Formation of non bonded organic layer around inorganic particles like iron sulfide and zeolites, was hypothesized as starting point for one of the possible mechanisms of the origin of life on earth. In this study, the general circumstances needed for creation of such organic layer was investigated. An aliphatic hydrocarbon (hexane), an aromatic hydrocarbon (toluene), an alcohol (n-octanol) and ...

Bachgroun: Hematopoietic stem cell derived from umbilical cord blood (UCB) has been used for regenerative medicine in hematological abnormalities. MicroRNAs are important regulators of gene expression that control both physiological and pathological processes such as development of tissue and cancer. Some studies have shown that miR-33, has a critical role in control of self-renewal cells. He...

roadmap is a strategic plan that describes the steps an organization needs to take to achieve stated outcomes and goals in different layers and these layers are closely related to each other. lower layer are more important in planning processes. acquisition layer is one of the most crucial layers in road mapping process. today there are some international organizations that do policy making and...

introduction the aim of this study was to compare the smear layer removal efficacies of 3% sodium hypochlorite (naocl), 17% ethylenediaminetetraacetic acid (edta), smearclear and biopure mtad using a common irrigation protocol. materials and methods: fifty freshly extracted human single rooted maxillary and mandibular teeth were prepared by a protaper rotary system up to an apical preparation f...

introduction: the purpose of this study was to determine the effects of citrus aurantifolia (ca) extract on smear layer removal in different parts of root canals. materials and methods: thirty-nine single-rooted human teeth were randomly divided into three experimental ( n =12) and one control ( n =3) groups. teeth were instrumented using mtwo rotary instruments. root canals were irrigated with...

introduction: the production of smear layer during canal instrumentation is thought to increase coronal microleakage even after canal obturation. previous studies have shown that the type of irrigant does not necessarily affect the seal of the obturation. our study aimed to evaluate the effect of three irrigation solutions (mtad, citric acid and edta/naocl) on the coronal microleakage of root c...

introduction: controversial results have been reported when organic acids, ultrasonic instruments and laser techniques were used to remove smear layer in endodontic treatments. the aim of this study was to evaluate the effect of removing debris and smear layer by er,cr:ysgg laser irradiation on the apical leakage of retrograde cavities. materials and methods: in this ex vivo study, 24 extracted...

introduction: the aim of this study was to compare the sealing ability of real seal (rs) and gutta-percha (gp). materials and methods: forty nine extracted human maxillary central incisors were used. the coronal part of each tooth was removed; the root canal was prepared using the crown down technique and apical enlargement to rotary file # 40. the specimens were randomly divided in to 3 groups...