Karyology of Abramis brama in the southern waters of Caspian sea

The karyology of bream (Abramis brama) were done for the first time in Iran. This study was conducted on chromosomal number, chromosome arms and karyotyping of bream from the -Southern part of the Caspian Sea with preparing chromosomal extensions on the base of Squash method. The number of metaphase plates using Squash method on renal and gill tissues was determined as to be 2n=50 and the number of chromosome arms was NF=82. The prepared karyotype of this species was consisted of 8 pairs of metacentric, 8 pairs of submetacentric and 9 pairs of acrocentric chromosomes

Gene 18s rRNA variation of cuttlefish population (Sepia pharaonis) in the Persian Gulf and the Oman Sea using PCR-RFLP method

We used PCR-RFLP method to identify cuttlefish (Sepia pharaonis) populations in the Persian Gulf and the Sea of Oman. Bottom trawling method was used to collect a range of 20 to 40 specimens from each 15 stations in the study area. Genomic DNA was extracted by phenol-chloroform method and one pair primer was designed for the analysis based on 1 Ss rRNA gene nucleotide sequences. A PCR product with 502 pair bases in length was obtained for all specimens and subjected to digestion by eight restriction enzymes Alui, Tacit, MO, Rsal, Hinalli, Dral, Prull and Mien DNA banding, patterns in all specimens were similar and no polymorphism was detected among them. We conclude that cuttlefish populations cannot be isolated using 18s rRNA gene extracts in the area of study

A microfluidic electroosmotic mixer and the effect of potential and frequency on its mixing efficiency

This paper presents the design and numerical simulation of a T-shape microfluidic electroosmotic micromixer. It is equipped with six microelectrodes that are embedded in the side surfaces of the microchannel. The electrode array consists of two sets of three 20 &Acirc;&iquest;m and 60 &Acirc;&iquest;m microelectrodes arranged in the form of two opposing triangles. Numerical analysis of electric potential and frequency effects on mixing efficiency of the micromixer is carried out by means of two sets of simulations. First, the electric potential is kept at 2 V while the frequency is varied within 10-50 Hz. The highest achieved mixing efficiency is 96% at 22 Hz. Next, the frequency is kept at 30 Hz whilst the electric potential is varied within 1-5 V. The best achieved mixing efficiency is 97% at 3 V.<br /

Identification and molecular analysis of mercury resistant bacteria in Kor River, Iran

Mercury (Hg) is one of the most important toxic pollutants widespread in the environment. It is being extensively used in industrial applications (chlor-alkali electrolysis, fungicides, disinfectants, dental products, etc), resulting in local hot spots of pollution and serious effects on biota and humans. The aim of this study was to identify mercury resistant bacteria and extract their plasmids and DNA. In this study, mercury-resistant bacteria were isolated and characterized from mercury-polluted sediments in Kor River in Iran. The samples were cultured in different media cultures, identified using biochemical tests, and due to the relationship between antibiotic and mercury resistance, they were isolated based on these two factors. The plasmids and DNA were extracted from the most resistant bacteria to both antibiotic and mercury and the sizes were determined using agarose gel electrophoresis. A 12.3 Kb plasmid from Serattia sp. and Escherichia coli and using Sau3A1 enzyme, some DNA fragments (4, 6, 8 and 10 Kb) from Pseudomonas sp., Serattia sp. and Escherichia coli were also extracted.Key words: Mercury, resistant, bacteria, DNA, plasmid extraction, restriction endonuclease

Chemiluminescent response of grass carp (Ctenopharyngodon idella) following exposure to sublethal concentrations of diazinon

Chemiluminescent response of grass carp (Ctenopharyngodon idella) was assessed to determine the effect of various concentrations of diazinon on the phagocytosis of grass carp in order to evaluate the fish immunity after exposure to this toxic chemical. One hundred and twenty specimens with individual weight of 850±155g were exposed to various concentrations of diazinon at 1, 2 and 4mg/L provided as a bath for 12 hours at 20±2°C in Institute of the Caspian Sea Ecology, Sari in 2003. Maximal values of spontaneous chemiluminescent responses (SCL) were found in all experimental fish only on days 1 and 7 post-exposing to the toxicant compared to control one (p0.05). Generally, the level of chemiluminescent response activated by zymosan (CRAZ) at all concentrations of toxicant were significantly higher than control group after 1, 7, 15, 30 and 45 days post-exposure to the toxicant (p<0.05)

Experimental investigation and finite element analysis for the study of residual stresses in roller burnished components

Burnishing is a surface modification process, which involves plastic deformation of the material at the surface of the component due to the application a highly polished and hard roller, under pressure. This results in the improvement of the surface finish of the component and induces residual compressive stresses on the surface of the component. The present work deals with the optimization of the burnishing force for the best surface finish, at constant speed and feed, for Aluminium and Mild steel workpieces. A 3dimensional finite element model is proposed for the simulation of the burnishing process, and the analysis is carried out at the optimum force determined experimentally. The induced compressive stress in the components is determined from the finite element analysis and this value is then compared with the results obtained from X-ray diffraction technique.<br /

Determination of diazinon LC50 in grass carp (Cetenopharyngodon idella) and the effect of sublethal concentration of toxin on some hematological and biochemical indices

Toxicity of the organophosphate, diazinon was studied in grass carp (Cetenopharyngodon idella) weighing 5±1.0g, under static water quality condition at 16°C. Also, some hematological and biochemical variables of fish weighing 50±5.0g were studied 12 hours post-exposing fish to the toxicant at sublethal concentration of 5.6mg/L at 16°C. Values of 18.19, 17.21, 16.68, and 15.13mg/L, were obtained as LC50 after 24, 48, 72 and 96 hours post-exposing fish to the toxicant, respectively. Levels of red blood cells (RBC), hematocrit (PCV), hemoglobin (Hb), mean corpuscular hemoglobin concentration (MCHC), leukocyte count (WBC), lymphocyte and monocyte were significantly lower in the exposed fish than control fish (p0.05). The obtained results show that although diazinon can be classified as a slight toxic chemical for grass carp, the toxicant negatively affects some immunophysiological functions of the fish including immunocompent cells

A case for an international consortium on system-of-systems engineering

A system-of-systems (SoS) conceptualization is essential in resolving issues involving heterogeneous independently operable systems to achieve a unique purpose. Successful operation as an SoS requires communication among appropriate individuals and groups across enterprises through an effective protocol. This paper presents a position on the creation of a consortium of concerned system engineers and scientists worldwide to examine the problems and solutions strategies associated with SoS. The consortium could lead efforts in clarifying ambiguities and in seeking remedies to numerous open questions with respect to SoS analysis, SoS engineering (SoSE), as well as differences between systems engineering (SE) and SoSE. The mission of this consortium is envisioned to: 1) act as a neutral party; 2) provide a forum to put forth Calls to Action; and 3) establish a community of interest to recommend a set of solutions. <br /

Unified selective sorting approach to analyse multi-electrode extracellular data

Extracellular data analysis has become a quintessential method for understanding the neurophysiological responses to stimuli. This demands stringent techniques owing to the complicated nature of the recording environment. In this paper, we highlight the challenges in extracellular multi-electrode recording and data analysis as well as the limitations pertaining to some of the currently employed methodologies. To address some of the challenges, we present a unified algorithm in the form of selective sorting. Selective sorting is modelled around hypothesized generative model, which addresses the natural phenomena of spikes triggered by an intricate neuronal population. The algorithm incorporates Cepstrum of Bispectrum, ad hoc clustering algorithms, wavelet transforms, least square and correlation concepts which strategically tailors a sequence to characterize and form distinctive clusters. Additionally, we demonstrate the influence of noise modelled wavelets to sort overlapping spikes. The algorithm is evaluated using both raw and synthesized data sets with different levels of complexity and the performances are tabulated for comparison using widely accepted qualitative and quantitative indicators