abstract amino acids are building blocks of proteins, and play a vital role in living beings existence and their functionality. the interaction of these compounds with metal ions is of great importance to biochemists, and chemists, because their functions can be utilized as a model in understanding enzymes mechanism for transport of metal ions to tissues. among twenty essential amino acids w...

in this thesis, a new optically active poly(amide-imide) (pai) was synthesized by the indirect polycondensation reaction of the l-phenylalanine based diacid chloride and 4,4?-diaminodiphenylether in the presence of triethylamine in n-methyl-2-pyrrolidone. the formation of pai was confirmed by ftir, 1h nmr and elemental analysis. in next step, the surface of titanium dioxide (tio2) nanoparticles...

in this thesis, we consider a mathematical model of cancer with completely unknown parameters. we study the stability of critical points which are biologically admissible. then we consider a control on the system and introduce situations at which solutions are attracted to critical points and so the cancer disease has auto healing. the lyapunov stability method is used for estimating the un...

the aim of the present study was to investigate the frequency and the type of discourse markers used in the argumentative and expository writings of iranian efl learners and the differences between these text features in the two essay genres. the study also aimed at examining the influence of the use of discourse markers on the participants’ writing quality. to this end the discourse markers us...

the subjects of the study are only the tefl teachers and students at gilan university. to obtain the desired data, a questionnaire which was based on the theories and disecussions gathered, was used as the main data gathering instrument. to determine the degree of relationship between variables, covariance and pearson product moment correlation coefficient were the formulas applied. the data we...

the aim of the present study was to determine the in?uence of presence or absence of corpus luteum (cl) on hormonal and metabolites composition of follicular ?uid (ff) harvested from different sized follicles and its relationship with blood serum concentrations in sanjabi ewes. ovaries and blood samples were collected from 60 clinically healthy adult ewes (sanjabi breed) 1–3 years of age in dio...

within communicative, interactive, and learner-centered framework of language teaching and learning, students need to learn four skills of listening, speaking, reading, and writing for their educational success. but of all the language skills, reading enjoys a paramount significance in so many second or foreign language academic contexts. in spite of its importance, language learners still have...

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...

for any educational program to be successful, many factors work hand in hand. based on pervious efl studies, teachers and learners are the keys to gain achievement. granted the fact that explicit and implicit practice plays a key role in education, knowledge of it can help teachers facilitate students’ vocabulary learning. this study investigated to determine the contribution of explicit and i...

abstract: about 60% of total premium of insurance industry is pertained?to life policies in the world; while the life insurance total premium in iran is less than 6% of total premium in insurance industry in 2008 (sigma, no 3/2009). among the reasons that discourage the life insurance industry is the problem of adverse selection. adverse selection theory describes a situation where the inf...