Abstract Due to assembly, wear and manufacturing errors clearance in the joints are inevitable. When is introduced into a mechanical system, impact force joint will cause undesirable vibration of system. In this paper, dynamic responses system with two revolute studied using computational experimental methodology. The considered as constraint. normal contact tangential friction between journal bearing modeled nonlinear model considering energy loss modified Coulomb coefficient, respectively....

Clearances in joints are unavoidable due to assemblage, manufacturing errors and wear, which will lead poor dynamic performances undesirable vibrations impact forces clearance joints. In dynamics analysis of planar mechanical system, it is usually assumed that the revolute joint with radial clearance. However, axial translational ignored. fact, even systems may exhibit out-of-plane motion misalignments. this work, a slider-crank mechanism used as example investigate effects mixed clearances...

To investigate the role of microRNA-145 (miR-145) in steroid-induced necrosis femoral head (SINFH) by evaluating its effects on OPG/RANK/RANKL signaling pathway.A rat model SINFH was constructed via injection lentiviral vector pLV-shRNA-miR-145. Pathological observation performed tartrate-resistant acid phosphatase (TRAP) staining, and serum OPG levels were detected ELISA. The mRNA expression miR-145, OPG, RANK RANKL THP-1 cells assessed RT-PCR, protein western blotting.The miR-145...

Clearances in the joints of real mechanisms are unavoidable due to assemblage, manufacturing errors, and wear. The dual-axis driving positioning mechanism is one kind space actuating for satellite antenna implement precise guidance positioning. However, dynamics analysis control system, it usually assumed that revolute joint system perfect without clearances or imperfect with planar radial clearance. axial clearance an always ignored. In this work, considered as a 3D spatial both clearances....

Titanium (Ti) and its alloys are widely used as metallic biomaterials for fabrication of dental orthopedic implants due to their favorable biocompatibility corrosion resistance in a body environment. However, the thin oxide layer (TiO2) on Ti substrate formed naturally air or many aqueous environments is bioinert surrounded by fibrous tissues without producing any chemical biological bond bone when implanted. In present work, Zinc-incorporated porous TiO2 coatings (Zn–TiO2) were prepared...

Sericin, a silk protein, has high potential for use as an extracellular matrix in tissue engineering applications. In this study, novel gelatin (GEL) and sericin (SS) were incorporated with polyvinyl alcohol) PVA hydrogel nanocomposite (GEL-SS-PVA) scaffold that can be applied to repair cartilage. Glutaraldehyde was used cross-linking agent, hydrochloric acid acting initiator. The microstructure characteristics of the obtained GEL-SS GEL-SS-PVA scaffolds also examined using FTIR XRD spectra...

An analytical technique, namely the homotopy analysis method (HAM), is applied to solve periodic solutions for superharmonic resonances of nonlinear oscillations with parametric excitation.Unlike perturbation methods, HAM does not depend on any small physical parameters at all.Thus, it valid both weakly and strongly problems.Besides, different from all other analytic techniques, provides us a simple way adjust control convergence region series solution by means an auxiliary parameter h.In...

The purpose of this study was to investigate the association g.27667T>A genetic variant in osteoprotegerin (OPG) gene with bone mineral density (BMD) and osteoporosis. A total 393 primary osteoporosis subjects 402 healthy controls were recruited. BMD femoral neck hip, lumbar spine (L2-4), hip evaluated by Norland XR-46 dual-energy X-ray absorptiometry. genotyped using created restriction site-polymerase chain reaction. Our data indicated significant differences among different genotypes....

Objective To observe the effect of hyperbaric oxygen (HBO) therapy on bone ingrowth into porous implant in a rabbit model avascular necrosis femoral head induced by dexamethasone. Methods Thirty-two New Zealand rabbits were subject to intramuscular injection dexamethasone twice week for 8 weeks.Then,rabbits divided 4 groups:control group,HBO group,recombinant human morphogenetie protein-2 (rhBMP-2) group and HBO + rhBMP-2 randomly.The femurs control implanted with bare implants,while...

To investigate the effectiveness of meshy fascia encapsulating cancellous bone graft in repair defect after limb fractures.

Objective To explore the feasibility and effect of autogenous cancellous bone graft wrapped by femoral fascia in treatment upper limb defects. Methods From June 2011 to December 2016, 12 patients with defects were treated wrapping internal fixation. Bone defect site: 3 cases humerus, 5 radius, 4 ulna. The length ranged from 2.5 6.0 cm, an average 4.0 cm. Results Delayed wound healing occurred 1 case complications 2 cases. All follow-up for 36 months 19 months. union all...

Objective To compare the effects of bone transport versus induced membrane technique for large segmental tibial defects. Methods The clinical data were analyzed retrospectively 89 patients with defect who had been treated at Department Orthopaedics, Wuxi No.9 People's Hospital from June 2005 to February 2017 using or technique. They 58 males and 31 females, aged 13 74 years (average, 38.0 years). The group 59 cases 30 cases. 2 groups compared in terms preoperative general...

Abstract Modern spacecraft usually has large deployment structure, which consisting of plenty joints could produce undesirable dynamic responses when considering clearances in and driving input fluctuation. However, the performance analysis space mechanism, fluctuation are always ignored. In this study, a flexible planar scissor-like truss mechanism with imperfect joint clearance investigated using computational methodology. First, mathematic model is established. The revolute considered as...