The marked effect which minute amounts of tissue and of yeast extracts have upon the growth of organisms has long been known, but the chemical composition of these organic substances, one or more of which are required by many organisms for growth, has been determined only during the past ten years. The determination of the chemical structure of these substances has made it possible to grow many...

phosphorus is an essential element for plants. much of the agricultural lands of iran has calcareous soils, in which, due to high ph, phosphorous availability is less, therefore, it appears as a limiting factor for plant growth. application of biofertilizers instead of chemical ones has gained attention in order to produce healthy crops, reduce pollution of soil and water resources by reducing ...

one of the possible threats in increasing use of nanomaterials is the emergence of toxicity in humans and other animals which is discussed in nanotoxicology. in addition to toxic effects of nanomaterials themselves, different chemical precursors which are usually used in bottom-up approaches for production of nanomaterials may have secondary toxic effects in living organisms. in contrast, less ...

In this study, silver nanoparticles were synthesized by chemical reduction method at different concentrations of Ag colloid in the range of 500-16000 ppm. Nanoparticles were deposited by spin coating method on pre-etched glass and Si substrates. Structural, optical and electrical properties of the samples were studied using Scanning Electron Microscopy equipped with EDAX, UV-Vis spectroph...

sediment core samples can provide useful information about aquatic environment. sedimentation rate, climate changes and heavy metal concentration are among the most important studies that are carried out on sediment cores. in this study, a sediment core of 70cm with aim of metal concentration investigation is collected from central part of the zarivar lake in the vicinity of the marivan city in...

zhumeria majdae is a rare an endemic medicinal plantspecies grown wild in iran. the hydro distilled essential aerial part oil of z. majdae analysed by gc–ms. thirty-one compounds representing 95.36% of the aerial part oil, respectively, were identified, of which linalool (48.14%), camphor (20.71%), limonene (4.83%), trans-linalool oxide (2.69%), 3-octanone (2.34%), terpinene-4-ol (2.30%), camph...

the transformation of biochemical information into a physical or chemical signal is the basic idea behind a biosensor. the efficient detection of charged biomolecules by biosensor with appropriate device has caught tremendous research interest in the present decade. the present work is related to the simulation study of the performance of a functionalized surface of a biologically sensitive fie...