JOURNAL OF SCIENCE (KHARAZMI UNIVERSITY)
Year:2014 | Volume:14 | Issue:3|Papers Count:8

In the present study, we investigated DC conduction mechanism of electron beam evaporated Bromoaluminium phthalocyanine (BrAlPc) thin films using aluminum and gold electrodes. The current-voltage characteristics of sandwich type device are evaluated for the temperature range 298-413K under dark conditions. It is observed that the current passing through the device is increased by increasing temperature at the same voltage in the range of 0-6v. It is found that at lower voltages about 0 to 2v, the current–voltage characteristics demonstrate Ohmic behavior, while the space charge limited current (SCLC) becomes apparent at higher voltages about 2 to 6v, which is restricted by single discrete trapping level. We obtained more than one linear region in the temperature dependence of electrical conductivity. Also, the values of charge carrier mobility and the activation energy of device are evaluated.

The aim of this study was to estimate Specific Absorption Rate (SAR) induced in human head tissues, by assuming human head as a cubical model filled with lossy dielectric material and exposed to electromagnetic plane waves. The research is carried out by computational simulation using C programming codes. The numerical technique used in this study was Finite Difference in Time Domain (FDTD) method, along with Perfectly Matched Layer (PML) as an appropriate absorbing boundary condition. Different conditions including exposure conditions as well as physical parameters are employed, in order to compare the results to the past literature. Finally, the penetration depth of one of the specified models is expressed by means of interpolation. The results which are in complete agreement with the others in some cases, suggests that considering the biological tissues as dispersive media, would result in correct estimations; whereas changing in the structure of the model, doesn’t differ if precise predictions are not important. Furthermore, the penetration depth correlation to frequency is in line with what is expressed in theoretical papers.

The concept of rotundity is not far from differentiability. There are several papers in the literature devoted to the study of relations between rotundity and smoothness in Banach spaces. In this paper, we study new relations between some kinds of rotundity and smoothness in Banach spaces. In particular, we investigate relations between one kind of rotundity, which is called strongly very rotund, and very smoothness, in Banach spaces. A Banach space is rotund if the midpoint of every two distinct points of unit sphere is in the open unit ball of the Banach space. A Banach space X is smooth if its norm is Gateaux differentiable at every non-zero point of the space and it is very smooth if the norm is very Gateaux differentiable, that is, the second dual norm in the second dual of X is Gateaux differentiable at every non zero point of  X.

In this paper rationalized Haar (RH) functions method is applied to approximate the numerical solution of the fractional Volterra integro-differential equations (FVIDEs). The fractional derivatives are described in Caputo sense. The properties of RH functions are presented, and the operational matrix of the fractional integration together with the product operational matrix is used to reduce the computation of FVIDEs into a system of algebraic equations. By using this technique for solving FVIDEs computation time is low. Numerical examples are given to demonstrate application of the presented method with RH functions base.

The methanol extracts of leaves and bulbs of Allium ampeloprasum L. (Alliaceae) were analyzed for their phenolic profiles and screened for their antioxidant and antibacterial activities. Two biochemical assays, namely DPPH free radical scavenging and  b -caroten/linoleic acid activity systems, were used to evaluate antioxidant activity. Total phenol and flavonoid contents of the species were determined by Folin-Ciocalteu and AlCl3 assays, respectively. Results indicated that the extracts are different in total phenolic content. Results from antioxidant activity showed that the extracts studied in DPPH radical scavenging assay are lower active than ascorbic acid and BHT as synthetic antioxidants. Antibacterial assay showed that the bulbs extract is more effective in inactivation of Haemophilus influenzae and Bacillus cereus and the leaves extract is more effective in inactivation of Bacillus cereus at 100 mg ml-1 than others. Then, the extracts of Allium ampeloprasum possess strong antioxidant activity.

Caryophyllaceae Juss. is a large family. The center of its distribution is in the Mediterranean region and adjoining parts of Europe, and in Western and Central Asia. The family has been divided into three subfamilies (Bittrich 1993). Genus Cerastium L. belongs to the subfamily of Alsinoideae Fenzl. This genus is classified into two subgenera and three sections in Flora Iranica area. The aim of this paper is to describe a new record and to compare it with its close relative based on morphology and micromorphology of seed and pollen. During a revision of the genus Cerastium in Iran, Cerastium pentandrum (L.) was identified as a new record according to Moschl (1988). Cerastium pentandrum is reported from Northwestern Iran and the Iranian plateau. It belongs to subgen. Cerastium sect. Orthodon Ser. Morphological characteristics, as well as a full description and distribution of the new record are provided. This taxon is compared with its closest relative C. balearicum Hermann. The ultrastructure of seed and pollen is examined by SEM.

Periwinkle (Catharanthus roseus L.) is one of the most important medicinal plants that is commonly used for its anticancer alkaloids. In this investigation, the effects of different tryptophan concentrations (0, 150, 250 and 350 mg/l) on in vitro regeneration conditions were studied. The regeneration of different explants on different tryptophan-free media compositions showed that the best media for growing nodal segments explants was MS medium containing (BAP, 0.5 mg/l)+(NAA, 1 mg/l). However, the rooting media composition was determined as half MS medium supplemented with (IBA, 0.1 mg/l). After adding tryptophan into this optimal medium, the maximum shooting and rooting percentages were obtained with 250 and 350 mg/l tryptophan, respectively. Furthermore, the measurement of shoot and root length, dry and fresh weight of shoot, fresh weight of root, chlorophyll a and carotenoid content and also, soluble sugars content of shoot and root, revealed that the best medium was in the presence of 350 mg/l tryptophan, while the maximum amount of root dry weight and chlorophyll b were obtained by 250 mg/l tryptophan containing medium. Finally, the analysis of total proteins content of shoot and root showed a significant difference between all groups and higher content of proteins for shoots and roots was observed in 250 mg/l and 350 mg/l tryptophan, respectively.