Nucleus replacement technologies are a minimally invasive alternative to spinal fusion and total disc replacement that have the potential to reduce pain and restore motion for patients with degenerative disc disease. Finite element modeling can be used to determine the biomechanics associated with nucleus replacement technologies. The current study focuses on a new nucleus replacement device de...

background and aims. the present study evaluated the most common reasons for replacing amalgam restorations in a university clinic. materials and methods. a total of 217 restorations which needed to be replaced were clinically and radiographically evaluated in a period of 4 months. the frequencies of reasons for replacing amalgam restorations were calculated: the assessed items included recurre...

age replacement policy is concerned with finding an optional time tominimize the cost, at which time the unit is replaced even if itdoes not fail. so far, age replacement policy involving random agehas been proposed. this paper will assume the age of the unit is anuncertain variable, and find the optimal time to replace the unit.

background & aim: repair or replacement of restorations is one of the main necessities for health promotion. however, it has its own physical, psychological and economical side effects. the aim of this study was to investigate the prevalence of factors causing restoration replacement or repair. methods & materials: a non probable sampling was used for this cross – sectional observational descri...

a greenhouse experiment was conducted to evaluate the competitive effects of different densities of wild mustardas against rapeseed. the experiment was performed in a randomized complete block design with four replicationsusing replacement series in which wild mustard and rapeseed were respectively planted in different ratios of 4:0, 3:1,2:2, 1:3 and 0:4 plants per pot. results indicated that t...

background total correction of tetralogy of fallot (tof) anomaly in early childhood has been practiced in many centers with good results, but in some of patients after few years sever pulmonary valve insufficiency occurred. materials and methods at a cross- sectional study from january 2015 to january 2016, 10 patients who had history of primary repair of tof with free pulmonary insufficiency (...

conversion of knee arthrodesis to total knee arthroplasty is a difficult procedure accompanied by many complications due to soft tissue and extensor mechanism contracture and bone defects. we report two cases of distal femur osteosarcoma that had been undergone wide resection arthrodesis initially. arthrodesis was converted to total knee arthroplasty with hinged prosthesis after many years. we ...

mucopolysaccharidoses are a group of rare mostly autosomal recessive metabolic and genetic disorders. because of the high rate of consanguinity, they are not uncommon in our population. clinical diagnosis is not difficult for experienced physicians, but it is not enough for treatment and prevention measures in the future pregnancies. so, it is necessary to detect the type of mps by measurement ...

This thesis develops integer linear programming models for and studies the complexity of problems in the areas of maintenance optimization and location–routing. We study how well the polyhedra defined by the linear programming relaxation of the models approximate the convex hull of the integer feasible solutions. Four of the papers consider a series of maintenance decision problems whereas the ...