the national bridge stock of iran consists of about 330,000 bridges, of which around 50% are older than 30 years. since 2010, iran road maintenance & transportation organization has started implementing a comprehensive bridge management system in order to manage this aged stock efficiently. to predict future conditions of bridge stock, a heuristic numerical method is presented. this methodology...

1Department of Genetics, University of Georgia, Athens, Georgia 30602; 2NMFS/ CZES, Genetics, 2725 Montlake Boulevard East, Seattle, Washington 98112; 3Savannah River Ecology Laboratory, Drawer E, Aiken, South Carolina 29801; ~Department of Microbiology and Immunology, School of Medicine, University of California, Los Angeles, California 90024; -SSchool of Veterinary Medicine, Virginia Tech Uni...

Bacterial conjugation normally involves the unidirectional transfer of DNA from donor to recipient. Occasionally, conjugation results in the transfer of DNA from recipient to donor, a phenomenon known as retrotransfer. Two distinct models have been generally considered for the mechanism of retrotransfer. In the two-way conduction model, no transfer of the conjugative plasmid is required. The es...

Oscillators are kernel components of electrical and electronic circuits. Discussion of history, mechanisms and design based on Barkhausens observation. Discussion of a Wien Bridge oscillator based on the question: Why does this circuit oscillate ?

Chromatin architecture is regulated through both enzymatic and non-enzymatic activities. For example, the Polycomb Group (PcG) proteins maintain developmental gene silencing using an array of chromatin-based mechanisms. The essential Drosophila PcG protein, Posterior Sex Combs (PSC), compacts chromatin and inhibits chromatin remodeling and transcription through a non-enzymatic mechanism involvi...

objective: leishmaniasis is one of the significant causes of morbidity and mortality in several countries. it is an important problem in endemic areas such as iran. the goal in treatment of leishmaniasis is to reduce the disease period and leave no evidence of any remaining scars or lesions. a derivative of artemisinin is artemether. scientists believe that the strong action of artemether again...

Ring-structured DNA and RNA exhibit a variety of unique features in chemistry, biology, medicine, material science, so on, which cannot be accomplished by their non-cyclic counterparts. In this review, both naturally occurring DNA/RNA rings artificially synthesized ones have been comprehensively covered, mainly to bridge these two growing fields. the first part, structures functions (extrachrom...

Excessive accumulation of DNA damage will generate chromosome stress, leading to various chromosome abnormalities such as chromatin bridge and result in genomic instability. Orchestra procession and regulation of DNA damage repair are vital for keeping genome stability. Despite of the key role of HDAC1/2 in double strand break (DSB) repair, the regulation for their mode of action is less well u...