introduction: the aim of the present in vitro study was to evaluate the efficacy of d-race, protaper retreatment kit and hand h-files in removal of obturating materials (om) from the curved root canals using cone-beam computed tomography (cbct). materials and methods: sixty extracted molars were prepared and obturated. the samples were divided into three groups ( n =20). in each group the om wa...

The theory of inhomogeneous analytic materials is developed. These are materials where the coefficients entering the equations involve analytic functions. Three types of analytic materials are identified. The first two types involve an integer p. If p takes its maximum value, then we have a complete analytic material. Otherwise, it is incomplete analytic material of rank p. For two-dimensional ...

Materials have central roles in all fields of engineering; they define, through structures and devices, our interfaces to the physical and the virtual world. The emergence of new materials catalyzes transformative advances in civilizations, to an extent that eras of human development are often defined by the prevailing materials used in engineered systems, from the Stone, Bronze, and Iron Ages ...

Life is a specific characteristic of our planet. The diversity of life, biodiversity, is one of the most fascinating phenomena. We know some 1.8 million different species, but all extrapolations show that probably 20 million or more species exist: We know less than 10% of the plants, animals and micro-organisms living on the planet Earth. The editors, who are both biologists, are well acquainte...

Unequal Opportunity: Learning to Read in the U.S.A. Jill Sunday Bartoli. 1995.

The label semiconductor itself provides a hint as to its characteristics. The prefix semis normally applied to a range of levels midway between two limits. The term conductor is applied to any material that will support a generous flow of charge when a voltage source of limited magnitude is applied across its terminals. An insulator is a material that offers a very low level of conductivity und...

Composite materials may be restricted to emphasize those materials that contain a continuous matrix constituent that binds together and provides form to an array of a stronger, stiffer reinforcement constituent. The resulting composite material has a balance of structural properties that is superior to either constituent material alone. Combining the advantages of inorganic and organic componen...

background the importance of preserving and maintaining printed materials is crucial for the libraries. fungi play the main role in destroying wood and paper. objectives this research aimed to study and identify threatening fungal agents of library resources in isfahan university of medical sciences. materials and methods this is a descriptive analytical study. 126 samples were collected and ex...