objective: the objective of this study was to investigate the invitro fluoride release of four new self-adhesive resin cements; set (sdi, australia), breeze (pentron, usa), embrace wetbond (pulpdent, usa), g-cem (gc, japan) and to assess the bonding performance of these self-adhesive resin cements for bonding of orthodontic brackets. materials and methods: for fluoride release experiment, six ...

this study purported to compare and contrast the use of self-mention and evidentials as two mtadiscourse features in opinion columns of persian and english newspapers. the theoretical basis of this study is the idea that metadiscourse features vary across cultural boundaries. for this purpose, 150 persian and 150 english opinion columns were collected based on three factors of topic, audience a...

introduction acetic acid bacteria are large group of obligate aerobic gram negative bacteria with the ability to oxidize ethanol to acetic acid (1). they are widely distributed in natural habitats and classified in family acetobacteraceae. members of this family are useful in industrial production of vinegar(2). acetic acid bacteria (aab) can use substrates as glucose, ethanol, lactate or glyc...

Early flowering and frost in native genotypes are among causes of reduction in almond production in most years. Therefore, a proper understanding of the resistance mechanisms is necessary for developing varieties with high quality and resistant to frost. In this research, four different genotypes were selected out of 40 genotypes based on flowering time and resistance to frost, including late f...

the main objective in sampling is to select a sample from a population in order to estimate some unknown population parameter, usually a total or a mean of some interesting variable. a simple way to take a sample of size n is to let all the possible samples have the same probability of being selected. this is called simple random sampling and then all units have the same probability of being ch...

In this study, Cannabis plants with different ploidy levels were compared in some growth and biochemical parameters. Tetraploid and mixoploid plants were achieved from previous experiment. Flow cytometry analysis was used to confirm the ploidy level. As a result, root and shoot fresh weight showed a significant increase in tetraploid plants compared to the diploid ones. Chimers showed a sig...

boron nitride semiconducting zigzag swcnt, $b_{cb}$$n_{cn}$$c_{1-cb-cn}$, as a potential candidate for making nanoelectronic devices was examined. in contrast to the previous dft calculations, wherein just one boron and nitrogen doping configuration have been considered, here for the average over all possible configurations, density of states (dos) was calculated in terms of boron and nitrogen ...

until now many studies have been done over recent decades throughout the world to show the right age to start english. in iran, research is still at an early stage in terms of evaluating teachers’ beliefs about teaching children english. the problem of at what age to start teaching english and how to teach english to elementary school children has not been solved neither in this country nor els...

Pennyroyal (Mentha pulegium L.) from the Lamiaceae family is a medicinal plant which has great antioxidant properties. Environmental stresses such as drought can result in changes in the activity of antioxidant enzymes and the content of some biochemical factors in plants. In this investigation, the effects of drought stress on the activity of supe-roxide dismutase, ascorbate peroxidase, catala...