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Search Results: 1 - 10 of 149706 matches for " H;Mehdinia "
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Origin, transfer and distribution of cantharidin-related compounds in the blister beetle Hycleus scabiosae
Nikbakhtzadeh, MR;Vahedi, M;Vatandoost, H;Mehdinia, A;
Journal of Venomous Animals and Toxins including Tropical Diseases , 2012, DOI: 10.1590/S1678-91992012000100011
Abstract: cantharidin provides chemical protection for the coleopteran families meloidae and oedemeridae. in the present study, it was observed that cantharidin concentration in hycleus scabiosae was slightly decreased from mated females (mean = 0.011 mg/mg of dry weight) to males (mean = 0.010 mg/mg) and considerably diminished in relation to virgin females (mean = 0.005 mg/mg). significant concentrations of palasonin (21.69 ng/mg among virgins and 17.49 ng/mg in mated females) and palasoninimide (14.62 ng/mg in virgins and 9.17 ng/mg in mated females) were found in h. scabiosae. palasonin, palasoninimide and cantharidinimide content of eggs were measured as 5.61, 7.69 and 7.80 ng/mg respectively. surprisingly, males showed no trace of cantharidin-related compounds (crcs); therefore crcs in h. scabiosae could not be transferred from males to females and based on experiments employing its deuterated form, cantharidin is probably independently synthesized in females from the male nuptial transfer. an inseminated female incorporates about 38.5 ng of cantharidin (0.34% of the maternal content), 196.35 ng of palasonin (91.82% of maternal content) and 269.15 ng of palasoninimide (96.70% maternal content) into each egg mass during oviposition. it seems that eggs of this meloid species exploit a different array of protective chemicals by increasing the ratio of crcs versus cantharidin. crcs are less toxic than cantharidin; therefore, such compounds might have been deposited in eggs as a safer substitute for cantharidin to provide effective protection, but does not simultaneously harm the susceptible embryo.
Determination of Amitraz in the Honey Samples by Dispersive Liquid-Liquid Microextraction Followed by Gas Chromatography—Flame Ionization Detection  [PDF]
Mostafa Bashiri-Juybari, Ali Mehdinia, Ali Jabbari, Yadollah Yamini
American Journal of Analytical Chemistry (AJAC) , 2011, DOI: 10.4236/ajac.2011.25072
Abstract: Dispersive liquid-liquid microextraction (DLLME) followed by gas chromatography–flame ionization detection (GC-FID), as a simple, rapid and efficient method, was developed for the determination of amitraz in honey samples. This method involves the use of an appropriate mixture of the extraction and disperser solvents for the formation of a cloudy solution in 5.0 mL aqueous sample containing amitraz. After extraction, phase separation was performed by centrifugation and the concentrated amitraz in the sedimented phase was determined by gas chromatography—flame ionization detection (GC-FID). Some important parameters such as the type and volume of extraction and disperser solvents, and the effect of pH and salt on the extraction recovery of amitraz were investigated. Under the optimum conditions (13 µL of carbon tetrachloride as an extraction solvent, 1 mL of acetonitrile as a disperser solvent, no salt addition and pH 6) preconcentration factor and the extraction recovery were 955 and 95.5%, respectively. The linear range was 0.01 - 1.0 mg?kg–1 and the limit of detection was 0.0015 mg?kg–1. The relative standard deviation (RSD, n = 4) for 0.1 mg?kg–1 of amitraz was 3.2%. The recoveries of amitraz from honey samples at the spiking levels of 0.1 mg?kg-1 were 78.8 and 98.2%. The results indicated that DLLME is an efficient technique for the extraction of amitraz in honey samples.
Single Drop Microextraction of Biphenyl and Biphenyl Oxide in Aqueous Samples by Gas Chromatography-Flame Ionization Detection  [PDF]
Maryam Sarkhosh, Ali Mehdinia, Ali Jabbari, Yadollah Yamini
American Journal of Analytical Chemistry (AJAC) , 2011, DOI: 10.4236/ajac.2011.26079
Abstract: In this work, biphenyl and biphenyl oxide were extracted by direct single drop microextraction (di- rect-SDME) and analyzed by gas chromatography flame ionization detection. The extraction occurred by suspending a 7 µL drop of toluene (as extracting solvent) containing acetonaphton (as internal standard) from the tip of a microsyringe in direct-SDME, respectively. The effect of different parameters such as nature of extraction solvent, microdrop and sample temperatures, stirring rate, microdrop and sample volumes, ionic strength and extracting time on the extraction efficiency of the analytes were investigated and optimized. Under optimized conditions the detection limits (S/N = 3) of the biphenyl and biphenyl oxide were 1.80 ± 0.03 and 1.10 ± 0.02 µg?mL–1, respectively. Good linearity was obtained for both analytes using extraction techniques with the correlation coefficients at least 0.997 and the relative standard deviations (R.S.D.) were in the range of 1% - 3%. The percent recoveries of the analytes from spiked water samples were near to 100%
Dispersive Liquid-Liquid Microextraction Based on Solidification of Floating Organic Drop Followed by Gas Chromatography-Electron Capture Detector for Determination of Some Pesticides in Water Samples
Mostafa Bashiri Juybari,Ali Mehdinia,Ali Jabbari,Yadollah Yamini
Chromatography Research International , 2011, DOI: 10.4061/2011/451712
Abstract: In this study dispersive liquid-liquid microextraction based on solidification of floating organic drop (DLLME-SFO) followed by gas chromatography-electron capture detection (GC-ECD) was developed for determination of some pesticides in the water samples. Some important parameters, such as type and volumes of extraction and disperser solvent and salt effect on the extraction recovery of analytes from aqueous solution were investigated. Under the optimum conditions (extraction solvent: 1-undecanol, 15.0 μL; disperser solvent: acetone, 1.0 mL, and without salt addition), the preconcentration factors were obtained ranged from 802 to 915 for analytes. The linear ranges were from 0.05 to 100 μg L−1, and detection limits ranged from 0.05 to 0.008 μg L−1. The relative standard deviations (RSDs%, =5) were between 3.2% and 6.7%. The proposed method was successfully applied to the determination of target analytes in the tap, sea, and river water samples, and satisfactory recoveries were obtained.
Determination of biphenyl and biphenyl oxide in aqueous samples by headspace single drop microextraction coupled to gas chromatography
Sarkhosh, Maryam;Mehdinia, Ali;Jabbari, Ali;Yamini, Yadollah;
Journal of the Brazilian Chemical Society , 2012, DOI: 10.1590/S0103-50532012000400004
Abstract: in this work, biphenyl and biphenyl oxide were extracted by headspace single drop microextraction (hs-sdme) and analyzed by gas chromatography-flame ionization detection (gc-fid). the extraction occurred from the tip of a microsyringe by suspending a 3.5 μl drop of toluene, as extracting solvent, containing acetonaphton, as internal standard. the effect of different parameters such as the nature of extraction solvent, microdrop and sample temperatures, stirring rate, microdrop and sample volumes, ionic strength and extracting time on the extraction efficiency of the analytes were investigated and optimized. under optimized conditions the limits of detection (s/n = 3) of biphenyl and biphenyl oxide were 0.40 ± 0.03 and 0.30 ± 0.06 μg ml?1, respectively. good linearities were obtained for both analytes with the correlation coefficients higher than 0.997 and the relative standard deviations (r.s.d.) were in the range of 1-3%. the recoveries of analytes from spiked water samples were near to 100%.
Investigation of the capability of regenerated rice husk silica to remove hydrogen sulfide pollution
Seyed Mahmoud Mehdinia,Puziah Binti Abdul Latif,Hassan Taghipour
Koomesh , 2012,
Abstract: Introduction: The main goal of this study was to investigate the capability of regenerated rice husk silicaafter saturation to remove Hydrogen sulfide (H2S). For this purpose, rice husk silica and regenerated ricehusk silica were used as adsorbents bed in filter.Material and Methods: A poly vinyl chloride filter with one liter of prepared bed was tested. Rice husksilica was prepared in a furnace at temperature of 800 oC for Four hours, after acid leaching. Saturated ricehusk silica was regenerated in a furnace at temperature of 800 oC for Four hours too. Removal efficiency,elimination capacity, and pressure drop were the three parameters to evaluate the filters bed. System wereoperated with empty bed residence time of 60 s and different inlet concentration of H2S from 10 to 300 partper million (ppm).Results: More than 98% of removal efficiency was observed for both packed filters at inletconcentrations of H2S. The maximum elimination capacity was 7.02 gm-3h-1 with H2S mass loading rateof 9.0 gm-3h-1 in the both beds. This study showed that at a 1.0 lmin-1 flow rate and differentconcentration of inlet H2S. There is no significant difference between the rice husk silica and theregenerated rice husk silica beds in the amount of removal efficiency (p< 0.01). Also, there is no significantdifference between these two beds in the amount of elimination capacity at the same condition (p< 0.01).Moreover, this study showed that the amount of pressure drop was undetectable (zero) in both filter’s bed.Conclusion: The results of this study showed the regenerated rice husk silica has the same performanceof the primary rice husk silica, Therefore it can be considered as a suitable and inexpensive bed to removeH2S at low concentration.
Fabrication of Bovine Serum Albumin Nanoparticles Self-assembled Coacervation Method for Drug Delivery Systems
M. Rahimnejad,M. Jahanshahi,G.D. Najafpour,M. Mehdinia
Iranica Journal of Energy and Environment (IJEE) , 2010,
Abstract: Bovine Serum Albumin (BSA) nanoparticles have been produced in the particle size between 112 to 468 (nm). Nanoparticles were purified with 48,800 g centrifuge following by dialysis, micro and ultra filtration. Photon Correlation Spectroscopy (PCS) and Scanning Electron Microscopy (SEM) were used to characterize the nanoparticles. Photographs obtained from SEM image shown nanoparticles have semi-spherical shape. However the influence of several parameters such as the rate of addition desolvating agent,the concentration of BSA, the gluttaraldehyde concentration, agitation speed and BSA/Ethanol volumetric ratio have been investigated while the temperature kept in 14°C.The mean nanoparticle size diameter has not been relatively changed by variation of solvent adding rate and cross linker concentration and in contrast mainly depended on the volumetric ratio of BSA/ Ethanol, BSA concentration and agitation speed.
Synthesize and Characterization of Rice Husk Silica to Remove the Hydrogen Sulfide through the Physical Filtration System
Seyed Mahmoud Mehdinia,Puziah Abdul Latif,Ahmad Makmom Abdullah,Hassan Taghipour
Asian Journal of Scientific Research , 2011,
Abstract: The main goal of this study was to synthesis and characterization of silica prepared from rice husk and its application to remove Hydrogen sulfide. Polyvinyl chloride filters with 50 cm in height and 7.5 cm in diameter have been used in this study. Rice husk silica (RHS) and regenerated rice husk silica (RRHS) were used as packing material in this work. System was studied at a constant empty bed residence time (EBRT) of 60 sec and different inlet concentration of H2S from 15 to 450 mg m-3. Brunauer-Emmett-Teller method showed rice husk silica has a very high surface area (226.3 m2 g-1) with median pore radius of 2.4 nm and mesoporous structure. The chemical composition analysis showed that the silica consisted of SiO2 up to 97.35%. The removal efficiency (RE) more than 98% were observed for both packed filters at a loading rate of 0.98 g H2S m-3 h-1 and 15 mg m-3 inlet concentrations of H2S. The maximum removal capacity of both packed filter were obtained 7.02 m-3 h-1 at a loading rate of 9.0 m-3 h-1 and 150 mg m-3 inlet concentration. The result from the analysis indicates that at a 1.0 L min-1 flow rate and different inlet concentration of H2S there is no significant difference between the RHS packed filter and the RRHS packed filter in the amount of removal efficiency and removal capacity (p<0.01). Also the result showed pressure drop was undetectable amount (zero) in both packed filter. The results of this study show the best performance of RHS and RRHS packed filters in low concentration of H2S.
Polycyclic Aromatic Hydrocarbons in Coastal Sediment of Klang Strait, Malaysia: Distribution Pattern, Risk Assessment and Sources
Seyedeh Belin Tavakoly Sany, Rosli Hashim, Aishah Salleh, Majid Rezayi, Ali Mehdinia, Omid Safari
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0094907
Abstract: Concentration, source, and ecological risk of polycyclic aromatic hydrocarbons (PAHs) were investigated in 22 stations from surface sediments in the areas of anthropogenic pollution in the Klang Strait (Malaysia). The total PAH level in the Klang Strait sediment was 994.02±918.1 μg/kg dw. The highest concentration was observed in stations near the coastline and mouth of the Klang River. These locations were dominated by high molecular weight PAHs. The results showed both pyrogenic and petrogenic sources are main sources of PAHs. Further analyses indicated that PAHs primarily originated from pyrogenic sources (coal combustion and vehicular emissions), with significant contribution from petroleum inputs. Regarding ecological risk estimation, only station 13 was moderately polluted, the rest of the stations suffered rare or slight adverse biological effects with PAH exposure in surface sediment, suggesting that PAHs are not considered as contaminants of concern in the Klang Strait.
Physiological performance of Persian acroporid corals in summer versus winter temperatures
Jahangir Vajed Samiei,Abolfazl Saleh,Ali Mehdinia,Arash Shirvani,Mohsen Kayal
PeerJ , 2015, DOI: 10.7287/peerj.preprints.713v1
Abstract: With ongoing climate change, coral susceptibility to thermal stress constitutes a central concern in reef conservation. In the Persian Gulf, coral reefs are confronted with the most extreme temperatures. Over the last decades, both annual hot and cold peak periods in this region have been associated with episodes of coral bleaching and mortality. Using physiological performance as a measure of coral health, we investigated the thermal susceptibility of the common acroporid coral from the Persian Gulf, Acropora downingi, in Hengam Island where temperature oscillates seasonally in the range 20.2-34.2°C. In a series of two short-term experiments, we exposed corals (1) to the constant temperature levels of summer versus winter, and (2) to progressive temperature deviations from the annual mean toward the two extreme seasonal values and beyond. We monitored four indictors of coral physiological performance: net photosynthesis (Pn), dark respiration (R), autotrophic capability (Pn/R), and survival. Warming revealed detrimental for Pn and survival of corals, while equivalent cooling did not. Pn/R was lower at the warmer thermal level within each season, and during summer compared to winter. Corals exposed to the maximum temperature of summer displayed Pn/R<1, inferring that photosynthetic performance could not support basal metabolic needs under this environment and that corals had to import organic matter or draw on their reserves to compensate for carbon losses during respiration. We therefore suggest that the Persian Gulf populations of A. downingi are more sensitive to the extreme temperatures endured in summer compared to that experienced in winter; and they may be impacted by future increases in water temperature.
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