modern research physics

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Halophilic bacteria can not growth without NaCl and they have optimum growth in high salinity media. Halobacteria are chemoorganotroph and the most species are aerobic. Bacteriorhodopsin is a light driven proton pump that found only in halobacteria. In this study H. salinarum that isolated in previous research from saline environment in Iran were used for isolation of purple membrane. The method of Yucel et al (1995) was applied for isolation of purple membrane of H. salinarum. The stages of this method include dialysis and centrifuge at high speed. Spectrophotometery analysis at 560 nm and absorbance ratio 280/560 nm were used for conform the purity of purple membrane. The activity of purple membrane was assayed as change of pH in salt solution contains MgCl2 and KCl. By using of microwave radiation apparatus the ability of microwave absorbance were measured. The result of isolation of purple membrane indicated that the 280/560 absorbance ratio in this spectrum was 3/3 that confirm the purity of purple membrane. Extracted purple membrane from 4 liter of culture media was 35 milligram. This extracted PM could decrease of pH (0.15 units per 6 hours) and absorb 60 % of microwave radiation. In conclusion there is very diversity between halophilic archaea in Iran ecosystem and extracted PM is favorable for nanotechnology application

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Light is one of the most important environmental factors in fish life. The effect of photoperiod on the growth performances and survival of rainbow trout (Oncorhynchus mykiss) larvae and fingerlings was investigated in two consecutive experiments. In both experiments fishes were exposed to four treatments (24L/0D, 16L/8D, 8L/16D, 0L/24D) (light: dark, L: D) in three replicates. The results of first experiment indicated that photoperiod affected on the growth performances in larval stage of rainbow trout. The best weight gain and specific growth rate was observed in 24L: 0D and 16L: 8D without significant differences between them and the lowest rates was achieved in 0L: 24D. Also in second experiment, the effect of photoperiod on the growth performances was significant difference and the highest growth rate and specific growth rate was observed in 8L: 16D and the lowest in 24L: 0D and 0L: 24D. Our results showed that the effect of photoperiod in rainbow trout depends to developmental stage and larvae unlike fingerlings have better growth in long light phases.

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In this article, tunneling resonance (transmission coefficient, current density and negative differential resistance) has been studied for Al_x Ga_1-x As / GaAs triangular double quantum wells. Time dependent Schrodinger equation has been used for triangular quantum wells structures accompanied with Airy function. Transmission and reflection coefficients before and after applying external electrical field were obtained for two symmetrical triangular quantum well in terms of effective mass approximation as a function of structural  parameters such as well width, barrier width, well depth and applied voltage. Results showed a negative differential resistance at this kind of quantum wells.

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In this paper, the Mutiple Multipoles method is employed to solve nonlinear eigenvalue problem and calculate band structure for a 2D photonic crystal. Band structure is calculated for both TE and TM polarizations. Simulation space is implemented for the first Brillouin zone by using physical properties such as rods radius, permittivity and susceptibility. To model fields inside and outside of object, Multipole centers were located around it and Bessel series inside the object is shown complex fields. We used Bloch theory to implement fictitious periodic boundary conditions for the first Brillouin zone. To validate the code, we simulated the band structure of a cubic lattice and compare the results with Plane Wave Expansion Method which illustrates the accuracy of the code. It is shown that this method can be applied to investigate photonic crystals with irregular shapes and different materials for different lattices such as cubic, trigonal and honeycomb. Furthermore it could be used for dielectric or dispersive material and experimental data. Numerical calculation shows that MMP method is accurate, fast and it can be used on Personal Computers.

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            Inverse time - dependent heat source   problems have an important role in many branches
     of science and  technology. The aim of this paper is to solve these classes of problems using a 
     variational  iteration  method(VIM). The method applied does not require discretization  of the
      region, as in the case  of classical methods based on the finite difference method,  the boundary
     element method  or the other methods.  Applying this method, we obtain a stable approximation
      to an  unknown source term  in an inverse heat equation   from  over-specified data  that the  source
      term is only time - dependent.  Some numerical examples using this approach are presented and
     discussed

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The present work was an attempt to investigate the parameters which can affect the process of hydrogel formation in the presence of ultrasound. These parameters were concentration of the reactants (monomers and cross linker), the reaction medium (solvent, ionic strength, and pH), and acoustic parameters (power and pulse). The monomers were acrylic acid and acrylamide, and the cross linker was methylene bis acrylamide. The experiments were performed at a constant temperature of 37 °C. Pulsed power ultrasound was irradiated to the reaction mixture from the tip of a probe system. The results showthatultrasonic irradiation significantly reduces the reaction time and increases efficiency. Additionally, increasing glycerol in the solution changes the viscosity of the reaction for the better and increases the reaction rate. However, ionic strength and pH were not significantly effective in this respect. Results  showed  that ultrasonic acrylic  hydrogel  are sensitive to pH and temperature. Therefore, these  hydrogels is capable for rapid drug absorption and release according to porosity in their structure. These findings provide a better understanding of hydrogel synthesis and enable us to control the pertinent parameters.

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    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 &beta-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 and may be used as new drug supplements in the future.

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Department of Chemistry, Takestan Branch, Islamic Azad University, Takestan, Iran High frequency sound wave, ultrasound, is widely used to facilitate chemical reactions, especially in the polymerization reactions.This paper reports a study which synthesized acrylic hydrogel in the presence of ultrasonic irradiation (20-kHz, power 80%, pulse 8) in a water/glycerol medium. Acrylic acid (AA) and acrylamide (AAm) were used as acrylic monomers, and methylene bisacrylamide (MBA) as the crosslinker. The experiments were performed at a constant temperature of 37 °C. It was found that hydrogel formation is faster in the presence of ultrasound than in its absence. In addition, FT-IR, UV-Vis, and SEM spectroscopy showed that the hydrogel synthesized ultrasonically has a higher swelling capacity and a more uniform and porous structure. It was also discovered that hydrogel formation speeds up at higher quantities of glycerol. However, an increase in crosslinker concentration proved ineffective although it changed the appearance of the hydrogel. The method proposed in this research can be used in the synthesis of biomedical materials and in the development of drug delivery systems.

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Abstract
Mesquite is one of the invasive, problematic and noxious weeds and special warm and dry areas. This plant in recent years due to high resistance to drought stress level in the vast agricultural lands and orchards spread. Management so it is very important. The following studies were conducted in plant protection of weed research Department Research Institute of during the years 2010: 1- Effect of constant temperature on germination that including 5, 10, 15, 18, 20, 25, 30, 35 and 40° C independent dark and independent light conditions 2- Effect of temperature fluctuations on seed germination: 0/10, 10/20 and 20/30° C 3- Effect of planting depth seed on seed germhnation. All experiments were conducted with 4 replications. mesquite seeds showed no dormancy when detachment from mother plant. Seed germination was strongly influenced by temperature. Light did not play a crucial role on seed germination of this weed. Therefore mesquite seeds were not photoblastic and temperature fluctuations did not increase seed germination of mesquite. The above characteristics are very important in making mesquite an invasive weed. Having precise information of these traits enables us to a better management and control of this troublesome weed.
Keyword: Prosopis farcta, seed germination, seed dormancy, constant and fluctuating temperature, planting depth.

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Microbial analysis of ground water, as a solely supplying water sources must be evaluated in many areas. Because of the treatment of water always cannot remove all pathogenic bacteria which are leaked from domestic wastewater, bacterial survey of Bojnourd groundwater sources were carried out in this study. For this reason, membrane filter (MF) technique and Most Probably Number (MPN) methods were used to evaluate the quality of the water. Escherichia coli (E. coli) and Enteroccocus faecalis (E. faecalis) were traced as excremental indices. E. coli was detected from three out of six stations and E. faecalis was only isolated from one of stations. Although molecular techniques are very rapid and exact technique for detection of microbial community and are able to identify Viable But Not Cultivable bacteria (VBNC) but are unable to distinct live and dead microorganisms. By using standard technique it is possible to study live microorganisms. It can be concluded that both E.coli and E.feacalis was detected in some stations. The sanitization of groundwater must be revised to less the microbial population in this groundwater.

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In the North of Bam city there were extensive volcanism and outcrops are basic and felsic volcanic rocks that crosscut by various dykes The volcanic rocks have sub alkaline and calc-alkaline to shoshonitic characteristic, however dykes are alkaline and potassic in nature. In the spider diagram all samples show enrichment in the LILEs and depletion and troughs in the HFSs elements that coincide with subduction related and upper crust rocks features. The studied samples represent enrichment in the LREE with various (La/Yb)N ratio and rhyolites show clear trough in Eu. According to geochemical features, studied rocks generated from different sources. Trachy andesy basalts and trachy andesites formed from 1-10% partial melting of metasomatized spinal lherzolite source. Dacitic magma generated from partial melting of mafic source in the lower crust while rhyolites formed from partial melting of metagreywacke source. The olivine basaltic and basaltic dykes generated from less than 1% and 3-5% partial melting of metasomatized garnet- spinel- bearing lherzolitic mantle source, respectively. Eocene volcanism in the Bam area has been occurred during subduction of Neo-Tethys oceanic crust beneath central Iran in the continental volcanic arc tectonic setting.

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The Almabulage complex is located in the Sanandaj-Sirjan structural zone, NW of Hamadan. This complex consists of low-grade metamorphic rocks, and two intrusions of felsic and mafic rocks. In this research, we have studied the mafic intrusion. The intrusion has ophitic, subophitic and inter-granular textures and is mainly composed of plagioclase, clinopyroxene, amphibole and minor amounts of K-feldspar, quartz and opaque minerals. Secondary minerals include epidote, chlorite and amphiboles formed in the rim of clinopyroxene. Clinopyroxene is of augite type, amphibole is tschermakite, plagioclase is in the range of andesine-labradorite, k-feldspar is anorthoclase and the opaque mineral is ilmenite. According to the bulk rock geochemistry and mineral chemistry of clinopyroxene, the mafic intrusion of the Almabulage complex has been crystallized from a calc-alkaline magma and is related to subduction area. The element Nb displays distinctive negative anomalies compared to the primitive mantle, which can suggest subduction-related magmatism. Emplacement temperatures and pressure of mafic rocks shown by pyroxene-amphibole thermometer and amphibole barometer indicate temperature and pressure ranges of 750 to 900 °C and 6 to 7 kbar, respectively.
Based on Sm/Yb and La/Sm rations, the parental melt of the mafic rocks of the Almabulage complex, derived from partial melting of garnet–spinel lherzolite. According to the bulk rock geochemistry and mineral chemistry of mafic rocks, the rocks formed in a subduction area during Late Jurassic-Early Cretaceous before the Neo-Tethys closure in Sanandaj- Sirjan zone.