soft tissue and adjuvant saline injection, respectively) and background electrical conductivity representing soft tissue, lung, and kidney (0.5, 0.1, and 3.3 S/m, respectively). In the third phase, the best and worst combinations of electrical and thermal conductivity characteristics were modeled in combination. Tissue heating patterns and the time required to heat the entire tumor +/-a 5 mm margin to >50 degrees C were assessed. Increasing background tissue thermal conductivity increases the time required to achieve a 50 degrees C isotherm for all tumor sizes and electrode types, but enabled ablation of a given tumor size at higher tissue perfusions. An inner thermal conductivity equivalent to soft tissue (0.5 W/m- degrees C) surrounded by fat (0.23 W/m- degrees C) permitted the greatest degree of tumor heating in the shortest time, while soft tissue surrounded by ascites (0.7 W/m- degrees C) took longer to achieve the 50 degrees C isotherm, and complete ablation could not be achieved at higher inner/outer perfusions (>4 kg/m(3)-s). For varied electrical conductivities in the setting of varied perfusion, greatest RF heating occurred for inner electrical conductivities simulating injection of saline around the electrode with an outer electrical conductivity of soft tissue, and the least amount of heating occurring while simulating renal cell carcinoma in normal kidney. Characterization of these scenarios demonstrated the role of electrical and thermal conductivity interactions, with the greatest differences in effect seen in the 3-4 cm tumor range, as almost all 2 cm tumors and almost no 5 cm tumors could be treated. Optimal combinations of thermal and electrical conductivity can partially negate the effect of perfusion. For clinically relevant tumor sizes, thermal and electrical conductivity impact which tumors can be successfully ablated even in the setting of almost non-existent perfusion.

Human eye-inspired soft optoelectronic device using high-density MoS2-graphene curved image sensor array.

PubMed

Choi, Changsoon; Choi, Moon Kee; Liu, Siyi; Kim, Min Sung; Park, Ok Kyu; Im, Changkyun; Kim, Jaemin; Qin, Xiaoliang; Lee, Gil Ju; Cho, Kyoung Won; Kim, Myungbin; Joh, Eehyung; Lee, Jongha; Son, Donghee; Kwon, Seung-Hae; Jeon, Noo Li; Song, Young Min; Lu, Nanshu; Kim, Dae-Hyeong

2017-11-21

Soft bioelectronic devices provide new opportunities for next-generation implantable devices owing to their soft mechanical nature that leads to minimal tissue damages and immune responses. However, a soft form of the implantable optoelectronic device for optical sensing and retinal stimulation has not been developed yet because of the bulkiness and rigidity of conventional imaging modules and their composing materials. Here, we describe a high-density and hemispherically curved image sensor array that leverages the atomically thin MoS 2 -graphene heterostructure and strain-releasing device designs. The hemispherically curved image sensor array exhibits infrared blindness and successfully acquires pixelated optical signals. We corroborate the validity of the proposed soft materials and ultrathin device designs through theoretical modeling and finite element analysis. Then, we propose the ultrathin hemispherically curved image sensor array as a promising imaging element in the soft retinal implant. The CurvIS array is applied as a human eye-inspired soft implantable optoelectronic device that can detect optical signals and apply programmed electrical stimulation to optic nerves with minimum mechanical side effects to the retina.

The use of soft robotics in cardiovascular therapy.

PubMed

Wamala, Isaac; Roche, Ellen T; Pigula, Frank A

2017-10-01

Robots have been employed in cardiovascular therapy as surgical tools and for automation of hospital systems. Soft robots are a new kind of robot made of soft deformable materials, that are uniquely suited for biomedical applications because they are inherently less likely to injure body tissues and more likely to adapt to biological environments. Awareness of the soft robotic systems under development will help promote clinician involvement in their successful clinical translation. Areas covered: The most advanced soft robotic systems, across the size scale from nano to macro, that have shown the most promise for clinical application in cardiovascular therapy because they offer solutions where a clear therapeutic need still exists. We discuss nano and micro scale technology that could help improve targeted therapy for cardiac regeneration in ischemic heart disease, and soft robots for mechanical circulatory support. Additionally, we suggest where the gaps in the technology currently lie. Expert commentary: Soft robotic technology has now matured from the proof-of-concept phase to successful animal testing. With further refinement in materials and clinician guided application, they will be a useful complement for cardiovascular therapy.

Tensile and shear bond strength of hard and soft denture relining materials to the conventional heat cured acrylic denture base resin: An In-vitro study.

PubMed

Lau, Mayank; Amarnath, G S; Muddugangadhar, B C; Swetha, M U; Das, Kopal Anshuraj Ashok Kumar

2014-04-01

The condition of the denture bearing tissues may be adversely affected by high stress concentration during function. Chairside Denture (Hard and Soft) reliners are used to distribute forces applied to soft tissues during function. Tensile and shear bond strength has been shown to be dependent on their chemical composition. A weak bond could harbor bacteria, promote staining and delamination of the lining material. To investigate tensile and shear bond strength of 4 different commercially available denture relining materials to conventional heat cured acrylic denture base resin. 4 mm sections in the middle of 160 Acrylic cylindrical specimens (20 mm x 8 mm) were removed, packed with test materials (Mollosil, G C Reline Soft, G C Reline Hard (Kooliner) and Ufi Gel Hard and polymerized. Specimens were divided into 8 groups of 20 each. Tensile and shear bond strength to the conventional heat cured acrylic denture base resin were examined by Instron Universal Tensile Testing Machine using the equation F=N/A (F-maximum force exerted on the specimen (Newton) and A-bonding area= 50.24 mm2). One-way ANOVA was used for multiple group comparisons followed by Bonferroni Test and Hsu's MCB for multiple pairwise comparisons to asses any significant differences between the groups. The highest mean Tensile bond strength value was obtained for Ufi Gel Hard (6.49+0.08 MPa) and lowest for G C Reline Soft (0.52+0.01 MPa). The highest mean Shear bond strength value was obtained for Ufi Gel Hard (16.19+0.1 MPa) and lowest for Mollosil (0.59+0.05 MPa). The Benferroni test showed a significant difference in the mean tensile bond strength and the mean shear bond strength when the two denture soft liners were compared as well as when the two denture hard liners were compared. Hsu's MCB implied that Ufi gel hard is better than its other closest competitors. The Tensile and Shear bond strength values of denture soft reliners were significantly lower than denture hard reliners. How to cite the article: Lau M, Amarnath GS, Muddugangadhar BC, Swetha MU, Das KA. Tensile and shear bond strength of hard and soft denture relining materials to the conventional heat cured acrylic denture base resin: An In-vitro study. J Int Oral Health 2014;6(2):55-61.

Interventions for replacing missing teeth: management of soft tissues for dental implants.

PubMed

Esposito, Marco; Maghaireh, Hassan; Grusovin, Maria Gabriella; Ziounas, Ioannis; Worthington, Helen V

2012-02-15

Dental implants are usually placed by elevating a soft tissue flap, but in some instances, they can also be placed flapless reducing patient discomfort. Several flap designs and suturing techniques have been proposed. Soft tissues are often manipulated and augmented for aesthetic reasons. It is often recommended that implants are surrounded by a sufficient width of attached/keratinised mucosa to improve their long-term prognosis. To evaluate whether (1a) flapless procedures are beneficial for patients, and (1b) which is the ideal flap design; whether (2a) soft tissue correction/augmentation techniques are beneficial for patients, and (2b) which are the best techniques; whether (3a) techniques to increase the peri-implant keratinised mucosa are beneficial for patients, and (3b) which are the best techniques; and (4) which are the best suturing techniques/materials. The following electronic databases were searched: the Cochrane Oral Health Group Trials Register (to 9 June 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 2), MEDLINE via OVID (1950 to 9 June 2011), EMBASE via OVID (1980 to 9 June 2011). Several dental journals were handsearched. There were no language restrictions. All randomised controlled trials (RCTs) of root-form osseointegrated dental implants, with a follow-up of at least 6 months after function, comparing various techniques to handle soft tissues in relation to dental implants. Outcome measures, according to the different hypotheses, were: prosthetic and implant failures, biological complications, aesthetics evaluated by patients and dentists, postoperative pain, marginal peri-implant bone level changes on periapical radiographs, patient preference, ease of maintenance by patient, soft tissue thickness changes and attached/keratinised mucosa height changes. Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were conducted at least in duplicate and independently by two or more review authors. Trial authors were contacted for missing information. Results were expressed using risk ratios for dichotomous outcomes and mean differences for continuous outcomes with 95% confidence intervals. Seventeen potentially eligible RCTs were identified but only six trials with 138 patients in total could be included. One study was at low risk of bias, two studies were judged to be at unclear risk of bias and three at high risk of bias. Two trials (56 patients) compared flapless placement of dental implants with conventional flap elevation, one trial (10 patients) compared crestal versus vestibular incisions, one trial (20 patients) Erbium:YAG laser versus flap elevation at the second-stage surgery for implant exposure, one split-mouth trial (10 patients) evaluated whether connective tissue graft at implant placement could be effective in augmenting peri-implant tissues, and one trial (40 patients) compared autograft with an animal-derived collagen matrix to increase the height of the keratinised mucosa. On a patient, rather than per implant basis, implants placed with a flapless technique and implant exposures performed with laser induced statistically significantly less postoperative pain than flap elevation. Sites augmented with soft tissues connective grafts showed a better aesthetic and thicker tissues. Both palatal autografts or the use of a porcine-derived collagen matrix are effective in increasing the height of keratinised mucosa at the price of a 0.5 mm recession of peri-implant soft tissues. There were no other statistically significant differences for any of the remaining analyses. There is limited weak evidence suggesting that flapless implant placement is feasible and has been shown to reduce patient postoperative discomfort in adequately selected patients, that augmentation at implant sites with soft tissue grafts is effective in increasing soft tissue thickness improving aesthetics and that one technique to increase the height of keratinised mucosa using autografts or an animal-derived collagen matrix was able to achieve its goal but at the price of a worsened aesthetic outcome (0.5 mm of recession). There is insufficient reliable evidence to provide recommendations on which is the ideal flap design, the best soft tissue augmentation technique, whether techniques to increase the width of keratinised/attached mucosa are beneficial to patients or not, and which are the best incision/suture techniques/materials. Properly designed and conducted RCTs, with at least 6 months of follow-up, are needed to provide reliable answers to these questions.

Fatigue characteristics of carbon nanotube blocks under compression

NASA Astrophysics Data System (ADS)

Suhr, J.; Ci, L.; Victor, P.; Ajayan, P. M.

2008-03-01

In this paper we investigate the mechanical response from repeated high compressive strains on freestanding, long, vertically aligned multiwalled carbon nanotube membranes and show that the arrays of nanotubes under compression behave very similar to soft tissue and exhibit viscoelastic behavior. Under compressive cyclic loading, the mechanical response of nanotube blocks shows initial preconditioning and hysteresis characteristic of viscoeleastic materials. Furthermore, no fatigue failure is observed even at high strain amplitudes up to half million cycles. The outstanding fatigue life and extraordinary soft tissue-like mechanical behavior suggest that properly engineered carbon nanotube structures could mimic artificial muscles.

Tracking of Drug Release and Material Fate for Naturally Derived Omega-3 Fatty Acid Biomaterials.

PubMed

Faucher, Keith M; Artzi, Natalie; Beck, Moshe; Beckerman, Rita; Moodie, Geoff; Albergo, Theresa; Conroy, Suzanne; Dale, Alicia; Corbeil, Scott; Martakos, Paul; Edelman, Elazer R

2016-03-01

In vitro and in vivo studies were conducted on omega-3 fatty acid-derived biomaterials to determine their utility as an implantable material for adhesion prevention following soft tissue hernia repair and as a means to allow for the local delivery of antimicrobial or antibiofilm agents. Naturally derived biomaterials offer several advantages over synthetic materials in the field of medical device development. These advantages include enhanced biocompatibility, elimination of risks posed by the presence of toxic catalysts and chemical crosslinking agents, and derivation from renewable resources. Omega-3 fatty acids are readily available from fish and plant sources and can be used to create implantable biomaterials either as a stand-alone device or as a device coating that can be utilized in local drug delivery applications. In-depth characterization of material erosion degradation over time using non-destructive imaging and chemical characterization techniques provided mechanistic insight into material structure: function relationship. This in turn guided rational tailoring of the material based on varying fatty acid composition to control material residence time and hence drug release. These studies demonstrate the utility of omega-3 fatty acid derived biomaterials as an absorbable material for soft tissue hernia repair and drug delivery applications.

Copolymer-in-oil phantom materials for elastography.

PubMed

Oudry, J; Bastard, C; Miette, V; Willinger, R; Sandrin, L

2009-07-01

Phantoms that mimic mechanical and acoustic properties of soft biological tissues are essential to elasticity imaging investigation and to elastography device characterization. Several materials including agar/gelatin, polyvinyl alcohol and polyacrylamide gels have been used successfully in the past to produce tissue phantoms, as reported in the literature. However, it is difficult to find a phantom material with a wide range of stiffness, good stability over time and high resistance to rupture. We aim at developing and testing a new copolymer-in-oil phantom material for elastography. The phantom is composed of a mixture of copolymer, mineral oil and additives for acoustic scattering. The mechanical properties of phantoms were evaluated with a mechanical test instrument and an ultrasound-based elastography technique. The acoustic properties were investigated using a through-transmission water-substituting method. We showed that copolymer-in-oil phantoms are stable over time. Their mechanical and acoustic properties mimic those of most soft tissues: the Young's modulus ranges from 2.2-150 kPa, the attenuation coefficient from 0.4-4.0 dB.cm(-1) and the ultrasound speed from 1420-1464 m/s. Their density is equal to 0.90 +/- 0.04 g/cm3. The results suggest that copolymer-in-oil phantoms are attractive materials for elastography.

Dosimetric feasibility of magnetic resonance imaging-guided tri-cobalt 60 preoperative intensity modulated radiation therapy for soft tissue sarcomas of the extremity.

PubMed

Kishan, Amar U; Cao, Minsong; Mikaeilian, Argin G; Low, Daniel A; Kupelian, Patrick A; Steinberg, Michael L; Kamrava, Mitchell

2015-01-01

The purpose of this study was to investigate the dosimetric differences of delivering preoperative intensity modulated radiation therapy (IMRT) to patients with soft tissue sarcomas of the extremity (ESTS) with a teletherapy system equipped with 3 rotating (60)Co sources and a built-in magnetic resonance imaging and with standard linear accelerator (LINAC)-based IMRT. The primary study population consisted of 9 patients treated with preoperative radiation for ESTS between 2008 and 2014 with LINAC-based static field IMRT. LINAC plans were designed to deliver 50 Gy in 25 fractions to 95% of the planning target volume (PTV). Tri-(60)Co system IMRT plans were designed with ViewRay system software. Tri-(60)Co-based IMRT plans achieved equivalent target coverage and dosimetry for organs at risk (long bone, skin, and skin corridor) compared with LINAC-based IMRT plans. The maximum and minimum PTV doses, heterogeneity indices, and ratio of the dose to 50% of the volume were equivalent for both planning systems. One LINAC plan violated the maximum bone dose constraint, whereas none of the tri-(60)Co plans did. Using a tri-(60)Co system, we were able to achieve equivalent dosimetry to the PTV and organs at risk for patients with ESTS compared with LINAC-based IMRT plans. The tri-(60)Co system may be advantageous over current treatment platforms by allowing PTV reduction and by elimination of the additional radiation dose associated with daily image guidance, but this needs to be evaluated prospectively. Copyright © 2015 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.

Bioactive Glass Nanoparticles: From Synthesis to Materials Design for Biomedical Applications

PubMed Central

Vichery, Charlotte; Nedelec, Jean-Marie

2016-01-01

Thanks to their high biocompatibility and bioactivity, bioactive glasses are very promising materials for soft and hard tissue repair and engineering. Because bioactivity and specific surface area intrinsically linked, the last decade has seen a focus on the development of highly porous and/or nano-sized materials. This review emphasizes the synthesis of bioactive glass nanoparticles and materials design strategies. The first part comprehensively covers mainly soft chemistry processes, which aim to obtain dispersible and monodispersed nanoparticles. The second part discusses the use of bioactive glass nanoparticles for medical applications, highlighting the design of materials. Mesoporous nanoparticles for drug delivery, injectable systems and scaffolds consisting of bioactive glass nanoparticles dispersed in a polymer, implant coatings and particle dispersions will be presented. PMID:28773412

Studying Genes in Tissue Samples From Younger and Adolescent Patients With Soft Tissue Sarcomas

ClinicalTrials.gov

2016-05-13

Childhood Alveolar Soft-part Sarcoma; Childhood Angiosarcoma; Childhood Desmoplastic Small Round Cell Tumor; Childhood Epithelioid Sarcoma; Childhood Fibrosarcoma; Childhood Leiomyosarcoma; Childhood Liposarcoma; Childhood Malignant Mesenchymoma; Childhood Neurofibrosarcoma; Childhood Synovial Sarcoma; Chordoma; Desmoid Tumor; Metastatic Childhood Soft Tissue Sarcoma; Nonmetastatic Childhood Soft Tissue Sarcoma; Recurrent Childhood Soft Tissue Sarcoma

In Vivo Determination of the Complex Elastic Moduli of Cetacean Head Tissue

DTIC Science & Technology

2012-09-30

and with harvested tissue samples. In vivo testing will be conducted on Navy dolphins . Ultrasound parameters (peak negative pressure, time averaged...A synthetic material was developed which mimicks the ultrasonic properties of living bottlenose dolphin soft tissues. RESULTS 1. System...NIVMS) and with a laser doppler vibrometer (Polytec PDV-100). A variety of pulse drive levels, durations, and bandwidths for both ultrasound

Hard, soft tissue and in vitro cell response to porous nickel-titanium: a biocompatibility evaluation.

PubMed

Rhalmi, S; Odin, M; Assad, M; Tabrizian, M; Rivard, C H; Yahia, L H

1999-01-01

Porous nickel-titanium (NiTi) alloys have demonstrated bone attachment as well as tissue ingrowth in the past. However, very few studies have compared porous NiTi soft and hard tissue reactions, and in vitro cell response. We therefore have evaluated the general muscle and bone reaction to porous nickel-titanium. The latter material was implanted in rabbit tibias and back muscle, and assessed after three, six and twelve weeks of implantation. Porous NiTi specimens did not cause any adverse effect regardless of both implantation site and post-surgery recovery time. Muscle tissue exhibited thin tightly adherent fibrous capsules with fibers penetrating into implant pores. We observed that attachment strength of the soft tissue to the porous implant seemed to increase with post-implantation time. Bone tissue demonstrated good healing of the osteotomy. There was bone remodeling characterized by osteoclastic and osteoblastic activity in the cortex. This general good in vivo biocompatibility with muscle and bone tissue corresponded very well with the in vitro cell culture results we obtained. Fibroblasts seeded on porous nickel-titanium sheets managed to grow into the pores and all around specimen edges showing an another interesting cytocompatibility behavior. These results indicate good biocompatibility acceptance of porous nickel-titanium and are very promising towards eventual NiTi medical device approbation.

Angiogenic effects of borate glass microfibers in a rodent model.

PubMed

Lin, Yinan; Brown, Roger F; Jung, Steven B; Day, Delbert E

2014-12-01

The primary objective of this research was to evaluate the use of bioactive borate-based glass microfibers for angiogenesis in soft tissue repair applications. The effect of these fibers on growth of capillaries and small blood vessels was compared to that of 45S5 silica glass microfibers and sham implant controls. Compressed mats of three types of glass microfibers were implanted subcutaneously in rats and tissues surrounding the implant sites histologically evaluated 2-4 weeks post surgery. Bioactive borate glass 13-93B3 supplemented with 0.4 wt % copper promoted extensive angiogenesis as compared to silica glass microfibers and sham control tissues. The angiogenic responses suggest the copper-containing 13-93B3 microfibers may be effective for treating chronic soft tissue wounds. A second objective was to assess the possible systemic cytotoxicity of dissolved borate ions and other materials released from implanted borate glass microfibers. Cytotoxicity was assessed via histological evaluation of kidney tissue collected from animals 4 weeks after subcutaneously implanting high amounts of the borate glass microfibers. The evaluation of the kidney tissue from these animals showed no evidence of chronic histopathological changes in the kidney. The overall results indicate the borate glass microfibers are safe and effective for soft tissue applications. © 2014 Wiley Periodicals, Inc.

Soft tissue modelling with conical springs.

PubMed

Omar, Nadzeri; Zhong, Yongmin; Jazar, Reza N; Subic, Aleksandar; Smith, Julian; Shirinzadeh, Bijan

2015-01-01

This paper presents a new method for real-time modelling soft tissue deformation. It improves the traditional mass-spring model with conical springs to deal with nonlinear mechanical behaviours of soft tissues. A conical spring model is developed to predict soft tissue deformation with reference to deformation patterns. The model parameters are formulated according to tissue deformation patterns and the nonlinear behaviours of soft tissues are modelled with the stiffness variation of conical spring. Experimental results show that the proposed method can describe different tissue deformation patterns using one single equation and also exhibit the typical mechanical behaviours of soft tissues.

Muscle-driven finite element simulation of human foot movements.

PubMed

Spyrou, L A; Aravas, N

2012-01-01

This paper describes a finite element scheme for realistic muscle-driven simulation of human foot movements. The scheme is used to simulate human ankle plantar flexion. A three-dimensional anatomically detailed finite element model of human foot and lower leg is developed and the idea of generating natural foot movement based entirely on the contraction of the plantar flexor muscles is used. The bones, ligaments, articular cartilage, muscles, tendons, as well as the rest soft tissues of human foot and lower leg are included in the model. A realistic three-dimensional continuum constitutive model that describes the biomechanical behaviour of muscles and tendons is used. Both the active and passive properties of muscle tissue are accounted for. The materials for bones and ligaments are considered as homogeneous, isotropic and linearly elastic, whereas the articular cartilage and the rest soft tissues (mainly fat) are defined as hyperelastic materials. The model is used to estimate muscle tissue deformations as well as stresses and strains that develop in the lower leg muscles during plantar flexion of the ankle. Stresses and strains that develop in Achilles tendon during such a movement are also investigated.

Soft Tissue Sarcoma—Health Professional Version

Cancer.gov

Soft tissue sarcomas are malignant tumors that arise in any of the mesodermal tissues of the extremities, trunk and retroperitoneum, or head and neck. Soft tissue sarcomas may be heterogeneous. Find evidence-based information on soft tissue sarcoma treatment and research.

In-vivo viscous properties of the heel pad by stress-relaxation experiment based on a spherical indentation.

PubMed

Suzuki, Ryo; Ito, Kohta; Lee, Taeyong; Ogihara, Naomichi

2017-12-01

Identifying the viscous properties of the plantar soft tissue is crucial not only for understanding the dynamic interaction of the foot with the ground during locomotion, but also for development of improved footwear products and therapeutic footwear interventions. In the present study, the viscous and hyperelastic material properties of the plantar soft tissue were experimentally identified using a spherical indentation test and an analytical contact model of the spherical indentation test. Force-relaxation curves of the heel pads were obtained from the indentation experiment. The curves were fit to the contact model incorporating a five-element Maxwell model to identify the viscous material parameters. The finite element method with the experimentally identified viscoelastic parameters could successfully reproduce the measured force-relaxation curves, indicating the material parameters were correctly estimated using the proposed method. Although there are some methodological limitations, the proposed framework to identify the viscous material properties may facilitate the development of subject-specific finite element modeling of the foot and other biological materials. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

Inter-Vertebral Flexibility of the Ostrich Neck: Implications for Estimating Sauropod Neck Flexibility

PubMed Central

Cobley, Matthew J.; Rayfield, Emily J.; Barrett, Paul M.

2013-01-01

The flexibility and posture of the neck in sauropod dinosaurs has long been contentious. Improved constraints on sauropod neck function will have major implications for what we know of their foraging strategies, ecology and overall biology. Several hypotheses have been proposed, based primarily on osteological data, suggesting different degrees of neck flexibility. This study attempts to assess the effects of reconstructed soft tissues on sauropod neck flexibility through systematic removal of muscle groups and measures of flexibility of the neck in a living analogue, the ostrich (Struthio camelus). The possible effect of cartilage on flexibility is also examined, as this was previously overlooked in osteological estimates of sauropod neck function. These comparisons show that soft tissues are likely to have limited the flexibility of the neck beyond the limits suggested by osteology alone. In addition, the inferred presence of cartilage, and varying the inter-vertebral spacing within the synovial capsule, also affect neck flexibility. One hypothesis proposed that flexibility is constrained by requiring a minimum overlap between successive zygapophyses equivalent to 50% of zygapophyseal articular surface length (ONP50). This assumption is tested by comparing the maximum flexibility of the articulated cervical column in ONP50 and the flexibility of the complete neck with all tissues intact. It is found that this model does not adequately convey the pattern of flexibility in the ostrich neck, suggesting that the ONP50 model may not be useful in determining neck function if considered in isolation from myological and other soft tissue data. PMID:23967284

Soft Tissue Augmentation with Autologous Platelet Gel and β-TCP: A Histologic and Histometric Study in Mice

PubMed Central

Ceccarelli, Maurizio; Marchetti, Massimiliano; Piattelli, Adriano; Mortellaro, Carmen

2016-01-01

Background. Facial aging is a dynamic process involving both soft tissue and bony structures. Skin atrophy, with loss of tone, elasticity, and distribution of facial fat, coupled with gravity and muscle activity, leads to wrinkling and folds. Purpose. The aim of the study was to evaluate microporous tricalcium phosphate (β-TCP) and autologous platelet gel (APG) mix in mice for oral and maxillofacial soft tissue augmentation. The hypothesis was that β-TCP added with APG was able to increase the biostimulating effect on fibroblasts and quicken resorption. Materials and Methods. Ten female, 6–8-week-old black-haired mice were selected. β-TCP/APG gel was injected into one cheek; the other was used as control. The animals were sacrificed at 8 weeks and histologically evaluated. Results. The new fibroblast was intensively stained with acid fuchsin and presented in contact with β-TCP. At higher magnification, actively secreting fibroblasts were observed at the periphery of β-TCP with a well differentiated fibroblast cell line and blood vessels. Acid fuchsin stained cutaneous structures in pink: no epidermal/dermal alterations or pathological inflammatory infiltrates were detected. The margins of β-TCP granules were clear and not diffused near tissues. Conclusion. APG with β-TCP preserves skin morphology, without immune response, with an excellent tolerability and is a promising scaffold for cells and biomaterial for soft tissue augmentation. PMID:27478828

Soft Tissue Augmentation with Autologous Platelet Gel and β-TCP: A Histologic and Histometric Study in Mice.

PubMed

Scarano, Antonio; Ceccarelli, Maurizio; Marchetti, Massimiliano; Piattelli, Adriano; Mortellaro, Carmen

2016-01-01

Background. Facial aging is a dynamic process involving both soft tissue and bony structures. Skin atrophy, with loss of tone, elasticity, and distribution of facial fat, coupled with gravity and muscle activity, leads to wrinkling and folds. Purpose. The aim of the study was to evaluate microporous tricalcium phosphate (β-TCP) and autologous platelet gel (APG) mix in mice for oral and maxillofacial soft tissue augmentation. The hypothesis was that β-TCP added with APG was able to increase the biostimulating effect on fibroblasts and quicken resorption. Materials and Methods. Ten female, 6-8-week-old black-haired mice were selected. β-TCP/APG gel was injected into one cheek; the other was used as control. The animals were sacrificed at 8 weeks and histologically evaluated. Results. The new fibroblast was intensively stained with acid fuchsin and presented in contact with β-TCP. At higher magnification, actively secreting fibroblasts were observed at the periphery of β-TCP with a well differentiated fibroblast cell line and blood vessels. Acid fuchsin stained cutaneous structures in pink: no epidermal/dermal alterations or pathological inflammatory infiltrates were detected. The margins of β-TCP granules were clear and not diffused near tissues. Conclusion. APG with β-TCP preserves skin morphology, without immune response, with an excellent tolerability and is a promising scaffold for cells and biomaterial for soft tissue augmentation.

Coupled porohyperelastic mass transport (PHEXPT) finite element models for soft tissues using ABAQUS.

PubMed

Vande Geest, Jonathan P; Simon, B R; Rigby, Paul H; Newberg, Tyler P

2011-04-01

Finite element models (FEMs) including characteristic large deformations in highly nonlinear materials (hyperelasticity and coupled diffusive/convective transport of neutral mobile species) will allow quantitative study of in vivo tissues. Such FEMs will provide basic understanding of normal and pathological tissue responses and lead to optimization of local drug delivery strategies. We present a coupled porohyperelastic mass transport (PHEXPT) finite element approach developed using a commercially available ABAQUS finite element software. The PHEXPT transient simulations are based on sequential solution of the porohyperelastic (PHE) and mass transport (XPT) problems where an Eulerian PHE FEM is coupled to a Lagrangian XPT FEM using a custom-written FORTRAN program. The PHEXPT theoretical background is derived in the context of porous media transport theory and extended to ABAQUS finite element formulations. The essential assumptions needed in order to use ABAQUS are clearly identified in the derivation. Representative benchmark finite element simulations are provided along with analytical solutions (when appropriate). These simulations demonstrate the differences in transient and steady state responses including finite deformations, total stress, fluid pressure, relative fluid, and mobile species flux. A detailed description of important model considerations (e.g., material property functions and jump discontinuities at material interfaces) is also presented in the context of finite deformations. The ABAQUS-based PHEXPT approach enables the use of the available ABAQUS capabilities (interactive FEM mesh generation, finite element libraries, nonlinear material laws, pre- and postprocessing, etc.). PHEXPT FEMs can be used to simulate the transport of a relatively large neutral species (negligible osmotic fluid flux) in highly deformable hydrated soft tissues and tissue-engineered materials.

Soft tissue adhesion of polished versus glazed lithium disilicate ceramic for dental applications.

PubMed

Brunot-Gohin, C; Duval, J-L; Azogui, E-E; Jannetta, R; Pezron, I; Laurent-Maquin, D; Gangloff, S C; Egles, C

2013-09-01

Ceramics are widely used materials for prosthesis, especially in dental fields. Despite multiple biomedical applications, little is known about ceramic surface modifications and the resulting cell behavior at its contact. The aim of this study is to evaluate the biological response of polished versus glazed surface treatments on lithium disilicate dental ceramic. We studied a lithium disilicate ceramic (IPS e.max(®) Press, Ivoclar Vivadent) with 3 different surface treatments: raw surface treatment, hand polished surface treatment, and glazed surface treatment (control samples are Thermanox(®), Nunc). In order to evaluate the possible modulation of cell response at the surface of ceramic, we compared polished versus glazed ceramics using an organotypic culture model of chicken epithelium. Our results show that the surface roughness is not modified as demonstrated by equivalent Ra measurements. On the contrary, the contact angle θ in water is very different between polished (84°) and glazed (33°) samples. The culture of epithelial tissues allowed a very precise assessment of histocompatibility of these interfaces and showed that polished samples increased cell adhesion and proliferation as compared to glazed samples. Lithium disilicate polished ceramic provided better adhesion and proliferation than lithium disilicate glazed ceramic. Taken together, our results demonstrate for the first time, how it is possible to use simple surface modifications to finely modulate the adhesion of tissues. Our results will help dental surgeons to choose the most appropriate surface treatment for a specific clinical application, in particular for the ceramic implant collar. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

A one-dimensional model for the propagation of transient pressure waves through the lung.

PubMed

Grimal, Quentin; Watzky, Alexandre; Naili, Salah

2002-08-01

The propagation of pressure waves in the lung has been investigated by many authors concerned with respiratory physiology, ultrasound medical techniques or thoracic impact injuries. In most of the theoretical studies, the lung has been modeled as an isotropic and homogeneous medium, and by using Hooke's constitutive law (see e.g. Ganesan et al. Respir. Physiol. 110 (1997) 19; Jahed et al. J. Appl. Physiol. 66 (1989) 2675; Grimal et al. C.R. Acad. Sci., Paris 329 (IIb) (2001) 655-662), or more elaborated material laws (see, e.g. Bush and Challener (Proceedings of the International Research Council on Biokinetics Impacts (IRCOBI), Bergish-gladbach, 1988); Stuhmiller et al. J. Trauma 28 (1988) S132; Yang and Wang, Finite element modeling of the human thorax. Web page: http://wwwils.nlm.nih.gov/research/visible/vhpconf98/AUTHORS/YANG/YANG.HTM.). The hypothesis of homogeneous medium may be inappropriate for certain problems. Because of its foam-like structure, the behavior of the lung-even if the air and the soft tissue are assumed to behave like linearly elastic materials-is susceptible to be frequency dependent. In the present study, the lung is viewed as a one-dimensional stack of air and soft tissue layers; wave propagation in such a stack can be investigated in an equivalent mass-spring chain (El-Raheb (J. Acoust. Soc. Am. 94 (1993) 172; Int. J. Solids Struct. 34 (1997) 2969), where the masses and springs, respectively, represent the alveolar walls and alveolar gas. Results are presented in the time and frequency domains. The frequency dependence (cutoff frequency, variations in phase velocity) of the lung model is found to be highly dependent on the mean alveolar size. We found that short pulses induced by high velocity impacts (bullet stopped by a bulletproof jacket) can be highly distorted during the propagation. The pressure differential between two alveoli is discussed as a possible injury criterion.

Model-based Iterative Reconstruction: Effect on Patient Radiation Dose and Image Quality in Pediatric Body CT

PubMed Central

Dillman, Jonathan R.; Goodsitt, Mitchell M.; Christodoulou, Emmanuel G.; Keshavarzi, Nahid; Strouse, Peter J.

2014-01-01

Purpose To retrospectively compare image quality and radiation dose between a reduced-dose computed tomographic (CT) protocol that uses model-based iterative reconstruction (MBIR) and a standard-dose CT protocol that uses 30% adaptive statistical iterative reconstruction (ASIR) with filtered back projection. Materials and Methods Institutional review board approval was obtained. Clinical CT images of the chest, abdomen, and pelvis obtained with a reduced-dose protocol were identified. Images were reconstructed with two algorithms: MBIR and 100% ASIR. All subjects had undergone standard-dose CT within the prior year, and the images were reconstructed with 30% ASIR. Reduced- and standard-dose images were evaluated objectively and subjectively. Reduced-dose images were evaluated for lesion detectability. Spatial resolution was assessed in a phantom. Radiation dose was estimated by using volumetric CT dose index (CTDIvol) and calculated size-specific dose estimates (SSDE). A combination of descriptive statistics, analysis of variance, and t tests was used for statistical analysis. Results In the 25 patients who underwent the reduced-dose protocol, mean decrease in CTDIvol was 46% (range, 19%–65%) and mean decrease in SSDE was 44% (range, 19%–64%). Reduced-dose MBIR images had less noise (P > .004). Spatial resolution was superior for reduced-dose MBIR images. Reduced-dose MBIR images were equivalent to standard-dose images for lungs and soft tissues (P > .05) but were inferior for bones (P = .004). Reduced-dose 100% ASIR images were inferior for soft tissues (P < .002), lungs (P < .001), and bones (P < .001). By using the same reduced-dose acquisition, lesion detectability was better (38% [32 of 84 rated lesions]) or the same (62% [52 of 84 rated lesions]) with MBIR as compared with 100% ASIR. Conclusion CT performed with a reduced-dose protocol and MBIR is feasible in the pediatric population, and it maintains diagnostic quality. © RSNA, 2013 Online supplemental material is available for this article. PMID:24091359

The differentiation of oral soft- and hard tissues using laser induced breakdown spectroscopy - a prospect for tissue specific laser surgery.

PubMed

Rohde, Maximilian; Mehari, Fanuel; Klämpfl, Florian; Adler, Werner; Neukam, Friedrich-Wilhelm; Schmidt, Michael; Stelzle, Florian

2017-10-01

Compared to conventional techniques, Laser surgery procedures provide a number of advantages, but may be associated with an increased risk of iatrogenic damage to important anatomical structures. The type of tissue ablated in the focus spot is unknown. Laser-Induced Breakdown-Spectroscopy (LIBS) has the potential to gain information about the type of material that is being ablated by the laser beam. This may form the basis for tissue selective laser surgery. In the present study, 7 different porcine tissues (cortical and cancellous bone, nerve, mucosa, enamel, dentine and pulp) from 6 animals were analyzed for their qualitative and semiquantitative molecular composition using LIBS. The so gathered data was used to first differentiate between the soft- and hard-tissues using a Calcium-Carbon emission based classifier. The tissues were then further classified using emission-ratio based analysis, principal component analysis (PCA) and linear discriminant analysis (LDA). The relatively higher concentration of Calcium in the hard tissues allows for an accurate first differentiation of soft- and hard tissues (100% sensitivity and specificity). The ratio based statistical differentiation approach yields results in the range from 65% (enamel-dentine pair) to 100% (nerve-pulp, cancellous bone-dentine, cancellous bone-enamel pairs) sensitivity and specificity. Experimental LIBS measuring setup. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quantifying dynamic mechanical properties of human placenta tissue using optimization techniques with specimen-specific finite-element models.

PubMed

Hu, Jingwen; Klinich, Kathleen D; Miller, Carl S; Nazmi, Giseli; Pearlman, Mark D; Schneider, Lawrence W; Rupp, Jonathan D

2009-11-13

Motor-vehicle crashes are the leading cause of fetal deaths resulting from maternal trauma in the United States, and placental abruption is the most common cause of these deaths. To minimize this injury, new assessment tools, such as crash-test dummies and computational models of pregnant women, are needed to evaluate vehicle restraint systems with respect to reducing the risk of placental abruption. Developing these models requires accurate material properties for tissues in the pregnant abdomen under dynamic loading conditions that can occur in crashes. A method has been developed for determining dynamic material properties of human soft tissues that combines results from uniaxial tensile tests, specimen-specific finite-element models based on laser scans that accurately capture non-uniform tissue-specimen geometry, and optimization techniques. The current study applies this method to characterizing material properties of placental tissue. For 21 placenta specimens tested at a strain rate of 12/s, the mean failure strain is 0.472+/-0.097 and the mean failure stress is 34.80+/-12.62 kPa. A first-order Ogden material model with ground-state shear modulus (mu) of 23.97+/-5.52 kPa and exponent (alpha(1)) of 3.66+/-1.90 best fits the test results. The new method provides a nearly 40% error reduction (p<0.001) compared to traditional curve-fitting methods by considering detailed specimen geometry, loading conditions, and dynamic effects from high-speed loading. The proposed method can be applied to determine mechanical properties of other soft biological tissues.

Metallic Scaffolds for Bone Regeneration

PubMed Central

Alvarez, Kelly; Nakajima, Hideo

2009-01-01

Bone tissue engineering is an emerging interdisciplinary field in Science, combining expertise in medicine, material science and biomechanics. Hard tissue engineering research is focused mainly in two areas, osteo and dental clinical applications. There is a lot of exciting research being performed worldwide in developing novel scaffolds for tissue engineering. Although, nowadays the majority of the research effort is in the development of scaffolds for non-load bearing applications, primarily using soft natural or synthetic polymers or natural scaffolds for soft tissue engineering; metallic scaffolds aimed for hard tissue engineering have been also the subject of in vitro and in vivo research and industrial development. In this article, descriptions of the different manufacturing technologies available to fabricate metallic scaffolds and a compilation of the reported biocompatibility of the currently developed metallic scaffolds have been performed. Finally, we highlight the positive aspects and the remaining problems that will drive future research in metallic constructs aimed for the reconstruction and repair of bone.

Soft tissue changes and its stability as a sequlae to mandibular advancement

PubMed Central

Uppada, Uday Kiran; Sinha, Ramen; Reddy, D. Sreenatha; Paul, Dushyanth

2014-01-01

Purpose of the Study: To predict the changes and evaluate the stability that occurs in the soft tissues following the skeletal movement subsequent to surgical advancement of the mandible through bilateral sagittal split osteotomy and to provide the patient reliable information with regard to esthetic changes that can be expected following the treatment. Materials and Methods: Twenty adult patients diagnosed with skeletal class II malocclusion and underwent bilateral sagittal split osteotomy for mandibular advancement by a mean of 8 mm using rigid fixation were included in the study. Soft tissue changes brought about by the surgical procedure and their stability over a period of time were evaluated prospectively using 12 linear (4 vertical and 8 horizontal) and 4 angular measurements on profile cephalograms which were taken preoperatively after the pre-surgical orthodontics (T1) and postoperatively with duration of 1 month (T2) and 6 months (T3) respectively. Results: It was observed that compared to the linear measurements, the angular measurements showed significant changes. The improvement in the esthetic outcome is a direct reflection of the angular changes whereas the linear changes played a contributing role. Following mandibular advancement surgery the profiles of the patients was perceived to have improved with reduction in the facial convexity, an increase in the lower facial height, decrease in the depth of the mentolabial sulcus and improvement in the lip competency with lengthening, straightening and thinning of the lower lip. Conclusion: The soft tissue response and its stability depends on the stability of the surgical procedure itself, postsurgical growth and remodeling of the hard tissues and soft tissue changes as a result of maturation and aging. PMID:25593860

Managing the peri-implant mucosa: a clinically reliable method for optimizing soft tissue contours and emergence profile.

PubMed

Parpaiola, Andrea; Sbricoli, Luca; Guazzo, Riccardo; Bressan, Eriberto; Lops, Diego

2013-10-01

The proper representation of soft tissue contours for a natural aspect of the peri-implant mucosa and its mimesis with the adjacent teeth is a crucial aspect of the esthetic area restoration. This paper describes a method for the easy transfer of the peri-implant tissue morphology onto impression material with a view to achieving an accurate, custom implant restoration. The procedure described is suitable both for single and multi-unit implant-supported prostheses. Once the peri-implant mucosa is sculpted by the provisional restoration, the emergence profile is duplicated. The implant analog is embedded into laboratory stone or plaster in a mixing cup and allowed to set. The provisional restoration is removed from the oral cavity and screwed to the implant analog; then, a polyether material is placed in the mixing cup so that the provisional restoration is put into impression material at the level of the prosthetic emergence profile. After the polyether polymerizing, the provisional prosthesis is unscrewed and replaced with the stock hexed transfer for the final impression. Next, cold self-curing resin is poured into this gap and left to set. A custom transfer for this single implant site is thus obtained. This modified transfer is then removed and screwed onto the implant in the oral cavity for the definitive impression. The technique described enables a faithful reproduction of the peri-implant soft tissues and emergence profile. An emergence profile that mimics the natural tooth should be obtained by successful esthetic implant restoration. Moreover, it allows proper hygiene, which is fundamental for implant maintenance. The best way to achieve the correct emergence profile is to sculpture the peri-implant mucosa by means of a provisional prosthesis. Prefabricated provisional crowns cannot mimic the complexity and the variations of human soft tissue. Therefore, only a chair-side modification of the provisional restoration can accomplish the optimal result. Such a requirement can be satisfied by the clinical method described in the present report. © 2013 Wiley Periodicals, Inc.

The influence of different soft-tissue grafting procedures at single implant placement on esthetics: A randomized controlled trial.

PubMed

Zuiderveld, Elise G; Meijer, Henny J A; Vissink, Arjan; Raghoebar, Gerry M

2018-05-13

Soft tissue grafting to thicken the soft tissue around dental implants was proposed to ameliorate the esthetic outcome. Traditionally, connective tissue is used as a grafting material, but a xenogeneic collagen matrix was introduced as an alternative to reduce patient morbidity. Sixty patients randomly received either no graft (n = 20, NG group), a connective tissue graft (n = 20, CTG group) or a xenogeneic collagen matrix (n = 20, XCM group) when placing an implant in a preserved alveolar ridge. Changes in mid-buccal mucosal level (MBML) at one (T 1 ) and twelve (T 12 ) months after final implant crown placement were compared to the pre-extraction situation. Additionally, esthetics, marginal bone level, clinical peri-implant parameters and patient satisfaction were assessed. At T 12 , mean changes in MBML were -0.48±1.5 mm, -0.04±1.1 mm and -0.17±1.3 mm in the NG, CTG and XCM groups (p = 0.56), respectively. Regarding the other outcome variables, no significant inter-group differences were observed. Soft tissue grafting at single implant placement in preserved alveolar ridges does not result in a better esthetic outcome or in better peri-implant health and should not be considered as a standard procedure. This article is protected by copyright. All rights reserved. © 2018 American Academy of Periodontology.

Soft shell clams Mya arenaria with disseminated neoplasia demonstrate reverse transcriptase activity

USGS Publications Warehouse

House, M.L.; Kim, C.H.; Reno, P.W.

1998-01-01

Disseminated neoplasia (DN), a proliferative cell disorder of the circulatory system of bivalves, was first reported in oysters in 1969. Since that time, the disease has been determined to be transmissible through water-borne exposure, but the etiological agent has not been unequivocally identified. In order to determine if a viral agent, possibly a retrovirus, could be the causative agent of DN, transmission experiments were performed, using both a cell-free filtrate and a sucrose gradient-purified preparation of a cell-free filtrate of DN positive materials. Additionally, a PCR-enhanced reverse transcriptase assay was used to determine if reverse transcriptase was present in tissues or hemolymph from DN positive soft shell clams Mya arenaria. DN was transmitted to healthy clams by injection with whole DN cells, but not with cell-free flitrates prepared from either tissues from DN positive clams, or DN cells. The cell-free preparations from DN-positive tissues and hemolymph having high levels of DN cells in circulation exhibited positive reactions in the PCR-enhanced reverse transcriptase assay. Cell-free preparations of hemolymph from clams having low levels of DN (<0.1% of cells abnormal), hemocytes from normal soft shell clams, and normal soft shell clam tissues did not produce a positive reaction in the PCR enhanced reverse transcriptase assay.

Therapeutic Ultrasound Enhancement of Drug Delivery to Soft Tissues

NASA Astrophysics Data System (ADS)

Lewis, George; Wang, Peng; Lewis, George; Olbricht, William

2009-04-01

Effects of exposure to 1.58 MHz focused ultrasound on transport of Evans Blue Dye (EBD) in soft tissues are investigated when an external pressure gradient is applied to induce convective flow through the tissue. The magnitude of the external pressure gradient is chosen to simulate conditions in brain parenchyma during convection-enhanced drug delivery (CED) to the brain. EBD uptake and transport are measured in equine brain, avian muscle and agarose brain-mimicking phantoms. Results show that ultrasound enhances EBD uptake and transport, and the greatest enhancement occurs when the external pressure gradient is applied. The results suggest that exposure of the brain parenchyma to ultrasound could enhance penetration of material infused into the brain during CED therapy.

The Dynamic Behaviour and Shock Recovery of a Porcine Skeletal Muscle Tissue

NASA Astrophysics Data System (ADS)

Wilgeroth, James; Hazell, Paul; Appleby-Thomas, Gareth

2011-06-01

Modern-day ballistic armours provide a high degree of protection to the individual. However, the effects of non-penetrating projectiles, blast, and high-energy blunt impact events may still cause severe tissue trauma/remote injury. The energies corresponding to such events allow for the formation and transmission of shock waves within body tissues. Consequently, the nature of trauma inflicted upon such soft tissues is likely to be intimately linked to their interaction with the shock waves that propagate through them. Notably, relatively little is known about the effect of shock upon the structure of biological materials, such as skeletal muscle tissue. In this study plate-impact experiments have been used to interrogate the dynamic response of a porcine skeletal muscle tissue under one-dimensional shock loading conditions. Additionally, development of a soft-capture system that has allowed recovery of shocked skeletal muscle tissue specimens is discussed and comparison made between experimental diagnostics and hydrocode simulations of the experiment.

Energy absorption buildup factors, exposure buildup factors and Kerma for optically stimulated luminescence materials and their tissue equivalence for radiation dosimetry

NASA Astrophysics Data System (ADS)

Singh, Vishwanath P.; Badiger, N. M.

2014-11-01

Optically stimulated luminescence (OSL) materials are sensitive dosimetric materials used for precise and accurate dose measurement for low-energy ionizing radiation. Low dose measurement capability with improved sensitivity makes these dosimeters very useful for diagnostic imaging, personnel monitoring and environmental radiation dosimetry. Gamma ray energy absorption buildup factors and exposure build factors were computed for OSL materials using the five-parameter Geometric Progression (G-P) fitting method in the energy range 0.015-15 MeV for penetration depths up to 40 mean free path. The computed energy absorption buildup factor and exposure buildup factor values were studied as a function of penetration depth and incident photon energy. Effective atomic numbers and Kerma relative to air of the selected OSL materials and tissue equivalence were computed and compared with that of water, PMMA and ICRU standard tissues. The buildup factors and kerma relative to air were found dependent upon effective atomic numbers. Buildup factors determined in the present work should be useful in radiation dosimetry, medical diagnostics and therapy, space dosimetry, accident dosimetry and personnel monitoring.

SU-E-T-102: Determination of Dose Distributions and Water-Equivalence of MAGIC-F Polymer Gel for 60Co and 192Ir Brachytherapy Sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quevedo, A; Nicolucci, P

2014-06-01

Purpose: Analyse the water-equivalence of MAGIC-f polymer gel for {sup 60}Co and {sup 192}Ir clinical brachytherapy sources, through dose distributions simulated with PENELOPE Monte Carlo code. Methods: The real geometry of {sup 60} (BEBIG, modelo Co0.A86) and {sup 192}192Ir (Varian, model GammaMed Plus) clinical brachytherapy sources were modelled on PENELOPE Monte Carlo simulation code. The most probable emission lines of photons were used for both sources: 17 emission lines for {sup 192}Ir and 12 lines for {sup 60}. The dose distributions were obtained in a cubic water or gel homogeneous phantom (30 × 30 × 30 cm{sup 3}), with themore » source positioned in the middle of the phantom. In all cases the number of simulation showers remained constant at 10{sup 9} particles. A specific material for gel was constructed in PENELOPE using weight fraction components of MAGIC-f: wH = 0,1062, wC = 0,0751, wN = 0,0139, wO = 0,8021, wS = 2,58×10{sup −6} e wCu = 5,08 × 10{sup −6}. The voxel size in the dose distributions was 0.6 mm. Dose distribution maps on the longitudinal and radial direction through the centre of the source were used to analyse the water-equivalence of MAGIC-f. Results: For the {sup 60} source, the maximum diferences in relative doses obtained in the gel and water were 0,65% and 1,90%, for radial and longitudinal direction, respectively. For {sup 192}Ir, the maximum difereces in relative doses were 0,30% and 1,05%, for radial and longitudinal direction, respectively. The materials equivalence can also be verified through the effective atomic number and density of each material: Zef-MAGIC-f = 7,07 e .MAGIC-f = 1,060 g/cm{sup 3} and Zef-water = 7,22. Conclusion: The results showed that MAGIC-f is water equivalent, consequently being suitable to simulate soft tissue, for Cobalt and Iridium energies. Hence, gel can be used as a dosimeter in clinical applications. Further investigation to its use in a clinical protocol is needed.« less

Space Radiation Dosimetry to Evaluate the Effect of Polyethylene Shielding in the Russian Segment of the International Space Station

NASA Astrophysics Data System (ADS)

Nagamatsu, Aiko; Casolino, Marco; Larsson, Oscar; Ito, Tsuyoshi; Yasuda, Nakahiro; Kitajo, Keiichi; Shimada, Ken; Takeda, Kazuo; Tsuda, Shuichi; Sato, Tatsuhiko

As a part of the Alteino Long Term Cosmic Ray measurements on board the International Space Station (ALTCRISS) project, the shielding effect of polyethylene (PE) were evaluated in the Russian segment of the ISS, using active and passive dosimeter systems covered with or without PE shielding. For the passive dosimeter system, PADLES (Passive Dosimeter for Life-Science and Experiments in Space) was used in the project, which consists of a Thermo-Luminescent Dosimeters (TLD) and CR-39 Plastic Nuclear Track Detectors (PNTDs) attached to a radiator. Not only CR-39 PNTD itself but also a tissue equivalent material, NAN-JAERI, were employed as the radiator in order to investigate whether CR-39 PNTD can be used as a surrogate of tissue equivalent material in space dosimetry or not. The agreements between the doses measured by PADLES with CR-39 PNTD and NAN-JAERI radiators were quite satisfactorily, indicating the tissue-equivalent dose can be measured by conventional PADLES even though CR-39 PNTD is not perfect tissue-equivalent material. It was found that the shielding effect of PE varies with location inside the spacecraft: it became less significant with an increase of the mean thickness of the wall. This tendency was also verified by Monte Carlo simulation using the PHITS code. Throughout the flight experiments, in a series of four phases in the ALTCRISS project from December 2005 to October 2007, we assessed the ability of PE to decrease radiation doses in Low Earth Orbit(LEO).

A tensile machine with a novel optical load cell for soft biological tissues application.

PubMed

Faturechi, Rahim; Hashemi, Ata; Abolfathi, Nabiollah

2014-11-01

The uniaxial tensile testing machine is the most common device used to measure the mechanical properties of industrial and biological materials. The need for a low-cost uniaxial tension testing device for small research centers has always been the subject of research. To address this need, a novel uniaxial tensile testing machine was designed and fabricated to measure the mechanical properties of soft biological tissues. The device is equipped with a new low-cost load cell which works based on the linear displacement/force relationship of beams. The deflection of the beam load cell is measured optically by a digital microscope with an accuracy of 1 µm. The stiffness of the designed load cell was experimentally and theoretically determined at 100 N mm(-1). The stiffness of the load cell can be easily adjusted according to the tissue's strength. The force-time behaviour of soft tissue specimens was obtained by an in-house image processing program. To demonstrate the efficiency of the fabricated device, the mechanical properties of amnion tissue was measured and compared with available data. The obtained results indicate a strong agreement with that of previous studies.

Modeling of Soft Poroelastic Tissue in Time-Harmonic MR Elastography

PubMed Central

Perriñez, Phillip R.; Kennedy, Francis E.; Van Houten, Elijah E. W.; Weaver, John B.; Paulsen, Keith D.

2010-01-01

Elastography is an emerging imaging technique that focuses on assessing the resistance to deformation of soft biological tissues in vivo. Magnetic resonance elastography (MRE) uses measured displacement fields resulting from low-amplitude, low-frequency (10 Hz–1 kHz) time-harmonic vibration to recover images of the elastic property distribution of tissues including breast, liver, muscle, prostate, and brain. While many soft tissues display complex time-dependent behavior not described by linear elasticity, the models most commonly employed in MRE parameter reconstructions are based on elastic assumptions. Further, elasticity models fail to include the interstitial fluid phase present in vivo. Alternative continuum models, such as consolidation theory, are able to represent tissue and other materials comprising two distinct phases, generally consisting of a porous elastic solid and penetrating fluid. MRE reconstructions of simulated elastic and poroelastic phantoms were performed to investigate the limitations of current-elasticity-based methods in producing accurate elastic parameter estimates in poroelastic media. The results indicate that linearly elastic reconstructions of fluid-saturated porous media at amplitudes and frequencies relevant to steady-state MRE can yield misleading effective property distributions resulting from the complex interaction between their solid and fluid phases. PMID:19272864

Instrument for determining the complex shear modulus of soft-tissue-like materials from 10 to 300 Hz

PubMed Central

Madsen, E L; Frank, G R; Hobson, M A; Lin-Gibson, S; Hall, T J; Jiang, J; Stiles, T A

2010-01-01

Accurate determination of the complex shear modulus of soft tissues and soft-tissue-like materials in the 10–300 Hz frequency range is very important to researchers in MR elastography and acoustic radiation force impulse (ARFI) imaging. A variety of instruments for making such measurements has been reported, but none of them is easily reproduced, and none have been tested to conform to causality via the Kramers–Kronig (K-K) relations. A promising linear oscillation instrument described in a previous brief report operates between 20 and 160 Hz, but results were not tested for conformity to the K-K relations. We have produced a similar instrument with our own version of the electronic components and have also accounted for instrumental effects on the data reduction, which is not addressed in the previous report. The improved instrument has been shown to conform to an accurate approximation of the K-K relations over the 10–300 Hz range. The K-K approximation is based on the Weichert mechanical circuit model. We also found that the sample thickness must be small enough to obtain agreement with a calibrated commercial rheometer. A complete description of the improved instrument is given, facilitating replication in other labs. PMID:18758002

Necrotizing soft tissue infection

MedlinePlus

Necrotizing fasciitis; Fasciitis - necrotizing; Flesh-eating bacteria; Soft tissue gangrene; Gangrene - soft tissue ... Many different types of bacteria can cause this infection. A very severe and usually deadly form of necrotizing soft tissue infection is due to the ...

The compressive mechanical properties of diabetic and non-diabetic plantar soft tissue.

PubMed

Pai, Shruti; Ledoux, William R

2010-06-18

Diabetic subjects are at an increased risk of developing plantar ulcers. Knowledge of the physiologic compressive properties of the plantar soft tissue is critical to understanding the possible mechanisms of ulcer formation and improving treatment options. The purpose of this study was to determine the compressive mechanical properties of the plantar soft tissue in both diabetic and non-diabetic specimens from six relevant locations beneath the foot, namely the hallux (big toe), first, third, and fifth metatarsal heads, lateral midfoot, and calcaneus (heel). Cylindrical specimens (1.905 cm diameter) from these locations were excised and separated from the skin and bone from 4 diabetic and 4 non-diabetic age-matched, elderly, fresh-frozen cadaveric feet. Specimens were then subjected to biomechanically realistic strains of approximately 50% in compression using triangle wave tests conducted at five frequencies ranging from 1 to 10 Hz to determine tissue modulus, energy loss, and strain rate dependence. Diabetic vs. non-diabetic results across all specimens, locations, and testing frequencies demonstrated altered mechanical properties with significantly increased modulus (1146.7 vs. 593.0 kPa) but no change in energy loss (68.5 vs. 67.9%). All tissue demonstrated strain rate dependence and tissue beneath the calcaneus was found to have decreased modulus and energy loss compared to other areas. The results of this study could be used to generate material properties for all areas of the plantar soft tissue in diabetic or non-diabetic feet, with implications for foot computational modeling efforts and potentially for pressure alleviating footwear that could reduce plantar ulcer incidence. Published by Elsevier Ltd.

The compressive mechanical properties of diabetic and non-diabetic plantar soft tissue

PubMed Central

Pai, Shruti; Ledoux, William R.

2010-01-01

Diabetic subjects are at an increased risk of developing plantar ulcers. Knowledge of the physiologic compressive properties of the plantar soft tissue is critical to understanding possible mechanisms of ulcer formation and improving treatment options. The purpose of this study was to determine the compressive mechanical properties of the plantar soft tissue in both diabetic and non-diabetic specimens from six relevant locations beneath the foot, namely the hallux (big toe), first, third, and fifth metatarsal heads, lateral midfoot, and calcaneus (heel). Cylindrical specimens (1.905cm diameter) from these locations were excised and separated from the skin and bone from 4 diabetic and 4 non-diabetic age-matched, elderly, fresh-frozen cadaveric feet. Specimens were then subjected to biomechanically realistic strains of ∼50% in compression using triangle wave tests conducted at five frequencies ranging from 1 to 10 Hz to determine tissue modulus, energy loss, and strain rate dependence. Diabetic vs. non-diabetic results across all specimens, locations, and testing frequencies demonstrated altered mechanical properties with significantly increased modulus (1146.7 vs. 593.0kPa) but no change in energy loss (68.5 vs. 67.9%). All tissue demonstrated strain rate dependence and tissue beneath the calcaneus was found to have decreased modulus and energy loss compared to other areas. The results of this study could be used to generate material properties for all areas of the plantar soft tissue in diabetic or non-diabetic feet, with implications for foot computational modeling efforts and potentially for pressure alleviating footwear that could reduce plantar ulcer incidence. PMID:20207359

The materials used in bone tissue engineering

NASA Astrophysics Data System (ADS)

Tereshchenko, V. P.; Kirilova, I. A.; Sadovoy, M. A.; Larionov, P. M.

2015-11-01

Bone tissue engineering looking for an alternative solution to the problem of skeletal injuries. The method is based on the creation of tissue engineered bone tissue equivalent with stem cells, osteogenic factors, and scaffolds - the carriers of these cells. For production of tissue engineered bone equivalent is advisable to create scaffolds similar in composition to natural extracellular matrix of the bone. This will provide optimal conditions for the cells, and produce favorable physico-mechanical properties of the final construction. This review article gives an analysis of the most promising materials for the manufacture of cell scaffolds. Biodegradable synthetic polymers are the basis for the scaffold, but it alone cannot provide adequate physical and mechanical properties of the construction, and favorable conditions for the cells. Addition of natural polymers improves the strength characteristics and bioactivity of constructions. Of the inorganic compounds, to create cell scaffolds the most widely used calcium phosphates, which give the structure adequate stiffness and significantly increase its osteoinductive capacity. Signaling molecules do not affect the physico-mechanical properties of the scaffold, but beneficial effect is on the processes of adhesion, proliferation and differentiation of cells. Biodegradation of the materials will help to fulfill the main task of bone tissue engineering - the ability to replace synthetic construct by natural tissues that will restore the original anatomical integrity of the bone.

An elasto-visco-plastic model for immortal foams or emulsions

NASA Astrophysics Data System (ADS)

Bénito, S.; Bruneau, C.-H.; Colin, T.; Gay, C.; Molino, F.

2008-03-01

A variety of complex fluids consists in soft, round objects (foams, emulsions, assemblies of copolymer micelles or of multilamellar vesicles--also known as onions). Their dense packing induces a slight deviation from their prefered circular or spherical shape. As a frustrated assembly of interacting bodies, such a material evolves from one conformation to another through a succession of discrete, topological events driven by finite external forces. As a result, the material exhibits a finite yield threshold. The individual objects usually evolve spontaneously (colloidal diffusion, object coalescence, molecular diffusion), and the material properties under low or vanishing stress may alter with time, a phenomenon known as aging. We neglect such effects to address the simpler behaviour of (uncommon) immortal fluids: we construct a minimal, fully tensorial, rheological model, equivalent to the (scalar) Bingham model. Importantly, the model consistently describes the ability of such soft materials to deform substantially in the elastic regime (be it compressible or not) before they undergo (incompressible) plastic creep--or viscous flow under even higher stresses.

Effect of surface texture by ion beam sputtering on implant biocompatibility and soft tissue attachment

NASA Technical Reports Server (NTRS)

Gibbons, D. F.

1977-01-01

The objectives in this report were to use the ion beam sputtering technique to produce surface textures on polymers, metals, and ceramics. The morphology of the texture was altered by varying both the width and depth of the square pits which were formed by ion beam erosion. The width of the ribs separating the pits were defined by the mask used to produce the texture. The area of the surface containing pits varies as the width was changed. The biological parameters used to evaluate the biological response to the texture were: (1) fibrous capsule and inflammatory response in subcutaneous soft tissue; (2) strength of the mechanical attachment of the textured surface by the soft tissue; and (3) morphology of the epidermal layer interfacing the textured surface of percutaneous connectors. Because the sputter yield on teflon ribs was approximately an order of magnitude larger than any other material the majority of the measurements presented in the report were obtained with teflon.

Stage-two surgery using collagen soft tissue grafts: clinical cases and ultrastructural analysis.

PubMed

Fischer, Kai R; Fickl, Stefan; Mardas, Nikos; Bozec, Laurent; Donos, Nikolaos

2014-01-01

To present the application of two different soft tissue grafts around dental implants during stage-two surgery. Furthermore, the ultrastructure of these materials is shown and discussed using scanning electron microscopy (SEM). Although soft tissue autografts may be currently regarded as the gold standard, harvesting of these grafts might lead to higher morbidity, longer chair time, and intra-/postoperative complications at the donor site. New developments in collagen scaff olds have provided an alternative to successfully replace autologous grafts in clinical practice. The SEM pictures clearly show the different composition of a bilayer scaff old (collagen matrix, CM) and a porcine acellular dermal matrix (ADM). These distinctive properties lead to different possible indications. Within the presented cases, ADM was used to augment the ridge contour and was placed into a buccal pouch to achieve complete coverage and an uneventful closed healing. On the other side, CM was left exposed to the oral cavity to successfully gain keratinized mucosa around and between two dental implants.

Characterization and validation of the thorax phantom Lungman for dose assessment in chest radiography optimization studies.

PubMed

Rodríguez Pérez, Sunay; Marshall, Nicholas William; Struelens, Lara; Bosmans, Hilde

2018-01-01

This work concerns the validation of the Kyoto-Kagaku thorax anthropomorphic phantom Lungman for use in chest radiography optimization. The equivalence in terms of polymethyl methacrylate (PMMA) was established for the lung and mediastinum regions of the phantom. Patient chest examination data acquired under automatic exposure control were collated over a 2-year period for a standard x-ray room. Parameters surveyed included exposure index, air kerma area product, and exposure time, which were compared with Lungman values. Finally, a voxel model was developed by segmenting computed tomography images of the phantom and implemented in PENELOPE/penEasy Monte Carlo code to compare phantom tissue-equivalent materials with materials from ICRP Publication 89 in terms of organ dose. PMMA equivalence varied depending on tube voltage, from 9.5 to 10.0 cm and from 13.5 to 13.7 cm, for the lungs and mediastinum regions, respectively. For the survey, close agreement was found between the phantom and the patients' median values (deviations lay between 8% and 14%). Differences in lung doses, an important organ for optimization in chest radiography, were below 13% when comparing the use of phantom tissue-equivalent materials versus ICRP materials. The study confirms the value of the Lungman for chest optimization studies.

Dual-energy index value of luminal air in fecal-tagging computed tomography colonography: findings and impact on electronic cleansing.

PubMed

Cai, Wenli; Zhang, Da; Lee, June-Goo; Shirai, Yu; Kim, Se Hyung; Yoshida, Hiroyuki

2013-01-01

The purpose of our study was to measure the dual-energy index (DEI) value of colonic luminal air in both phantom and clinical fecal-tagging dual-energy computed tomography (CT) colonography (DE-CTC) images and to demonstrate its impact on dual-energy electronic cleansing. For the phantom study, a custom-ordered colon phantom was scanned by a dual-energy CT scanner (SOMATON Definition Flash; Siemens Healthcare, Forchheim, Germany) at two photon energies: 80 and 140 kVp. Before imaging, the phantom was filled with a 300-mL mixture of simulated fecal materials tagged by a nonionic iodinated contrast agent at three contrast concentrations: 20, 40, and 60 mg/mL. Ten regions-of-interest (ROIs) were randomly placed in each of the colonic luminal air, abdominal fat, bony structure, and tagged material in each scan. For the clinical study, 22 DE-CTC (80 and 140 kVp) patient cases were collected, who underwent a low-fiber, low-residue diet bowel preparation and orally administered iodine-based fecal tagging. Twenty ROIs were randomly placed in each of the colonic luminal air, abdominal fat, abdominal soft tissue, and tagged fecal material in each scan. For each ROI, the mean CT values in both 80- and 140-kVp images were measured, and then its DEI was calculated. In the phantom study, the mean DEI values of luminal air were 0.270, 0.298, 0.386, and 0.402 for the four groups of tagging conditions: no tagged material and tagged with three groups of contrast concentrations at 20, 40, and 60 mg/mL. In the clinical study, the mean DEI values were 0.341, -0.012, -0.002, and 0.188 for colonic luminal air, abdominal fat, abdominal soft tissue, and tagged fecal material, respectively. In our study, we observed that the DEI values of colonic luminal air in DE-CTC images (>0.10) were substantially higher than the theoretical value of 0.0063. In addition, the observed DEI values of colonic luminal air were significantly higher than those of soft tissue. These findings have an important impact on electronic cleansing: it may provide an effective means of differentiating colonic soft-tissue structures from the air-tagging mixture caused by the partial volume effect and thus of minimizing the cleansing artifacts.

Safety of radiofrequency treatment over human skin previously injected with medium-term injectable soft-tissue augmentation materials: a controlled pilot trial.

PubMed

Alam, Murad; Levy, Ross; Pajvani, Urvi; Pavjani, Urvi; Ramierez, James A; Guitart, Joan; Veen, Heather; Gladstone, Hayes B

2006-03-01

Several soft-tissue augmentation materials are now available for reduction of nasolabial fold creases and perioral rhytides. Nasolabial folds and perioral rhytides can also be improved by skin tightening delivered by non-ablative radiofrequency (RF) treatment. The purpose of this study was to assess the safety of RF treatment over skin areas recently injected with medium-term injectable soft-tissue augmentation materials. Five subjects were assigned to the experimental arm (augmentation materials plus RF) and one to the control arm (augmentation materials alone). Each subject received injections of 0.3 mL of hyaluronic acid derivative (Restylane) and calcium hydroxylapatite (Radiesse) 3 cm apart on the upper inner arm. Two weeks later, two non-overlapping passes of RF (Thermage ThermaCool TC) were delivered at 63.5 setting with medium-fast 1.5 cm2 tip over injected sites in all of the experimental subjects. Punch skin biopsies were obtained 3 days later from each of the two injection sites on each subject. Light microscopy and digital photomicrographs obtained at low, medium, and high power showed no difference between filler materials in experimental and control subjects. In both cases filler was evident at the deep dermal-subcutaneous junction. Nodule formation, foreign body extravasation, or hemorrhage/clot was not observed grossly or histologically. Subjects and physicians did not report any difference in signs and symptoms between the experimental and control arms. Slightly increased transitory pain was noted when RF was delivered over filler versus over normal skin. Applying RF treatment over the same area 2 weeks after deep dermal injection with hyaluronic acid derivatives or calcium hydroxylapatite does not appear to cause gross morphological changes in the filler material or surrounding skin. Further studies with different parameters are necessary to confirm these findings. 2006 Wiley-Liss, Inc.

3D-Printed Models of Cleft Lip and Palate for Surgical Training and Patient Education.

PubMed

Chou, Pang-Yun; Hallac, Rami R; Shih, Ellen; Trieu, Jenny; Penumatcha, Anjani; Das, Priyanka; Meyer, Clark A; Seaward, James R; Kane, Alex A

2018-03-01

Sculpted physical models and castings of the anatomy of cleft lip and palate are used for parent, patient, and trainee education of cleft lip and palate conditions. In this study, we designed a suite of digital 3-dimensional (3D) models of cleft lip and palate anatomy with additive manufacturing techniques for patient education. CT scans of subjects with isolated cleft palate, unilateral and bilateral cleft lip and palate, and a control were obtained. Soft tissue and bony structures were segmented and reconstructed into digital 3D models. The oral soft tissues overlying the cleft palate were manually molded with silicone putty and scanned using CT to create digital 3D models. These were then combined with the original model to integrate with segmentable soft tissues. Bone and soft tissues were 3D printed in different materials to mimic the rigidity/softness of the relevant anatomy. These models were presented to the parents/patients at our craniofacial clinic. Visual analog scale (VAS) surveys were obtained pertaining to the particular use of the models, to ascertain their value in parental education. A total of 30 parents of children with cleft conditions completed VAS evaluations. The models provided the parents with a better understanding of their child's condition with an overall evaluation score of 9.35 ± 0.5. We introduce a suite of 3D-printed models of cleft conditions that has a useful role in patient, parental, and allied health education with highly positive feedback.

Development and characterization of a novel hydrogel adhesive for soft tissue applications

NASA Astrophysics Data System (ADS)

Sanders, Lindsey Kennedy

With laparoscopic and robotic surgical techniques advancing, the need for an injectable surgical adhesive is growing. To be effective, surgical adhesives for internal organs require bulk strength and compliance to avoid rips and tears, and adhesive strength to avoid leakage at the application site, while not hindering the natural healing process. Although a number of tissue adhesives and sealants approved by the FDA for surgical use are currently available, attaining a useful balance in all of these qualities has proven difficult, particularly when considering applications involving highly expandable tissue, such as bladder and lung. The long-term goal of this project is to develop a hydrogel-based tissue adhesive that provides proper mechanical properties to eliminate the need for sutures in various soft tissue applications. Tetronic (BASF), a 4-arm poly(propylene oxide)-poly(ethylene oxide) (PPO-PEO) block copolymer, has been selected as the base material for the adhesive hydrogel system. Solutions of Tetronic T1107 can support reverse thermal gelation at physiological temperatures, which can be combined with covalent crosslinking to achieve a "tandem gelation" process making it ideal for use as a tissue adhesive. The objective of this doctoral thesis research is to improve the performance of the hydrogel based tissue adhesive developed previously by Cho and co-workers by applying a multi-functionalization of Tetronic. Specifically, this research aimed to improve bonding strength of Tetronic tissue adhesive using bi-functional modification, incorporate hemostatic function to the bi-functional Tetronic hydrogel, and evaluate the safety of bi-functional Tetronic tissue adhesive both in vitro and in vivo. In summary, we have developed a fast-curing, mechanically strong hemostatic tissue adhesive that can control blood loss in wet conditions during wound treatment applications (bladder, liver and muscle). Specifically, the bi-functional Tetronic adhesive (TAS) with a proper blend ratio may be used to achieve an accurate balance in bulk and tissue bond strengths, as well as the compliance and durability for expandable organ application, such as the bladder. Incorporation of chitosan expanded the utility of the bi-functional modified T1107 (TAS) adhesive to tissue wounds on highly vascularized organs (e.g., liver, kidney). Further, we demonstrated that the modified Tetronic adhesive is biocompatible and safe for treatment of small soft tissue wounds on rat's muscle using FDA requirements. The current findings helped our understanding of the material and mechanical properties of the modified Tetronic adhesive and ultimately progress the field of surgical adhesives and sealants by providing a tunable adhesive system for various internal soft tissue wound applications.

Spectral optimization for micro-CT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hupfer, Martin; Nowak, Tristan; Brauweiler, Robert

2012-06-15

Purpose: To optimize micro-CT protocols with respect to x-ray spectra and thereby reduce radiation dose at unimpaired image quality. Methods: Simulations were performed to assess image contrast, noise, and radiation dose for different imaging tasks. The figure of merit used to determine the optimal spectrum was the dose-weighted contrast-to-noise ratio (CNRD). Both optimal photon energy and tube voltage were considered. Three different types of filtration were investigated for polychromatic x-ray spectra: 0.5 mm Al, 3.0 mm Al, and 0.2 mm Cu. Phantoms consisted of water cylinders of 20, 32, and 50 mm in diameter with a central insert of 9more » mm which was filled with different contrast materials: an iodine-based contrast medium (CM) to mimic contrast-enhanced (CE) imaging, hydroxyapatite to mimic bone structures, and water with reduced density to mimic soft tissue contrast. Validation measurements were conducted on a commercially available micro-CT scanner using phantoms consisting of water-equivalent plastics. Measurements on a mouse cadaver were performed to assess potential artifacts like beam hardening and to further validate simulation results. Results: The optimal photon energy for CE imaging was found at 34 keV. For bone imaging, optimal energies were 17, 20, and 23 keV for the 20, 32, and 50 mm phantom, respectively. For density differences, optimal energies varied between 18 and 50 keV for the 20 and 50 mm phantom, respectively. For the 32 mm phantom and density differences, CNRD was found to be constant within 2.5% for the energy range of 21-60 keV. For polychromatic spectra and CMs, optimal settings were 50 kV with 0.2 mm Cu filtration, allowing for a dose reduction of 58% compared to the optimal setting for 0.5 mm Al filtration. For bone imaging, optimal tube voltages were below 35 kV. For soft tissue imaging, optimal tube settings strongly depended on phantom size. For 20 mm, low voltages were preferred. For 32 mm, CNRD was found to be almost independent of tube voltage. For 50 mm, voltages larger than 50 kV were preferred. For all three phantom sizes stronger filtration led to notable dose reduction for soft tissue imaging. Validation measurements were found to match simulations well, with deviations being less than 10%. Mouse measurements confirmed simulation results. Conclusions: Optimal photon energies and tube settings strongly depend on both phantom size and imaging task at hand. For in vivo CE imaging and density differences, strong filtration and voltages of 50-65 kV showed good overall results. For soft tissue imaging of animals the size of a rat or larger, voltages higher than 65 kV allow to greatly reduce scan times while maintaining dose efficiency. For imaging of bone structures, usage of only minimum filtration and low tube voltages of 40 kV and below allow exploiting the high contrast of bone at very low energies. Therefore, a combination of two filtrations could prove beneficial for micro-CT: a soft filtration allowing for bone imaging at low voltages, and a variable stronger filtration (e.g., 0.2 mm Cu) for soft tissue and contrast-enhanced imaging.« less

Soft Plumbing: Direct-Writing and Controllable Perfusion of Tubular Soft Materials

NASA Astrophysics Data System (ADS)

Guenther, Axel; Omoruwa, Patricia; Chen, Haotian; McAllister, Arianna; Jeronimo, Mark; Malladi, Shashi; Hakimi, Navid; Cao, Li; Ramchandran, Arun

2016-11-01

Tubular and ductular structures are abundant in tissues in a wide variety of diameters, wall thicknesses, and compositions. In spite of their relevance to engineered tissues, organs-on-chips and soft robotics, the rapid and consistent preparation of tubular structures remains a challenge. Here, we use a microfabricated printhead to direct-write biopolymeric tubes with dimensional and compositional control. A biopolymer solution is introduced to the center layer of the printhead, and the confining fluids to the top and the bottom layers. The radially flowing biopolymer solution is sandwiched between confining solutions that initiate gelation, initially assuming the shape of a funnel until emerging through a cylindrical confinement as a continuous biopolymer tube. Tubular constructs of sodium alginate and collagen I were obtained with inner diameters (0.6-2.2mm) and wall thicknesses (0.1-0.4mm) in favorable agreement with predictions of analytical models. We obtained homogeneous tubes with smooth and buckled walls and heterotypic constructs that possessed compositions that vary along the tube circumference or radius. Ductular soft materials were reversibly hosted in 3D printed fluidic devices for the perfusion at well-defined transmural pressures to explore the rich variety of dynamical features associated with collapsible tubes that include buckling, complete collapse, and self-oscillation.

In vivo quantification of lead in bone with a portable x-ray fluorescence system--methodology and feasibility.

PubMed

Nie, L H; Sanchez, S; Newton, K; Grodzins, L; Cleveland, R O; Weisskopf, M G

2011-02-07

This study was conducted to investigate the methodology and feasibility of developing a portable x-ray fluorescence (XRF) technology to quantify lead (Pb) in bone in vivo. A portable XRF device was set up and optimal settings of voltage, current, and filter combination for bone lead quantification were selected to achieve the lowest detection limit. The minimum radiation dose delivered to the subject was calculated by Monte Carlo simulations. An ultrasound device was used to measure soft tissue thickness to account for signal attenuation, and an alternative method to obtain soft tissue thickness from the XRF spectrum was developed and shown to be equivalent to the ultrasound measurements (intraclass correlation coefficient, ICC = 0.82). We tested the correlation of in vivo bone lead concentrations between the standard KXRF technology and the portable XRF technology. There was a significant correlation between the bone lead concentrations obtained from the standard KXRF technology and those obtained from the portable XRF technology (ICC = 0.65). The detection limit for the portable XRF device was about 8.4 ppm with 2 mm soft tissue thickness. The entrance skin dose delivered to the human subject was about 13 mSv and the total body effective dose was about 1.5 µSv and should pose minimal radiation risk. In conclusion, portable XRF technology can be used for in vivo bone lead measurement with sensitivity comparable to the KXRF technology and good correlation with KXRF measurements.

In Vivo Quantification of Lead in Bone with a Portable X-ray Fluorescence (XRF) System – Methodology and Feasibility

PubMed Central

Nie, LH; Sanchez, S; Newton, K; Grodzins, L; Cleveland, RO; Weisskopf, MG

2013-01-01

This study was conducted to investigate the methodology and feasibility of developing a portable XRF technology to quantify lead (Pb) in bone in vivo. A portable XRF device was set up and optimal setting of voltage, current, and filter combination for bone lead quantification were selected to achieve the lowest detection limit. The minimum radiation dose delivered to the subject was calculated by Monte Carlo simulations. An ultrasound device was used to measure soft tissue thickness to account for signal attenuation, and an alternative method to obtain soft tissue thickness from the XRF spectrum was developed and shown to be equivalent to the ultrasound measurements (Intraclass Correlation Coefficient, ICC=0.82). We tested the correlation of in vivo bone lead concentrations between the standard KXRF technology and the portable XRF technology. There was a significant correlation between the bone lead concentrations obtained from the standard KXRF technology and those obtained from the portable XRF technology (ICC=0.65). The detection limit for the portable XRF device was about 8.4 ppm with 2 mm soft tissue thickness. The entrance skin dose delivered to the human subject was about 13 mSv and the total body effective dose was about 1.5 μSv and should pose a minimal radiation risk. In conclusion, portable XRF technology can be used for in vivo bone lead measurement with sensitivity comparable to the KXRF technology and good correlation with KXRF measurements. PMID:21242629

Mechanical Designs for Inorganic Stretchable Circuits in Soft Electronics.

PubMed

Wang, Shuodao; Huang, Yonggang; Rogers, John A

2015-09-01

Mechanical concepts and designs in inorganic circuits for different levels of stretchability are reviewed in this paper, through discussions of the underlying mechanics and material theories, fabrication procedures for the constituent microscale/nanoscale devices, and experimental characterization. All of the designs reported here adopt heterogeneous structures of rigid and brittle inorganic materials on soft and elastic elastomeric substrates, with mechanical design layouts that isolate large deformations to the elastomer, thereby avoiding potentially destructive plastic strains in the brittle materials. The overall stiffnesses of the electronics, their stretchability, and curvilinear shapes can be designed to match the mechanical properties of biological tissues. The result is a class of soft stretchable electronic systems that are compatible with traditional high-performance inorganic semiconductor technologies. These systems afford promising options for applications in portable biomedical and health-monitoring devices. Mechanics theories and modeling play a key role in understanding the underlining physics and optimization of these systems.

Mechanical Designs for Inorganic Stretchable Circuits in Soft Electronics

PubMed Central

Wang, Shuodao; Huang, Yonggang; Rogers, John A.

2016-01-01

Mechanical concepts and designs in inorganic circuits for different levels of stretchability are reviewed in this paper, through discussions of the underlying mechanics and material theories, fabrication procedures for the constituent microscale/nanoscale devices, and experimental characterization. All of the designs reported here adopt heterogeneous structures of rigid and brittle inorganic materials on soft and elastic elastomeric substrates, with mechanical design layouts that isolate large deformations to the elastomer, thereby avoiding potentially destructive plastic strains in the brittle materials. The overall stiffnesses of the electronics, their stretchability, and curvilinear shapes can be designed to match the mechanical properties of biological tissues. The result is a class of soft stretchable electronic systems that are compatible with traditional high-performance inorganic semiconductor technologies. These systems afford promising options for applications in portable biomedical and health-monitoring devices. Mechanics theories and modeling play a key role in understanding the underlining physics and optimization of these systems. PMID:27668126

On the dynamic behavior of three readily available soft tissue simulants

NASA Astrophysics Data System (ADS)

Appleby-Thomas, G. J.; Hazell, P. J.; Wilgeroth, J. M.; Shepherd, C. J.; Wood, D. C.; Roberts, A.

2011-04-01

Plate-impact experiments have been employed to investigate the dynamic response of three readily available tissue simulants for ballistic purposes: gelatin, ballistic soap (both subdermal tissue simulants), and lard (adipose layers). All three materials exhibited linear Hugoniot equations-of-state in the US-uP plane. While gelatin behaved hydrodynamically under shock, soap and lard appeared to strengthen under increased loading. Interestingly, the simulants under test appeared to strengthen in a material-independent manner on shock arrival (tentatively attributed to a rearrangement of the amorphous molecular chains under loading). However, material-specific behavior was apparent behind the shock. This behavior appeared to correlate with microstructural complexity, suggesting a steric hindrance effect.

Science, Technology and Requirements - Forum

DTIC Science & Technology

2012-10-18

Visable Absorbing and Electrostatically Adhesive Taggants •2008 Removal of CBRN Materials from Soil & Water using Nanosize Hydroxyapaptite •2009...Ribbon Composite for Optically Transparent Armor Windows •2010 UV Retroreflector Covert Taggants •2013 Proposed Warfighter Bandaging System Company... Bandaging System - Proposed Properties: •Bioactive fiber tissue scaffolding (bonds to both hard and soft tissue) •Hemostatic and Bioresorbable

Soft Tissue Alterations in Esthetic Postextraction Sites: A 3-Dimensional Analysis.

PubMed

Chappuis, V; Engel, O; Shahim, K; Reyes, M; Katsaros, C; Buser, D

2015-09-01

Dimensional alterations of the facial soft and bone tissues following tooth extraction in the esthetic zone play an essential role to achieve successful outcomes in implant therapy. This prospective study is the first to investigate the interplay between the soft tissue dimensions and the underlying bone anatomy during an 8-wk healing period. The analysis is based on sequential 3-dimensional digital surface model superimpositions of the soft and bone tissues using digital impressions and cone beam computed tomography during an 8-wk healing period. Soft tissue thickness in thin and thick bone phenotypes at extraction was similar, averaging 0.7 mm and 0.8 mm, respectively. Interestingly, thin bone phenotypes revealed a 7-fold increase in soft tissue thickness after an 8-wk healing period, whereas in thick bone phenotypes, the soft tissue dimensions remained unchanged. The observed spontaneous soft tissue thickening in thin bone phenotypes resulted in a vertical soft tissue loss of only 1.6 mm, which concealed the underlying vertical bone resorption of 7.5 mm. Because of spontaneous soft tissue thickening, no significant differences were detected in the total tissue loss between thin and thick bone phenotypes at 2, 4, 6, and 8 wk. More than 51% of these dimensional alterations occurred within 2 wk of healing. Even though the observed spontaneous soft tissue thickening in thin bone phenotypes following tooth extraction conceals the pronounced underlying bone resorption pattern by masking the true bone deficiency, spontaneous soft tissue thickening offers advantages for subsequent bone regeneration and implant therapies in sites with high esthetic demand (Clinicaltrials.gov NCT02403700). © International & American Associations for Dental Research.

Experimental Evaluation of Equivalent-Fluid Models for Melamine Foam

NASA Technical Reports Server (NTRS)

Allen, Albert R.; Schiller, Noah H.

2016-01-01

Melamine foam is a soft porous material commonly used in noise control applications. Many models exist to represent porous materials at various levels of fidelity. This work focuses on rigid frame equivalent fluid models, which represent the foam as a fluid with a complex speed of sound and density. There are several empirical models available to determine these frequency dependent parameters based on an estimate of the material flow resistivity. Alternatively, these properties can be experimentally educed using an impedance tube setup. Since vibroacoustic models are generally sensitive to these properties, this paper assesses the accuracy of several empirical models relative to impedance tube measurements collected with melamine foam samples. Diffuse field sound absorption measurements collected using large test articles in a laboratory are also compared with absorption predictions determined using model-based and measured foam properties. Melamine foam slabs of various thicknesses are considered.

Analysis of energy dispersive x-ray diffraction profiles for material identification, imaging and system control

NASA Astrophysics Data System (ADS)

Cook, Emily Jane

2008-12-01

This thesis presents the analysis of low angle X-ray scatter measurements taken with an energy dispersive system for substance identification, imaging and system control. Diffraction measurements were made on illicit drugs, which have pseudo- crystalline structures and thus produce diffraction patterns comprising a se ries of sharp peaks. Though the diffraction profiles of each drug are visually characteristic, automated detection systems require a substance identification algorithm, and multivariate analysis was selected as suitable. The software was trained with measured diffraction data from 60 samples covering 7 illicit drugs and 5 common cutting agents, collected with a range of statistical qual ities and used to predict the content of 7 unknown samples. In all cases the constituents were identified correctly and the contents predicted to within 15%. Soft tissues exhibit broad peaks in their diffraction patterns. Diffraction data were collected from formalin fixed breast tissue samples and used to gen erate images. Maximum contrast between healthy and suspicious regions was achieved using momentum transfer windows 1.04-1.10 and 1.84-1.90 nm_1. The resulting images had an average contrast of 24.6% and 38.9% compared to the corresponding transmission X-ray images (18.3%). The data was used to simulate the feedback for an adaptive imaging system and the ratio of the aforementioned momentum transfer regions found to be an excellent pa rameter. Investigation into the effects of formalin fixation on human breast tissue and animal tissue equivalents indicated that fixation in standard 10% buffered formalin does not alter the diffraction profiles of tissue in the mo mentum transfer regions examined, though 100% unbuffered formalin affects the profile of porcine muscle tissue (a substitute for glandular and tumourous tissue), though fat is unaffected.

Nanobiotechnology: soft lithography.

PubMed

Mele, Elisa; Pisignano, Dario

2009-01-01

An entirely new scientific and technological area has been born from the combination of nanotechnology and biology: nanobiotechnology. Such a field is primed especially by the strong potential synergy enabled by the integration of technologies, protocols, and investigation methods, since, while biomolecules represent functional nanosystems interesting for nanotechnology, micro- and nano-devices can be very useful instruments for studying biological materials. In particular, the research of new approaches for manipulating matter and fabricating structures with micrometre- and sub-micrometre resolution has determined the development of soft lithography, a new set of non-photolithographic patterning techniques applied to the realization of selective proteins and cells attachment, microfluidic circuits for protein and DNA chips, and 3D scaffolds for tissue engineering. Today, soft lithographies have become an asset of nanobiotechnology. This Chapter examines the biological applications of various soft lithographic techniques, with particular attention to the main general features of soft lithography and of materials commonly employed with these methods. We present approaches particularly suitable for biological materials, such as microcontact printing (muCP) and microfluidic lithography, and some key micro- and nanobiotechnology applications, such as the patterning of protein and DNA microarrays and the realization of microfluidic-based analytical devices.

Cone-Beam Computed Tomography Evaluation of Horizontal and Vertical Dimensional Changes in Buccal Peri-Implant Alveolar Bone and Soft Tissue: A 1-Year Prospective Clinical Study.

PubMed

Kaminaka, Akihiro; Nakano, Tamaki; Ono, Shinji; Kato, Tokinori; Yatani, Hirofumi

2015-10-01

This study evaluated changes in the horizontal and vertical dimensions of the buccal alveolar bone and soft tissue over a 1-year period following implant prosthesis. Thirty-three participants with no history of guided bone regeneration or soft tissue augmentation underwent dental implant placement with different types of connections. The dimensions of the buccal alveolar bone and soft tissue were evaluated immediately and at 1 year after prosthesis from reconstructions of cross-sectional cone-beam computed tomography images. The vertical and horizontal loss of buccal bone and soft tissue around implants with conical connections were lower than around those with external or internal connections. Statistically significant negative correlations were observed between initial horizontal bone thickness and changes in vertical bone and soft tissue height (p < .05), and between initial horizontal soft tissue thickness and the change in vertical soft tissue height (p < .05). Implants with a conical connection preserve peri-implant alveolar bone and soft tissue more effectively than other connection types. Furthermore, the initial buccal alveolar bone and soft tissue thickness around the implant platform may influence their vertical dimensional changes at 1 year after implant prosthesis. © 2014 Wiley Periodicals, Inc.

Evaluation of the tissue reaction to a new bilayered collagen matrix in vivo and its translation to the clinic.

PubMed

Ghanaati, Shahram; Schlee, Markus; Webber, Matthew J; Willershausen, Ines; Barbeck, Mike; Balic, Ela; Görlach, Christoph; Stupp, Samuel I; Sader, Robert A; Kirkpatrick, C James

2011-02-01

This study evaluates a new collagen matrix that is designed with a bilayered structure in order to promote guided tissue regeneration and integration within the host tissue. This material induced a mild tissue reaction when assessed in a murine model and was well integrated within the host tissue, persisting in the implantation bed throughout the in vivo study. A more porous layer was rapidly infiltrated by host mesenchymal cells, while a layer designed to be a barrier allowed cell attachment and host tissue integration, but at the same time remained impermeable to invading cells for the first 30 days of the study. The tissue reaction was favorable, and unlike a typical foreign body response, did not include the presence of multinucleated giant cells, lymphocytes, or granulation tissue. In the context of translation, we show preliminary results from the clinical use of this biomaterial applied to soft tissue regeneration in the treatment of gingival tissue recession and exposed roots of human teeth. Such a condition would greatly benefit from guided tissue regeneration strategies. Our findings demonstrate that this material successfully promoted the ingrowth of gingival tissue and reversed gingival tissue recession. Of particular importance is the fact that the histological evidence from these human studies corroborates our findings in the murine model, with the barrier layer preventing unspecific tissue ingrowth, as the scaffold becomes infiltrated by mesenchymal cells from adjacent tissue into the porous layer. Also in the clinical situation no multinucleated giant cells, no granulation tissue and no evidence of a marked inflammatory response were observed. In conclusion, this bilayered matrix elicits a favorable tissue reaction, demonstrates potential as a barrier for preferential tissue ingrowth, and achieves a desirable therapeutic result when applied in humans for soft tissue regeneration.

Validation of a Radiography-Based Quantification Designed to Longitudinally Monitor Soft Tissue Calcification in Skeletal Muscle.

PubMed

Moore, Stephanie N; Hawley, Gregory D; Smith, Emily N; Mignemi, Nicholas A; Ihejirika, Rivka C; Yuasa, Masato; Cates, Justin M M; Liu, Xulei; Schoenecker, Jonathan G

2016-01-01

Soft tissue calcification, including both dystrophic calcification and heterotopic ossification, may occur following injury. These lesions have variable fates as they are either resorbed or persist. Persistent soft tissue calcification may result in chronic inflammation and/or loss of function of that soft tissue. The molecular mechanisms that result in the development and maturation of calcifications are uncertain. As a result, directed therapies that prevent or resorb soft tissue calcifications remain largely unsuccessful. Animal models of post-traumatic soft tissue calcification that allow for cost-effective, serial analysis of an individual animal over time are necessary to derive and test novel therapies. We have determined that a cardiotoxin-induced injury of the muscles in the posterior compartment of the lower extremity represents a useful model in which soft tissue calcification develops remote from adjacent bones, thereby allowing for serial analysis by plain radiography. The purpose of the study was to design and validate a method for quantifying soft tissue calcifications in mice longitudinally using plain radiographic techniques and an ordinal scoring system. Muscle injury was induced by injecting cardiotoxin into the posterior compartment of the lower extremity in mice susceptible to developing soft tissue calcification. Seven days following injury, radiographs were obtained under anesthesia. Multiple researchers applied methods designed to standardize post-image processing of digital radiographs (N = 4) and quantify soft tissue calcification (N = 6) in these images using an ordinal scoring system. Inter- and intra-observer agreement for both post-image processing and the scoring system used was assessed using weighted kappa statistics. Soft tissue calcification quantifications by the ordinal scale were compared to mineral volume measurements (threshold 450.7mgHA/cm3) determined by μCT. Finally, sample-size calculations necessary to discriminate between a 25%, 50%, 75%, and 100% difference in STiCSS score 7 days following burn/CTX induced muscle injury were determined. Precision analysis demonstrated substantial to good agreement for both post-image processing (κ = 0.73 to 0.90) and scoring (κ = 0.88 to 0.93), with low inter- and intra-observer variability. Additionally, there was a strong correlation in quantification of soft tissue calcification between the ordinal system and by mineral volume quantification by μCT (Spearman r = 0.83 to 0.89). The ordinal scoring system reliably quantified soft tissue calcification in a burn/CTX-induced soft tissue calcification model compared to non-injured controls (Mann-Whitney rank test: P = 0.0002, ***). Sample size calculations revealed that 6 mice per group would be required to detect a 50% difference in STiCSS score with a power of 0.8. Finally, the STiCSS was demonstrated to reliably quantify soft tissue calcification [dystrophic calcification and heterotopic ossification] by radiographic analysis, independent of the histopathological state of the mineralization. Radiographic analysis can discriminate muscle injury-induced soft tissue calcification from adjacent bone and follow its clinical course over time without requiring the sacrifice of the animal. While the STiCSS cannot identify the specific type of soft tissue calcification present, it is still a useful and valid method by which to quantify the degree of soft tissue calcification. This methodology allows for longitudinal measurements of soft tissue calcification in a single animal, which is relatively less expensive, less time-consuming, and exposes the animal to less radiation than in vivo μCT. Therefore, this high-throughput, longitudinal analytic method for quantifying soft tissue calcification is a viable alternative for the study of soft tissue calcification.

Validation of a Radiography-Based Quantification Designed to Longitudinally Monitor Soft Tissue Calcification in Skeletal Muscle

PubMed Central

Moore, Stephanie N.; Hawley, Gregory D.; Smith, Emily N.; Mignemi, Nicholas A.; Ihejirika, Rivka C.; Yuasa, Masato; Cates, Justin M. M.; Liu, Xulei; Schoenecker, Jonathan G.

2016-01-01

Introduction Soft tissue calcification, including both dystrophic calcification and heterotopic ossification, may occur following injury. These lesions have variable fates as they are either resorbed or persist. Persistent soft tissue calcification may result in chronic inflammation and/or loss of function of that soft tissue. The molecular mechanisms that result in the development and maturation of calcifications are uncertain. As a result, directed therapies that prevent or resorb soft tissue calcifications remain largely unsuccessful. Animal models of post-traumatic soft tissue calcification that allow for cost-effective, serial analysis of an individual animal over time are necessary to derive and test novel therapies. We have determined that a cardiotoxin-induced injury of the muscles in the posterior compartment of the lower extremity represents a useful model in which soft tissue calcification develops remote from adjacent bones, thereby allowing for serial analysis by plain radiography. The purpose of the study was to design and validate a method for quantifying soft tissue calcifications in mice longitudinally using plain radiographic techniques and an ordinal scoring system. Methods Muscle injury was induced by injecting cardiotoxin into the posterior compartment of the lower extremity in mice susceptible to developing soft tissue calcification. Seven days following injury, radiographs were obtained under anesthesia. Multiple researchers applied methods designed to standardize post-image processing of digital radiographs (N = 4) and quantify soft tissue calcification (N = 6) in these images using an ordinal scoring system. Inter- and intra-observer agreement for both post-image processing and the scoring system used was assessed using weighted kappa statistics. Soft tissue calcification quantifications by the ordinal scale were compared to mineral volume measurements (threshold 450.7mgHA/cm3) determined by μCT. Finally, sample-size calculations necessary to discriminate between a 25%, 50%, 75%, and 100% difference in STiCSS score 7 days following burn/CTX induced muscle injury were determined. Results Precision analysis demonstrated substantial to good agreement for both post-image processing (κ = 0.73 to 0.90) and scoring (κ = 0.88 to 0.93), with low inter- and intra-observer variability. Additionally, there was a strong correlation in quantification of soft tissue calcification between the ordinal system and by mineral volume quantification by μCT (Spearman r = 0.83 to 0.89). The ordinal scoring system reliably quantified soft tissue calcification in a burn/CTX-induced soft tissue calcification model compared to non-injured controls (Mann-Whitney rank test: P = 0.0002, ***). Sample size calculations revealed that 6 mice per group would be required to detect a 50% difference in STiCSS score with a power of 0.8. Finally, the STiCSS was demonstrated to reliably quantify soft tissue calcification [dystrophic calcification and heterotopic ossification] by radiographic analysis, independent of the histopathological state of the mineralization. Conclusions Radiographic analysis can discriminate muscle injury-induced soft tissue calcification from adjacent bone and follow its clinical course over time without requiring the sacrifice of the animal. While the STiCSS cannot identify the specific type of soft tissue calcification present, it is still a useful and valid method by which to quantify the degree of soft tissue calcification. This methodology allows for longitudinal measurements of soft tissue calcification in a single animal, which is relatively less expensive, less time-consuming, and exposes the animal to less radiation than in vivo μCT. Therefore, this high-throughput, longitudinal analytic method for quantifying soft tissue calcification is a viable alternative for the study of soft tissue calcification. PMID:27438007

10 CFR 30.4 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Commission has entered into an effective agreement under subsection 274b. of the Act. Non-agreement State... access control measures that are not related to the safe use of, or security of, radiological materials... equivalent means the sum of the products of the dose equivalent to the organ or tissue and the weighting...

Bone regeneration and stem cells

PubMed Central

Arvidson, K; Abdallah, B M; Applegate, L A; Baldini, N; Cenni, E; Gomez-Barrena, E; Granchi, D; Kassem, M; Konttinen, Y T; Mustafa, K; Pioletti, D P; Sillat, T; Finne-Wistrand, A

2011-01-01

Abstract This invited review covers research areas of central importance for orthopaedic and maxillofacial bone tissue repair, including normal fracture healing and healing problems, biomaterial scaffolds for tissue engineering, mesenchymal and foetal stem cells, effects of sex steroids on mesenchymal stem cells, use of platelet-rich plasma for tissue repair, osteogenesis and its molecular markers. A variety of cells in addition to stem cells, as well as advances in materials science to meet specific requirements for bone and soft tissue regeneration by addition of bioactive molecules, are discussed. PMID:21129153

Detection of blunt, sharp force and gunshot lesions on burnt remains: a cautionary note.

PubMed

Poppa, Pasquale; Porta, Davide; Gibelli, Daniele; Mazzucchi, Alessandra; Brandone, Alberto; Grandi, Marco; Cattaneo, Cristina

2011-09-01

The study of skin and bone lesions may give information concerning type and manner of production, but in burnt material modification of tissues by the high temperatures may considerably change the morphological characteristics of the lesions. This study aims at pointing out the effects of burning head of pigs with several types of lesions (blunt trauma, sharp force, and gunshot lesions) on soft tissues and bones, both from a morphological and chemical point of view. Results show that the charring process does not completely destroy signs of lesions on bones, which can often be recovered by cleaning bone surface from charred soft-tissue residues. Furthermore, neutron activation analysis test proved that antimony may be detectable also on gunshot entry wounds at the final stages of charring process.

Treatment of Vascular Soft Tissue Sarcomas With Razoxane, Vindesine, and Radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rhomberg, Walter; Wink, Anna; Pokrajac, Boris

2009-05-01

Purpose: In previous studies, razoxane and vindesine together with radiotherapy was proved to be effective in soft tissue sarcomas (STS). Because razoxane leads to a redifferentiation of pathological tumor blood vessels, it was of particular interest to study the influence of this drug combination in vascular soft tissue sarcomas. Methods and Materials: This open multicenter Phase II study was performed by the Austrian Society of Radiooncology. Among 13 evaluable patients (10 angiosarcomas and 3 hemangio-pericytomas), 9 had unresectable measurable disease, 3 showed microscopic residuals, and 1 had a resection with clear margins. They received a basic treatment with razoxane andmore » vindesine supported by radiation therapy. Outcome measures were objective response rates, survival time, and the incidence of distant metastases. Results: In nine patients with measurable vascular soft tissue sarcomas (eight angiosarcomas and one hemangiopericytoma), 6 complete remissions, 2 partial remissions, and 1 minor remission were achieved, corresponding to a major response rate of 89%. A maintenance therapy with razoxane and vindesine of 1 year or longer led to a suppression of distant metastases. The median survival time from the start of the treatment is 23+ months (range, 3-120+) for 12 patients with macroscopic and microscopic residual disease. The progression-free survival at 6 months was 75%. The combined treatment was associated with a low general toxicity, but attention must be given to increased normal tissue reactions. Conclusions: This trimodal treatment leads to excellent response rates, and it suppresses distant metastases when given as maintenance therapy.« less

Analysis of prevertebral soft-tissue swelling and dysphagia in multilevel anterior cervical discectomy and fusion with recombinant human bone morphogenetic protein-2 in patients at risk for pseudarthrosis.

PubMed

Stachniak, Joseph B; Diebner, Jeffrey D; Brunk, Estee S; Speed, Shelley M

2011-02-01

The goal of this study was to demonstrate the incidence of fusion and soft-tissue swelling in multilevel anterior cervical discectomies and fusions (ACDFs) using polyetheretherketone (PEEK) spacers with recombinant human bone morphogenetic protein-2 (rhBMP-2) impregnated in a Type I collagen sponge and titanium plates. A single surgeon performed 30 multilevel ACDFs using PEEK spacers with an rhBMP-2 impregnated collagen sponge (0.4 ml, or the equivalent of 0.6 mg rhBMP-2). Soft-tissue swelling was assessed using cervical spine radiographs on postoperative Day 1 and at 2, 6, and 10 weeks and 6 months after surgery. Incidence of dysphagia was assessed with the Cervical Spine Research Society Swallowing-Quality of Life tool. Clinical success was evaluated with the Neck Disability Index, neck pain scores, and arm pain scores. Final fusion was assessed with CT by an independent neuroradiologist. Patients were followed for 6 months unless they had an incomplete fusion; those patients were reassessed at 9 months. Twenty-four patients underwent 2-level ACDFs and 6 underwent 3-level ACDFs were performed on patients with the following risk factors for pseudarthrosis: smoking (33%), diabetes (13%), and obesity (body mass index ≥ 30 [43%]). Seventeen percent of the patients had multiple risk factors. Soft-tissue swelling peaked at 2 weeks regardless of level of surgery or number of levels treated surgically and decreased to near preoperative levels by 6 months. At 2 weeks, Swallowing-Quality of Life evaluation showed 19% of patients frequently choking on food, 4.8% frequently choking when drinking, and 47.6% with frequent food sticking in the throat. Scores continued to improve, and at 6 months, 0% had frequent choking on food, 6.7% had frequent difficulty drinking, and 6.7% had frequent food sticking in the throat. The Neck Disability Index, neck pain, and arm pain scores all improved progressively over 6 months. Incidence of fusion was 95% at 6 months and 100% at 9 months. There were no rehospitalizations or reoperations for soft-tissue swelling or dysphagia. Multilevel ACDF procedures using PEEK grafts and rhBMP-2 can be performed safely in patients with multiple risk factors for pseudarthrosis with excellent fusion outcomes.

A high-vacuum wound drainage system reduces pain and length of treatment for pediatric soft tissue abscesses.

PubMed

Yang, Chao; Wang, Shan; Li, Chang-Chun; Kong, Xiang-Ru; Zhao, Zhenzhen; Deng, Xiao-Bin; Peng, Liang; Zhang, Jun

2017-02-01

Open incision and drainage (I&D) and wound packing is accepted as the standard treatment for soft tissue abscesses. However, conventional I&D has a number of problems in practice which prompt us to improve the I&D methods that would minimize the pain associated with packing during dressing changes. In order to compare the pain associated with dressing changes in the conventional I&D group to the vacuum system group and the treatment time of both groups, we performed a randomized trial in pediatric patients between 0 and 18 years of age who are undergoing abscess drainage in the operating room from April 2011 to April 2015. Patients treated with open I&D (n = 648) were compared to those treated with placement of high-vacuum wound drainage system (n = 776) through the abscess cavities. Both groups received equivalent antibiotic treatment, and all patients were followed up in the outpatient clinics until the infection has been resolved. The mean FACES scale pain scores were significantly higher in the open I&D group than in the vacuum system group. The vacuum system group had a shorter length of stay and less need for community doctor or outpatient dressing changes than the open I&D group (p < 0.001). No recurrent abscesses were observed in the vacuum system group, and 10 patients in the open I&D group required another drainage at the exact same location. High-vacuum wound drainage system was an efficient and safe alternative to the traditional I&D for community-acquired soft tissue abscesses with few complications in short term. What is Known: • Open incision and drainage (I&D) followed by irrigation and wound packing is the standard treatment for soft tissue abscesses. • The painful daily packing may cause emotional trauma to the child and lead to an unwelcoming challenge to the caretakers and health care providers. What is New: • We modified the method of I&D by adding primary suturing of the wound and placement of a high-vacuum wound drainage system. • This technique was proved to be an efficient and safe alternative to the traditional I&D method for soft tissue abscesses with small complications in short term.

A visco-hyperelastic constitutive model and its application in bovine tongue tissue.

PubMed

Yousefi, Ali-Akbar Karkhaneh; Nazari, Mohammad Ali; Perrier, Pascal; Panahi, Masoud Shariat; Payan, Yohan

2018-04-11

Material properties of the human tongue tissue have a significant role in understanding its function in speech, respiration, suckling, and swallowing. Tongue as a combination of various muscles is surrounded by the mucous membrane and is a complicated architecture to study. As a first step before the quantitative mechanical characterization of human tongue tissues, the passive biomechanical properties in the superior longitudinal muscle (SLM) and the mucous tissues of a bovine tongue have been measured. Since the rate of loading has a sizeable contribution to the resultant stress of soft tissues, the rate dependent behavior of tongue tissues has been investigated via uniaxial tension tests (UTTs). A method to determine the mechanical properties of transversely isotropic tissues using UTTs and inverse finite element (FE) method has been proposed. Assuming the strain energy as a general nonlinear relationship with respect to the stretch and the rate of stretch, two visco-hyperelastic constitutive laws (CLs) have been proposed for isotropic and transversely isotropic soft tissues to model their stress-stretch behavior. Both of them have been implemented in ABAQUS explicit through coding a user-defined material subroutine called VUMAT and the experimental stress-stretch points have been well tracked by the results of FE analyses. It has been demonstrated that the proposed laws make a good description of the viscous nature of tongue tissues. Reliability of the proposed models has been compared with similar nonlinear visco-hyperelastic CLs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Tissue Cells Feel and Respond to the Stiffness of Their Substrate

NASA Astrophysics Data System (ADS)

Discher, Dennis E.; Janmey, Paul; Wang, Yu-li

2005-11-01

Normal tissue cells are generally not viable when suspended in a fluid and are therefore said to be anchorage dependent. Such cells must adhere to a solid, but a solid can be as rigid as glass or softer than a baby's skin. The behavior of some cells on soft materials is characteristic of important phenotypes; for example, cell growth on soft agar gels is used to identify cancer cells. However, an understanding of how tissue cells-including fibroblasts, myocytes, neurons, and other cell types-sense matrix stiffness is just emerging with quantitative studies of cells adhering to gels (or to other cells) with which elasticity can be tuned to approximate that of tissues. Key roles in molecular pathways are played by adhesion complexes and the actin-myosin cytoskeleton, whose contractile forces are transmitted through transcellular structures. The feedback of local matrix stiffness on cell state likely has important implications for development, differentiation, disease, and regeneration.

Multi-view 3D echocardiography compounding based on feature consistency

NASA Astrophysics Data System (ADS)

Yao, Cheng; Simpson, John M.; Schaeffter, Tobias; Penney, Graeme P.

2011-09-01

Echocardiography (echo) is a widely available method to obtain images of the heart; however, echo can suffer due to the presence of artefacts, high noise and a restricted field of view. One method to overcome these limitations is to use multiple images, using the 'best' parts from each image to produce a higher quality 'compounded' image. This paper describes our compounding algorithm which specifically aims to reduce the effect of echo artefacts as well as improving the signal-to-noise ratio, contrast and extending the field of view. Our method weights image information based on a local feature coherence/consistency between all the overlapping images. Validation has been carried out using phantom, volunteer and patient datasets consisting of up to ten multi-view 3D images. Multiple sets of phantom images were acquired, some directly from the phantom surface, and others by imaging through hard and soft tissue mimicking material to degrade the image quality. Our compounding method is compared to the original, uncompounded echocardiography images, and to two basic statistical compounding methods (mean and maximum). Results show that our method is able to take a set of ten images, degraded by soft and hard tissue artefacts, and produce a compounded image of equivalent quality to images acquired directly from the phantom. Our method on phantom, volunteer and patient data achieves almost the same signal-to-noise improvement as the mean method, while simultaneously almost achieving the same contrast improvement as the maximum method. We show a statistically significant improvement in image quality by using an increased number of images (ten compared to five), and visual inspection studies by three clinicians showed very strong preference for our compounded volumes in terms of overall high image quality, large field of view, high endocardial border definition and low cavity noise.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitera, Gunita, E-mail: Gunita.Mitera@Sunnybrook.ca; Probyn, Linda; Ford, Michael

Purpose: To correlate computed tomography (CT) imaging features of spinal metastases with pain relief after radiotherapy (RT). Methods and Materials: Thirty-three patients receiving computed tomography (CT)-simulated RT for spinal metastases in an outpatient palliative RT clinic from January 2007 to October 2008 were retrospectively reviewed. Forty spinal metastases were evaluated. Pain response was rated using the International Bone Metastases Consensus Working Party endpoints. Three musculoskeletal radiologists and two orthopaedic surgeons evaluated CT features, including osseous and soft tissue tumor extent, presence of a pathologic fracture, severity of vertebral height loss, and presence of kyphosis. Results: The mean patient age wasmore » 69 years; 24 were men and 9 were women. The mean worst pain score was 7/10, and the mean total daily oral morphine equivalent was 77.3 mg. Treatment doses included 8 Gy in one fraction (22/33), 20 Gy in five fractions (10/33), and 20 Gy in eight fractions (1/33). The CT imaging appearance of spinal metastases included vertebral body involvement (40/40), pedicle involvement (23/40), and lamina involvement (18/40). Soft tissue component (10/40) and nerve root compression (9/40) were less common. Pathologic fractures existed in 11/40 lesions, with resultant vertebral body height loss in 10/40 and kyphosis in 2/40 lesions. At months 1, 2, and 3 after RT, 18%, 69%, and 70% of patients experienced pain relief. Pain response was observed with various CT imaging features. Conclusions: Pain response after RT did not differ in patients with and without pathologic fracture, kyphosis, or any other CT features related to extent of tumor involvement. All patients with painful spinal metastases may benefit from palliative RT.« less

Exploring the potential of polyurethane-based soft foam as cell-free scaffold for soft tissue regeneration.

PubMed

Gerges, Irini; Tamplenizza, Margherita; Martello, Federico; Recordati, Camilla; Martelli, Cristina; Ottobrini, Luisa; Tamplenizza, Mariacaterina; Guelcher, Scott A; Tocchio, Alessandro; Lenardi, Cristina

2018-06-01

Reconstructive treatment after trauma and tumor resection would greatly benefit from an effective soft tissue regeneration. The use of cell-free scaffolds for adipose tissue regeneration in vivo is emerging as an attractive alternative to tissue-engineered constructs, since this approach avoids complications due to cell manipulation and lack of synchronous vascularization. In this study, we developed a biodegradable polyurethane-based scaffold for soft tissue regeneration, characterized by an exceptional combination between softness and resilience. Exploring the potential as a cell-free scaffold required profound understanding of the impact of its intrinsic physico-chemical properties on the biological performance in vivo. We investigated the effect of the scaffold's hydrophilic character, degradation kinetics, and internal morphology on (i) the local inflammatory response and activation of MGCs (foreign body response); (ii) its ability to promote rapid vascularisation, cell infiltration and migration through the scaffold over time; and (iii) the grade of maturation of the newly formed tissue into vascularized soft tissue in a murine model. The study revealed that soft tissue regeneration in vivo proceeded by gradual infiltration of undifferentiated mesenchymal cells though the periphery toward the center of the scaffold, where the rapid formation of a functional and well-formed vascular network supported cell viability overtime. Exploring the potential of polyurethane-based soft foam as cell-free scaffold for soft tissue regeneration. In this work, we address the unmet need for synthetic functional soft tissue substitutes that provide adequate biological and mechanical support to soft tissue. We developed a series of flexible cross-linked polyurethane copolymer scaffolds with remarkable fatigue-resistance and tunable physico-chemical properties for soft tissue regeneration in vivo. Accordingly, we could extend the potential of this class of biomaterials, which was so far confined for bone and osteochondral tissue regeneration, to other types of connective tissue. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Combination Chemotherapy in Treating Patients With Previously Untreated Rhabdomyosarcoma

ClinicalTrials.gov

2013-06-13

Adult Malignant Mesenchymoma; Adult Rhabdomyosarcoma; Alveolar Childhood Rhabdomyosarcoma; Childhood Malignant Mesenchymoma; Embryonal Childhood Rhabdomyosarcoma; Embryonal-botryoid Childhood Rhabdomyosarcoma; Nonmetastatic Childhood Soft Tissue Sarcoma; Previously Untreated Childhood Rhabdomyosarcoma; Stage I Adult Soft Tissue Sarcoma; Stage II Adult Soft Tissue Sarcoma; Stage III Adult Soft Tissue Sarcoma

Advances in Materials for Recent Low-Profile Implantable Bioelectronics.

PubMed

Chen, Yanfei; Kim, Yun-Soung; Tillman, Bryan W; Yeo, Woon-Hong; Chun, Youngjae

2018-03-29

The rapid development of micro/nanofabrication technologies to engineer a variety of materials has enabled new types of bioelectronics for health monitoring and disease diagnostics. In this review, we summarize widely used electronic materials in recent low-profile implantable systems, including traditional metals and semiconductors, soft polymers, biodegradable metals, and organic materials. Silicon-based compounds have represented the traditional materials in medical devices, due to the fully established fabrication processes. Examples include miniaturized sensors for monitoring intraocular pressure and blood pressure, which are designed in an ultra-thin diaphragm to react with the applied pressure. These sensors are integrated into rigid circuits and multiple modules; this brings challenges regarding the fundamental material's property mismatch with the targeted human tissues, which are intrinsically soft. Therefore, many polymeric materials have been investigated for hybrid integration with well-characterized functional materials such as silicon membranes and metal interconnects, which enable soft implantable bioelectronics. The most recent trend in implantable systems uses transient materials that naturally dissolve in body fluid after a programmed lifetime. Such biodegradable metallic materials are advantageous in the design of electronics due to their proven electrical properties. Collectively, this review delivers the development history of materials in implantable devices, while introducing new bioelectronics based on bioresorbable materials with multiple functionalities.

MUSCLE EQUIVALENT MATERIAL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kawashima, K.; Takaku, Y.; Inada, T.

1961-01-01

A tissue-equivalent material was constructed from the following components: polyethylene (CH/sub 2/)/sub n/, 71.4% (by weight), NaNO/sub 3/ 21.3%, Al/sub 2/O/sub 3/ 5.5%, and TiC/sub 2/ 1.8%. The attenuation coefficients of this solid compound, Mix. p in x or gamma rays (40kev --1.25 Mev), were shown to be equal to those of a section of pork loin (m. longissimus dorsi). Thus, Mix. p is concluded to be good phantom material for depth dose measuremeat and suitable material for walls of ionizatlon chambers. (Abstr. Japan Med., 2: No. 3, March 1962)

Dimensional soft tissue changes following soft tissue grafting in conjunction with implant placement or around present dental implants: a systematic review.

PubMed

Poskevicius, Lukas; Sidlauskas, Antanas; Galindo-Moreno, Pablo; Juodzbalys, Gintaras

2017-01-01

To systematically review changes in mucosal soft tissue thickness and keratinised mucosa width after soft tissue grafting around dental implants. An electronic literature search was conducted of the MEDLINE database published between 2009 and 2014. Sequential screenings at the title, abstract, and full-text levels were performed. Clinical human studies in the English language that had reported changes in soft tissue thickness or keratinised mucosa width after soft tissue grafting at implant placement or around a present implant at 6-month follow-up or longer were included. The search resulted in fourteen articles meeting the inclusion criteria: Six of them reported connective tissue grafting around present dental implants, compared to eight at the time of implant placement. Better long-term soft tissue thickness outcomes were reported for soft tissue augmentation around dental implants (0.8-1.4 mm), compared with augmentation at implant placement (-0.25-1.43 mm). Both techniques were effective in increasing keratinised tissue width: at implant placement (2.5 mm) or around present dental implants (2.33-2.57 mm). The present systematic review discovered that connective tissue grafts enhanced keratinised mucosa width and soft tissue thickness for an observation period of up to 48 months. However, some shrinkage may occur, resulting in decreases in soft tissue, mostly for the first three months. Further investigations using accurate evaluation methods need to be done to evaluate the appropriate time for grafting. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Soft-tissue tension total knee arthroplasty.

PubMed

Asano, Hiroshi; Hoshino, Akiho; Wilton, Tim J

2004-08-01

It is far from clear how best to define the proper strength of soft-tissue tensioning in total knee arthroplasty (TKA). We attached a torque driver to the Monogram balancer/tensor device and measured soft-tissue tension in full extension and 90 degrees flexion during TKA. In our surgical procedure, when we felt proper soft-tissue tension was being applied, the mean distraction force was noted to be 126N in extension and 121N in flexion. There was no significant correlation between soft-tissue tension and the postoperative flexion angle finally achieved. To the best of our knowledge, this is the first study to assess the actual distraction forces in relation to soft-tissue tension in TKA. Further study may reveal the most appropriate forces to achieve proper soft-tissue tension in the wide variety of circumstances presenting at knee arthroplasty.

SU-F-T-369: Validation of Monte-Carlo Beam Model for a Range of Small Fields in Heterogeneous Medium - A Measurement Based Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karthikeyan, N; Bharathiya University, Coimbatore, Tamilnadu; Ganesh, KM

Purpose: To validate the Monaco montecorlo beam model for a range of small field in the heterogeneous medium. Methods: A in-house phantom with three different medium of Foam, PMMA and derlin resembling the densities of lung, soft tissue, and bone was used for the study. The field sizes of 8, 16, 24, 32 and 48mm were studied for the validation of montecarlo algorithm using 0.01cc volume ionchamber and gafchromic films. The 6MV photon beam from Elekta Beam modulator was used with 100cm SAD setup. The outputs were measured at the depth of 5, 10 and 20mm in every second mediummore » with 3cm buildup of first medium for the interface of lung-bone, lung-soft tissue, soft tissue-bone, bone-lung and soft tissue-lung. Similarly, the 2D dose analysis with gamma criteria of 2%2mm were done at the same depths using gafchromic film. For all the measurements 10.4×10.4cm were taken as reference to which the other field sizes were compared. Monaco TPSv.3.20 was used to calculate the dose distribution for all the simulated measurement setups. Results: The average maximum difference among the field sizes of 8, 16, 24, 32 and 48mm at the depth of 5mm in second medium with the interface of lung-bone, lung-soft tissue, soft tissue-bone, bone-lung and soft tissue-lung were observed as 1.29±0.14%, 0.49±0.16%, 0.87±0.23%, 0.92±0.11%, 1.01±0.19% respectively. The minimum and maximum variation of dose among different materials for the smallest field size of 8mm were observed as 0.23% and 1.67% respectively. The 2D analysis showed the average gamma passing of 98.9±0.5%. The calculated two-tailed P-value were showed insignificance with values of 0.562 and 0.452 for both ionchamber and film measurements. Conclusion: The accuracy of dose calculation for the small fields in Monaco Montecarlo TPS algorithm was validated in different inhomogeneous medium and found the results were well correlated with measurement data.« less

Efficacy of Exclusive Lingual Nerve Block versus Conventional Inferior Alveolar Nerve Block in Achieving Lingual Soft-tissue Anesthesia

PubMed Central

Balasubramanian, Sasikala; Paneerselvam, Elavenil; Guruprasad, T; Pathumai, M; Abraham, Simin; Krishnakumar Raja, V. B.

2017-01-01

Objective: The aim of this randomized clinical trial was to assess the efficacy of exclusive lingual nerve block (LNB) in achieving selective lingual soft-tissue anesthesia in comparison with conventional inferior alveolar nerve block (IANB). Materials and Methods: A total of 200 patients indicated for the extraction of lower premolars were recruited for the study. The samples were allocated by randomization into control and study groups. Lingual soft-tissue anesthesia was achieved by IANB and exclusive LNB in the control and study group, respectively. The primary outcome variable studied was anesthesia of ipsilateral lingual mucoperiosteum, floor of mouth and tongue. The secondary variables assessed were (1) taste sensation immediately following administration of local anesthesia and (2) mouth opening and lingual nerve paresthesia on the first postoperative day. Results: Data analysis for descriptive and inferential statistics was performed using SPSS (IBM SPSS Statistics for Windows, Version 22.0, Armonk, NY: IBM Corp. Released 2013) and a P < 0.05 was considered statistically significant. In comparison with the control group, the study group (LNB) showed statistically significant anesthesia of the lingual gingiva of incisors, molars, anterior floor of the mouth, and anterior tongue. Conclusion: Exclusive LNB is superior to IAN nerve block in achieving selective anesthesia of lingual soft tissues. It is technically simple and associated with minimal complications as compared to IAN block. PMID:29264294

Long Term Stability Following Genioplasty: A Cephalometric Study

PubMed Central

Kumar, B Lakshman; Raju, G Kranthi Praveen; Kumar, N Dilip; Reddy, G Vivek; Naik, B Ravindra; Achary, C Ravindranath

2015-01-01

Background: A receding chin associated with an orthognathic mandible is a common situation and surgical changes in chin position are often required to improve the overall harmony of the face. Genioplasty is one such procedure. Stability of hard and soft tissue changes following genioplasty on a long term basis needs to be assessed. Studies on the stability of hard and soft tissue changes following genioplasty on a short term basis have revealed it as a procedure with good stability. This study is done to assess the stability of hard and soft tissue changes following genioplasty on a long term basis. Materials and Methods: Pre-surgical, postsurgical and long term post-surgical cephalograms of 15 cases treated by vertical reduction augmentation genioplasty were obtained. Paired t-test was used to compare the changes between pre-surgical, postsurgical and long term postsurgical cephalograms. Results: Findings of this study demonstrated that genioplasty is a stable procedure. After long term follow-up period, there was a relapse of 1.5 mm at the pogonion accounting for 24% of the surgical advancement. This is attributed to the remodeling that occurs at the surgical site, but not the instability due to the surgical procedure. Conclusion: With the present study, it can be concluded that vertical reduction and advancement genioplasty can be considered as an adjunctive procedure that produces predictable results and the bony and soft tissue stability were generally very good. PMID:25954070

Fabrication, characterization, and biocompatibility assessment of a novel elastomeric nanofibrous scaffold: A potential scaffold for soft tissue engineering.

PubMed

Shamirzaei Jeshvaghani, Elham; Ghasemi-Mobarakeh, Laleh; Mansurnezhad, Reza; Ajalloueian, Fatemeh; Kharaziha, Mahshid; Dinari, Mohammad; Sami Jokandan, Maryam; Chronakis, Ioannis S

2017-11-23

With regard to flexibility and strength properties requirements of soft biological tissue, elastomeric materials could be more beneficial in soft tissue engineering applications. The present work investigates the use of an elastic polymer, (polycaprolactone fumarate [PCLF]), for fabricating an electrospun scaffold. PCLF with number-average molecular weight of 13,284 g/mol was synthetized, electrospun PCLF:polycaprolactone (PCL) (70:30) nanofibrous scaffolds were fabricated and a novel strategy (in situ photo-crosslinking along with wet electrospinning) was applied for crosslinking of PCLF in the structure of PCLF:PCL nanofibers was presented. Sol fraction results, Fourier-transform infrared spectroscopy, and mechanical tests confirmed occurrence of crosslinking reaction. Strain at break and Young's modulus of crosslinked PCLF:PCL nanofibers fabricated was found to be 114.5 ± 3.9% and 0.6 ± 0.1 MPa, respectively, and dynamic mechanical analysis results revealed elasticity of nanofibers. MTS assay showed biocompatibility of PCLF:PCL (70:30) nanofibrous scaffolds. Our overall results showed that electrospun PCLF:PCL nanofibrous scaffold could be considered as a candidate for further in vitro and in vivo experiments and its application for engineering of soft tissues subjected to in vivo cyclic mechanical stresses. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2017. © 2017 Wiley Periodicals, Inc.

Pericellular plasma clot negates the influence of scaffold stiffness on chondrogenic differentiation.

PubMed

Arora, Aditya; Kothari, Anjaney; Katti, Dhirendra S

2016-12-01

Matrix stiffness is known to play a pivotal role in cellular differentiation. Studies have shown that soft scaffolds (<2-3kPa) promote cellular aggregation and chondrogenesis, whereas, stiffer ones (>10kPa) show poor chondrogenesis in vitro. In this work we investigated if fibrin matrix from clotted blood can act as a soft surrogate which nullifies the influence of the underlying stiff scaffold, thus promoting chondrogenesis irrespective of bulk scale scaffold stiffness. For this we performed in vitro chondrogenesis on soft (∼1.5kPa) and stiff (∼40kPa) gelatin scaffolds in the presence and absence of pericellular plasma clot. Our results demonstrated that in absence of pericellular plasma clot, chondrocytes showed efficient condensation and cartilaginous matrix secretion only on soft scaffolds, whereas, in presence of pericellular plasma clot, cell rounding and cartilaginous matrix secretion was observed in both soft and stiff scaffolds. More specifically, significantly higher collagen II, chondroitin sulfate and aggrecan deposition was observed in soft scaffolds, and soft and stiff scaffolds with pericellular plasma clot as compared to stiff scaffolds without pericellular plasma clot. Moreover, collagen type I, a fibrocartilage/bone marker was significantly higher only in stiff scaffolds without plasma clot. Therefore, it can be concluded that chondrocytes surrounded by a soft fibrin network were unable to sense the stiffness of the underlying scaffold/substrate and hence facilitate chondrogenesis even on stiff scaffolds. This understanding can have significant implications in the design of scaffolds for cartilage tissue engineering. Cell fate is influenced by the mechanical properties of cell culture substrates. Outside the body, cartilage progenitor cells express significant amounts of cartilage-specific markers on soft scaffolds but not on stiff scaffolds. However, when implanted in joints, stiff scaffolds show equivalent expression of markers as seen in soft scaffolds. This disparity in existing literature prompted our study. Our results suggest that encapsulation of cells in a soft plasma clot, present in any surgical intervention, prevents their perception of stiffness of the underlying scaffold, and hence the ability to distinguish between soft and stiff scaffolds vanishes. This finding would aid the design of new scaffolds that elicit cartilage-like biochemical properties while simultaneously being mechanically comparable to cartilage tissue. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

SU-E-T-424: Feasibility of 3D Printed Radiological Equivalent Customizable Tissue Like Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, D; Ferreira, C; Ahmad, S

Purpose: To investigate the feasibility of 3D printing CT# specific radiological equivalent tissue like materials. Methods: A desktop 3D printer was utilized to create a series of 3 cm x 3 cm x 2 cm PLA plastic blocks of varying fill densities. The fill pattern was selected to be hexagonal (Figure 1). A series of blocks was filled with paraffin and compared to a series filled with air. The blocks were evaluated with a “GE Lightspeed” 16 slice CT scanner and average CT# of the centers of the materials was determined. The attenuation properties of the subsequent blocks were alsomore » evaluated through their isocentric irradiation via “TrueBeam” accelerator under six beam energies. Blocks were placed upon plastic-water slabs of 4 cm in thickness assuring electronic equilibrium and data was collected via Sun Nuclear “Edge” diode detector. Relative changes in dose were compared with those predicted by Varian “Eclipse” TPS. Results: The CT# of 3D printed blocks was found to be a controllable variable. The fill material was able to narrow the range of variability in each sample. The attenuation of the block tracked with the density of the total fill structure. Assigned CT values in the TPS were seen to fall within an expected range predicted by the CT scans of the 3D printed blocks. Conclusion: We have demonstrated that it is possible to 3D print materials of varying tissue equivalencies, and that these materials have radiological properties that are customizable and predictable.« less

Tribology of bio-inspired nanowrinkled films on ultrasoft substrates.

PubMed

Lackner, Juergen M; Waldhauser, Wolfgang; Major, Lukasz; Teichert, Christian; Hartmann, Paul

2013-01-01

Biomimetic design of new materials uses nature as antetype, learning from billions of years of evolution. This work emphasizes the mechanical and tribological properties of skin, combining both hardness and wear resistance of its surface (the stratum corneum) with high elasticity of the bulk (epidermis, dermis, hypodermis). The key for combination of such opposite properties is wrinkling, being consequence of intrinsic stresses in the bulk (soft tissue): Tribological contact to counterparts below the stress threshold for tissue trauma occurs on the thick hard stratum corneum layer pads, while tensile loads smooth out wrinkles in between these pads. Similar mechanism offers high tribological resistance to hard films on soft, flexible polymers, which is shown for diamond-like carbon (DLC) and titanium nitride thin films on ultrasoft polyurethane and harder polycarbonate substrates. The choice of these two compared substrate materials will show that ultra-soft substrate materials are decisive for the distinct tribological material. Hierarchical wrinkled structures of films on these substrates are due to high intrinsic compressive stress, which evolves during high energetic film growth. Incremental relaxation of these stresses occurs by compound deformation of film and elastic substrate surface, appearing in hierarchical nano-wrinkles. Nano-wrinkled topographies enable high elastic deformability of thin hard films, while overstressing results in zigzag film fracture along larger hierarchical wrinkle structures. Tribologically, these fracture mechanisms are highly important for ploughing and sliding of sharp and flat counterparts on hard-coated ultra-soft substrates like polyurethane. Concentration of polyurethane deformation under the applied normal loads occurs below these zigzag cracks. Unloading closes these cracks again. Even cyclic testing do not lead to film delamination and retain low friction behavior, if the adhesion to the substrate is high and the initial friction coefficient of the film against the sliding counterpart low, e.g. found for DLC.

Tribology of bio-inspired nanowrinkled films on ultrasoft substrates

PubMed Central

Lackner, Juergen M.; Waldhauser, Wolfgang; Major, Lukasz; Teichert, Christian; Hartmann, Paul

2013-01-01

Biomimetic design of new materials uses nature as antetype, learning from billions of years of evolution. This work emphasizes the mechanical and tribological properties of skin, combining both hardness and wear resistance of its surface (the stratum corneum) with high elasticity of the bulk (epidermis, dermis, hypodermis). The key for combination of such opposite properties is wrinkling, being consequence of intrinsic stresses in the bulk (soft tissue): Tribological contact to counterparts below the stress threshold for tissue trauma occurs on the thick hard stratum corneum layer pads, while tensile loads smooth out wrinkles in between these pads. Similar mechanism offers high tribological resistance to hard films on soft, flexible polymers, which is shown for diamond-like carbon (DLC) and titanium nitride thin films on ultrasoft polyurethane and harder polycarbonate substrates. The choice of these two compared substrate materials will show that ultra-soft substrate materials are decisive for the distinct tribological material. Hierarchical wrinkled structures of films on these substrates are due to high intrinsic compressive stress, which evolves during high energetic film growth. Incremental relaxation of these stresses occurs by compound deformation of film and elastic substrate surface, appearing in hierarchical nano-wrinkles. Nano-wrinkled topographies enable high elastic deformability of thin hard films, while overstressing results in zigzag film fracture along larger hierarchical wrinkle structures. Tribologically, these fracture mechanisms are highly important for ploughing and sliding of sharp and flat counterparts on hard-coated ultra-soft substrates like polyurethane. Concentration of polyurethane deformation under the applied normal loads occurs below these zigzag cracks. Unloading closes these cracks again. Even cyclic testing do not lead to film delamination and retain low friction behavior, if the adhesion to the substrate is high and the initial friction coefficient of the film against the sliding counterpart low, e.g. found for DLC. PMID:24688710

High thermal conductivity in soft elastomers with elongated liquid metal inclusions.

NASA Astrophysics Data System (ADS)

Kazem, Navid; Bartlett, Michael D.; Powell-Palm, Matthew J.; Huang, Xiaonan; Sun, Wenhuan; Malen, Jonathan A.; Majidi, Carmel

Soft dielectric materials typically exhibit poor heat transfer properties due to the dynamics of phonon transport, which constrains thermal conductivity (k) to decrease monotonically with decreasing elastic modulus (E) . This is limiting for wearable computing, soft robotics, and other emerging applications that require materials with both high thermal conductivity and low mechanical stiffness. Here, we overcome this constraint with a dielectric composite that exhibits an unprecedented combination of metal-like thermal conductivity, an elastic compliance similar to soft biological tissue (E <100kPa), and extreme deformations capability (>600% strain). By incorporating liquid metal (LM) microdroplets into a soft elastomer, we achieve a 25x increase in thermal conductivity (4.7 +/-0.2 W/mK) over the base polymer (0.20 +/-0.01 W/mK) under stress-free conditions and a 50x increase (9.8 +/-0.8 W/mK) when strained. This exceptional combination of thermal and mechanical properties is through the deformation of the LM inclusions to create thermally conductive pathways in situ. Moreover, these materials offer new possibilities for passive heat exchange in stretchable electronics and bio-inspired robotics, which we demonstrate through the rapid heat dissipation of an elastomer-mounted extreme high power LED lamp and a swimming soft robot. AFOSR Young Investigator Program (Mechanics of Multifunctional Materials and Microsystems; Dr. Les Lee; FA9550-13-1-0123), NASA Early Career Faculty Award (NNX14AO49G), Army Research Office Grant W911NF-14-0350.

Structure and mechanical properties of Octopus vulgaris suckers.

PubMed

Tramacere, Francesca; Kovalev, Alexander; Kleinteich, Thomas; Gorb, Stanislav N; Mazzolai, Barbara

2014-02-06

In this study, we investigate the morphology and mechanical features of Octopus vulgaris suckers, which may serve as a model for the creation of a new generation of attachment devices. Octopus suckers attach to a wide range of substrates in wet conditions, including rough surfaces. This amazing feature is made possible by the sucker's tissues, which are pliable to the substrate profile. Previous studies have described a peculiar internal structure that plays a fundamental role in the attachment and detachment processes of the sucker. In this work, we present a mechanical characterization of the tissues involved in the attachment process, which was performed using microindentation tests. We evaluated the elasticity modulus and viscoelastic parameters of the natural tissues (E ∼ 10 kPa) and measured the mechanical properties of some artificial materials that have previously been used in soft robotics. Such a comparison of biological prototypes and artificial material that mimics octopus-sucker tissue is crucial for the design of innovative artificial suction cups for use in wet environments. We conclude that the properties of the common elastomers that are generally used in soft robotics are quite dissimilar to the properties of biological suckers.

Structure and mechanical properties of Octopus vulgaris suckers

PubMed Central

Tramacere, Francesca; Kovalev, Alexander; Kleinteich, Thomas; Gorb, Stanislav N.; Mazzolai, Barbara

2014-01-01

In this study, we investigate the morphology and mechanical features of Octopus vulgaris suckers, which may serve as a model for the creation of a new generation of attachment devices. Octopus suckers attach to a wide range of substrates in wet conditions, including rough surfaces. This amazing feature is made possible by the sucker's tissues, which are pliable to the substrate profile. Previous studies have described a peculiar internal structure that plays a fundamental role in the attachment and detachment processes of the sucker. In this work, we present a mechanical characterization of the tissues involved in the attachment process, which was performed using microindentation tests. We evaluated the elasticity modulus and viscoelastic parameters of the natural tissues (E ∼ 10 kPa) and measured the mechanical properties of some artificial materials that have previously been used in soft robotics. Such a comparison of biological prototypes and artificial material that mimics octopus-sucker tissue is crucial for the design of innovative artificial suction cups for use in wet environments. We conclude that the properties of the common elastomers that are generally used in soft robotics are quite dissimilar to the properties of biological suckers. PMID:24284894

Finite-element modeling of soft tissue rolling indentation.

PubMed

Sangpradit, Kiattisak; Liu, Hongbin; Dasgupta, Prokar; Althoefer, Kaspar; Seneviratne, Lakmal D

2011-12-01

We describe a finite-element (FE) model for simulating wheel-rolling tissue deformations using a rolling FE model (RFEM). A wheeled probe performing rolling tissue indentation has proven to be a promising approach for compensating for the loss of haptic and tactile feedback experienced during robotic-assisted minimally invasive surgery (H. Liu, D. P. Noonan, B. J. Challacombe, P. Dasgupta, L. D. Seneviratne, and K. Althoefer, "Rolling mechanical imaging for tissue abnormality localization during minimally invasive surgery, " IEEE Trans. Biomed. Eng., vol. 57, no. 2, pp. 404-414, Feb. 2010; K. Sangpradit, H. Liu, L. Seneviratne, and K. Althoefer, "Tissue identification using inverse finite element analysis of rolling indentation," in Proc. IEEE Int. Conf. Robot. Autom. , Kobe, Japan, 2009, pp. 1250-1255; H. Liu, D. Noonan, K. Althoefer, and L. Seneviratne, "The rolling approach for soft tissue modeling and mechanical imaging during robot-assisted minimally invasive surgery," in Proc. IEEE Int. Conf. Robot. Autom., May 2008, pp. 845-850; H. Liu, P. Puangmali, D. Zbyszewski, O. Elhage, P. Dasgupta, J. S. Dai, L. Seneviratne, and K. Althoefer, "An indentation depth-force sensing wheeled probe for abnormality identification during minimally invasive surgery," Proc. Inst. Mech. Eng., H, vol. 224, no. 6, pp. 751-63, 2010; D. Noonan, H. Liu, Y. Zweiri, K. Althoefer, and L. Seneviratne, "A dual-function wheeled probe for tissue viscoelastic property identification during minimally invasive surgery," in Proc. IEEE Int. Conf. Robot. Autom. , 2008, pp. 2629-2634; H. Liu, J. Li, Q. I. Poon, L. D. Seneviratne, and K. Althoefer, "Miniaturized force indentation-depth sensor for tissue abnormality identification," IEEE Int. Conf. Robot. Autom., May 2010, pp. 3654-3659). A sound understanding of wheel-tissue rolling interaction dynamics will facilitate the evaluation of signals from rolling indentation. In this paper, we model the dynamic interactions between a wheeled probe and a soft tissue sample using the ABAQUS FE software package. The aim of this work is to more precisely locate abnormalities within soft tissue organs using RFEM and hence aid surgeons to improve diagnostic ability. The soft tissue is modeled as a nonlinear hyperelastic material with geometrical nonlinearity. The proposed RFEM was validated on a silicone phantom and a porcine kidney sample. The results show that the proposed method can predict the wheel-tissue interaction forces of rolling indentation with good accuracy and can also accurately identify the location and depth of simulated tumors.

Soft Tissue Sarcoma—Patient Version

Cancer.gov

Soft tissue sarcoma is a cancer that starts in soft tissues like muscle, tendons, fat, lymph vessels, blood vessels, and nerves. These cancers can develop anywhere in the body but are found mostly in the arms, legs, chest, and abdomen. Start here to find information on soft tissue sarcoma treatment and research.

Combination Chemotherapy and Radiation Therapy in Treating Patients With Newly Diagnosed Rhabdomyosarcoma

ClinicalTrials.gov

2017-06-27

Adult Malignant Mesenchymoma; Adult Rhabdomyosarcoma; Childhood Alveolar Rhabdomyosarcoma; Childhood Botryoid-Type Embryonal Rhabdomyosarcoma; Childhood Embryonal Rhabdomyosarcoma; Childhood Malignant Mesenchymoma; Non-Metastatic Childhood Soft Tissue Sarcoma; Stage I Adult Soft Tissue Sarcoma; Stage II Adult Soft Tissue Sarcoma; Stage III Adult Soft Tissue Sarcoma; Untreated Childhood Rhabdomyosarcoma

In situ evaluation of surface roughness and micromorphology of temporary soft denture liner materials at different time intervals.

PubMed

Araújo, Célio U; Basting, Roberta T

2018-03-01

To perform an in situ evaluation of surface roughness and micromorphology of two soft liner materials for dentures at different time intervals. The surface roughness of materials may influence the adhesion of micro-organisms and inflammation of the mucosal tissues. The in situ evaluation of surface roughness and the micromorphology of soft liner materials over the course of time may present results different from those of in vitro studies, considering the constant presence of saliva and food, the changes in temperature and the pH level in the oral cavity. Forty-eight rectangular specimens of each of the two soft liner materials were fabricated: a silicone-based material (Mucopren Soft) and an acrylic resin-based material (Trusoft). The specimens were placed in the dentures of 12 participants (n = 12), and the materials were evaluated for surface roughness and micromorphology at different time intervals: 0, 7, 30 and 60 days. Roughness (Ra) was evaluated by means of a roughness tester. Surface micromorphology was evaluated by scanning electron microscopy. Analysis of variance for randomised block design and Tukey's test showed that surface roughness values were lower in the groups using the silicone-based material at all the time intervals (P < .0001). The average surface roughness was higher at time interval 0 than at the other intervals, for both materials (P < .0001). The surface micromorphology showed that the silicone material presented a more regular and smoother surface than the acrylic resin-based material. The surface roughness of acrylic resin-based and silicone-based denture soft liner materials decreased after 7 days of evaluation, leading to a smoother surface over time. The silicone-based material showed lower roughness values and a smoother surface than the acrylic resin-based material, thereby making it preferred when selecting more appropriate material, due its tendency to promote less biofilm build-up. © 2017 John Wiley & Sons A/S and The Gerodontology Association. Published by John Wiley & Sons Ltd.

Advances in Materials for Recent Low-Profile Implantable Bioelectronics

PubMed Central

Kim, Yun-Soung; Tillman, Bryan W.; Chun, Youngjae

2018-01-01

The rapid development of micro/nanofabrication technologies to engineer a variety of materials has enabled new types of bioelectronics for health monitoring and disease diagnostics. In this review, we summarize widely used electronic materials in recent low-profile implantable systems, including traditional metals and semiconductors, soft polymers, biodegradable metals, and organic materials. Silicon-based compounds have represented the traditional materials in medical devices, due to the fully established fabrication processes. Examples include miniaturized sensors for monitoring intraocular pressure and blood pressure, which are designed in an ultra-thin diaphragm to react with the applied pressure. These sensors are integrated into rigid circuits and multiple modules; this brings challenges regarding the fundamental material’s property mismatch with the targeted human tissues, which are intrinsically soft. Therefore, many polymeric materials have been investigated for hybrid integration with well-characterized functional materials such as silicon membranes and metal interconnects, which enable soft implantable bioelectronics. The most recent trend in implantable systems uses transient materials that naturally dissolve in body fluid after a programmed lifetime. Such biodegradable metallic materials are advantageous in the design of electronics due to their proven electrical properties. Collectively, this review delivers the development history of materials in implantable devices, while introducing new bioelectronics based on bioresorbable materials with multiple functionalities. PMID:29596359

[Clinical-morphological and histometric characteristics of soft tissue wounds in maxilla-facial region of patients in different terms after trauma].

PubMed

Fedorina, T A; Braĭlovskaia, T V

2009-01-01

504 patients with open traumas of face soft tissues which were given primary surgical wounds treatment with reconstructive operations in maxilla-facial surgical clinics of Samara State Medical University in 2005-2008 also received detailed description. The results of statistical analysis of patients' surgical treatment for the previous 5 year period were listed. It was noted that in the majority of cases (75,5%) patients turned to stomatological aid in first hours or first day and night after receiving the injury, more often there were isolated soft tissue injuries (73,3%), tear-contused and cut wounds put together 80,5%. Morphological and histometric studies of operational-biopsy material let determine the character of changes of leucocyte infiltration and of epithelium - stromal interrelation in different zones of wound edges in patients incoming in different terms after trauma. Objective criteria of tissue excision volumes were received in the process of surgical wound treatment. During last 3 years esthetic results of patient treatment with maxilla-facial traumas improved, the postoperative complications frequency was reduced by 8,1% if compared with the previous 5-year period.

The materials used in bone tissue engineering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tereshchenko, V. P., E-mail: tervp@ngs.ru; Kirilova, I. A.; Sadovoy, M. A.

Bone tissue engineering looking for an alternative solution to the problem of skeletal injuries. The method is based on the creation of tissue engineered bone tissue equivalent with stem cells, osteogenic factors, and scaffolds - the carriers of these cells. For production of tissue engineered bone equivalent is advisable to create scaffolds similar in composition to natural extracellular matrix of the bone. This will provide optimal conditions for the cells, and produce favorable physico-mechanical properties of the final construction. This review article gives an analysis of the most promising materials for the manufacture of cell scaffolds. Biodegradable synthetic polymers aremore » the basis for the scaffold, but it alone cannot provide adequate physical and mechanical properties of the construction, and favorable conditions for the cells. Addition of natural polymers improves the strength characteristics and bioactivity of constructions. Of the inorganic compounds, to create cell scaffolds the most widely used calcium phosphates, which give the structure adequate stiffness and significantly increase its osteoinductive capacity. Signaling molecules do not affect the physico-mechanical properties of the scaffold, but beneficial effect is on the processes of adhesion, proliferation and differentiation of cells. Biodegradation of the materials will help to fulfill the main task of bone tissue engineering - the ability to replace synthetic construct by natural tissues that will restore the original anatomical integrity of the bone.« less

Soft-Tissue Grafting Techniques Associated With Immediate Implant Placement.

PubMed

Bishara, Mark; Kurtzman, Gregori M; Khan, Waji; Choukroun, Joseph; Miron, Richard J

2018-02-01

Immediate implant placement often presents challenges in terms of predictably obtaining soft-tissue coverage over the implant site. While delayed implant placement offers the ability for soft tissues to grow and invade the extraction socket making their attachment around implants more predictable, immediate implant placement poses a significant risk of bacterial invasion towards the implant surface as a result of insignificant soft-tissue volume. Soft-tissue grafting techniques have often been proposed for use during immediate implant placement to augment soft-tissue deficiencies, including the use of either palatal connective tissue grafts (CTGs) or collagen-derived scaffolds. However, both of these approaches have significant drawbacks in that CTGs are harvested with high patient morbidity and collagen scaffolds remain avascular and acelluar posing a risk of infection/implant contamination. More recently, platelet-rich fibrin (PRF) has been proposed as an economical and biological means to speed soft-tissue wound healing. In combination with immediate implant placement, PRF offers an easily procurable low-cost regenerative modality that offers an efficient way to improve soft-tissue attachment around implants. Furthermore, the supra-physiological concentration of defense-fighting leukocytes in PRF, combined with a dense fibrin meshwork, is known to prevent early bacterial contamination of implant surfaces, and the biological concentrations of autologous growth factors in PRF is known to increase tissue regeneration. This article discusses soft-tissue grafting techniques associated with immediate implant placement, presents several cases demonstrating the use of PRF in routine immediate implant placement, and further discusses the biological and economic advantages of PRF for the management of soft-tissue grafting during immediate implant placement.

Porous Nanogold/Polyurethane Scaffolds with Improved Antibiofilm, Mechanical, and Thermal Properties and with Reduced Effects on Cell Viability: A Suitable Material for Soft Tissue Applications.

PubMed

Tamayo, L; Acuña, D; Riveros, A L; Kogan, M J; Azócar, M I; Páez, M; Leal, M; Urzúa, M; Cerda, E

2018-04-25

The use of implants carries on a series of problems, among them infections, poor biocompatibility, high levels of cytotoxicity, and significant mechanical differences between implants and host organs that promote stress shielding effects. These problems indicate that the materials used to make implants must meet essential requirements and high standards for implantations to be successful. In this work, we present the synthesis, characterization and evaluation of the antibiofilm, mechanical, and thermal properties, and cytotoxic effect of a nanocomposite-based scaffold on polyurethane (PU) and gold nanoparticles (AuNPs) for soft tissue applications. The effect of the quantity of AuNPs on the antibacterial activity of nanocomposite scaffolds was evaluated against Staphylococcus epidermidis and Klebsiella spp., with a resulting 99.99% inhibition of both bacteria using a small quantity of nanoparticles. Cytotoxicity was evaluated with the T10 1/2 test against fibroblast cells. The results demonstrated that porous nanogold/PU scaffolds have no toxic effects on fibroblast cells to the 5 day exposition. With respect to mechanical properties, stress-strain curves showed that the compressive modulus and yield strength of PU scaffolds were significantly enhanced by AuNPs (by at least 10 times). This is due to changes in the arrangement of hard segments of PU, which increase the stiffness of the polymer. Thermogravimetric analysis showed that the degradation onset temperature rises with an increase in the quantity of AuNPs. These properties and characteristics demonstrate that porous nanogold/PU scaffolds are suitable material for use in soft tissue implants.

Nuclear reaction measurements on tissue-equivalent materials and GEANT4 Monte Carlo simulations for hadrontherapy

NASA Astrophysics Data System (ADS)

De Napoli, M.; Romano, F.; D'Urso, D.; Licciardello, T.; Agodi, C.; Candiano, G.; Cappuzzello, F.; Cirrone, G. A. P.; Cuttone, G.; Musumarra, A.; Pandola, L.; Scuderi, V.

2014-12-01

When a carbon beam interacts with human tissues, many secondary fragments are produced into the tumor region and the surrounding healthy tissues. Therefore, in hadrontherapy precise dose calculations require Monte Carlo tools equipped with complex nuclear reaction models. To get realistic predictions, however, simulation codes must be validated against experimental results; the wider the dataset is, the more the models are finely tuned. Since no fragmentation data for tissue-equivalent materials at Fermi energies are available in literature, we measured secondary fragments produced by the interaction of a 55.6 MeV u-1 12C beam with thick muscle and cortical bone targets. Three reaction models used by the Geant4 Monte Carlo code, the Binary Light Ions Cascade, the Quantum Molecular Dynamic and the Liege Intranuclear Cascade, have been benchmarked against the collected data. In this work we present the experimental results and we discuss the predictive power of the above mentioned models.

Melorheostosis with recurrent soft-tissue components: a histologically confirmed case.

PubMed

Hasegawa, Shoichi; Kanda, Shotaro; Imada, Hiroki; Yamaguchi, Takehiko; Akiyama, Toru

2017-03-01

Melorheostosis is a very rare disorder characterized by irregular cortical thickening seen on radiographs. In this paper, we present a case of melorheostosis with microscopically confirmed soft-tissue components. The patient was a 51-year-old man who complained of severe pain in the lateral aspect of his right knee. The excision of an ossified soft-tissue lesion relieved intractable pain that had lasted 20 years. Microscopically, the cortex of the affected fibula was composed of thick compact bone and the soft-tissue component consisted of dense compact bone without endochondral ossification. The presence of soft-tissue osseous nodules around the joints is one of the specific conditions for melorheostosis and should be differentiated from synovial chondromatosis. The ossified soft-tissue lesion in our patient is to our knowledge the first reported case of the histologically confirmed soft-tissue component of melorheostosis, which differs from that of synovial chondromatosis.

Fiber-reinforced scaffolds in soft tissue engineering

PubMed Central

Wang, Wei; Fan, Yubo; Wang, Xiumei; Watari, Fumio

2017-01-01

Abstract Soft tissue engineering has been developed as a new strategy for repairing damaged or diseased soft tissues and organs to overcome the limitations of current therapies. Since most of soft tissues in the human body are usually supported by collagen fibers to form a three-dimensional microstructure, fiber-reinforced scaffolds have the advantage to mimic the structure, mechanical and biological environment of natural soft tissues, which benefits for their regeneration and remodeling. This article reviews and discusses the latest research advances on design and manufacture of novel fiber-reinforced scaffolds for soft tissue repair and how fiber addition affects their structural characteristics, mechanical strength and biological activities in vitro and in vivo. In general, the concept of fiber-reinforced scaffolds with adjustable microstructures, mechanical properties and degradation rates can provide an effective platform and promising method for developing satisfactory biomechanically functional implantations for soft tissue engineering or regenerative medicine. PMID:28798872

Concomitant Correction of a Soft-Tissue Fenestration with Keratinised Tissue Augmentation By Using A Rotated Double-Pedicle Flap During Second-Stage Implant Surgery- A Case Report

PubMed Central

Reddy, Aileni Amarender; Kumar, P. Anoop; Sailaja, Sistla; Chakravarthy, Yshs

2015-01-01

Soft tissue deficiencies and defects around dental implants have been observed frequently. Soft-tissue defects after implant procedures originate from the process of modelling of periimplant mucosa and often cause aesthetic disharmony, food debris accumulation and soft tissue shrinkage. Periimplant mucogingival surgery focuses on creating an optimum band of keratinized tissue resulting in soft tissue architecture similar to the gingiva around natural teeth. A 23-year-old male reported to the Department of Periodontology with a complaint of gum soreness, foul smell and food accumulation at a site where a 3.75 x 11.5mm implant was placed previously. On clinical examination, fenestration of tissue above the cover screw was observed and there appeared to be a keratinized tissue of 1mm surrounding the implant. The case was managed by use of a rotated double-pedicle flap during second-stage implant surgery to correct the soft-tissue fenestration defect and to obtain a keratinized periimplant soft tissue. A periosteal bed was prepared by giving a horizontal incision at the mucogingival junction to a depth of 4 mm. Two split-thickness keratinized pedicles were dissected from the mesial and distal interproximal tissues near the implant. After rotation, both the pedicles were sutured to each other mid-buccally and the pedicles were rigidly immobilized with sutures. At 1 month, there was a 3mm band of stable and firm keratinized tissue over the underlying tissues. The procedure resulted in an aesthetic improvement due to enhanced soft tissue architecture and optimum integration between the peri-implant soft tissue and the final prosthesis. PMID:26816998

Planning and Conducting Research Activities.

ERIC Educational Resources Information Center

Christiansen, Richard L.

1983-01-01

Some directions and influences on dental research activities in the near future are discussed. Current challenges include international competition, fellowships, and equipment. Potential research activity includes preventive medicine, epidemiology, chronic illness, the elderly, bioengineering, materials research, nutrition, soft tissue research,…

Prevalence of Soft Tissue Calcifications in CBCT Images of Mandibular Region.

PubMed

Khojastepour, Leila; Haghnegahdar, Abdolaziz; Sayar, Hamed

2017-06-01

Most of the soft tissue calcifications within the head and neck region might not be accompanied by clinical symptoms but may indicate some pathological conditions. The aim of this research was to determine the prevalence of soft tissue calcifications in cone beam computed tomography (CBCT) images of mandibular region. In this cross sectional study the CBCT images of 602 patients including 294 men and 308 women with mean age 41.38±15.18 years were evaluated regarding the presence, anatomical location; type (single or multiple) and size of soft tissue calcification in mandibular region. All CBCT images were acquired by NewTom VGi scanner. Odds ratio and chi-square tests were used for data analysis and p < 0.05 was considered to be statistically significant. 156 out of 602 patients had at least one soft tissue calcification in their mandibular region (25.9%. of studied population with mean age 51.7±18.03 years). Men showed significantly higher rate of soft tissue calcification than women (30.3% vs. 21.8%). Soft tissue calcification was predominantly seen at posterior region of the mandible (88%) and most of them were single (60.7%). The prevalence of soft tissue calcification increased with age. Most of the detected soft tissue calcifications were smaller than 3mm (90%). Soft tissue calcifications in mandibular area were a relatively common finding especially in posterior region and more likely to happen in men and in older age group.

[Study of susceptibility weighted imaging on MR and pathologic findings to distinguish benign or malignant soft tissue tumor].

PubMed

Liu, J; Chen, Y; Bao, X M; Ling, X L; Ding, J P; Zhang, Z K

2017-05-23

Objective: To explore the diagnostic performance of susceptibility weighted imaging (SWI)in distinguishing benign or malignant soft tissue tumor, and to study pathological observation. Methods: Sixty-eight patients with soft tissue tumor, who received no previous treatment or invasive examination, received routine preoperative MRI examination and SWI scanning. The graduation and distribution of intratumoral susceptibility signal intensity(ITSS) and proportion of tumor volume were observed.The pathological results were also included for comparative analysis. Results: Fourty of 68 patients were benign and 28 were malignant. 72.5% (29/40) patients with benign soft tissue tumors were ITSS grade 1 and ITSS grade 3 (hemangioma). 89.3%(25/28) patients with malignant soft tissue tumors were ITSS grade 2 and ITSS grade 3. The difference was statistically significant ( P <0.01). The distribution of ITSS in patients with benign soft tissue tumors was dominated by peripheral distribution and diffuse distribution (hemangioma), accounting for 90.0% (36/40). The distribution of ITSS in patients with malignant soft tissue tumors mainly distributed in the central region, accounting for 78.6% (22 /28). The difference was statistically significant ( P <0.01). The proportion of tumor volume occupied by ITSS in benign soft tissue tumors was <1/3 and> 2/3 (hemangioma), accounting for 90.0% (36/40). The volume of malignant soft tissue tumors were predominantly <1/3 , accounting for 82.1% (23/28). The difference was statistically significant ( P <0.01). Conclusion: SWI is sensitive in displaying the vein and blood metabolites in soft tissue lesions, which is helpful for the differential diagnosis of benign and malignant tumors in soft tissue.

The efficacy of the modified classification system of soft tissue injury in extension injury of the lower cervical spine.

PubMed

Song, Kyung-Jin; Kim, Gyu-Hyung; Lee, Kwang-Bok

2008-07-01

To classify comprehensively the severity of soft tissue injury for extension injuries of the lower cervical spine by magnetic resonance imaging (MRI). To investigate severity of extension injuries using a modified classification system for soft tissue injury by MRI, and to determine the possibility of predicting cord injury by determining the severity of soft tissue injury. It is difficult to diagnose extension injuries by plain radiography and computed tomography. MRI is considered to be the best method of diagnosing soft tissue injuries. The authors examined whether an MRI based diagnostic standard could be devised for extension injuries of the cervical spine. MRI was performed before surgery in 81 patients that had experienced a distractive-extension injury during the past 5 years. Severities of soft tissue injury were subdivided into 5 stages. The retropharyngeal space and the retrotracheal space were measured, and their correlations with the severity of soft tissue injury were examined, as was the relation between canal stenosis and cord injury. Cord injury developed in injuries greater than Grade III (according to our devised system) accompanied by posterior longitudinal ligament rupture (P < 0.01). As the severity of soft tissue injury increased, the cord signal change increased (P < 0.01), the retropharyngeal space and the retrotracheal space increased, and swelling severity in each stage were statistically significant (P < 0.01). In canal stenosis patients, soft tissue damage and cord injury were not found to be associated (P = 0.45). In cases of distractive-extension injury, levels of soft tissue injury were determined accurately by MRI. Moreover, the severity of soft tissue injury was found to be closely associated with the development of cord injury.

A study of cephalometric soft tissue profile among adolescents from the three West African countries of Nigeria, Ghana and Senegal.

PubMed

Fadeju, A D; Otuyemi, O D; Ngom, P I; Newman-Nartey, M

2013-03-01

Since the introduction of cephalometry, numerous studies have established normal values for Caucasian populations. In Africa, most investigations have established norms and ethnic variations associated with the skeletal pattern. To date, there has been no study comparing soft tissue patterns among adolescents in the West African sub-region. The objective of this investigation was to determine and compare soft tissue patterns among 12- to 16-year-old Nigerian, Ghanaian and Senegalese adolescents, establish any gender dimorphism and compare them with published Caucasian norms. Lateral cephalometric radiographs of adolescents with a normal incisor relationship aged between 12 and 16 years from Nigeria, Ghana, and Senegal were taken under standardized conditions and traced to determine soft tissue patterns. Data obtained were subjected to statistical analysis. The total sample consisted of 165 females and 135 males with a mean age of 13·96 (1·58) years. A number of soft tissue parameters showed significant differences (P<0·05). These included comparison between males and females, and Nigerian, Ghanaian and Senegalese, including lip separation, upper lip length, upper lip exposure, Li-esthetic line, lower lip-NP, nasal tip angle, N-Pr-Pg, Pg-Ls, B-N pogonion and pogonion-mandibular angle. Differences also existed between these West African soft tissue values and published Caucasian norms, including nasolabial angle, mentolabial angle, nasal depth, nose tip, total soft tissue facial convexity and nasal depth angle. The comparative analysis of soft tissue patterns among 12- to 16-year-old adolescents from Nigeria, Ghana and Senegal demonstrated statistically significant differences in soft tissue value between these West African adolescents and published Caucasian soft tissue norms. This study provides useful data in relation to soft tissue parameters for subjects originating from the West African sub-region.

Towards traceable transient pressure metrology

NASA Astrophysics Data System (ADS)

Hanson, Edward; Olson, Douglas A.; Liu, Haijun; Ahmed, Zeeshan; Douglass, Kevin O.

2018-04-01

We describe our progress in developing the infrastructure for traceable transient measurements of pressure. Towards that end, we have built and characterized a dual diaphragm shock tube that allows us to achieve shock amplitude reproducibility of approximately 2.3% for shocks with Mach speeds ranging from 1.26-1.5. In this proof-of-concept study we use our shock tube to characterize the dynamic response of photonic sensors embedded in polydimethylsiloxane (PDMS), a material of choice for soft tissue phantoms. Our results indicate that the PDMS-embedded photonic sensors response to shock evolves over a tens to hundreds of microseconds time scale making it a useful system for studying transient pressures in soft tissue.

Effect of sealer coating and storage methods on the surface roughness of soft liners.

PubMed

Usta Kutlu, Ilknur; Yanikoğlu, Nuran Dinckal; Kul, Esra; Duymuş, Zeynep Yesïl; Sağsöz, Nurdan Polat

2016-03-01

A soft lining is applied under a removable prosthesis for various reasons. The porosity of the lining material may increase colonization by microorganisms and cause tissue inflammation. The purpose of this in vitro study was to evaluate the effect of sealer coating on the surface roughness of soft lining materials under 4 different conditions. A total of 125 specimens were prepared. One high-temperature silicone-based soft lining material and 2 room-temperature-polymerized soft lining materials (1 silicone-based and 1 methacrylate-based) were used. Twenty-five specimens of each room-temperature soft lining material were coated with 2 layers of surface sealer. Additionally, 5 specimens of each material were stored in either distilled water, Coca-Cola, denture cleanser, saliva, or air. The surface roughness was measured at baseline and after 1, 7, 14, and 28 days. Surface roughness values were analyzed with repeated measures analysis of variance, and the Bonferroni multiple comparison test was performed using time-dependent groups and storage methods. In the time-dependent groups, methacrylate-based sealer-coated soft liners exhibited a significant increase in roughness (1.74-2.09 μm, P<.001), and silicone-based sealer-coated soft liners exhibited a decrease in roughness, but it was not significant (2.16-2.02 μm, P>.05). Therefore, the sealer coating was not effective in reducing surface roughness. Among the time-dependent storage methods, the denture cleanser exhibited an almost significant increase in roughness (1.83-1.99 μm, P=.054). Coca-Cola and artificial saliva did not show a significant difference (P>.05). However, a significant decrease in roughness was found with distilled water (P=.02) and air (P<.001). Statistically significant differences in surface roughness were found among the different types of soft liners. The sealer coating had no significant effect, and denture cleanser slightly increased the surface roughness. Contrary to expectations, the roughness did not increase in all groups over time. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Validation of Ultrasound Elastography Imaging for Nondestructive Characterization of Stiffer Biomaterials.

PubMed

Zhou, Haoyan; Goss, Monika; Hernandez, Christopher; Mansour, Joseph M; Exner, Agata

2016-05-01

Ultrasound elastography (UE) has been widely used as a "digital palpation" tool to characterize tissue mechanical properties in the clinic. UE benefits from the capability of noninvasively generating 2-D elasticity encoded maps. This spatial distribution of elasticity can be especially useful in the in vivo assessment of tissue engineering scaffolds and implantable drug delivery platforms. However, the detection limitations have not been fully characterized and thus its true potential has not been completely discovered. Characterization studies have focused primarily on the range of moduli corresponding to soft tissues, 20-600 kPa. However, polymeric biomaterials used in biomedical applications such as tissue scaffolds, stents, and implantable drug delivery devices can be much stiffer. In order to explore UE's potential to assess mechanical properties of biomaterials in a broader range of applications, this work investigated the detection limit of UE strain imaging beyond soft tissue range. To determine the detection limit, measurements using standard mechanical testing and UE on the same polydimethylsiloxane samples were compared and statistically evaluated. The broadest detection range found based on the current optimized setup is between 47 kPa and 4 MPa which exceeds the modulus of normal soft tissue suggesting the possibility of using this technique for stiffer materials' mechanical characterization. The detectable difference was found to be as low as 157 kPa depending on sample stiffness and experimental setup.

Laser-based three-dimensional multiscale micropatterning of biocompatible hydrogels for customized tissue engineering scaffolds

PubMed Central

Applegate, Matthew B.; Coburn, Jeannine; Partlow, Benjamin P.; Moreau, Jodie E.; Mondia, Jessica P.; Marelli, Benedetto; Kaplan, David L.; Omenetto, Fiorenzo G.

2015-01-01

Light-induced material phase transitions enable the formation of shapes and patterns from the nano- to the macroscale. From lithographic techniques that enable high-density silicon circuit integration, to laser cutting and welding, light–matter interactions are pervasive in everyday materials fabrication and transformation. These noncontact patterning techniques are ideally suited to reshape soft materials of biological relevance. We present here the use of relatively low-energy (< 2 nJ) ultrafast laser pulses to generate 2D and 3D multiscale patterns in soft silk protein hydrogels without exogenous or chemical cross-linkers. We find that high-resolution features can be generated within bulk hydrogels through nearly 1 cm of material, which is 1.5 orders of magnitude deeper than other biocompatible materials. Examples illustrating the materials, results, and the performance of the machined geometries in vitro and in vivo are presented to demonstrate the versatility of the approach. PMID:26374842

Stretchable and Soft Electronics using Liquid Metals.

PubMed

Dickey, Michael D

2017-07-01

The use of liquid metals based on gallium for soft and stretchable electronics is discussed. This emerging class of electronics is motivated, in part, by the new opportunities that arise from devices that have mechanical properties similar to those encountered in the human experience, such as skin, tissue, textiles, and clothing. These types of electronics (e.g., wearable or implantable electronics, sensors for soft robotics, e-skin) must operate during deformation. Liquid metals are compelling materials for these applications because, in principle, they are infinitely deformable while retaining metallic conductivity. Liquid metals have been used for stretchable wires and interconnects, reconfigurable antennas, soft sensors, self-healing circuits, and conformal electrodes. In contrast to Hg, liquid metals based on gallium have low toxicity and essentially no vapor pressure and are therefore considered safe to handle. Whereas most liquids bead up to minimize surface energy, the presence of a surface oxide on these metals makes it possible to pattern them into useful shapes using a variety of techniques, including fluidic injection and 3D printing. In addition to forming excellent conductors, these metals can be used actively to form memory devices, sensors, and diodes that are completely built from soft materials. The properties of these materials, their applications within soft and stretchable electronics, and future opportunities and challenges are considered. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High thermal conductivity in soft elastomers with elongated liquid metal inclusions.

PubMed

Bartlett, Michael D; Kazem, Navid; Powell-Palm, Matthew J; Huang, Xiaonan; Sun, Wenhuan; Malen, Jonathan A; Majidi, Carmel

2017-02-28

Soft dielectric materials typically exhibit poor heat transfer properties due to the dynamics of phonon transport, which constrain thermal conductivity ( k ) to decrease monotonically with decreasing elastic modulus ( E ). This thermal-mechanical trade-off is limiting for wearable computing, soft robotics, and other emerging applications that require materials with both high thermal conductivity and low mechanical stiffness. Here, we overcome this constraint with an electrically insulating composite that exhibits an unprecedented combination of metal-like thermal conductivity, an elastic compliance similar to soft biological tissue (Young's modulus < 100 kPa), and the capability to undergo extreme deformations (>600% strain). By incorporating liquid metal (LM) microdroplets into a soft elastomer, we achieve a ∼25× increase in thermal conductivity (4.7 ± 0.2 W⋅m -1 ⋅K -1 ) over the base polymer (0.20 ± 0.01 W⋅m -1 ·K -1 ) under stress-free conditions and a ∼50× increase (9.8 ± 0.8 W⋅m -1 ·K -1 ) when strained. This exceptional combination of thermal and mechanical properties is enabled by a unique thermal-mechanical coupling that exploits the deformability of the LM inclusions to create thermally conductive pathways in situ. Moreover, these materials offer possibilities for passive heat exchange in stretchable electronics and bioinspired robotics, which we demonstrate through the rapid heat dissipation of an elastomer-mounted extreme high-power LED lamp and a swimming soft robot.

Single-stage Reconstruction of Elbow Flexion Associated with Massive Soft-Tissue Defect Using the Latissimus Dorsi Muscle Bipolar Rotational Transfer

PubMed Central

Cuéllar, Vanessa G.; Ghiassi, Alidad; Sharpe, Frances

2016-01-01

Introduction: In the upper extremity, the latissimus dorsi muscle can be used as an ipsilateral rotational muscle flap for soft-tissue coverage or functional reconstruction of arm and elbow. Patients who have both major soft-tissue loss and functional deficits can be successfully treated with a single-stage functional latissimus dorsi rotational muscle transfer that provides simultaneous soft-tissue coverage and functional reconstruction. Methods: Our data base was queried for all patients undergoing a rotational latissimus dorsi muscle transfer for simultaneous soft-tissue coverage and functional reconstruction of elbow flexion. Four patients were identified. A chart review documented the mechanism of injury, associated injuries, soft-tissue defect size, number of surgical procedures, length of follow-up, last elbow range of motion, and flexion strength. Results: Four patients with loss of elbow flexion due to traumatic loss of the anterior compartment muscles and the overlying soft tissue underwent simultaneous soft-tissue coverage and elbow flexorplasty using the ipsilateral latissimus dorsi as a bipolar muscle rotational tissue transfer. All flaps survived and had a recovery of Medical Research Council Grade 4/5 elbow flexion strength. No additional procedures were required for elbow flexion. The surgical technique is described and supplemented with surgical technique video and patient outcome. Conclusions: This patient series augments the data provided in other series supporting the safety and efficacy of this procedure which provides both soft-tissue coverage and functional restoration of elbow flexion as a single-stage procedure in the setting of massive traumatic soft-tissue loss of the arm. PMID:27757363

Single-stage Reconstruction of Elbow Flexion Associated with Massive Soft-Tissue Defect Using the Latissimus Dorsi Muscle Bipolar Rotational Transfer.

PubMed

Stevanovic, Milan V; Cuéllar, Vanessa G; Ghiassi, Alidad; Sharpe, Frances

2016-09-01

In the upper extremity, the latissimus dorsi muscle can be used as an ipsilateral rotational muscle flap for soft-tissue coverage or functional reconstruction of arm and elbow. Patients who have both major soft-tissue loss and functional deficits can be successfully treated with a single-stage functional latissimus dorsi rotational muscle transfer that provides simultaneous soft-tissue coverage and functional reconstruction. Our data base was queried for all patients undergoing a rotational latissimus dorsi muscle transfer for simultaneous soft-tissue coverage and functional reconstruction of elbow flexion. Four patients were identified. A chart review documented the mechanism of injury, associated injuries, soft-tissue defect size, number of surgical procedures, length of follow-up, last elbow range of motion, and flexion strength. Four patients with loss of elbow flexion due to traumatic loss of the anterior compartment muscles and the overlying soft tissue underwent simultaneous soft-tissue coverage and elbow flexorplasty using the ipsilateral latissimus dorsi as a bipolar muscle rotational tissue transfer. All flaps survived and had a recovery of Medical Research Council Grade 4/5 elbow flexion strength. No additional procedures were required for elbow flexion. The surgical technique is described and supplemented with surgical technique video and patient outcome. This patient series augments the data provided in other series supporting the safety and efficacy of this procedure which provides both soft-tissue coverage and functional restoration of elbow flexion as a single-stage procedure in the setting of massive traumatic soft-tissue loss of the arm.

Study of Dose Perturbation at Bone-Tissue Interfaces in Megavoltage Photon Beam Therapy.

NASA Astrophysics Data System (ADS)

Das, Indra Jeet

Dose perturbations during photon beam irradiation occur at interfaces between two dissimilar media due to the loss of electronic equilibrium. The human body contains many different types of interfaces between soft tissue and other media such as, air cavities, lungs, bones, and high atomic number (Z) materials. The dose to critical organs in the vicinity of high Z interfaces, is what leads to this project. This work describes the dose perturbation at high Z (from bone to lead) interfaces with soft tissue for clinically used megavoltage photon beams in the range of CO-60 gamma rays to 24 MV X-rays. It is divided into three main sections: (1) the dose outside the inhomogeneity in the direction of backscatter, (2) the dose inside the inhomogeneity, and (3) the dose on the photon transmission side of the inhomogeneity. Using different types of parallel plate ion chambers, TLD (powder and chip), and film as dosimeters, the dose perturbation is studied as a function of photon energy, thickness, width, and depth of inhomogeneity, distance from the interface and radiation field size. The concept of Bragg-Gray cavity theory is applied and verified for dose determination inside the inhomogeneity. A significant dose enhancement has been observed on the backscatter side for all photon energies. It is strongly dependent on the atomic number of the inhomogeneity and less dependent on the photon energy, thickness, depth, width, and field size. In the forward direction, a dose reduction occurs at the interface at beam energies lower than 10 MV, whereas a dose enhancement occurs for higher photon energies. The interface effect persists up to a few millimeters on the backscatter side but a distance equivalent to the secondary electron range for the particular photon beams in the forward direction. The dose perturbation is explained on the basis of production and transport of secondary electrons. Empirical functions are derived from the experimental data to predict the dose distribution in the vicinity of an inhomogeneity. These equations could form the basis of a treatment planning system that would accurately represent the dose both at the interface and surrounding tissue.

The biophysical characteristics of human composite flexor tendon allograft for upper extremity reconstruction.

PubMed

DeGeorge, Brent R; Rodeheaver, George T; Drake, David B

2014-01-01

Devastating volar hand injuries with significant damage to the skin and soft tissues, pulley structures and fibro-osseous sheath, flexor tendons, and volar plates pose a major problem to the reconstructive hand surgeon. Despite advances in tendon handling, operative technique, and postoperative hand rehabilitation, patients who have undergone flexor tendon reconstruction are often plagued by chronic pain, stiffness, and decreased range of motion with resultant decreased ability to work and poor quality of life. In this article, we expand the technique of human composite flexor tendon allografts (CFTAs), pioneered by Dr E.E. Peacock, Jr, which consist of both the intrasynovial and extrasynovial flexor digitorum superficialis and flexor digitorum profundus tendons and their respective fibro-osseous sheath consisting of the digital pulley structures, periosteum, and volar plates procured from cadaveric donors with the use of modern tissue processing techniques. Human cadaveric CFTAs were procured and divided into 2 groups-unprocessed CFTAs and processed CFTAs, which are cleansed and sterilized to a sterility assurance level of 10(-6). Physical length and width relationships as well as tensile strength and gliding resistance assessments were recorded pre-tissue and post-tissue processing. The histologic properties of the composite allografts were assessed before and after tissue processing. There was no significant difference with respect to physical properties of the composite allografts before or after tissue processing. The processed composite allografts demonstrated equivalent maximum load to failure and elastic modulus compared to unprocessed tendons. The gliding resistance of the composite tendon allografts was not significantly different between the 2 groups. The use of CFTAs addresses the issues of adhesion formation and lack of suitable donor material by providing a source of intrasynovial tendon in its unaltered fibro-osseous sheath without donor morbidity. This approach represents an important step toward designing an ideal material for complex flexor tendon reconstruction, which takes advantage of an intrasynovial flexor tendon in its native fibro-osseous sheath without the need for additional donor morbidity using a construct which can be engineered to have minimal tissue reactivity, negligible potential for disease transmission, and improved tendon healing properties versus standard tendon allograft.

A functional evaluation of feeding in the surgeonfish Ctenochaetus striatus: the role of soft tissues

PubMed Central

Mihalitsis, Michalis

2018-01-01

Ctenochaetus striatus is one of the most abundant surgeonfishes on Indo-Pacific coral reefs, yet the functional role and feeding ecology of this species remain unclear. This species is reported to possess a rigid structure in its palate that is used for scraping, but some authors have reported that this element is comprised of soft tissue. To resolve the nature and role of this structure in the feeding ecology of C. striatus we examined evidence from anatomical observations, scanning electron microscopy, histology, X-ray micro-computed tomography scanning, high-speed video and field observations. We found that C. striatus from the Great Barrier Reef possess a retention plate (RP) on their palates immediately posterior to the premaxillary teeth which is soft, covered in a thin veneer of keratin with a papillate surface. This RP appears to be used during feeding, but does not appear to be responsible for the removal of material, which is achieved primarily by a fast closure of the lower jaw. We infer that the RP acts primarily as a ‘dustpan’, in a ‘dustpan and brush’ feeding mechanism, to facilitate the collection of particulate material from algal turfs. PMID:29410825

Photo-acoustic excitation and optical detection of fundamental flexural guided wave in coated bone phantoms.

PubMed

Moilanen, Petro; Zhao, Zuomin; Karppinen, Pasi; Karppinen, Timo; Kilappa, Vantte; Pirhonen, Jalmari; Myllylä, Risto; Haeggström, Edward; Timonen, Jussi

2014-03-01

Photo-acoustic (PA) imaging was combined with skeletal quantitative ultrasound (QUS) for assessment of human long bones. This approach permitted low-frequency excitation and detection of ultrasound so as to efficiently receive the thickness-sensitive fundamental flexural guided wave (FFGW) through a coating of soft tissue. The method was tested on seven axisymmetric bone phantoms, whose 1- to 5-mm wall thickness and 16-mm diameter mimicked those of the human radius. Phantoms were made of a composite material and coated with a 2.5- to 7.5-mm layer of soft material that mimicked soft tissue. Ultrasound was excited with a pulsed Nd:YAG laser at 1064-nm wavelength and received on the same side of the coated phantom with a heterodyne interferometer. The FFGW was detected at 30-kHz frequency. Fitting the FFGW phase velocity by the FLC(1,1) tube mode provided an accurate (9.5 ± 4.0%) wall thickness estimate. Ultrasonic in vivo characterization of cortical bone thickness may thus become possible. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Flexible-Device Injector with a Microflap Array for Subcutaneously Implanting Flexible Medical Electronics.

PubMed

Song, Kwangsun; Kim, Juho; Cho, Sungbum; Kim, Namyun; Jung, Dongwuk; Choo, Hyuck; Lee, Jongho

2018-06-25

Implantable electronics in soft and flexible forms can reduce undesired outcomes such as irritations and chronic damages to surrounding biological tissues due to the improved mechanical compatibility with soft tissues. However, the same mechanical flexibility also makes it difficult to insert such implants through the skin because of reduced stiffness. In this paper, a flexible-device injector that enables the subcutaneous implantation of flexible medical electronics is reported. The injector consists of a customized blade at the tip and a microflap array which holds the flexible implant while the injector penetrates through soft tissues. The microflap array eliminates the need of additional materials such as adhesives that require an extended period to release a flexible medical electronic implant from an injector inside the skin. The mechanical properties of the injection system during the insertion process are experimentally characterized, and the injection of a flexible optical pulse sensor and electrocardiogram sensor is successfully demonstrated in vivo in live pig animal models to establish the practical feasibility of the concept. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

First cosmic-ray images of bone and soft tissue

NASA Astrophysics Data System (ADS)

Mrdja, Dusan; Bikit, Istvan; Bikit, Kristina; Slivka, Jaroslav; Hansman, Jan; Oláh, László; Varga, Dezső

2016-11-01

More than 120 years after Roentgen's first X-ray image, the first cosmic-ray muon images of bone and soft tissue are created. The pictures, shown in the present paper, represent the first radiographies of structures of organic origin ever recorded by cosmic rays. This result is achieved by a uniquely designed, simple and versatile cosmic-ray muon-imaging system, which consists of four plastic scintillation detectors and a muon tracker. This system does not use scattering or absorption of muons in order to deduct image information, but takes advantage of the production rate of secondaries in the target materials, detected in coincidence with muons. The 2D image slices of cow femur bone are obtained at several depths along the bone axis, together with the corresponding 3D image. Real organic soft tissue, polymethyl methacrylate and water, never seen before by any other muon imaging techniques, are also registered in the images. Thus, similar imaging systems, placed around structures of organic or inorganic origin, can be used for tomographic imaging using only the omnipresent cosmic radiation.

Testing methods of pressure distribution of bra cups on breasts soft tissue

NASA Astrophysics Data System (ADS)

Musilova, B.; Nemcokova, R.; Svoboda, M.

2017-10-01

Objective of this study is to evaluate testing methods of pressure distribution of bra cups on breasts soft tissue, the system which do not affect the space between the wearer's body surface and bra cups and thus do not influence the geometry of the measured body surface and thus investigate the functional performance of brassieres. Two measuring systems were used for the pressure comfort evaluating: 1) The pressure distribution of a wearing bra during 20 minutes on women's breasts has been directly measured using pressure sensor, a dielectricum which is elastic polyurethane foam bra cups. Twelve points were measured in bra cups. 2) Simultaneously the change of temperature in the same points bra was tested with the help of noncontact system the thermal imager. The results indicate that both of those systems can identify different pressure distribution at different points. The same size of bra designing features bra cups made from the same material and which is define by the help of same standardised body dimensions (bust and underbust) can cause different value of a compression on different shape of a woman´s breast soft tissue.

A versatile fabrication strategy of three-dimensional foams for soft and hard tissue engineering.

PubMed

Xu, Changlu; Bai, Yanjie; Yang, Shaofeng; Yang, Huilin; Stout, David A; Tran, Phong; Yang, Lei

2017-12-15

The fabrication strategies of three-dimensional porous biomaterials have been extensively studied and well established in the past decades, yet the biocompatibility and versatility in preparing porous architecture still lacks. Herewith, we present a novel and green fabrication technique of 3D porous foams for both soft and hard engineering. By utilizing the gelatinization and retrogradation property of starches, stabilized porous constructs made of various building blocks from living cells to ceramic particles were created for the first time. In soft tissue engineering applications, 3D cultured tissue foam (CTF) with controlled release property of cells was developed and the foams constituted by osteoblasts, fibroblasts and vascular endothelial cells all exhibited high mechanical stability and preservation of cell viability or functions. More importantly, the CTF achieved sustained self-release of cells controlled by serum (containing amylase) concentration and the released cells also maintained high viability and functions. In the context of hard tissue engineering applications, ceramic/bioglass (BG) foam scaffolds were developed by the similar starch-assisted foaming strategy where the resultant bone scaffolds of hydroxyapatite (HA)/BG and Si3N4/BG possessed>70% porosity with interconnected macropores (sizes 200~400μm) and fine pores (sizes1~10 μm) and superior mechanical properties despite the high porosity. Additionally, in vitro and in vivo evaluations on the biological properties revealed that porous HA/BG foam exhibited desired biocompatibility and osteogenesis. The in vivo study indicated new bone ingrowth after 1 week and significant increases in new bone volume after 2 weeks. In conclusion, the presented foaming strategy provides opportunities for biofabricating CTF with different cells for different target soft tissues and preparing porous ceramic/BG foams with different material components and high strengths-showing great versatility in soft and hard tissue engineering. © 2017 IOP Publishing Ltd.

Histological evaluations and inflammatory responses of different dental implant abutment materials: A human histology pilot study.

PubMed

Sampatanukul, Teeratida; Serichetaphongse, Pravej; Pimkhaokham, Atiphan

2018-04-01

Improvements of soft tissue to the abutment surface results in more stable peri-implant conditions, however, few human histological studies have compared soft tissue responses around different abutment materials. To describe the peri-implant tissue around 3 abutment materials; titanium, zirconia, and gold alloy, over an 8-week healing period. Fifteen edentulous sites were treated with implants. Eight weeks later, peri-implant tissue was harvested and processed using a nonseparation resin embedded technique. The tissue attachment characteristics were assessed at clinical stages using the gingival index (GI) score, surgical stage (surgical score), and histological stage (histological attachment percentage). Additionally, the inflammatory responses were evaluated using inflammatory extent and inflammatory cellularity grades. Nonparametrical statistics were used to describe the GI and surgical scores, and analytical statistics were used to analyze the histological attachment percentages as well as the inflammatory extent and cellularity grades amongst the 3 groups. There were no statistically significant differences among the groups for GI score (P = .071) and surgical score (P = .262). Titanium and zirconia exhibited nearly similar mean histological attachment percentages while gold alloy had a significantly lower percentage (P = .004). For the inflammatory extent and cellularity grades, the odds of being one grade higher for gold alloy abutment was 5.18 and 17.8 times that of titanium abutment, respectively. However, for the zirconia abutment, the odds were 0.87 and 7.5 times higher than the titanium group. The tissue around the gold alloy abutments resulted in worse attachment conditions compared with the titanium and zirconia abutments. Inflammation tended to be higher in the tissue around the gold alloy abutments than the titanium and zirconia abutments. © 2017 Wiley Periodicals, Inc.

Distribution and elimination of [14C] sarafloxacin hydrochloride from tissues of juvenile channel catfish (Ictalurus punctatus)

USGS Publications Warehouse

Gingerich, W.H.; Meinertz, J.R.; Dawson, V.K.; Gofus, J.E.; Delaney, L.J.; Bunnell, P.R.

1995-01-01

The distribution and loss of radioactivity from tissues were determined in 60 juvenile channel catfish (Ictalurus punctatus) following oral dosing with the candidate fish therapeutant Sarafin® ([14C] sarafloxacin hydrochloride) at 10 mg/kg for 5 consecutive days. Twelve groups of 5 fish each were sampled at selected times ranging from 3 to 240 h after the last dose was administered, The concentration and content of sarafloxacin-equivalent activity was determined in liver, gallbladder, kidney, skin, and skinless fillet by sample oxidation and liquid scintillation counting; content of sarafloxacin-equivalent activity was determined in stomach and anterior and posterior intestines, Skinless fillet tissues were also analyzed for sarafloxacin and for potential metabolites by gradient-elution high-performance liquid chromatography (HPLC) with in-line radiometric and fluorescence detection, Loss of radioactivity from the whole body conformed to a bimodal elimination pattern with a rapid initial phase (t1/2=11 h) and a slower secondary phase (t1/2=222 h). Tissue and contents of the gastrointestinal tract (i.e. stomach and anterior and posterior intestines) were a principal depot of activity during the first four sample times (3, 6, 12, and 24 h); the combined head, skeleton, and fins (i.e. residual carcass) were the principal depot of activity in samples taken after 24 h. Of those tissues sampled 3 h after the last dose, relative sarafloxacin concentration was greatest in the liver (4.06 μg equivalents/g) and least in the residual carcass (1.13 μg equivalents/g), Intermediate concentrations were found in the kidney (2.04 μg equivalents/g), skinless fillet (1.71 μg equivalents/ g), and the skin (1.51 μg equivalents/g). Concentrations of sarafloxacin-equivalent residues in edible skinless fillet were consistently among the lowest of all tissues examined. The highest mean concentration of parent-equivalent material in the fillet tissue was found 12 h after administration of the last dose (2.27 μg equivalents/g) and declined thereafter, Sarafloxacin constituted between 80 and 90% of the extractable radioactive residues from the fillet homogenates. No other peaks were resolved in any of the fillet tissue samples analyzed by HPLC with in-line radiometric detection.

Melorheostosis of the axial skeleton with associated fibrolipomatous lesions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garver, P.; Resnick, D.; Haghighi, P.

1982-11-01

Two patients with melorheostotic-like lesions of the axial skeleton are described. In each case adjacent soft tissue masses containing both fatty and fibrous tissues were evident. The presence of such soft tissue tumors as well as other soft tissue abnormalities in melorheostosis emphasizes that the diesease should not be regarded as one confined to bone. The precise pathogenesis of the osseous and soft tissue abnormalities in melorheostosis remains obscure.

Mechanical verification of soft-tissue attachment on bioactive glasses and titanium implants.

PubMed

Zhao, Desheng; Moritz, Niko; Vedel, Erik; Hupa, Leena; Aro, Hannu T

2008-07-01

Soft-tissue attachment is a desired feature of many clinical biomaterials. The aim of the current study was to design a suitable experimental method for tensile testing of implant incorporation with soft-tissues. Conical implants were made of three compositions of bioactive glass (SiO(2)-P(2)O(5)-B(2)O(3)-Na(2)O-K(2)O-CaO-MgO) or titanium fiber mesh (porosity 84.7%). The implants were surgically inserted into the dorsal subcutaneous soft-tissue or back muscles in the rat. Soft-tissue attachment was evaluated by pull-out testing using a custom-made jig 8 weeks after implantation. Titanium fiber mesh implants had developed a relatively high pull-out force in subcutaneous tissue (12.33+/-5.29 N, mean+/-SD) and also measurable attachment with muscle tissue (2.46+/-1.33 N). The bioactive glass implants failed to show mechanically relevant soft-tissue bonding. The experimental set-up of mechanical testing seems to be feasible for verification studies of soft-tissue attachment. The inexpensive small animal model is beneficial for large-scale in vivo screening of new biomaterials.

A Comparison of Equivalent Doses of Lidocaine and Articaine in Maxillary Posterior Tooth Extractions: Case Series

PubMed Central

Friedl, Christopher C.; Bashutski, Jill

2012-01-01

ABSTRACT Objectives Local anaesthesia is the standard of care during dental extractions. With the advent of newer local anesthetic agents, it is often difficult for the clinician to decide which agent would be most efficacious in a given clinical scenario. This study assessed the efficacy of equal-milligram doses of lidocaine and articaine in achieving surgical anaesthesia of maxillary posterior teeth diagnosed with irreversible pulpitis. Material and Methods This case-series evaluated a total of 41 patients diagnosed with irreversible pulpitis in a maxillary posterior tooth. Patients randomly received an infiltration of either 3.6 mL (72 mg) 2% lidocaine with 1:100,000 epinephrine or 1.8 mL (72 mg) 4% articaine with 1:100,000 epinephrine in the buccal fold and palatal soft tissue adjacent to the tooth. After 10 minutes, initial anaesthesia of the tooth was assessed by introducing a sterile 27-gauge needle into the gingival tissue adjacent to the tooth, followed by relief of the gingival cuff. Successful treatment was considered to have occurred when the tooth was extracted with no reported pain. Data was analyzed with the Fisher's exact test, unpaired t-test and normality test. Results Twenty-one patients received lidocaine and 20 received articaine. Forty of the 41 patients achieved initial anaesthesia 10 minutes after injection: 21 after lidocaine and 19 after articaine (P = 0.488). Pain-free extraction was accomplished in 33 patients: 19 after lidocaine and 14 after articaine buccal and palatal infiltrations (P = 0.226). Conclusions There was no significant difference in efficacy between equivalent doses of lidocaine and articaine in the anaesthesia of maxillary posterior teeth with irreversible pulpitis. PMID:24422011

Development and Characterization of Mechanically Robust, 3D-Printable Photopolymers

NASA Astrophysics Data System (ADS)

Sycks, Dalton George

3D printing has seen an explosion of interest and growth in recent years, especially within the biomedical space. Prized for its efficiency, ability to produce complex geometries, and facile material processing, additive manufacturing is rapidly being used to create medical devices ranging from orthopedic implants to tissue scaffolds. However, 3D printing is currently limited to a select few material choices, especially when one considers soft tissue replacement or augmentation. To this end, my research focuses on developing material systems that are simultaneously 1) 3D printable, 2) biocompatible, and 3) mechanically robust with properties appropriate for soft-tissue replacement or augmentation applications. Two systems were developed toward this goal: an interpenetrating network (IPN) hydrogel consisting of covalently crosslinked poly (ethylene glycol) diacrylate (PEGDA) and ionically crosslinked brown sodium alginate, and semi-crystalline thiol-ene photopolymers containing spiroacetal molecules in the polymer main-chain backbone. In addition to successfully being incorporated into existing 3D printing systems (extrusion-deposition for the PEGDA-alginate hydrogel and digital light processing for the thiol-ene polymers) both systems exhibited biocompatibility and superior thermomechanical properties such as tensile modulus, failure strain, and toughness. This work offers two fully-developed, novel polymer platforms with outstanding performance; further, structure-property relationships are highlighted and discussed on a molecular and morphological level to provide material insights that are useful to researchers and engineers in the design of highly tuned and mechanically robust polymers.

FASH and MASH: female and male adult human phantoms based on polygon mesh surfaces: II. Dosimetric calculations

NASA Astrophysics Data System (ADS)

Kramer, R.; Cassola, V. F.; Khoury, H. J.; Vieira, J. W.; de Melo Lima, V. J.; Robson Brown, K.

2010-01-01

Female and male adult human phantoms, called FASH (Female Adult meSH) and MASH (Male Adult meSH), have been developed in the first part of this study using 3D animation software and anatomical atlases to replace the image-based FAX06 and the MAX06 voxel phantoms. 3D modelling methods allow for phantom development independent from medical images of patients, volunteers or cadavers. The second part of this study investigates the dosimetric implications for organ and tissue equivalent doses due to the anatomical differences between the new and the old phantoms. These differences are mainly caused by the supine position of human bodies during scanning in order to acquire digital images for voxel phantom development. Compared to an upright standing person, in image-based voxel phantoms organs are often coronally shifted towards the head and sometimes the sagittal diameter of the trunk is reduced by a gravitational change of the fat distribution. In addition, volumes of adipose and muscle tissue shielding internal organs are sometimes too small, because adaptation of organ volumes to ICRP-based organ masses often occurs at the expense of general soft tissues, such as adipose, muscle or unspecified soft tissue. These effects have dosimetric consequences, especially for partial body exposure, such as in x-ray diagnosis, but also for whole body external exposure and for internal exposure. Using the EGSnrc Monte Carlo code, internal and external exposure to photons and electrons has been simulated with both pairs of phantoms. The results show differences between organ and tissue equivalent doses for the upright standing FASH/MASH and the image-based supine FAX06/MAX06 phantoms of up to 80% for external exposure and up to 100% for internal exposure. Similar differences were found for external exposure between FASH/MASH and REGINA/REX, the reference voxel phantoms of the International Commission on Radiological Protection. Comparison of effective doses for external photon exposure showed good agreement between FASH/MASH and REGINA/REX, but large differences between FASH/MASH and the mesh-based RPI_AM and the RPI_AF phantoms, developed at the Rensselaer Polytechnic Institute (RPI).

Gemcitabine Hydrochloride With or Without Pazopanib Hydrochloride in Treating Patients With Refractory Soft Tissue Sarcoma

ClinicalTrials.gov

2017-11-01

Adult Alveolar Soft Part Sarcoma; Adult Angiosarcoma; Adult Desmoplastic Small Round Cell Tumor; Adult Epithelioid Hemangioendothelioma; Adult Epithelioid Sarcoma; Adult Extraskeletal Myxoid Chondrosarcoma; Adult Extraskeletal Osteosarcoma; Adult Fibrosarcoma; Adult Leiomyosarcoma; Adult Liposarcoma; Adult Malignant Mesenchymoma; Adult Malignant Peripheral Nerve Sheath Tumor; Adult Rhabdomyosarcoma; Adult Synovial Sarcoma; Adult Undifferentiated Pleomorphic Sarcoma; Malignant Adult Hemangiopericytoma; Recurrent Adult Soft Tissue Sarcoma; Stage III Adult Soft Tissue Sarcoma; Stage IV Adult Soft Tissue Sarcoma

Depsipeptide (Romidepsin) in Treating Patients With Metastatic or Unresectable Soft Tissue Sarcoma

ClinicalTrials.gov

2017-05-18

Adult Alveolar Soft-part Sarcoma; Adult Angiosarcoma; Adult Epithelioid Sarcoma; Adult Extraskeletal Chondrosarcoma; Adult Extraskeletal Osteosarcoma; Adult Fibrosarcoma; Adult Leiomyosarcoma; Adult Liposarcoma; Adult Malignant Fibrous Histiocytoma; Adult Malignant Hemangiopericytoma; Adult Malignant Mesenchymoma; Adult Neurofibrosarcoma; Adult Rhabdomyosarcoma; Adult Synovial Sarcoma; Gastrointestinal Stromal Tumor; Metastatic Ewing Sarcoma/Peripheral Primitive Neuroectodermal Tumor; Recurrent Adult Soft Tissue Sarcoma; Recurrent Ewing Sarcoma/Peripheral Primitive Neuroectodermal Tumor; Stage III Adult Soft Tissue Sarcoma; Stage IV Adult Soft Tissue Sarcoma

Soft tissue changes from maxillary distraction osteogenesis versus orthognathic surgery in patients with cleft lip and palate--a randomized controlled clinical trial.

PubMed

Chua, Hannah Daile P; Cheung, Lim Kwong

2012-07-01

The objective of this randomized controlled clinical trial was to compare the soft tissue changes after maxillary advancement using conventional orthognathic surgery (CO) and distraction osteogenesis (DO) in patients with cleft lip and palate (CLP). The study group of 39 CLP patients with maxillary hypoplasia underwent either CO or DO with 4 to 10 mm of maxillary advancement. Lateral cephalographs were taken preoperatively and postoperatively at regular intervals. A series of skeletal, dental, and soft tissue landmarks was used to evaluate the changes in the soft tissue and the correlation of hard and soft tissue changes and ratios. Significant differences were found between the CO and DO patients at A point in both maxillary advancement and downgrafting in the early follow-up period. On soft tissue landmarks of pronasale, subnasale, and labial superius, significant differences were found between the 2 groups at 6 months postoperatively only with maxillary advancement. There was better correlation of hard and soft tissue changes with maxillary advancement. The nasal projection was significantly different between the 2 groups at the early and intermediate period. There was much more consistent hard to soft tissue ratios in maxillary advancement with DO than with CO. Both CO and DO can induce significant soft tissue changes of the upper lip and nose, particularly with maxillary advancement. DO generates more consistent hard to soft tissue ratios. Copyright © 2012 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

A PEG-Based Hydrogel for Effective Wound Care Management

PubMed Central

Chen, Sen-Lu; Fu, Ru-Huei; Liao, Shih-Fei; Liu, Shih-Ping; Lin, Shinn-Zong; Wang, Yu-Chi

2018-01-01

It is extremely challenging to achieve strong adhesion in soft tissues while minimizing toxicity, tissue damage, and other side effects caused by wound sealing materials. In this study, flexible synthetic hydrogel sealants were prepared based on polyethylene glycol (PEG) materials. PEG is a synthetic material that is nontoxic and inert and, thus, suitable for use in medical products. We evaluated the in vitro biocompatibility tests of the dressings to assess cytotoxicity and irritation, sensitization, pyrogen toxicity, and systemic toxicity following the International Organization for Standardization 10993 standards and the in vivo effects of the hydrogel samples using Coloskin liquid bandages as control samples for potential in wound closure. PMID:29637814

Cabozantinib-S-Malate in Treating Younger Patients With Recurrent, Refractory, or Newly Diagnosed Sarcomas, Wilms Tumor, or Other Rare Tumors

ClinicalTrials.gov

2018-06-25

Adrenal Cortex Carcinoma; Adult Alveolar Soft Part Sarcoma; Adult Clear Cell Sarcoma of Soft Parts; Adult Hepatocellular Carcinoma; Adult Rhabdomyosarcoma; Adult Soft Tissue Sarcoma; Childhood Alveolar Soft Part Sarcoma; Childhood Central Nervous System Neoplasm; Childhood Clear Cell Sarcoma of Soft Parts; Childhood Hepatocellular Carcinoma; Childhood Rhabdomyosarcoma; Childhood Soft Tissue Sarcoma; Childhood Solid Neoplasm; Ewing Sarcoma; Hepatoblastoma; Hepatocellular Carcinoma; Recurrent Adrenal Cortex Carcinoma; Recurrent Adult Hepatocellular Carcinoma; Recurrent Adult Soft Tissue Sarcoma; Recurrent Alveolar Soft Part Sarcoma; Recurrent Childhood Central Nervous System Neoplasm; Recurrent Childhood Hepatocellular Carcinoma; Recurrent Childhood Soft Tissue Sarcoma; Recurrent Ewing Sarcoma; Recurrent Hepatoblastoma; Recurrent Malignant Solid Neoplasm; Recurrent Osteosarcoma; Recurrent Renal Cell Carcinoma; Recurrent Rhabdomyosarcoma; Refractory Osteosarcoma; Renal Cell Carcinoma; Thyroid Gland Medullary Carcinoma; Wilms Tumor

Quantitative morphology in canine cutaneous soft tissue sarcomas.

PubMed

Simeonov, R; Ananiev, J; Gulubova, M

2015-12-01

Stained cytological specimens from 24 dogs with spontaneous soft tissue sarcomas [fibrosarcoma (n = 8), liposarcoma (n = 8) and haemangiopericytoma (n = 8)], and 24 dogs with reactive connective tissue lesions [granulation tissue (n = 12) and dermal fibrosis (n = 12)] were analysed by computer-assisted nuclear morphometry. The studied morphometric parameters were: mean nuclear area (MNA; µm(2)), mean nuclear perimeter (MNP; µm), mean nuclear diameter (MND mean; µm), minimum nuclear diameter (Dmin; µm) and maximum nuclear diameter (Dmax; µm). The study aimed to evaluate (1) possibility for quantitative differentiation of soft tissue sarcomas from reactive connective tissue lesions and (2) by using cytomorphometry, to differentiate the various histopathological soft tissue sarcomas subtypes in dogs. The mean values of all nuclear cytomorphometric parameters (except for Dmax) were statistically significantly higher in reactive connective tissue processes than in soft tissue sarcomas. At the same time, however, there were no considerable differences among the different sarcoma subtypes. The results demonstrated that the quantitative differentiation of reactive connective tissue processes from soft tissue sarcomas in dogs is possible, but the same was not true for the different canine soft tissue sarcoma subtypes. Further investigations on this topic are necessary for thorough explication of the role of quantitative morphology in the diagnostics of mesenchymal neoplasms and tumour-like fibrous lesions in dogs. © 2014 John Wiley & Sons Ltd.

[Fitting of the reconstructed craniofacial hard and soft tissues based on 2-D digital radiographs].

PubMed

Feng, Yao-Pu; Qiao, Min; Zhou, Hong; Zhang, Yan-Ning; Si, Xin-Qin

2017-02-01

In this study, we reconstructed the craniofacial hard and soft tissues based on the data from digital cephalometric radiographs and laser scanning. The effective fitting of the craniofacial hard and soft tissues was performed in order to increase the level of orthognathic diagnosis and treatment, and promote the communication between doctors and patients. A small lead point was put on the face of a volunteer and frontal and lateral digital cephalometric radiographs were taken. 3-D reconstruction system of the craniofacial hard tissue based on 2-D digital radiograph was used to get the craniofacial hard tissue model by means of hard tissue deformation modeling. 3-D model of facial soft tissue was obtained by using laser scanning data. By matching the lead point coordinate, the hard tissue and soft tissue were fitted. The 3-D model of the craniofacial hard and soft tissues was rebuilt reflecting the real craniofacial tissue structure, and effective fitting of the craniofacial hard and soft tissues was realized. The effective reconstruction and fitting of the 3-D craniofacial structures have been realized, which lays a foundation for further orthognathic simulation and facial appearance prediction. The fitting result is reliable, and could be used in clinical practice.

The Diagnostic and Prognostic Value of Hematological and Chemical Abnormalities in Soft Tissue Sarcoma: A Comparative Study in Patients with Benign and Malignant Soft Tissue Tumors.

PubMed

Ariizumi, Takashi; Kawashima, Hiroyuki; Ogose, Akira; Sasaki, Taro; Hotta, Tetsuo; Hatano, Hiroshi; Morita, Tetsuro; Endo, Naoto

2018-01-01

The value of routine blood tests in malignant soft tissue tumors remains uncertain. To determine if these tests can be used for screening, the routine pretreatment blood test findings were retrospectively investigated in 359 patients with benign and malignant soft tissue tumors. Additionally, the prognostic potential of pretreatment blood abnormalities was evaluated in patients with soft tissue sarcomas. We compared clinical factors and blood tests findings between patients with benign and malignant soft tissue tumors using univariate and multivariate analysis. Subsequently, patients with malignant tumors were divided into two groups based on blood test reference values, and the prognostic significance of each parameter was evaluated. In the univariate analysis, age, tumor size, and tumor depth were significant clinical diagnostic factors. Significant increases in the granulocyte count, C-reactive protein (CRP) level, erythrocyte sedimentation rate (ESR), and γ-glutamyl transpeptidase (γ-GTP) levels were found in patients with malignant soft tissue tumors. Multiple logistic regression showed that tumor size and ESR were independent factors that predicted malignant soft tissue tumors. The Kaplan-Meier survival analysis revealed that granulocyte counts, γ-GTP levels, and CRP levels correlated significantly with overall survival. Thus, pretreatment routine blood tests are useful diagnostic and prognostic markers for diagnosing soft tissue sarcoma. © 2018 by the Association of Clinical Scientists, Inc.

Radiation Therapy With or Without Combination Chemotherapy or Pazopanib Hydrochloride Before Surgery in Treating Patients With Newly Diagnosed Non-rhabdomyosarcoma Soft Tissue Sarcomas That Can Be Removed by Surgery

ClinicalTrials.gov

2018-06-20

Adult Fibrosarcoma; Alveolar Soft Part Sarcoma; Angiomatoid Fibrous Histiocytoma; Atypical Fibroxanthoma; Clear Cell Sarcoma of Soft Tissue; Epithelioid Malignant Peripheral Nerve Sheath Tumor; Epithelioid Sarcoma; Extraskeletal Myxoid Chondrosarcoma; Extraskeletal Osteosarcoma; Fibrohistiocytic Neoplasm; Glomus Tumor of the Skin; Inflammatory Myofibroblastic Tumor; Intimal Sarcoma; Leiomyosarcoma; Liposarcoma; Low Grade Fibromyxoid Sarcoma; Low Grade Myofibroblastic Sarcoma; Malignant Cutaneous Granular Cell Tumor; Malignant Peripheral Nerve Sheath Tumor; Malignant Triton Tumor; Mesenchymal Chondrosarcoma; Myxofibrosarcoma; Myxoid Chondrosarcoma; Myxoinflammatory Fibroblastic Sarcoma; Nerve Sheath Neoplasm; PEComa; Pericytic Neoplasm; Plexiform Fibrohistiocytic Tumor; Sclerosing Epithelioid Fibrosarcoma; Stage IB Soft Tissue Sarcoma AJCC v7; Stage IIB Soft Tissue Sarcoma AJCC v7; Stage III Soft Tissue Sarcoma AJCC v7; Stage IV Soft Tissue Sarcoma AJCC v7; Synovial Sarcoma; Undifferentiated (Embryonal) Sarcoma; Undifferentiated High Grade Pleomorphic Sarcoma of Bone

National Training Course. Emergency Medical Technician. Paramedic. Instructor's Lesson Plans. Module VIII. Soft Tissue Injuries.

ERIC Educational Resources Information Center

National Highway Traffic Safety Administration (DOT), Washington, DC.

This instructor's lesson plan guide on soft tissue injuries is one of fifteen modules designed for use in the training of emergency medical technicians (paramedics). Six units of study are presented: (1) anatomy and physiology of the skin; (2) patient assessment for soft-tissue injuries; (3) pathophysiology and management of soft tissue injuries;…

EF5 to Evaluate Tumor Hypoxia in Patients With High-Grade Soft Tissue Sarcoma or Mouth Cancer

ClinicalTrials.gov

2013-01-15

Stage I Adult Soft Tissue Sarcoma; Stage I Squamous Cell Carcinoma of the Lip and Oral Cavity; Stage II Adult Soft Tissue Sarcoma; Stage II Squamous Cell Carcinoma of the Lip and Oral Cavity; Stage III Adult Soft Tissue Sarcoma; Stage III Squamous Cell Carcinoma of the Lip and Oral Cavity

Modern Soft Tissue Pathology | Center for Cancer Research

Cancer.gov

This book comprehensively covers modern soft tissue pathology and includes both tumors and non-neoplastic entities. Soft tissues make up a large bulk of the human body, and they are susceptible to a wide range of diseases. Many soft-tissue tumors are biologically very aggressive, and the chance of them metastasizing to vital organs is quite high. In recent years, the outlook

Soft tissue management for dental implants: what are the most effective techniques? A Cochrane systematic review.

PubMed

Esposito, Marco; Maghaireh, Hassan; Grusovin, Maria Gabriella; Ziounas, Ioannis; Worthington, Helen V

2012-01-01

This review is based on a Cochrane systematic review entitled 'Interventions for replacing missing teeth: management of soft tissues for dental implants' published in The Cochrane Library (see http:// www.cochrane.org/ for information). Cochrane systematic reviews are regularly updated to include new research, and in response to comments and criticisms from readers. If you wish to comment on this review, please send your comments to the Cochrane website or to Marco Esposito. The Cochrane Library should be consulted for the most recent version of the review. The results of a Cochrane review can be interpreted differently, depending on people's perspectives and circumstances. Please consider the conclusions presented carefully. They are the opinions of the review authors, and are not necessarily shared by the Cochrane Collaboration. To evaluate whether flapless procedures are beneficial for patients and which is the ideal flap design, whether soft tissue correction/augmentation techniques are beneficial for patients and which are the best techniques, whether techniques to increase the peri-implant keratinised mucosa are beneficial for patients and which are the best techniques, and which are the best suturing techniques/ materials. The Cochrane Oral Health Group's Trials Register, CENTRAL, MEDLINE and EMBASE were searched up to the 9th of June 2011 for randomised controlled trials (RCTs) of rootform osseointegrated dental implants, with a follow-up of at least 6 months after function, comparing various techniques to handle soft tissues in relation to dental implants. Primary outcome measures were prosthetic failures, implant failures and biological complications. Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were conducted at least in duplicate and independently by two or more review authors. The statistical unit was the patient and not the prosthesis, the procedure or the implant. RESULTS were expressed using risk ratios for dichotomous outcomes and mean differences for continuous outcomes with 95% confidence intervals (CI). Seventeen potentially eligible RCTs were identified but only six trials with 138 patients in total could be included. The following techniques were compared in the six included studies: flapless placement of dental implants versus conventional flap elevation (2 trials, 56 patients), crestal versus vestibular incisions (1 trial, 10 patients), Erbium:YAG laser versus flap elevation at the second-stage surgery for implant exposure (1 trial, 20 patients), whether a connective tissue graft at implant placement could be effective in augmenting peri-implant tissues (1 split-mouth trial, 10 patients), and autograft versus an animal-derived collagen matrix to increase the height of the keratinised mucosa (1 trial, 40 patients). On a patient rather than per implant basis, implants placed with a flapless technique and implant exposures performed with laser lead to statistically significantly less postoperative pain than flap elevation. Sites augmented with soft tissue connective grafts had better aesthetics and thicker tissues. Both palatal autografts or the use of a porcine-derived collagen matrix are effective in increasing the height of keratinised mucosa at the cost of a 0.5 mm recession of peri-implant soft tissues. There were no other statistically significant differences for any of the remaining analyses. There is limited weak evidence suggesting that flapless implant placement is feasible and has been shown to reduce patient postoperative discomfort in adequately selected patients, that augmentation at implant sites with soft tissue grafts is effective in increasing soft tissue thickness and improving aesthetics, and that one technique to increase the height of keratinised mucosa using autografts or an animal-derived collagen matrix was able to achieve its goal but at the cost of a worsened aesthetic outcome (0.5 mm of recession). There is insufficient reliable evidence to provide recommendations on which is the ideal flap design, the best soft tissue augmentation technique, whether techniques to increase the width of keratinised/attached mucosa are beneficial to patients or not, and which are the best incision/suture techniques/materials. Properly designed and conducted RCTs, with at least 6 months of follow-up, are needed to provide reliable answers to these questions.

Utilization of robotic-arm assisted total knee arthroplasty for soft tissue protection.

PubMed

Sultan, Assem A; Piuzzi, Nicolas; Khlopas, Anton; Chughtai, Morad; Sodhi, Nipun; Mont, Michael A

2017-12-01

Despite the well-established success of total knee arthroplasty (TKA), iatrogenic ligamentous and soft tissue injuries are infrequent, but potential complications that can have devastating impact on clinical outcomes. These injuries are often related to technical errors and excessive soft tissue manipulation, particularly during bony resections. Recently, robotic-arm assisted TKA was introduced and demonstrated promising results with potential technical advantages over manual surgery in implant positioning and mechanical accuracy. Furthermore, soft tissue protection is an additional potential advantage offered by these systems that can reduce inadvertent human technical errors encountered during standard manual resections. Therefore, due to the relative paucity of literature, we attempted to answer the following questions: 1) does robotic-arm assisted TKA offer a technical advantage that allows enhanced soft tissue protection? 2) What is the available evidence about soft tissue protection? Recently introduced models of robotic-arm assisted TKA systems with advanced technology showed promising clinical outcomes and soft tissue protection in the short- and mid-term follow-up with results comparable or superior to manual TKA. In this review, we attempted to explore this dimension of robotics in TKA and investigate the soft tissue related complications currently reported in the literature.

Soft tissue and cellular preservation in vertebrate skeletal elements from the Cretaceous to the present

PubMed Central

Schweitzer, Mary Higby; Wittmeyer, Jennifer L; Horner, John R

2006-01-01

Soft tissues and cell-like microstructures derived from skeletal elements of a well-preserved Tyrannosaurus rex (MOR 1125) were represented by four components in fragments of demineralized cortical and/or medullary bone: flexible and fibrous bone matrix; transparent, hollow and pliable blood vessels; intravascular material, including in some cases, structures morphologically reminiscent of vertebrate red blood cells; and osteocytes with intracellular contents and flexible filipodia. The present study attempts to trace the occurrence of these four components in bone from specimens spanning multiple geological time periods and varied depositional environments. At least three of the four components persist in some skeletal elements of specimens dating to the Campanian. Fibrous bone matrix is more altered over time in morphology and less likely to persist than vessels and/or osteocytes. Vessels vary greatly in preservation, even within the same specimen, with some regions retaining pliability and other regions almost crystalline. Osteocytes also vary, with some retaining long filipodia and transparency, while others present with short and stubby filipodia and deeply pigmented nuclei, or are pigmented throughout with no nucleus visible. Alternative hypotheses are considered to explain the origin/source of observed materials. Finally, a two-part mechanism, involving first cross-linking of molecular components and subsequent mineralization, is proposed to explain the surprising presence of still-soft elements in fossil bone. These results suggest that present models of fossilization processes may be incomplete and that soft tissue elements may be more commonly preserved, even in older specimens, than previously thought. Additionally, in many cases, osteocytes with defined nuclei are preserved, and may represent an important source for informative molecular data. PMID:17148248

Soft tissue and cellular preservation in vertebrate skeletal elements from the Cretaceous to the present.

PubMed

Schweitzer, Mary Higby; Wittmeyer, Jennifer L; Horner, John R

2007-01-22

Soft tissues and cell-like microstructures derived from skeletal elements of a well-preserved Tyrannosaurus rex (MOR 1125) were represented by four components in fragments of demineralized cortical and/or medullary bone: flexible and fibrous bone matrix; transparent, hollow and pliable blood vessels; intravascular material, including in some cases, structures morphologically reminiscent of vertebrate red blood cells; and osteocytes with intracellular contents and flexible filipodia. The present study attempts to trace the occurrence of these four components in bone from specimens spanning multiple geological time periods and varied depositional environments. At least three of the four components persist in some skeletal elements of specimens dating to the Campanian. Fibrous bone matrix is more altered over time in morphology and less likely to persist than vessels and/or osteocytes. Vessels vary greatly in preservation, even within the same specimen, with some regions retaining pliability and other regions almost crystalline. Osteocytes also vary, with some retaining long filipodia and transparency, while others present with short and stubby filipodia and deeply pigmented nuclei, or are pigmented throughout with no nucleus visible. Alternative hypotheses are considered to explain the origin/source of observed materials. Finally, a two-part mechanism, involving first cross-linking of molecular components and subsequent mineralization, is proposed to explain the surprising presence of still-soft elements in fossil bone. These results suggest that present models of fossilization processes may be incomplete and that soft tissue elements may be more commonly preserved, even in older specimens, than previously thought. Additionally, in many cases, osteocytes with defined nuclei are preserved, and may represent an important source for informative molecular data.

Testing of Space Suit Materials for Mars

NASA Technical Reports Server (NTRS)

Larson, Kristine

2016-01-01

Human missions to Mars may require radical changes in our approach to EVA suit design. A major challenge is the balance of building a suit robust enough to complete 50 EVAs in the dirt under intense UV exposure without losing mechanical strength or compromising its mobility. We conducted ground testing on both current and new space suit materials to determine performance degradation after exposure to 2500 hours of Mars mission equivalent UV. This testing will help mature the material technologies and provide performance data that can be used by not only the space suit development teams but for all Mars inflatable and soft goods derived structures from airlocks to habitats.

Viscoelastic characterization of soft biological materials

NASA Astrophysics Data System (ADS)

Nayar, Vinod Timothy

Progressive and irreversible retinal diseases are among the primary causes of blindness in the United States, attacking the cells in the eye that transform environmental light into neural signals for the optic pathway. Medical implants designed to restore visual function to afflicted patients can cause mechanical stress and ultimately damage to the host tissues. Research shows that an accurate understanding of the mechanical properties of the biological tissues can reduce damage and lead to designs with improved safety and efficacy. Prior studies on the mechanical properties of biological tissues show characterization of these materials can be affected by environmental, length-scale, time, mounting, stiffness, size, viscoelastic, and methodological conditions. Using porcine sclera tissue, the effects of environmental, time, and mounting conditions are evaluated when using nanoindentation. Quasi-static tests are used to measure reduced modulus during extended exposure to phosphate-buffered saline (PBS), as well as the chemical and mechanical analysis of mounting the sample to a solid substrate using cyanoacrylate. The less destructive nature of nanoindentation tests allows for variance of tests within a single sample to be compared to the variance between samples. The results indicate that the environmental, time, and mounting conditions can be controlled for using modified nanoindentation procedures for biological samples and are in line with averages modulus values from previous studies but with increased precision. By using the quasi-static and dynamic characterization capabilities of the nanoindentation setup, the additional stiffness and viscoelastic variables are measured. Different quasi-static control methods were evaluated along with maximum load parameters and produced no significant difference in reported reduced modulus values. Dynamic characterization tests varied frequency and quasi-static load, showing that the agar could be modeled as a linearly elastic material. The effects of sample stiffness were evaluated by testing both the quasi-static and dynamic mechanical properties of different concentration agar samples, ranging from 0.5% to 5.0%. The dynamic nanoindentation protocol showed some sensitivity to sample stiffness, but characterization remained consistently applicable to soft biological materials. Comparative experiments were performed on both 0.5% and 5.0% agar as well as porcine eye tissue samples using published dynamic macrocompression standards. By comparing these new tests to those obtained with nanoindentation, the effects due to length-scale, stiffness, size, viscoelastic, and methodological conditions are evaluated. Both testing methodologies can be adapted for the environmental and mounting conditions, but the limitations of standardized macro-scale tests are explored. The factors affecting mechanical characterization of soft and thin viscoelastic biological materials are researched and a comprehensive protocol is presented. This work produces material mechanical properties for use in improving future medical implant designs on a wide variety of biological tissue and materials.

High-Density Stretchable Electrode Grids for Chronic Neural Recording

PubMed Central

Tybrandt, Klas; Khodagholy, Dion; Dielacher, Bernd; Stauffer, Flurin; Renz, Aline F.; Buzsáki, György; Vörös, János

2018-01-01

Electrical interfacing with neural tissue is key to advancing diagnosis and therapies for neurological disorders, as well as providing detailed information about neural signals. A challenge for creating long-term stable interfaces between electronics and neural tissue is the huge mechanical mismatch between the systems. So far, materials and fabrication processes have restricted the development of soft electrode grids able to combine high performance, long-term stability, and high electrode density, aspects all essential for neural interfacing. Here, this challenge is addressed by developing a soft, high-density, stretchable electrode grid based on an inert, high-performance composite material comprising gold-coated titanium dioxide nanowires embedded in a silicone matrix. The developed grid can resolve high spatiotemporal neural signals from the surface of the cortex in freely moving rats with stable neural recording quality and preserved electrode signal coherence during 3 months of implantation. Due to its flexible and stretchable nature, it is possible to minimize the size of the craniotomy required for placement, further reducing the level of invasiveness. The material and device technology presented herein have potential for a wide range of emerging biomedical applications. PMID:29488263

Use of maxillofacial laboratory materials to construct a tissue-equivalent head phantom with removable titanium implantable devices for use in verification of the dose of intensity-modulated radiotherapy.

PubMed

Morris, K

2017-06-01

The dose of radiotherapy is often verified by measuring the dose of radiation at specific points within a phantom. The presence of high-density implant materials such as titanium, however, may cause complications both during calculation and delivery of the dose. Numerous studies have reported photon/electron backscatter and alteration of the dose by high-density implants, but we know of no evidence of a dosimetry phantom that incorporates high density implants or fixtures. The aim of the study was to design and manufacture a tissue-equivalent head phantom for use in verification of the dose in radiotherapy using a combination of traditional laboratory materials and techniques and 3-dimensional technology that can incorporate titanium maxillofacial devices. Digital designs were used together with Mimics® 18.0 (Materialise NV) and FreeForm® software. DICOM data were downloaded and manipulated into the final pieces of the phantom mould. Three-dimensional digital objects were converted into STL files and exported for additional stereolithography. Phantoms were constructed in four stages: material testing and selection, design of a 3-dimensional mould, manufacture of implants, and final fabrication of the phantom using traditional laboratory techniques. Three tissue-equivalent materials were found and used to successfully manufacture a suitable phantom with interchangeable sections that contained three versions of titanium maxillofacial implants. Maxillofacial and other materials can be used to successfully construct a head phantom with interchangeable titanium implant sections for use in verification of doses of radiotherapy. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Effect of bone-soft tissue friction on ultrasound axial shear strain elastography

NASA Astrophysics Data System (ADS)

Tang, Songyuan; Chaudhry, Anuj; Kim, Namhee; Reddy, J. N.; Righetti, Raffaella

2017-08-01

Bone-soft tissue friction is an important factor affecting several musculoskeletal disorders, frictional syndromes and the ability of a bone fracture to heal. However, this parameter is difficult to determine using non-invasive imaging modalities, especially in clinical settings. Ultrasound axial shear strain elastography is a non-invasive imaging modality that has been used in the recent past to estimate the bonding between different tissue layers. As most elastography methods, axial shear strain elastography is primarily used in soft tissues. More recently, this technique has been proposed to assess the bone-soft tissue interface. In this paper, we investigate the effect of a variation in bone-soft tissue friction coefficient in the resulting axial shear strain elastograms. Finite element poroelastic models of bone specimens exhibiting different bone-soft tissue friction coefficients were created and mechanically analyzed. These models were then imported to an ultrasound elastography simulation module to assess the presence of axial shear strain patterns. In vitro experiments were performed to corroborate selected simulation results. The results of this study show that the normalized axial shear strain estimated at the bone-soft tissue interface is statistically correlated to the bone-soft tissue coefficient of friction. This information may prove useful to better interpret ultrasound elastography results obtained in bone-related applications and, possibly, monitor bone healing.

Effect of bone-soft tissue friction on ultrasound axial shear strain elastography.

PubMed

Tang, Songyuan; Chaudhry, Anuj; Kim, Namhee; Reddy, J N; Righetti, Raffaella

2017-07-12

Bone-soft tissue friction is an important factor affecting several musculoskeletal disorders, frictional syndromes and the ability of a bone fracture to heal. However, this parameter is difficult to determine using non-invasive imaging modalities, especially in clinical settings. Ultrasound axial shear strain elastography is a non-invasive imaging modality that has been used in the recent past to estimate the bonding between different tissue layers. As most elastography methods, axial shear strain elastography is primarily used in soft tissues. More recently, this technique has been proposed to assess the bone-soft tissue interface. In this paper, we investigate the effect of a variation in bone-soft tissue friction coefficient in the resulting axial shear strain elastograms. Finite element poroelastic models of bone specimens exhibiting different bone-soft tissue friction coefficients were created and mechanically analyzed. These models were then imported to an ultrasound elastography simulation module to assess the presence of axial shear strain patterns. In vitro experiments were performed to corroborate selected simulation results. The results of this study show that the normalized axial shear strain estimated at the bone-soft tissue interface is statistically correlated to the bone-soft tissue coefficient of friction. This information may prove useful to better interpret ultrasound elastography results obtained in bone-related applications and, possibly, monitor bone healing.

Use of loading-unloading compression curves in medical device design

NASA Astrophysics Data System (ADS)

Ciornei, M. C.; Alaci, S.; Ciornei, F. C.; Romanu, I. C.

2017-08-01

The paper presents a method and experimental results regarding mechanical testing of soft materials. In order to characterize the mechanical behaviour of technological materials used in prosthesis, a large number of material constants are required, as well as the comparison to the original. The present paper proposes as methodology the comparison between compression loading-unloading curves corresponding to a soft biological tissue and to a synthetic material. To this purpose, a device was designed based on the principle of the dynamic harness test. A moving load is considered and the force upon the indenter is controlled for loading-unloading phases. The load and specimen deformation are simultaneously recorded. A significant contribution of this paper is the interpolation of experimental data by power law functions, a difficult task because of the instability of the system of equations to be optimized. Finding the interpolation function was simplified, from solving a system of transcendental equations to solving a unique equation. The characteristic parameters of the experimentally curves must be compared to the ones corresponding to actual tissue. The tests were performed for two cases: first, using a spherical punch, and second, for a flat-ended cylindrical punch.

Local deformation for soft tissue simulation

PubMed Central

Omar, Nadzeri; Zhong, Yongmin; Smith, Julian; Gu, Chengfan

2016-01-01

ABSTRACT This paper presents a new methodology to localize the deformation range to improve the computational efficiency for soft tissue simulation. This methodology identifies the local deformation range from the stress distribution in soft tissues due to an external force. A stress estimation method is used based on elastic theory to estimate the stress in soft tissues according to a depth from the contact surface. The proposed methodology can be used with both mass-spring and finite element modeling approaches for soft tissue deformation. Experimental results show that the proposed methodology can improve the computational efficiency while maintaining the modeling realism. PMID:27286482

X-ray Phase Contrast Allows Three Dimensional, Quantitative Imaging of Hydrogel Implants

PubMed Central

Appel, Alyssa A.; Larson, Jeffery C.; Jiang, Bin; Zhong, Zhong; Anastasio, Mark A.; Brey, Eric M.

2015-01-01

Three dimensional imaging techniques are needed for the evaluation and assessment of biomaterials used for tissue engineering and drug delivery applications. Hydrogels are a particularly popular class of materials for medical applications but are difficult to image in tissue using most available imaging modalities. Imaging techniques based on X-ray Phase Contrast (XPC) have shown promise for tissue engineering applications due to their ability to provide image contrast based on multiple X-ray properties. In this manuscript, we investigate the use of XPC for imaging a model hydrogel and soft tissue structure. Porous fibrin loaded poly(ethylene glycol) hydrogels were synthesized and implanted in a rodent subcutaneous model. Samples were explanted and imaged with an analyzer-based XPC technique and processed and stained for histology for comparison. Both hydrogel and soft tissues structures could be identified in XPC images. Structure in skeletal muscle adjacent could be visualized and invading fibrovascular tissue could be quantified. There were no differences between invading tissue measurements from XPC and the gold-standard histology. These results provide evidence of the significant potential of techniques based on XPC for 3D imaging of hydrogel structure and local tissue response. PMID:26487123

Contribution of trochanteric soft tissues to fall force estimates, the factor of risk, and prediction of hip fracture risk.

PubMed

Bouxsein, Mary L; Szulc, Pawel; Munoz, Fracoise; Thrall, Erica; Sornay-Rendu, Elizabeth; Delmas, Pierre D

2007-06-01

We compared trochanteric soft tissue thickness, femoral aBMD, and the ratio of fall force to femoral strength (i.e., factor of risk) in 21 postmenopausal women with incident hip fracture and 42 age-matched controls. Reduced trochanteric soft tissue thickness, low femoral aBMD, and increased ratio of fall force to femoral strength (i.e., factor of risk) were associated with increased risk of hip fracture. The contribution of trochanteric soft tissue thickness to hip fracture risk is incompletely understood. A biomechanical approach to assessing hip fracture risk that compares forces applied to the hip during a sideways fall to femoral strength may by improved by incorporating the force-attenuating effects of trochanteric soft tissues. We determined the relationship between femoral areal BMD (aBMD) and femoral failure load in 49 human cadaveric specimens, 53-99 yr of age. We compared femoral aBMD, trochanteric soft tissue thickness, and the ratio of fall forces to bone strength (i.e., the factor of risk for hip fracture, phi), before and after accounting for the force-attenuating properties of trochanteric soft tissue in 21 postmenopausal women with incident hip fracture and 42 age-matched controls. Femoral aBMD correlated strongly with femoral failure load (r2 = 0.73-0.83). Age, height, and weight did not differ; however, women with hip fracture had lower total femur aBMD (OR = 2.06; 95% CI, 1.19-3.56) and trochanteric soft tissue thickness (OR = 1.82; 95% CI, 1.01, 3.31). Incorporation of trochanteric soft tissue thickness measurements reduced the estimates of fall forces by approximately 50%. After accounting for force-attenuating properties of trochanteric soft tissue, the ratio of fall forces to femoral strength was 50% higher in cases than controls (0.92 +/- 0.44 versus 0.65 +/- 0.50, respectively; p = 0.04). It is possible to compute a biomechanically based estimate of hip fracture risk by combining estimates of femoral strength based on an empirical relationship between femoral aBMD and bone strength in cadaveric femora, along with estimates of loads applied to the hip during a sideways fall that account for thickness of trochanteric soft tissues. Our findings suggest that trochanteric soft tissue thickness may influence hip fracture risk by attenuating forces applied to the femur during a sideways fall and provide rationale for developing improved measurements of trochanteric soft tissue and for studying a larger cohort to determine whether trochanteric soft tissue thickness contributes to hip fracture risk independently of aBMD.

Quantitative Digital Tomosynthesis Mammography for Improved Breast Cancer Detection and Diagnosis

DTIC Science & Technology

2008-04-01

include breast-shape slabs consisted of breast- tissue-equivalent materials, i.e. heterogeneous mixture of fibroglandular-tissue- mimicking material. We...collected previ- ously in the Department of Radiology at the University of Michigan for our CAD study.46 The resulting mean effi- ciency ratio for 96 CC...may obscure the characteristics of mass margins. Development of CAD systems for DBT is still at an early stage. In this preliminary study, we compared

Equivalence of Gyn GEC-ESTRO guidelines for image guided cervical brachytherapy with EUD-based dose prescription

PubMed Central

2013-01-01

Background To establish a generalized equivalent uniform dose (gEUD) -based prescription method for Image Guided Brachytherapy (IGBT) that reproduces the Gyn GEC-ESTRO WG (GGE) prescription for cervix carcinoma patients on CT images with limited soft tissue resolution. Methods The equivalence of two IGBT planning approaches was investigated in 20 patients who received external beam radiotherapy (EBT) and 5 concomitant high dose rate IGBT treatments. The GGE planning strategy based on dose to the most exposed 2 cm3 (D2cc) was used to derive criteria for the gEUD-based planning of the bladder and rectum. The safety of gEUD constraints in terms of GGE criteria was tested by maximizing dose to the gEUD constraints for individual fractions. Results The gEUD constraints of 3.55 Gy for the rectum and 5.19 Gy for the bladder were derived. Rectum and bladder gEUD-maximized plans resulted in D2cc averages very similar to the initial GGE criteria. Average D2ccs and EUDs from the full treatment course were comparable for the two techniques within both sets of normal tissue constraints. The same was found for the tumor doses. Conclusions The derived gEUD criteria for normal organs result in GGE-equivalent IGBT treatment plans. The gEUD-based planning considers the entire dose distribution of organs in contrast to a single dose-volume-histogram point. PMID:24225184

An efficient method to predict and include Bragg curve degradation due to lung-equivalent materials in Monte Carlo codes by applying a density modulation

NASA Astrophysics Data System (ADS)

Baumann, Kilian-Simon; Witt, Matthias; Weber, Uli; Engenhart-Cabillic, Rita; Zink, Klemens

2017-05-01

Sub-millimetre-sized heterogeneities such as lung parenchyma cause Bragg peak degradation which can lead to an underdose of the tumor and an overdose of healthy tissue when not accounted for in treatment planning. Since commonly used treatment-planning CTs do not resolve the fine structure of lungs, this degradation can hardly be considered. We present a mathematical model capable of predicting and describing Bragg peak degradation due to a lung-equivalent geometry consisting of sub-millimetre voxels filled with either lung tissue or air. The material characteristic ‘modulation power’ is introduced to quantify the Bragg peak degradation. A strategy was developed to transfer the modulating effects of such fine structures to rougher structures such as 2 mm thick CT voxels, which is the resolution of typically used CTs. This is done by using the modulation power to derive a density distribution applicable to these voxels. By replacing the previously used sub-millimetre voxels by 2 mm thick voxels filled with lung tissue and modulating the lung tissue’s density in each voxel individually, we were able to reproduce the Bragg peak degradation. Hence a solution is found to include Bragg curve degradation due to lung-equivalent materials in Monte Carlo-based treatment-planning systems.

Water and tissue equivalence properties of biological materials for photons, electrons, protons and alpha particles in the energy region 10 keV-1 GeV: a comparative study.

PubMed

Kurudirek, Murat

2016-09-01

To compare some biological materials in respect to the water and tissue equivalence properties for photon, electron, proton and alpha particle interactions as means of the effective atomic number (Zeff) and electron density (Ne). A Z-wise interpolation procedure has been adopted for calculation of Zeff using the mass attenuation coefficients for photons and the mass stopping powers for charged particles. At relatively low energies (100 keV-3 MeV), Zeff and Ne for photons and electrons were found to be constant while they vary much more for protons and alpha particles. In contrast, Zeff and Ne for protons and alpha particles were found to be constant after 3 MeV whereas for photons and electrons they were found to increase with the increasing energy. Also, muscle eq. liquid (with sucrose) have Zeff and Ne values close to the Muscle Skeletal (ICRP) and Muscle Striated (ICRU) within low relative differences below 9%. Muscle eq. liquid (without sucrose) have Zeff and Ne values close to the Muscle Skeletal (ICRP) and Muscle Striated (ICRU) with difference below 10%. The reported data should be useful in determining best water as well as tissue equivalent materials for photon, electron, proton and alpha particle interactions.

Soft-tissue and phase-contrast imaging at the Swiss Light Source

NASA Astrophysics Data System (ADS)

Schneider, Philipp; Mohan, Nishant; Stampanoni, Marco; Muller, Ralph

2004-05-01

Recent results show that bone vasculature is a major contributor to local tissue porosity, and therefore can be directly linked to the mechanical properties of bone tissue. With the advent of third generation synchrotron radiation (SR) sources, micro-computed tomography (μCT) with resolutions in the order of 1 μm and better has become feasible. This technique has been employed frequently to analyze trabecular architecture and local bone tissue properties, i.e. the hard or mineralized bone tissue. Nevertheless, less is known about the soft tissues in bone, mainly due to inadequate imaging capabilities. Here, we discuss three different methods and applications to visualize soft tissues. The first approach is referred to as negative imaging. In this case the material around the soft tissue provides the absorption contrast necessary for X-ray based tomography. Bone vasculature from two different mouse strains was investigated and compared qualitatively. Differences were observed in terms of local vessel number and vessel orientation. The second technique represents corrosion casting, which is principally adapted for imaging of vascular systems. The technique of corrosion casting has already been applied successfully at the Swiss Light Source. Using the technology we were able to show that pathological features reminiscent of Alzheimer"s disease could be distinguished in the brain vasculature of APP transgenic mice. The third technique discussed here is phase contrast imaging exploiting the high degree of coherence of third generation synchrotron light sources, which provide the necessary physical conditions for phase contrast. The in-line approach followed here for phase contrast retrieval is a modification of the Gerchberg-Saxton-Fienup type. Several measurements and theoretical thoughts concerning phase contrast imaging are presented, including mathematical phase retrieval. Although up-to-now only phase images have been computed, the approach is now ready to retrieve the phase for a large number of angular positions of the specimen allowing application of holotomography, which is the three-dimensional reconstruction of phase images.

Pharmacokinetic equivalence of a levothyroxine sodium soft capsule manufactured using the new food and drug administration potency guidelines in healthy volunteers under fasting conditions.

PubMed

Colucci, Philippe; D'Angelo, Pina; Mautone, Giuseppe; Scarsi, Claudia; Ducharme, Murray P

2011-06-01

To assess the pharmacokinetic equivalence of a new soft capsule formulation of levothyroxine versus a marketed reference product and to assess the soft capsule formulated with stricter potency guidelines versus the capsule before the implementation of the new potency rule. Two single-dose randomized two-way crossover pharmacokinetic equivalence studies and one dosage form proportionality single-dose study comparing low, medium, and high strengths of the new formulation. All three studies were performed in a clinical setting. Participants were healthy male and female adult subjects with normal levothyroxine levels. A total of 90 subjects participated in the three studies. Pharmacokinetic parameters were calculated on baseline- adjusted concentrations. The first pharmacokinetic equivalence study compared the levothyroxine sodium soft capsule formulation (Tirosint) with the reference Synthroid tablets and the two products were considered bioequivalent. The dosage form proportionality study compared the 50-, 100-, and 150-μg test capsules strengths dosed at the same level (600 μg) and all three strengths were considered equivalent when given at the same dosage. The last study compared the test capsule used in the first two studies with a new capsule formulation following the new potency guideline (±5%) set forward by the Food and Drug Administration and the two capsules were considered bioequivalent. Doses were well tolerated by subjects in all three studies with no serious adverse events reported. The levothyroxine soft capsule formulated with the stricter new potency guideline set forward by the Food and Drug Administration met equivalence criteria in terms of rate and extent of exposure under fasting conditions to the reference tablet formulation. Clinical doses of the capsule formulation can be given using any combination of the commercialized strengths.

Fractal ladder models and power law wave equations

PubMed Central

Kelly, James F.; McGough, Robert J.

2009-01-01

The ultrasonic attenuation coefficient in mammalian tissue is approximated by a frequency-dependent power law for frequencies less than 100 MHz. To describe this power law behavior in soft tissue, a hierarchical fractal network model is proposed. The viscoelastic and self-similar properties of tissue are captured by a constitutive equation based on a lumped parameter infinite-ladder topology involving alternating springs and dashpots. In the low-frequency limit, this ladder network yields a stress-strain constitutive equation with a time-fractional derivative. By combining this constitutive equation with linearized conservation principles and an adiabatic equation of state, a fractional partial differential equation that describes power law attenuation is derived. The resulting attenuation coefficient is a power law with exponent ranging between 1 and 2, while the phase velocity is in agreement with the Kramers–Kronig relations. The fractal ladder model is compared to published attenuation coefficient data, thus providing equivalent lumped parameters. PMID:19813816

Iatrogenic Bone and Soft Tissue Trauma in Robotic-Arm Assisted Total Knee Arthroplasty Compared With Conventional Jig-Based Total Knee Arthroplasty: A Prospective Cohort Study and Validation of a New Classification System.

PubMed

Kayani, Babar; Konan, Sujith; Pietrzak, Jurek R T; Haddad, Fares S

2018-03-27

The objective of this study was to compare macroscopic bone and soft tissue injury between robotic-arm assisted total knee arthroplasty (RA-TKA) and conventional jig-based total knee arthroplasty (CJ-TKA) and create a validated classification system for reporting iatrogenic bone and periarticular soft tissue injury after TKA. This study included 30 consecutive CJ-TKAs followed by 30 consecutive RA-TKAs performed by a single surgeon. Intraoperative photographs of the femur, tibia, and periarticular soft tissues were taken before implantation of prostheses. Using these outcomes, the macroscopic soft tissue injury (MASTI) classification system was developed to grade iatrogenic bone and soft tissue injuries. Interobserver and Intraobserver validity of the proposed classification system was assessed. Patients undergoing RA-TKA had reduced medial soft tissue injury in both passively correctible (P < .05) and noncorrectible varus deformities (P < .05); more pristine femoral (P < .05) and tibial (P < .05) bone resection cuts; and improved MASTI scores compared to CJ-TKA (P < .05). There was high interobserver (intraclass correlation coefficient 0.92 [95% confidence interval: 0.88-0.96], P < .05) and intraobserver agreement (intraclass correlation coefficient 0.94 [95% confidence interval: 0.92-0.97], P < .05) of the proposed MASTI classification system. There is reduced bone and periarticular soft tissue injury in patients undergoing RA-TKA compared to CJ-TKA. The proposed MASTI classification system is a reproducible grading scheme for describing iatrogenic bone and soft tissue injury in TKA. RA-TKA is associated with reduced bone and soft tissue injury compared with conventional jig-based TKA. The proposed MASTI classification may facilitate further research correlating macroscopic soft tissue injury during TKA to long-term clinical and functional outcomes. Copyright © 2018 Elsevier Inc. All rights reserved.

Long-term stability of peri-implant tissues after bone or soft tissue augmentation. Effect of zirconia or titanium abutments on peri-implant soft tissues. Summary and consensus statements. The 4th EAO Consensus Conference 2015.

PubMed

Sicilia, Alberto; Quirynen, Marc; Fontolliet, Alain; Francisco, Helena; Friedman, Anton; Linkevicius, Tomas; Lutz, Rainer; Meijer, Henny J; Rompen, Eric; Rotundo, Roberto; Schwarz, Frank; Simion, Massimo; Teughels, Wim; Wennerberg, Ann; Zuhr, Otto

2015-09-01

Several surgical techniques and prosthetic devices have been developed in the last decades, aiming to improve aesthetic, hygienic and functional outcomes that may affect the peri-implant tissues, such as procedures of bone and soft tissue augmentation and the use of custom-made abutments of titanium and zirconium. Three systematic reviews, based on randomized clinical trials and prospective studies covering the above reported topics were analysed, and the detected evidence was exposed to interactive experts' discussion during the group's and general assembly's meetings of the 4th EAO Consensus Conference. The results are reported using the following abbreviations: S-T: short-term evidence, M-T: medium-term evidence; L-T: long-term evidence; LE: limited evidence. Soft tissue augmentation procedures may be indicated for the increase of soft tissue thickness and keratinized tissue, the reduction of interproximal peri-implant bone loss, and the coverage of shallow peri-implant soft tissue recessions (S-T, LE), L-T is lacking. Guided bone regeneration approaches (GBR) showed efficacy when used for ridge reconstruction after the complete healing of the soft tissues (S-T & L-T), and the stability of the augmented bone may play a role in the maintenance of the soft tissue position and dimensions (LE). No significant differences were observed between titanium and zirconia abutments when evaluating probing pocket depth, bleeding on probing, marginal bone levels and mucosal recessions. Zirconia abutments were associated with more biological complications but demonstrated superiority in terms of achieving natural soft tissue colour (S-T). © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Doxorubicin With Upfront Dexrazoxane Plus Olaratumab for the Treatment of Advanced or Metastatic Soft Tissue Sarcoma

ClinicalTrials.gov

2018-02-08

Sarcoma, Soft Tissue; Soft Tissue Sarcoma; Undifferentiated Pleomorphic Sarcoma; Leiomyosarcoma; Liposarcoma; Synovial Sarcoma; Myxofibrosarcoma; Angiosarcoma; Fibrosarcoma; Malignant Peripheral Nerve Sheath Tumor; Epithelioid Sarcoma

Multi-modality gellan gum-based tissue-mimicking phantom with targeted mechanical, electrical, and thermal properties.

PubMed

Chen, Roland K; Shih, A J

2013-08-21

This study develops a new class of gellan gum-based tissue-mimicking phantom material and a model to predict and control the elastic modulus, thermal conductivity, and electrical conductivity by adjusting the mass fractions of gellan gum, propylene glycol, and sodium chloride, respectively. One of the advantages of gellan gum is its gelling efficiency allowing highly regulable mechanical properties (elastic modulus, toughness, etc). An experiment was performed on 16 gellan gum-based tissue-mimicking phantoms and a regression model was fit to quantitatively predict three material properties (elastic modulus, thermal conductivity, and electrical conductivity) based on the phantom material's composition. Based on these material properties and the regression model developed, tissue-mimicking phantoms of porcine spinal cord and liver were formulated. These gellan gum tissue-mimicking phantoms have the mechanical, thermal, and electrical properties approximately equivalent to those of the spinal cord and the liver.

High-level expression of podoplanin in benign and malignant soft tissue tumors: immunohistochemical and quantitative real-time RT-PCR analysis.

PubMed

Xu, Yongjun; Ogose, Akira; Kawashima, Hiroyuki; Hotta, Tetsuo; Ariizumi, Takashi; Li, Guidong; Umezu, Hajime; Endo, Naoto

2011-03-01

Podoplanin is a 38 kDa mucin-type transmembrane glycoprotein that was first identified in rat glomerular epithelial cells (podocytes). It is expressed in normal lymphatic endothelium, but is absent from vascular endothelial cells. D2-40 is a commercially available mouse monoclonal antibody which binds to an epitope on human podoplanin. D2-40 immunoreactivity is therefore highly sensitive and specific for lymphatic endothelium. Recent investigations have shown widespread applications of immunohistochemical staining with D2-40 in evaluating podoplanin expression as an immunohistochemical marker for diagnosis and prognosis in various tumors. To determine whether the podoplanin (D2-40) antibody may be useful for the diagnosis of soft tissue tumors, 125 cases, including 4 kinds of benign tumors, 15 kinds of malignant tumors and 3 kinds of tumor-like lesions were immunostained using the D2-40 antibody. Total RNA was extracted from frozen tumor tissue obtained from 41 corresponding soft tissue tumor patients and 12 kinds of soft tissue tumor cell lines. Quantitative real-time PCR reactions were performed. Immunohistochemical and quantitative real-time RT-PCR analyses demonstrated the expression of the podoplanin protein and mRNA in the majority of benign and malignant soft tissue tumors and tumor-like lesions examined, with the exception of alveolar soft part sarcoma, embryonal and alveolar rhabdomyosarcoma, extraskeletal Ewing's sarcoma/peripheral primitive neuro-ectodermal tumor and lipoma, which were completely negative for podoplanin. Since it is widely and highly expressed in nearly all kinds of soft tissue tumors, especially in spindle cell sarcoma, myxoid type soft tissue tumors and soft tissue tumors of the nervous system, podoplanin is considered to have little value in the differential diagnosis of soft tissue tumors.

A Novel Esthetic Approach using Connective Tissue Graft for Soft Tissue Defect Following Surgical Excision of Gingival Fibrolipoma

PubMed Central

Parthasarathy, Harinath; Kumar, Praveenkrishna; Gajendran, Priyalochana; Appukuttan, Devapriya

2014-01-01

The aim of the present case report is to evaluate the adjunctive use of a connective tissue graft to overcome soft tissue defects following excision of a gingival fibrolipoma in the aesthetic region. Connective tissue graft has been well documented for treating defects of esthetic concern. However, the literature does not contain many reports on the esthetic clinical outcome following the use of connective tissue graft secondary to excision of soft tissue tumours. A 28-year-old male patient reported with a complaint of a recurrent growth in relation to his lower front tooth region. The lesion which was provisionally diagnosed as fibroma was treated with a complete surgical excision, following which a modified coronally advanced flap and connective tissue graft was adopted to overcome the soft tissue defect. The excised growth was diagnosed histologically as fibrolipoma. One year follow up showed no recurrence of the lesion and good esthetics.The adjunctive use of the connective tissue graft and modified coronally advanced flap predictably yields optimal soft tissue fill and excellent esthetics. Hence, routine use of this procedure may be recommended for surgical excision of soft tissue growths in esthetically sensitive areas. PMID:25584336

Evidence-based knowledge on the aesthetics and maintenance of peri-implant soft tissues: Osteology Foundation Consensus Report Part 1-Effects of soft tissue augmentation procedures on the maintenance of peri-implant soft tissue health.

PubMed

Giannobile, William V; Jung, Ronald E; Schwarz, Frank

2018-03-01

The goal of Working Group 1 at the 2nd Consensus Meeting of the Osteology Foundation was to comprehensively assess the effects of soft tissue augmentation procedures on peri-implant health or disease. A systematic review and meta-analysis on the effects of soft tissue augmentation procedures included a total of 10 studies (mucosal thickness: n = 6; keratinized tissue: n = 4). Consensus statements, clinical recommendations, and implications for future research were based on structured group discussions and a plenary session approval. Soft tissue grafting to increase the width of keratinized tissue around implants was associated with greater reductions in gingival and plaque indices when compared to non-augmented sites. Statistically significant differences were noted for final marginal bone levels in favor of an apically positioned flap plus autogenous graft vs. all standard-of-care control treatments investigated. Soft tissue grafting (i.e., autogenous connective tissue) to increase the mucosal thickness around implants in the aesthetic zone was associated with significantly less marginal bone loss over time, but no significant changes in bleeding on probing, probing depths, or plaque scores when compared to sites without grafting. The limited evidence available supports the use of soft tissue augmentation procedures to promote peri-implant health. © 2018 The Authors. Clinical Oral Implants Research Published by John Wiley & Sons Ltd.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kiarashi, Nooshin; Nolte, Adam C.; Sturgeon, Gregory M.

Purpose: Physical phantoms are essential for the development, optimization, and evaluation of x-ray breast imaging systems. Recognizing the major effect of anatomy on image quality and clinical performance, such phantoms should ideally reflect the three-dimensional structure of the human breast. Currently, there is no commercially available three-dimensional physical breast phantom that is anthropomorphic. The authors present the development of a new suite of physical breast phantoms based on human data. Methods: The phantoms were designed to match the extended cardiac-torso virtual breast phantoms that were based on dedicated breast computed tomography images of human subjects. The phantoms were fabricated bymore » high-resolution multimaterial additive manufacturing (3D printing) technology. The glandular equivalency of the photopolymer materials was measured relative to breast tissue-equivalent plastic materials. Based on the current state-of-the-art in the technology and available materials, two variations were fabricated. The first was a dual-material phantom, the Doublet. Fibroglandular tissue and skin were represented by the most radiographically dense material available; adipose tissue was represented by the least radiographically dense material. The second variation, the Singlet, was fabricated with a single material to represent fibroglandular tissue and skin. It was subsequently filled with adipose-equivalent materials including oil, beeswax, and permanent urethane-based polymer. Simulated microcalcification clusters were further included in the phantoms via crushed eggshells. The phantoms were imaged and characterized visually and quantitatively. Results: The mammographic projections and tomosynthesis reconstructed images of the fabricated phantoms yielded realistic breast background. The mammograms of the phantoms demonstrated close correlation with simulated mammographic projection images of the corresponding virtual phantoms. Furthermore, power-law descriptions of the phantom images were in general agreement with real human images. The Singlet approach offered more realistic contrast as compared to the Doublet approach, but at the expense of air bubbles and air pockets that formed during the filling process. Conclusions: The presented physical breast phantoms and their matching virtual breast phantoms offer realistic breast anatomy, patient variability, and ease of use, making them a potential candidate for performing both system quality control testing and virtual clinical trials.« less

Liver fat quantification using fast kVp-switching dual energy CT

NASA Astrophysics Data System (ADS)

Kriston, Andras; Mendonça, Paulo; Silva, Alvin; Paden, Robert G.; Pavlicek, William; Sahani, Dushyant; Janos Kis, Benedek; Rusko, Laszlo; Okerlund, Darin; Bhotika, Rahul

2011-03-01

Nonalcoholic steatohepatitis (NASH) is a liver disease that occurs in patients that lack a history of the well-proven association of alcohol use. A major symptom of NASH is increased fat deposition in the liver. Gemstone Spectral Imaging (GSI) with fast kVp-switching enables projection-based material decomposition, offering the opportunity to accurately characterize tissue types, e.g., fat and healthy liver tissue, based on their energy-sensitive material attenuation and density. We describe our pilot efforts to apply GSI to locate and quantify the amount of fat deposition in the liver. Two approaches are presented, one that computes percentage fat from the difference in HU values at high and low energies and the second based on directly computing fat volume fraction at each voxel using multi-material decomposition. Simulation software was used to create a phantom with a set of concentric rings, each composed of fat and soft tissue in different relative amounts with attenuation values obtained from the National Institute of Standards and Technology. Monte Carlo 80 and 140 kVp X-ray projections were acquired and CT images of the phantom were reconstructed. Results demonstrated the sensitivity of dual energy CT to the presence of fat and its ability to distinguish fat from soft tissue. Additionally, actual patient (liver) datasets were acquired using GSI and monochromatic images at 70 and 140 keV were reconstructed. Preliminary results demonstrate a tissue sensitivity that appears sufficient to quantify fat content with a degree of accuracy as may be needed for non-invasive clinical assessment of NASH.

Precision and accuracy of 3D lower extremity residua measurement systems

NASA Astrophysics Data System (ADS)

Commean, Paul K.; Smith, Kirk E.; Vannier, Michael W.; Hildebolt, Charles F.; Pilgram, Thomas K.

1996-04-01

Accurate and reproducible geometric measurement of lower extremity residua is required for custom prosthetic socket design. We compared spiral x-ray computed tomography (SXCT) and 3D optical surface scanning (OSS) with caliper measurements and evaluated the precision and accuracy of each system. Spiral volumetric CT scanned surface and subsurface information was used to make external and internal measurements, and finite element models (FEMs). SXCT and OSS were used to measure lower limb residuum geometry of 13 below knee (BK) adult amputees. Six markers were placed on each subject's BK residuum and corresponding plaster casts and distance measurements were taken to determine precision and accuracy for each system. Solid models were created from spiral CT scan data sets with the prosthesis in situ under different loads using p-version finite element analysis (FEA). Tissue properties of the residuum were estimated iteratively and compared with values taken from the biomechanics literature. The OSS and SXCT measurements were precise within 1% in vivo and 0.5% on plaster casts, and accuracy was within 3.5% in vivo and 1% on plaster casts compared with caliper measures. Three-dimensional optical surface and SXCT imaging systems are feasible for capturing the comprehensive 3D surface geometry of BK residua, and provide distance measurements statistically equivalent to calipers. In addition, SXCT can readily distinguish internal soft tissue and bony structure of the residuum. FEM can be applied to determine tissue material properties interactively using inverse methods.

Commissioning and initial acceptance tests for a commercial convolution dose calculation algorithm for radiotherapy treatment planning in comparison with Monte Carlo simulation and measurement

PubMed Central

Moradi, Farhad; Mahdavi, Seyed Rabi; Mostaar, Ahmad; Motamedi, Mohsen

2012-01-01

In this study the commissioning of a dose calculation algorithm in a currently used treatment planning system was performed and the calculation accuracy of two available methods in the treatment planning system i.e., collapsed cone convolution (CCC) and equivalent tissue air ratio (ETAR) was verified in tissue heterogeneities. For this purpose an inhomogeneous phantom (IMRT thorax phantom) was used and dose curves obtained by the TPS (treatment planning system) were compared with experimental measurements and Monte Carlo (MCNP code) simulation. Dose measurements were performed by using EDR2 radiographic films within the phantom. Dose difference (DD) between experimental results and two calculation methods was obtained. Results indicate maximum difference of 12% in the lung and 3% in the bone tissue of the phantom between two methods and the CCC algorithm shows more accurate depth dose curves in tissue heterogeneities. Simulation results show the accurate dose estimation by MCNP4C in soft tissue region of the phantom and also better results than ETAR method in bone and lung tissues. PMID:22973081

Two Stage Repair of Composite Craniofacial Defects with Antibiotic Releasing Porous Poly(methyl methacrylate) Space Maintainers and Bone Regeneration

NASA Astrophysics Data System (ADS)

Spicer, Patrick

Craniofacial defects resulting from trauma and resection present many challenges to reconstruction due to the complex structure, combinations of tissues, and environment, with exposure to the oral, skin and nasal mucosal pathogens. Tissue engineering seeks to regenerate the tissues lost in these defects; however, the composite nature and proximity to colonizing bacteria remain difficult to overcome. Additionally, many tissue engineering approaches have further hurdles to overcome in the regulatory process to clinical translation. As such these studies investigated a two stage strategy employing an antibiotic-releasing porous polymethylmethacrylate space maintainer fabricated with materials currently part of products approved or cleared by the United States Food and Drug Administration, expediting the translation to the clinic. This porous space maintainer holds the bone defect open allowing soft tissue to heal around the defect. The space maintainer can then be removed and one regenerated in the defect. These studies investigated the individual components of this strategy. The porous space maintainer showed similar soft tissue healing and response to non-porous space maintainers in a rabbit composite tissue defect. The antibiotic-releasing space maintainers showed release of antibiotics from 1-5 weeks, which could be controlled by loading and fabrication parameters. In vivo, space maintainers releasing a high dose of antibiotics for an extended period of time increased soft tissue healing over burst release space maintainers in an infected composite tissue defect model in a rabbit mandible. Finally, stabilization of bone defects and regeneration could be improved through scaffold structures and delivery of a bone forming growth factor. These studies illustrate the possibility of the two stage strategy for repair of composite tissue defects of the craniofacial complex.

Cixutumumab and Doxorubicin Hydrochloride in Treating Patients With Unresectable, Locally Advanced, or Metastatic Soft Tissue Sarcoma

ClinicalTrials.gov

2016-05-16

Adult Angiosarcoma; Adult Desmoplastic Small Round Cell Tumor; Adult Epithelioid Sarcoma; Adult Extraskeletal Myxoid Chondrosarcoma; Adult Extraskeletal Osteosarcoma; Adult Fibrosarcoma; Adult Leiomyosarcoma; Adult Liposarcoma; Adult Malignant Mesenchymoma; Adult Malignant Peripheral Nerve Sheath Tumor; Adult Rhabdomyosarcoma; Adult Synovial Sarcoma; Adult Undifferentiated High Grade Pleomorphic Sarcoma of Bone; Childhood Angiosarcoma; Childhood Desmoplastic Small Round Cell Tumor; Childhood Epithelioid Sarcoma; Childhood Fibrosarcoma; Childhood Leiomyosarcoma; Childhood Liposarcoma; Childhood Malignant Mesenchymoma; Childhood Malignant Peripheral Nerve Sheath Tumor; Childhood Pleomorphic Rhabdomyosarcoma; Childhood Rhabdomyosarcoma With Mixed Embryonal and Alveolar Features; Childhood Synovial Sarcoma; Dermatofibrosarcoma Protuberans; Malignant Adult Hemangiopericytoma; Malignant Childhood Hemangiopericytoma; Metastatic Childhood Soft Tissue Sarcoma; Previously Treated Childhood Rhabdomyosarcoma; Recurrent Adult Soft Tissue Sarcoma; Recurrent Childhood Rhabdomyosarcoma; Recurrent Childhood Soft Tissue Sarcoma; Stage III Adult Soft Tissue Sarcoma; Stage IV Adult Soft Tissue Sarcoma; Untreated Childhood Rhabdomyosarcoma

Inner power, physical strength and existential well-being in daily life: relatives' experiences of receiving soft tissue massage in palliative home care.

PubMed

Cronfalk, Berit Seiger; Strang, Peter; Ternestedt, Britt-Marie

2009-08-01

This article explores relatives' experiences of receiving soft tissue massage as a support supplement while caring for a dying family member at home. In palliative home care, relatives play an important role as carers to seriously ill and dying family members. To improve their quality of life, different support strategies are of importance. Complementary methods, such as soft tissue massage have become an appreciated supplement for these patients. However, only few studies focus on relatives experiences of receiving soft tissue massage as a supplemental support. Qualitative design Nineteen relatives received soft tissue massage (hand or foot) nine times (25 minutes) in their homes. Open-ended semi-structured tape-recorded interviews were conducted once per relative after the nine times of massage, using qualitative content analysis. Soft tissue massage gave the relatives' feelings of 'being cared for', 'body vitality' and 'peace of mind'. For a while, they put worries of daily life aside as they just experienced 'being'. During massage, it became apparent that body and mind is constituted of an indestructible completeness. The overarching theme was 'inner power, physical strength and existential well-being in their daily lives'. All relatives experienced soft tissue massage positively, although they were under considerable stress. Soft tissue massage could be an option to comfort and support relatives in palliative home care. In palliative nursing care, soft tissue massage could present a worthy supplement in supporting caring relatives.

Soft tissue thin-plate spline analysis of pre-pubertal Korean and European-Americans with untreated Angle's Class III malocclusions.

PubMed

Singh, G D; McNamara, J A; Lozanoff, S

1999-01-01

The purpose of this study was to assess soft tissue facial matrices in subjects of diverse ethnic origins with underlying dentoskeletal malocclusions. Pre-treatment lateral cephalographs of 71 Korean and 70 European-American children aged between 5 and 11 years with Angle's Class III malocclusions were traced, and 12 homologous, soft tissue landmarks digitized. Comparing mean Korean and European-American Class III soft tissue profiles, Procrustes analysis established statistical difference (P < 0.001) between the configurations, and this difference was also true at all seven age groups tested (P < 0.001). Comparing the overall European-American and Korean transformation, thin-plate spline analysis indicated that both affine and non-affine transformations contribute towards the total spline (deformation) of the averaged Class III soft tissue configurations. For non-affine transformations, partial warp (PW) 8 had the highest magnitude, indicating large-scale deformations visualized as labio-mental protrusion, predominantly. In addition, PW9, PW4, and PW5 also had high magnitudes, demonstrating labio-mental vertical compression and antero-posterior compression of the lower labio-mental soft tissues. Thus, Korean children with Class III malocclusions demonstrate antero-posterior and vertical deformations of the labio-mental soft tissue complex with respect to their European-American counterparts. Morphological heterogeneity of the soft tissue integument in subjects of diverse ethnic origin may obscure the underlying skeletal morphology, but the soft tissue integument appears to have minimal ontogenetic association with Class III malocclusions.

Dehomogenized Elastic Properties of Heterogeneous Layered Materials in AFM Indentation Experiments.

PubMed

Lee, Jia-Jye; Rao, Satish; Kaushik, Gaurav; Azeloglu, Evren U; Costa, Kevin D

2018-06-05

Atomic force microscopy (AFM) is used to study mechanical properties of biological materials at submicron length scales. However, such samples are often structurally heterogeneous even at the local level, with different regions having distinct mechanical properties. Physical or chemical disruption can isolate individual structural elements but may alter the properties being measured. Therefore, to determine the micromechanical properties of intact heterogeneous multilayered samples indented by AFM, we propose the Hybrid Eshelby Decomposition (HED) analysis, which combines a modified homogenization theory and finite element modeling to extract layer-specific elastic moduli of composite structures from single indentations, utilizing knowledge of the component distribution to achieve solution uniqueness. Using finite element model-simulated indentation of layered samples with micron-scale thickness dimensions, biologically relevant elastic properties for incompressible soft tissues, and layer-specific heterogeneity of an order of magnitude or less, HED analysis recovered the prescribed modulus values typically within 10% error. Experimental validation using bilayer spin-coated polydimethylsiloxane samples also yielded self-consistent layer-specific modulus values whether arranged as stiff layer on soft substrate or soft layer on stiff substrate. We further examined a biophysical application by characterizing layer-specific microelastic properties of full-thickness mouse aortic wall tissue, demonstrating that the HED-extracted modulus of the tunica media was more than fivefold stiffer than the intima and not significantly different from direct indentation of exposed media tissue. Our results show that the elastic properties of surface and subsurface layers of microscale synthetic and biological samples can be simultaneously extracted from the composite material response to AFM indentation. HED analysis offers a robust approach to studying regional micromechanics of heterogeneous multilayered samples without destructively separating individual components before testing. Copyright © 2018 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Deep multi-spectral ensemble learning for electronic cleansing in dual-energy CT colonography

NASA Astrophysics Data System (ADS)

Tachibana, Rie; Näppi, Janne J.; Hironaka, Toru; Kim, Se Hyung; Yoshida, Hiroyuki

2017-03-01

We developed a novel electronic cleansing (EC) method for dual-energy CT colonography (DE-CTC) based on an ensemble deep convolution neural network (DCNN) and multi-spectral multi-slice image patches. In the method, an ensemble DCNN is used to classify each voxel of a DE-CTC image volume into five classes: luminal air, soft tissue, tagged fecal materials, and partial-volume boundaries between air and tagging and those between soft tissue and tagging. Each DCNN acts as a voxel classifier, where an input image patch centered at the voxel is generated as input to the DCNNs. An image patch has three channels that are mapped from a region-of-interest containing the image plane of the voxel and the two adjacent image planes. Six different types of spectral input image datasets were derived using two dual-energy CT images, two virtual monochromatic images, and two material images. An ensemble DCNN was constructed by use of a meta-classifier that combines the output of multiple DCNNs, each of which was trained with a different type of multi-spectral image patches. The electronically cleansed CTC images were calculated by removal of regions classified as other than soft tissue, followed by a colon surface reconstruction. For pilot evaluation, 359 volumes of interest (VOIs) representing sources of subtraction artifacts observed in current EC schemes were sampled from 30 clinical CTC cases. Preliminary results showed that the ensemble DCNN can yield high accuracy in labeling of the VOIs, indicating that deep learning of multi-spectral EC with multi-slice imaging could accurately remove residual fecal materials from CTC images without generating major EC artifacts.

Cannula Versus Sharp Needle for Placement of Soft Tissue Fillers: An Observational Cadaver Study.

PubMed

van Loghem, Jani A J; Humzah, Dalvi; Kerscher, Martina

2017-12-13

Soft-tissue fillers have become important products for facial rejuvenation. Deep fat compartments and facial bones lose volume during the natural aging process. For the most natural-looking results, deep volumetric injections at strategic sites are therefore preferred. Supraperiosteal placement is performed with a sharp needle or a non-traumatic cannula. The primary objective was to determine whether there is a difference in precision between supraperiosteal placement with a sharp needle compared with a non-traumatic cannula in cadaver specimens. A secondary objective was to analyze the safety profiles of both injection techniques. Cadaver heads were injected with dye material and soft-tissue fillers at multiple aesthetic facial sites on the supraperiosteum and subsequently dissected for observation of dye and filler placement. The non-traumatic cannula technique resulted in product being confined to the deep anatomic layers. In contrast, with the sharp needle technique, material was placed in multiple anatomic layers, from the periosteum to more superficial skin layers. For both techniques results were consistent for all facial sites. Although direct extrapolation from cadavers to the in vivo situation cannot be made, cannulae showed more precision in placement of product. With the sharp needle, the material was injected on the periosteum, and then migrated in a retrograde direction along the trajectory of the needle path, ending up in multiple anatomic layers. The sharp needle technique also showed a higher complication risk with intra-arterial injection occurring, even though the needle tip was positioned on the periosteum and the product was injected with the needle in constant contact with the periosteum. © 2016 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com

Acellularization-Induced Changes in Tensile Properties Are Organ Specific - An In-Vitro Mechanical and Structural Analysis of Porcine Soft Tissues

PubMed Central

Aust, Gabriela; Boldt, Andreas; Fritsch, Sebastian; Keil, Isabel; Koch, Holger; Möbius, Robert; Scheidt, Holger A.; Wagner, Martin F. X.; Hammer, Niels

2016-01-01

Introduction Though xenogeneic acellular scaffolds are frequently used for surgical reconstruction, knowledge of their mechanical properties is lacking. This study compared the mechanical, histological and ultrastructural properties of various native and acellular specimens. Materials and Methods Porcine esophagi, ureters and skin were tested mechanically in a native or acellular condition, focusing on the elastic modulus, ultimate tensile stress and maximum strain. The testing protocol for soft tissues was standardized, including the adaption of the tissue’s water content and partial plastination to minimize material slippage as well as templates for normed sample dimensions and precise cross-section measurements. The native and acellular tissues were compared at the microscopic and ultrastructural level with a focus on type I collagens. Results Increased elastic modulus and ultimate tensile stress values were quantified in acellular esophagi and ureters compared to the native condition. In contrast, these values were strongly decreased in the skin after acellularization. Acellularization-related decreases in maximum strain were found in all tissues. Type I collagens were well-preserved in these samples; however, clotting and a loss of cross-linking type I collagens was observed ultrastructurally. Elastins and fibronectins were preserved in the esophagi and ureters. A loss of the epidermal layer and decreased fibronectin content was present in the skin. Discussion Acellularization induces changes in the tensile properties of soft tissues. Some of these changes appear to be organ specific. Loss of cross-linking type I collagen may indicate increased mechanical strength due to decreasing transverse forces acting upon the scaffolds, whereas fibronectin loss may be related to decreased load-bearing capacity. Potentially, the alterations in tissue mechanics are linked to organ function and to the interplay of cells and the extracellular matrix, which is different in hollow organs when compared to skin. PMID:26960134

Identification of the viscoelastic properties of soft materials at low frequency: performance, ill-conditioning and extrapolation capabilities of fractional and exponential models.

PubMed

Ciambella, J; Paolone, A; Vidoli, S

2014-09-01

We report about the experimental identification of viscoelastic constitutive models for frequencies ranging within 0-10Hz. Dynamic moduli data are fitted forseveral materials of interest to medical applications: liver tissue (Chatelin et al., 2011), bioadhesive gel (Andrews et al., 2005), spleen tissue (Nicolle et al., 2012) and synthetic elastomer (Osanaiye, 1996). These materials actually represent a rather wide class of soft viscoelastic materials which are usually subjected to low frequencies deformations. We also provide prescriptions for the correct extrapolation of the material behavior at higher frequencies. Indeed, while experimental tests are more easily carried out at low frequency, the identified viscoelastic models are often used outside the frequency range of the actual test. We consider two different classes of models according to their relaxation function: Debye models, whose kernel decays exponentially fast, and fractional models, including Cole-Cole, Davidson-Cole, Nutting and Havriliak-Negami, characterized by a slower decay rate of the material memory. Candidate constitutive models are hence rated according to the accurateness of the identification and to their robustness to extrapolation. It is shown that all kernels whose decay rate is too fast lead to a poor fitting and high errors when the material behavior is extrapolated to broader frequency ranges. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

Mechanically robust cryogels with injectability and bioprinting supportability for adipose tissue engineering.

PubMed

Qi, Dianjun; Wu, Shaohua; Kuss, Mitchell A; Shi, Wen; Chung, Soonkyu; Deegan, Paul T; Kamenskiy, Alexey; He, Yini; Duan, Bin

2018-05-26

Bioengineered adipose tissues have gained increased interest as a promising alternative to autologous tissue flaps and synthetic adipose fillers for soft tissue augmentation and defect reconstruction in clinic. Although many scaffolding materials and biofabrication methods have been investigated for adipose tissue engineering in the last decades, there are still challenges to recapitulate the appropriate adipose tissue microenvironment, maintain volume stability, and induce vascularization to achieve long-term function and integration. In the present research, we fabricated cryogels consisting of methacrylated gelatin, methacrylated hyaluronic acid, and 4arm poly(ethylene glycol) acrylate (PEG-4A) by using cryopolymerization. The cryogels were repeatedly injectable and stretchable, and the addition of PEG-4A improved the robustness and mechanical properties. The cryogels supported human adipose progenitor cell (HWA) and adipose derived mesenchymal stromal cell adhesion, proliferation, and adipogenic differentiation and maturation, regardless of the addition of PEG-4A. The HWA laden cryogels facilitated the co-culture of human umbilical vein endothelial cells (HUVEC) and capillary-like network formation, which in return also promoted adipogenesis. We further combined cryogels with 3D bioprinting to generate handleable adipose constructs with clinically relevant size. 3D bioprinting enabled the deposition of multiple bioinks onto the cryogels. The bioprinted flap-like constructs had an integrated structure without delamination and supported vascularization. Adipose tissue engineering is promising for reconstruction of soft tissue defects, and also challenging for restoring and maintaining soft tissue volume and shape, and achieving vascularization and integration. In this study, we fabricated cryogels with mechanical robustness, injectability, and stretchability by using cryopolymerization. The cryogels promoted cell adhesion, proliferation, and adipogenic differentiation and maturation of human adipose progenitor cells and adipose derived mesenchymal stromal cells. Moreover, the cryogels also supported 3D bioprinting on top, forming vascularized adipose constructs. This study demonstrates the potential of the implementation of cryogels for generating volume-stable adipose tissue constructs and provides a strategy to fabricate vascularized flap-like constructs for complex soft tissue regeneration. Copyright © 2018. Published by Elsevier Ltd.

Instrumented cardiac microphysiological devices via multimaterial three-dimensional printing

NASA Astrophysics Data System (ADS)

Lind, Johan U.; Busbee, Travis A.; Valentine, Alexander D.; Pasqualini, Francesco S.; Yuan, Hongyan; Yadid, Moran; Park, Sung-Jin; Kotikian, Arda; Nesmith, Alexander P.; Campbell, Patrick H.; Vlassak, Joost J.; Lewis, Jennifer A.; Parker, Kevin K.

2017-03-01

Biomedical research has relied on animal studies and conventional cell cultures for decades. Recently, microphysiological systems (MPS), also known as organs-on-chips, that recapitulate the structure and function of native tissues in vitro, have emerged as a promising alternative. However, current MPS typically lack integrated sensors and their fabrication requires multi-step lithographic processes. Here, we introduce a facile route for fabricating a new class of instrumented cardiac microphysiological devices via multimaterial three-dimensional (3D) printing. Specifically, we designed six functional inks, based on piezo-resistive, high-conductance, and biocompatible soft materials that enable integration of soft strain gauge sensors within micro-architectures that guide the self-assembly of physio-mimetic laminar cardiac tissues. We validated that these embedded sensors provide non-invasive, electronic readouts of tissue contractile stresses inside cell incubator environments. We further applied these devices to study drug responses, as well as the contractile development of human stem cell-derived laminar cardiac tissues over four weeks.

3D Printed Organ Models with Physical Properties of Tissue and Integrated Sensors.

PubMed

Qiu, Kaiyan; Zhao, Zichen; Haghiashtiani, Ghazaleh; Guo, Shuang-Zhuang; He, Mingyu; Su, Ruitao; Zhu, Zhijie; Bhuiyan, Didarul B; Murugan, Paari; Meng, Fanben; Park, Sung Hyun; Chu, Chih-Chang; Ogle, Brenda M; Saltzman, Daniel A; Konety, Badrinath R; Sweet, Robert M; McAlpine, Michael C

2018-03-01

The design and development of novel methodologies and customized materials to fabricate patient-specific 3D printed organ models with integrated sensing capabilities could yield advances in smart surgical aids for preoperative planning and rehearsal. Here, we demonstrate 3D printed prostate models with physical properties of tissue and integrated soft electronic sensors using custom-formulated polymeric inks. The models show high quantitative fidelity in static and dynamic mechanical properties, optical characteristics, and anatomical geometries to patient tissues and organs. The models offer tissue-mimicking tactile sensation and behavior and thus can be used for the prediction of organ physical behavior under deformation. The prediction results show good agreement with values obtained from simulations. The models also allow the application of surgical and diagnostic tools to their surface and inner channels. Finally, via the conformal integration of 3D printed soft electronic sensors, pressure applied to the models with surgical tools can be quantitatively measured.

3D Printed Organ Models with Physical Properties of Tissue and Integrated Sensors

PubMed Central

Qiu, Kaiyan; Zhao, Zichen; Haghiashtiani, Ghazaleh; Guo, Shuang-Zhuang; He, Mingyu; Su, Ruitao; Zhu, Zhijie; Bhuiyan, Didarul B.; Murugan, Paari; Meng, Fanben; Park, Sung Hyun; Chu, Chih-Chang; Ogle, Brenda M.; Saltzman, Daniel A.; Konety, Badrinath R.

2017-01-01

The design and development of novel methodologies and customized materials to fabricate patient-specific 3D printed organ models with integrated sensing capabilities could yield advances in smart surgical aids for preoperative planning and rehearsal. Here, we demonstrate 3D printed prostate models with physical properties of tissue and integrated soft electronic sensors using custom-formulated polymeric inks. The models show high quantitative fidelity in static and dynamic mechanical properties, optical characteristics, and anatomical geometries to patient tissues and organs. The models offer tissue-mimicking tactile sensation and behavior and thus can be used for the prediction of organ physical behavior under deformation. The prediction results show good agreement with values obtained from simulations. The models also allow the application of surgical and diagnostic tools to their surface and inner channels. Finally, via the conformal integration of 3D printed soft electronic sensors, pressure applied to the models with surgical tools can be quantitatively measured. PMID:29608202

Improved Rubin-Bodner Model for the Prediction of Soft Tissue Deformations

PubMed Central

Zhang, Guangming; Xia, James J.; Liebschner, Michael; Zhang, Xiaoyan; Kim, Daeseung; Zhou, Xiaobo

2016-01-01

In craniomaxillofacial (CMF) surgery, a reliable way of simulating the soft tissue deformation resulted from skeletal reconstruction is vitally important for preventing the risks of facial distortion postoperatively. However, it is difficult to simulate the soft tissue behaviors affected by different types of CMF surgery. This study presents an integrated bio-mechanical and statistical learning model to improve accuracy and reliability of predictions on soft facial tissue behavior. The Rubin-Bodner (RB) model is initially used to describe the biomechanical behavior of the soft facial tissue. Subsequently, a finite element model (FEM) computers the stress of each node in soft facial tissue mesh data resulted from bone displacement. Next, the Generalized Regression Neural Network (GRNN) method is implemented to obtain the relationship between the facial soft tissue deformation and the stress distribution corresponding to different CMF surgical types and to improve evaluation of elastic parameters included in the RB model. Therefore, the soft facial tissue deformation can be predicted by biomechanical properties and statistical model. Leave-one-out cross-validation is used on eleven patients. As a result, the average prediction error of our model (0.7035mm) is lower than those resulting from other approaches. It also demonstrates that the more accurate bio-mechanical information the model has, the better prediction performance it could achieve. PMID:27717593

Large poroelastic deformation of a soft material

NASA Astrophysics Data System (ADS)

MacMinn, Christopher W.; Dufresne, Eric R.; Wettlaufer, John S.

2014-11-01

Flow through a porous material will drive mechanical deformation when the fluid pressure becomes comparable to the stiffness of the solid skeleton. This has applications ranging from hydraulic fracture for recovery of shale gas, where fluid is injected at high pressure, to the mechanics of biological cells and tissues, where the solid skeleton is very soft. The traditional linear theory of poroelasticity captures this fluid-solid coupling by combining Darcy's law with linear elasticity. However, linear elasticity is only volume-conservative to first order in the strain, which can become problematic when damage, plasticity, or extreme softness lead to large deformations. Here, we compare the predictions of linear poroelasticity with those of a large-deformation framework in the context of two model problems. We show that errors in volume conservation are compounded and amplified by coupling with the fluid flow, and can become important even when the deformation is small. We also illustrate these results with a laboratory experiment.

Two-piece impression procedure for implant-retained orbital prostheses.

PubMed

Ozcelik, Tuncer Burak; Yilmaz, Burak

2012-01-01

Obtaining an accurate impression of facial tissues with undercuts and extraoral implants has always been a challenge for both clinicians and patients. This report describes a three-step, two-piece technique that enables an accurate and comfortable impression of undercut tissues and extraoral implants in an orbital defect. An impression of the basal tissue surface of the defect area was made using a medium-body polyether impression material followed by an impression of the entire face of the patient made with a polyvinyl siloxane (PVS) impression material. First, the PVS impression material was removed; second, the impression posts were removed from the magnets; and third, the polyether impression was removed from the defect. The impression posts were attached to the implant analogs and placed in the negative spaces in the polyether impression. The polyether impression, which carries the implant analogs and impression posts, was placed in the PVS impression through the negative spaces. This technique minimizes trauma to the soft tissues and implants during impression making and also does not require additional materials.

Alveolar soft part sarcoma causing perianal abscess.

PubMed

Sullivan, Niall; McCulloch, Tom; Leverton, David

2011-07-01

A 34-year-old woman presented with a perianal abscess that communicated with the vagina. There was a background of a one-year history of a conservatively treated, traumatic, paravaginal haematoma. Histology of the fistula tract showed alveolar soft part sarcoma and subsequent imaging identified a large soft tissue mass in the pelvis with lung metastases. Alveolar soft part sarcoma is a rare soft tissue sarcoma of unknown cellular origin affecting predominantly young women, often in deep soft tissues and lower extremities.

Temperature dependent of viscoelasticity measurement on fat emulsion phantom using acoustic radiation force elasticity imaging method

PubMed Central

Xie, Peng; Wang, Mengke; Guo, Yanrong; Wen, Huiying; Chen, Xin; Chen, Siping; Lin, Haoming

2018-01-01

During the past two decades, tissue elasticity has been extensively studied and has been used in clinical disease diagnosis. But biological soft tissues are viscoelastic in nature. Therefore, they should be simultaneously characterized in terms of elasticity and viscosity. In addition, the mechanical properties of soft tissues are temperature dependent. However, how the temperature influences the shear wave dispersion and the viscoelasticity of soft tissue are still unclear. The aim of this study is to compare viscoelasticity of fat emulsion phantom with different temperature using acoustic radiation force elasticity imaging method. In our experiment, we produced four proportions of ultrasonic phantom by adding fat emulsion gelatin. Through adjusting the component of the fat emulsion, we change the viscoelasticity of the ultrasonic phantom. We used verasonics system to gather data and voigt model to fit the elasticity and viscosity value of the ultrasonic phantom we made. The influence of temperature to the ultrasonic phantom also measured in our study. The results show that the addition of fat emulsion to the phantom can increase the viscosity of the phantom, and the shear wave phase velocity decreases gradually at each frequency with the temperature increases, which provides a new material for the production of viscoelastic phantom. PMID:29758968

Temperature dependent of viscoelasticity measurement on fat emulsion phantom using acoustic radiation force elasticity imaging method.

PubMed

Xie, Peng; Wang, Mengke; Guo, Yanrong; Wen, Huiying; Chen, Xin; Chen, Siping; Lin, Haoming

2018-04-27

During the past two decades, tissue elasticity has been extensively studied and has been used in clinical disease diagnosis. But biological soft tissues are viscoelastic in nature. Therefore, they should be simultaneously characterized in terms of elasticity and viscosity. In addition, the mechanical properties of soft tissues are temperature dependent. However, how the temperature influences the shear wave dispersion and the viscoelasticity of soft tissue are still unclear. The aim of this study is to compare viscoelasticity of fat emulsion phantom with different temperature using acoustic radiation force elasticity imaging method. In our experiment, we produced four proportions of ultrasonic phantom by adding fat emulsion gelatin. Through adjusting the component of the fat emulsion, we change the viscoelasticity of the ultrasonic phantom. We used verasonics system to gather data and voigt model to fit the elasticity and viscosity value of the ultrasonic phantom we made. The influence of temperature to the ultrasonic phantom also measured in our study. The results show that the addition of fat emulsion to the phantom can increase the viscosity of the phantom, and the shear wave phase velocity decreases gradually at each frequency with the temperature increases, which provides a new material for the production of viscoelastic phantom.

[Diagnosis and therapy of particle disease in total hip arthroplasty].

PubMed

Müller, M; Wassilew, G; Perka, C

2015-04-01

Particle disease is caused by periarticular accumulation of attrition particles and the inflammatory reaction of the body's tissue. This process may result in osteolysis or soft tissue transformation which presents itself symptomless in the beginning and can proceed to aseptic implant loosening, fracture, implant breaking as a result of the inappropriate osseous support and to algetic and destructive soft tissue reactions as well. Attrition particles originate from tribological pairing, and the extent of the attrition or the particle concentration depend on different factors as there are the tribological pairing's material, the head size, the patient's level of activity, and the implant position. Attrition particles can also be found in the range of any modular connection. Particle disease and its resulting morphological alterations of the tribological pairing is one of the most frequent reasons for re-operation in hip endoprosthetics. Georg Thieme Verlag KG Stuttgart · New York.

The Future of Biologic Coatings for Orthopaedic Implants

PubMed Central

Goodman, Stuart B.; Yao, Zhenyu; Keeney, Michael; Yang, Fan

2013-01-01

Implants are widely used for othopaedic applications such as fixing fractures, repairing nonunions, obtaining a joint arthrodesis, total joint arthroplasty, spinal reconstruction, and soft tissue anchorage. Previously, orthopaedic implants were designed simply as mechanical devices; the biological aspects of the implant were a byproduct of stable internal/external fixation of the device to the surrounding bone or soft tissue. More recently, biologic coatings have been incorporated into orthopaedic implants in order to modulate the surrounding biological environment. This opinion article reviews current and potential future use of biologic coatings for orthopaedic implants to facilitate osseointegration and mitigate possible adverse tissue responses including the foreign body reaction and implant infection. While many of these coatings are still in the preclinical testing stage, bioengineers, material scientists and surgeons continue to explore surface coatings as a means of improving clinical outcome of patients undergoing orthopaedic surgery. PMID:23391496

A micro X-ray computed tomography dataset of South African hermit crabs (Crustacea: Decapoda: Anomura: Paguroidea) containing scans of two rare specimens and three recently described species.

PubMed

Landschoff, Jannes; Du Plessis, Anton; Griffiths, Charles L

2018-04-01

Along with the conventional deposition of physical types at natural history museums, the deposition of 3-dimensional (3D) image data has been proposed for rare and valuable museum specimens, such as irreplaceable type material. Micro computed tomography (μCT) scan data of 5 hermit crab species from South Africa, including rare specimens and type material, depicted main identification characteristics of calcified body parts. However, low-image contrasts, especially in larger (>50 mm total length) specimens, did not allow sufficient 3D reconstructions of weakly calcified and fine characteristics, such as soft tissue of the pleon, mouthparts, gills, and setation. Reconstructions of soft tissue were sometimes possible, depending on individual sample and scanning characteristics. The raw data of seven scans are publicly available for download from the GigaDB repository. Calcified body parts visualized from μCT data can aid taxonomic validation and provide additional, virtual deposition of rare specimens. The use of a nondestructive, nonstaining μCT approach for taxonomy, reconstructions of soft tissue structures, microscopic spines, and setae depend on species characteristics. Constrained to these limitations, the presented dataset can be used for future morphological studies. However, our virtual specimens will be most valuable to taxonomists who can download a digital avatar for 3D examination. Simultaneously, in the event of physical damage to or loss of the original physical specimen, this dataset serves as a vital insurance policy.

Late revision or correction of facial trauma-related soft-tissue deformities.

PubMed

Rieck, Kevin L; Fillmore, W Jonathan; Ettinger, Kyle S

2013-11-01

Surgical approaches used in accessing the facial skeleton for fracture repair are often the same as or similar to those used for cosmetic enhancement of the face. Rarely does facial trauma result in injuries that do not in some way affect the facial soft-tissue envelope either directly or as sequelae of the surgical repair. Knowledge of both skeletal and facial soft-tissue anatomy is paramount to successful clinical outcomes. Facial soft-tissue deformities can arise that require specific evaluation and management for correction. This article focuses on revision and correction of these soft-tissue-related injuries secondary to facial trauma. Copyright © 2013. Published by Elsevier Inc.

The influence of fiber orientation on the equilibrium properties of neutral and charged biphasic tissues.

PubMed

Nagel, Thomas; Kelly, Daniel J

2010-11-01

Constitutive models facilitate investigation into load bearing mechanisms of biological tissues and may aid attempts to engineer tissue replacements. In soft tissue models, a commonly made assumption is that collagen fibers can only bear tensile loads. Previous computational studies have demonstrated that radially aligned fibers stiffen a material in unconfined compression most by limiting lateral expansion while vertically aligned fibers buckle under the compressive loads. In this short communication, we show that in conjunction with swelling, these intuitive statements can be violated at small strains. Under such conditions, a tissue with fibers aligned parallel to the direction of load initially provides the greatest resistance to compression. The results are further put into the context of a Benninghoff architecture for articular cartilage. The predictions of this computational study demonstrate the effects of varying fiber orientations and an initial tare strain on the apparent material parameters obtained from unconfined compression tests of charged tissues.

General Information about Childhood Soft Tissue Sarcoma

MedlinePlus

... Soft Tissue Sarcoma Treatment (PDQ®)–Patient Version General Information About Childhood Soft Tissue Sarcoma Go to Health ... the PDQ Pediatric Treatment Editorial Board . Clinical Trial Information A clinical trial is a study to answer ...

General Information about Adult Soft Tissue Sarcoma

MedlinePlus

... Soft Tissue Sarcoma Treatment (PDQ®)–Patient Version General Information About Adult Soft Tissue Sarcoma Go to Health ... the PDQ Adult Treatment Editorial Board . Clinical Trial Information A clinical trial is a study to answer ...

High thermal conductivity in soft elastomers with elongated liquid metal inclusions

PubMed Central

Bartlett, Michael D.; Powell-Palm, Matthew J.; Huang, Xiaonan; Sun, Wenhuan; Malen, Jonathan A.; Majidi, Carmel

2017-01-01

Soft dielectric materials typically exhibit poor heat transfer properties due to the dynamics of phonon transport, which constrain thermal conductivity (k) to decrease monotonically with decreasing elastic modulus (E). This thermal−mechanical trade-off is limiting for wearable computing, soft robotics, and other emerging applications that require materials with both high thermal conductivity and low mechanical stiffness. Here, we overcome this constraint with an electrically insulating composite that exhibits an unprecedented combination of metal-like thermal conductivity, an elastic compliance similar to soft biological tissue (Young’s modulus < 100 kPa), and the capability to undergo extreme deformations (>600% strain). By incorporating liquid metal (LM) microdroplets into a soft elastomer, we achieve a ∼25× increase in thermal conductivity (4.7 ± 0.2 W⋅m−1⋅K−1) over the base polymer (0.20 ± 0.01 W⋅m−1·K−1) under stress-free conditions and a ∼50× increase (9.8 ± 0.8 W⋅m−1·K−1) when strained. This exceptional combination of thermal and mechanical properties is enabled by a unique thermal−mechanical coupling that exploits the deformability of the LM inclusions to create thermally conductive pathways in situ. Moreover, these materials offer possibilities for passive heat exchange in stretchable electronics and bioinspired robotics, which we demonstrate through the rapid heat dissipation of an elastomer-mounted extreme high-power LED lamp and a swimming soft robot. PMID:28193902

Antifungal Efficacy and the Mechanical Properties of Soft Liners against Candida albicans after the Incorporation of Garlic and Neem: An In vitro Study

PubMed Central

Kumar, Seenivasan Madhan; Kumar, V. Anand; Natarajan, Parathasarthy; Sreenivasan, Gayathri

2018-01-01

Objectives: To evaluate the in vitro growth inhibition of Candida albicans, in the soft-liner material and Shore A hardness from resin-based denture soft lining materials modified by neem or garlic incorporation. Materials and Methods: Resin discs were prepared with poly methyl methacrylate (PMMA) and soft liners incorporated with varying concentrations of neem or garlic. For antifungal activity, resin discs were placed on agar plates inoculated with C. albicans and were evaluated after 2, 4, and 7 days using the streaking method. The hardness of the PMMA was evaluated with the use of Shore A at 2, 4, and 7 days. Data were statistically processed by SPSS software (IBM Company, Chicago, USA) using Kruskal–Wallis test, and post hoc comparisons were done using Dunn's test. P <0.05 was considered statistically significant. Results: Neem and garlic added to PMMA soft liner had an inhibitory effect on C. albicans. Both the neem and garlic when added showed positive results against C. albicans when compared to the control group. The soft liner hardness increased statistically by time but not for the different plant extract concentrations. Conclusions: Within the limitations of this in vitro study, it was found that neem and garlic can be used as an additive to tissue conditioner to reduce the adherence of C. albicans without significantly affecting the hardness of the heat-polymerized acrylic resin. PMID:29911057

[Reconstruction of facial soft tissue defects with pedicled expanded flaps].

PubMed

Yangqun, Li; Yong, Tang; Wen, Chen; Zhe, Yang; Muxin, Zhao; Lisi, Xu; Chunmei, Hu; Yuanyuan, Liu; Ning, Ma; Jun, Feng; Weixin, Wang

2014-09-01

To investigate the application of pedicled expanded flaps for the reconstruction of facial soft tissue defects. The expanded skin flaps, pedicled with orbicularis oculi muscle, submental artery, the branch of facial artery, superficial temporal artery, interior upper arm artery, had similar texture and color as facial soft tissue. The pedicled expanded flaps have repaired the facial soft tissue defects. Between Jan. 2003 to Dec. 2013, 157 cases with facial soft tissue defects were reconstructed by pedicled expanded flaps. Epidermal necrosis happened at the distal end of 8 expanded flaps, pedicled with interior upper arm artery(4 cases), orbicularis oculi muscle(3 cases) and submental artery(1 case), which healed spontaneously after dressing. All the other flaps survived completely with similar color and inconspicuous scar. 112 cases were followed up for 8 months to 8 years. Satisfactory results were achieved in 75 cases. 37 cases with hypertrophic scar at incisions need secondary operation. Island pedicled expanded flap with similar texture and color as facial soft tissue is suitable for facial soft tissue defects. The facial extra-incision and large dog-ear deformity could be avoided.

Differential diagnosis between benign and malignant soft tissue tumors utilizing ultrasound parameters.

PubMed

Morii, Takeshi; Kishino, Tomonori; Shimamori, Naoko; Motohashi, Mitsue; Ohnishi, Hiroaki; Honya, Keita; Aoyagi, Takayuki; Tajima, Takashi; Ichimura, Shoichi

2018-01-01

Preoperative discrimination between benign and malignant soft tissue tumors is critical for the prevention of excess application of magnetic resonance imaging and biopsy as well as unplanned resection. Although ultrasound, including power Doppler imaging, is an easy, noninvasive, and cost-effective modality for screening soft tissue tumors, few studies have investigated reliable discrimination between benign and malignant soft tissue tumors. To establish a modality for discrimination between benign and malignant soft tissue tumors using ultrasound, we extracted the significant risk factors for malignancy based on ultrasound information from 40 malignant and 56 benign pathologically diagnosed soft tissue tumors and established a scoring system based on these risk factors. The maximum size, tumor margin, and vascularity evaluated using ultrasound were extracted as significant risk factors. Using the odds ratio from a multivariate regression model, a scoring system was established. Receiver operating characteristic analyses revealed a high area under the curve value (0.85), confirming the accuracy of the scoring system. Ultrasound is a useful modality for establishing the differential diagnosis between benign and malignant soft tissue tumors.

X-ray Phase Contrast Allows Three Dimensional, Quantitative Imaging of Hydrogel Implants

DOE PAGES

Appel, Alyssa A.; Larson, Jeffrey C.; Jiang, Bin; ...

2015-10-20

Three dimensional imaging techniques are needed for the evaluation and assessment of biomaterials used for tissue engineering and drug delivery applications. Hydrogels are a particularly popular class of materials for medical applications but are difficult to image in tissue using most available imaging modalities. Imaging techniques based on X-ray Phase Contrast (XPC) have shown promise for tissue engineering applications due to their ability to provide image contrast based on multiple X-ray properties. In this manuscript we describe results using XPC to image a model hydrogel and soft tissue structure. Porous fibrin loaded poly(ethylene glycol) hydrogels were synthesized and implanted inmore » a rodent subcutaneous model. Samples were explanted and imaged with an analyzer-based XPC technique and processed and stained for histology for comparison. Both hydrogel and soft tissues structures could be identified in XPC images. Structure in skeletal muscle adjacent could be visualized and invading fibrovascular tissue could be quantified. In quantitative results, there were no differences between XPC and the gold-standard histological measurements. These results provide evidence of the significant potential of techniques based on XPC for 3D imaging of hydrogel structure and local tissue response.« less

Interaction of high intensity focused ultrasound with biological materials

NASA Technical Reports Server (NTRS)

Bar-Cohen, Y.; Mal, A.; Feng, F.; Kabo, M.; Wang, J.

2002-01-01

This work is motivated by the possible medical application of focused ultrasound in minimally invasive treatment of a variety of disorders including those associated with soft tissue or disk element disruption in the vicinity of the spine causing impingement on the spinal cord.

Mineralized soft-tissue structure and chemistry in a mummified hadrosaur from the Hell Creek Formation, North Dakota (USA).

PubMed

Manning, Phillip L; Morris, Peter M; McMahon, Adam; Jones, Emrys; Gize, Andy; Macquaker, Joe H S; Wolff, George; Thompson, Anu; Marshall, Jim; Taylor, Kevin G; Lyson, Tyler; Gaskell, Simon; Reamtong, Onrapak; Sellers, William I; van Dongen, Bart E; Buckley, Mike; Wogelius, Roy A

2009-10-07

An extremely well-preserved dinosaur (Cf. Edmontosaurus sp.) found in the Hell Creek Formation (Upper Cretaceous, North Dakota) retains soft-tissue replacement structures and associated organic compounds. Mineral cements precipitated in the skin apparently follow original cell boundaries, partially preserving epidermis microstructure. Infrared and electron microprobe images of ossified tendon clearly show preserved mineral zonation, with silica and trapped carbon dioxide forming thin linings on Haversian canals within apatite. Furthermore, Fourier transform infrared spectroscopy (FTIR) of materials recovered from the skin and terminal ungual phalanx suggests the presence of compounds containing amide groups. Amino acid composition analyses of the mineralized skin envelope clearly differ from the surrounding matrix; however, intact proteins could not be obtained using protein mass spectrometry. The presence of endogenously derived organics from the skin was further demonstrated by pyrolysis gas chromatography mass spectrometry (Py-GCMS), indicating survival and presence of macromolecules that were in part aliphatic (see the electronic supplementary material).

Mineralized soft-tissue structure and chemistry in a mummified hadrosaur from the Hell Creek Formation, North Dakota (USA)

PubMed Central

Manning, Phillip L.; Morris, Peter M.; McMahon, Adam; Jones, Emrys; Gize, Andy; Macquaker, Joe H. S.; Wolff, George; Thompson, Anu; Marshall, Jim; Taylor, Kevin G.; Lyson, Tyler; Gaskell, Simon; Reamtong, Onrapak; Sellers, William I.; van Dongen, Bart E.; Buckley, Mike; Wogelius, Roy A.

2009-01-01

An extremely well-preserved dinosaur (Cf. Edmontosaurus sp.) found in the Hell Creek Formation (Upper Cretaceous, North Dakota) retains soft-tissue replacement structures and associated organic compounds. Mineral cements precipitated in the skin apparently follow original cell boundaries, partially preserving epidermis microstructure. Infrared and electron microprobe images of ossified tendon clearly show preserved mineral zonation, with silica and trapped carbon dioxide forming thin linings on Haversian canals within apatite. Furthermore, Fourier transform infrared spectroscopy (FTIR) of materials recovered from the skin and terminal ungual phalanx suggests the presence of compounds containing amide groups. Amino acid composition analyses of the mineralized skin envelope clearly differ from the surrounding matrix; however, intact proteins could not be obtained using protein mass spectrometry. The presence of endogenously derived organics from the skin was further demonstrated by pyrolysis gas chromatography mass spectrometry (Py-GCMS), indicating survival and presence of macromolecules that were in part aliphatic (see the electronic supplementary material). PMID:19570788

Surface Modification of Dental Titanium Implant by Layer-by-Layer Electrostatic Self-Assembly

PubMed Central

Shi, Quan; Qian, Zhiyong; Liu, Donghua; Liu, Hongchen

2017-01-01

In vivo implants that are composed of titanium and titanium alloys as raw materials are widely used in the fields of biology and medicine. In the field of dental medicine, titanium is considered to be an ideal dental implant material. Good osseointegration and soft tissue closure are the foundation for the success of dental implants. Therefore, the enhancement of the osseointegration and antibacterial abilities of titanium and its alloys has been the focus of much research. With its many advantages, layer-by-layer (LbL) assembly is a self-assembly technique that is used to develop multilayer films based on complementary interactions between differently charged polyelectrolytes. The LbL approach provides new methods and applications for the surface modification of dental titanium implant. In this review, the application of the LbL technique to surface modification of titanium including promoting osteogenesis and osseointegration, promoting the formation and healing of soft tissues, improving the antibacterial properties of titanium implant, achieving local drug delivery and sustained release is summarized. PMID:28824462

Childhood Soft Tissue Sarcoma Treatment (PDQ®)—Health Professional Version

Cancer.gov

Pediatric soft tissue sarcomas are a heterogenous group of malignant tumors that originate from primitive mesenchymal tissue and account for 7% of all childhood tumors. Get detailed information about clinical presentation, diagnosis, prognosis, and treatment of newly diagnosed and recurrent soft tissue sarcoma in this summary for clinicians.

Influence of storage methods on the surface roughness of tissue conditioners.

PubMed

Hong, Guan; Li, YingAi; Maeda, Takeshi; Mizumachi, Wataru; Sadamori, Shinsuke; Hamada, Taizo; Murata, Hiroshi

2008-03-01

The purpose of this study was to compare the influence of three kinds of storage methods on surface roughness of tissue conditioners. Four commercial tissue conditioners (GC Soft Liner, Softone, Fictioner, and Hydro-Cast) were used in this study. Five samples of each material were stored in distilled water, air, and a denture cleanser (Polident). Mean surface roughness (R(a)) values of dental stone casts made from the tissue conditioners were measured after 0, 1, 3, 7, and 14 days of immersion using a profilometer. Significant differences in the R(a) values of the specimens were found among the three storage methods. The values of R(a) significantly increased with increase in immersion time for each storage method, except for the materials stored in air. It was found that the materials stored in air showed the most stable and lowest values of R(a). Results obtained suggested that a tissue conditioner exhibited smooth and minimal change in surface roughness with time when stored in air than in distilled water and denture cleanser.

Decomposition of Fuzzy Soft Sets with Finite Value Spaces

PubMed Central

Jun, Young Bae

2014-01-01

The notion of fuzzy soft sets is a hybrid soft computing model that integrates both gradualness and parameterization methods in harmony to deal with uncertainty. The decomposition of fuzzy soft sets is of great importance in both theory and practical applications with regard to decision making under uncertainty. This study aims to explore decomposition of fuzzy soft sets with finite value spaces. Scalar uni-product and int-product operations of fuzzy soft sets are introduced and some related properties are investigated. Using t-level soft sets, we define level equivalent relations and show that the quotient structure of the unit interval induced by level equivalent relations is isomorphic to the lattice consisting of all t-level soft sets of a given fuzzy soft set. We also introduce the concepts of crucial threshold values and complete threshold sets. Finally, some decomposition theorems for fuzzy soft sets with finite value spaces are established, illustrated by an example concerning the classification and rating of multimedia cell phones. The obtained results extend some classical decomposition theorems of fuzzy sets, since every fuzzy set can be viewed as a fuzzy soft set with a single parameter. PMID:24558342

Decomposition of fuzzy soft sets with finite value spaces.

PubMed

Feng, Feng; Fujita, Hamido; Jun, Young Bae; Khan, Madad

2014-01-01

The notion of fuzzy soft sets is a hybrid soft computing model that integrates both gradualness and parameterization methods in harmony to deal with uncertainty. The decomposition of fuzzy soft sets is of great importance in both theory and practical applications with regard to decision making under uncertainty. This study aims to explore decomposition of fuzzy soft sets with finite value spaces. Scalar uni-product and int-product operations of fuzzy soft sets are introduced and some related properties are investigated. Using t-level soft sets, we define level equivalent relations and show that the quotient structure of the unit interval induced by level equivalent relations is isomorphic to the lattice consisting of all t-level soft sets of a given fuzzy soft set. We also introduce the concepts of crucial threshold values and complete threshold sets. Finally, some decomposition theorems for fuzzy soft sets with finite value spaces are established, illustrated by an example concerning the classification and rating of multimedia cell phones. The obtained results extend some classical decomposition theorems of fuzzy sets, since every fuzzy set can be viewed as a fuzzy soft set with a single parameter.

Equivalence between short-time biphasic and incompressible elastic material responses.

PubMed

Ateshian, Gerard A; Ellis, Benjamin J; Weiss, Jeffrey A

2007-06-01

Porous-permeable tissues have often been modeled using porous media theories such as the biphasic theory. This study examines the equivalence of the short-time biphasic and incompressible elastic responses for arbitrary deformations and constitutive relations from first principles. This equivalence is illustrated in problems of unconfined compression of a disk, and of articular contact under finite deformation, using two different constitutive relations for the solid matrix of cartilage, one of which accounts for the large disparity observed between the tensile and compressive moduli in this tissue. Demonstrating this equivalence under general conditions provides a rationale for using available finite element codes for incompressible elastic materials as a practical substitute for biphasic analyses, so long as only the short-time biphasic response is sought. In practice, an incompressible elastic analysis is representative of a biphasic analysis over the short-term response deltat

Potential biomedical applications of ion beam technology

NASA Technical Reports Server (NTRS)

Banks, B. A.; Weigand, A. J.; Babbush, C. A.; Vankampen, C. L.

1976-01-01

Electron bombardment ion thrusters used as ion sources have demonstrated a unique capability to vary the surface morphology of surgical implant materials. The microscopically rough surface texture produced by ion beam sputtering of these materials may result in improvements in the biological response and/or performance of implanted devices. Control of surface roughness may result in improved attachment of the implant to soft tissue, hard tissue, bone cement, or components deposited from blood. Potential biomedical applications of ion beam texturing discussed include: vascular prostheses, artificial heart pump diaphragms, pacemaker fixation, percutaneous connectors, orthopedic pros-thesis fixtion, and dental implants.