OBJECTIVE To investigate the biosynthetic response of elderly human femoral head articular cartilage to mechanical stimulation in vitro and its variation with site. METHOD Full-depth cartilage biopsies of articular cartilage were removed from defined sites on 10 femoral heads from patients aged 68-95 years. Cartilage explants were subjected to either static or cyclic (2s on/2s off) loading in...

The assessment of response of composite seismic force resisting systems requires accurate nonlinear formulations for the composite members. In this work, reporting the first phase of a NEES project, a three-dimensional distributed plasticity formulation is presented for both circular and rectangular composite concrete-filled steel tubes (CFTs) that includes new constitutive models for the concr...

In contrast to nailed connections, little research has been done on bolted connections using a reversed cyclic loading scheme, although cyclic loading provides important information about energy absorption and damping properties, which is essential when analyzing seismic performance. Dowrick (1986) noted that the hysteretic characteristics for the primary connection of a subassembly govern its ...

The safety of lifelines, as the most important urban facilities, under different conditions highly depends on the safe design and performance of these buried structures. This cannot be achieved unless their actual behaviors are well understood and considered at the designing stage. A new physical model was developed in Amirkabir University of Technology to study the behavior of buried pipes und...

OBJECTIVES Microbial leakage through the implant-abutment (I-A) interface results in bacterial colonization in two-piece implants. The aim of this study was to compare microleakage rates in three types of Replace abutments namely Snappy, GoldAdapt, and customized ceramic using radiotracing. MATERIALS AND METHODS Three groups, one for each abutment type, of five implants and one positive and o...

Cranial sutures are unique to skull bones and consist of multiple connective tissue cell lineages such as mesenchymal cells, fibroblast-like cells, and osteogenic cells, in addition to osteoclasts. Mechanical modulation of intramembranous bone growth in the craniofacial suture is not well understood, especially during postnatal development. This study investigated whether in vivo mechanical for...

Abstract: Reduced Beam Section (RBS) and Drilled Beam Section (DBS) are seismic moment resistant frame connections, introduced after 1994 Northridge earthquake. RBS connection has been tested under cyclic loading and showed acceptable performance. In this paper, seismic behavior of Drilled Beam Section (DBS) connection is studied numerically using finite element method. A drilled beam section ...

BACKGROUND Cumulative trauma disorder is commonly reported by workers engaged in prolonged repetitive/cyclic occupational activities. Recent experimental evidence confirms that relatively short periods of cyclic lumbar flexion at high loads result in substantial creep of viscoelastic tissues, prolonged periods of its recovery to baseline together with a neuromuscular disorder and exposure to in...

BACKGROUND We compared different plates in an experimental calcaneal fracture model under biocompatible loading. METHODS Four plates were tested: a plate without locked screws (Synthes), and three different plates with locked screws (Newdeal, Darco, Synthes). Synthetic calcanei (Sawbone) were osteotomized to create a fracture model, and the plates were fixed onto them. Seven specimens for eac...

The energy absorption of concrete filled, hollow-steel bracing was analyzed respect to geometric and mechanical parameters including the width-to-thickness section ratio, slenderness level, and strength of the steel and concrete. Local buckling and ductility were also investigated with respect to variation in the cross-section. The infill increased the compression resistance, even after multipl...