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An ultrafine-grained nickel material is stronger and more thermally stable than previously reported materials of this kind. [Also see Report by Liu et al. ] Ultrafine-grained (UFG) materials with grain sizes below 1 µm have been a subject of extensive investigation over the past two decades because of their unusual properties, including resistance to wear, fracture strength, and resistance to corrosion even at high temperatures. On page 337 of this issue, Liu et al. ( 1 ) report a UFG material with a nanolaminated structure. The hardness and thermal stability of this material exceeds that of other known UFG materials. To produce the material, the authors apply a very high-rate shear deformation with high strain gradients to the top surface layer of a pure bulk nickel rod, thereby inducing the formation of two-dimensional nanometer-thick laminated structures. The resulting material has gradients in both geometrical grain structure and mechanical properties and also shows high thermal stability.

Muscle structure is an essential component in typical computational models of the musculoskeletal system. Almost all musculoskeletal models represent muscle geometry using a set of line segments. The straight-line approach limits models’ ability to accurately predict the paths of muscles with complex geometry. This approach needs knowledge of how the muscle changes shape and interacts with fundamental structures like muscles, bones, and joints that move. Moreover, the moment arms are supposed to be equivalent to all the fibers in the muscle. This study aims to create a shoulder musculoskeletal model that includes complex muscle geometries. We reconstructed the shape of fibers in the entire volume of six muscles adjacent to the shoulder using an automated technique. This method generates many fibers from the surface geometry of the skeletal muscle and its attachment areas. Highly discretized muscle representations for all muscles were created and used to simulate different shoulder movements. The moment arms of each muscle were calculated and validated against cadaveric measurements and models of the same muscles from the literature. We found that simulations using the developed musculoskeletal models generated more realistic geometries, which expands the physical representation of muscles compared to line segments. The shoulder musculoskeletal model with complex muscle geometry is created to increase the anatomical reality of models and the lines action of muscle fibers, and to be used for finite element investigations.

The development of advanced materials for biomedical implants has made significant progress in the search for biomaterials with functional surfaces which enhance compatibility, prevent implant corrosion, and reduce the growth of microorganisms in the form of biofilms. This article reviews various materials used in implants, among which yttria-stabilized zirconia (YSZ) and hydroxyapatite (HAp) stand out due to their unique properties which favor osseointegration. Additionally, strategies for doping with additional elements, notably the addition of silver for its antimicrobial properties, are highlighted. Different methods of coating implant surfaces with these materials are evaluated. Finally, it is concluded that multilayer coating systems [YSZ/HAp-Ag]n significantly improve corrosion resistance, biocompatibility, and the ability to inhibit bacterial proliferation in implants. Implementing these implant coatings could increase their durability and effectiveness in biomedical applications, contributing to better integration into bone tissue and reducing postoperative infections.

The development of advanced materials for biomedical implants has made significant progress in the search for biomaterials with functional surfaces which enhance compatibility, prevent implant corrosion, and reduce the growth of microorganisms in the form of biofilms. This article reviews various materials used in implants, among which yttria-stabilized zirconia (YSZ) and hydroxyapatite (HAp) stand out due to their unique properties which favor osseointegration. Additionally, strategies for doping with additional elements, notably the addition of silver for its antimicrobial properties, are highlighted. Different methods of coating implant surfaces with these materials are evaluated. Finally, it is concluded that multilayer coating systems [YSZ/HAp-Ag]n significantly improve corrosion resistance, biocompatibility, and the ability to inhibit bacterial proliferation in implants. Implementing these implant coatings could increase their durability and effectiveness in biomedical applications, contributing to better integration into bone tissue and reducing postoperative infections.

This paper aims to construct a general framework of coupling tumor–bone remodeling processes in order to produce plausible outcomes of the effects of tumors on the number of osteoclasts, osteoblasts, and the frequency of the bone turnover cycle. In this document, Komarova’s model has been extended to include the effect of tumors on the bone remodeling processes. Thus, we explored three alternatives for coupling tumor presence into Komarova’s model: first, using a “damage” parameter that depends on the tumor cell concentration. A second model follows the original structure of Komarova, including the tumor presence in those equations powered up to a new parameter, called the paracrine effect of the tumor on osteoclasts and osteoblasts; the last model is replicated from Ayati and collaborators in which the impact of the tumor is included into the paracrine parameters. Through the models, we studied their stability and considered some examples that can reproduce the tumor effects seen in clinic and experimentally. Therefore, this paper has three parts: the exposition of the three models, the results and discussion (where we explore some aspects and examples of the solution of the models), and the conclusion.

Due to their elastomeric behavior, polyurethane-based scaffolds can find various applications in soft-tissue engineering. However, their relatively inert surface has to be modified in order to improve cell colonization and control cell fate. The present study focuses on porous biodegradable scaffolds based on poly(ester-urea-urethane), functionalized concomitantly to the scaffold elaboration with low-molecular-weight (LMW) fucoidan; and their bio-activation with platelet rich plasma (PRP) formulations with the aim to promote cell response. The LMW fucoidan-functionalization was obtained in a very homogeneous way, and was stable after the scaffold sterilization and incubation in phosphate-buffered saline. Biomolecules from PRP readily penetrated into the functionalized scaffold, leading to a biological frame on the pore walls. Preliminary in vitro assays were assessed to demonstrate the improvement of scaffold behavior towards cell response. The scaffold bio-activation drastically improved cell migration. Moreover, cells interacted with all pore sides into the bio-activated scaffold forming cell bridges across pores. Our work brought out an easy and versatile way of developing functionalized and bio-activated elastomeric poly(ester-urea-urethane) scaffolds with a better cell response.

Abstract Bone loss can occur as a result of various pathologies, traumas and injuries and poor bone healing leads to functionally debilitating condition, loss of self-sufficiency and deterioration in life quality. Given the increasing incidence of facial trauma and the emergence of new procedural techniques, advanced scaffolds are currently developed as substitutes for bone tissue engineering. In this study, we investigated the capability of a chemically cross-linked ε-caprolactone-based poly(ester-urethane-urea) (PCLU) scaffold to support bone regeneration. In vitro assays demonstrated that PCLU scaffolds could be colonized by cells through direct cell seeding and cell migration from outside to scaffold inside. Moreover, PCLU scaffolds could provide a suitable environment for stem cells proliferation in a 3D spatial arrangement, and allowed osteogenic differentiation under appropriate induction. In vivo results revealed the osteogenic properties of PCLU scaffolds through a drilled-hole femoral bone defect repair improvement in rats. Using histology and microtomography analysis, we showed that PCLU scaffolds fit well the bone cavity and were eventually entrapped between the newly formed trabeculae. Finally, no sign of inflammation or rejection was noticed. We envision that PCLU scaffolds can provide the clinicians with a substitute having appropriate characteristics for the treatment of bone defects.

The present work tries to make an attempt to improve previous work which offers a simple but effective way to construct satisfied predicating model. Indeed, recent work due to Peng et al. [13] and dealing with a two-step homogenization scheme is revisited here by introducing an iterative process which allows us to take into account differently the porosity of the elastic media. Several homogenization schemes (dilute, Mori-Tanaka, self-consistent ...) are presented and compared with experimental data. One can say that the current approach provides reasonably accurate predictions for the effective moduli of multiphase composites without using the n parameter as proposed by Peng et al. [13]