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Sol-gel derived nanocrystalline and mesoporous barium strontium titanate prepared at room temperature

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Particuology 2011年第3期9卷 235-242页

作者： Mohammad reza mohammadi Derek J.Fray Department of Materials Science & Engineering Sharif University of Technology Department of Materials Science & Metallurgy University of Cambridge

Perovskite-type barium strontium titanate （BST） thin films and powders with nanocrystalline and mesoporous structure were prepared by a straightforward particulate sol-gel route at room temperature. The prepared sol had a narrow particle size distribution of about 20 nm. X-ray diffraction （XRD） revealed that phase composition and preferable orientation growth of BST depended upon the annealing temperature. Transmission electron microscope （TEM） images showed that the crystallite size of the powders decreased with increasing annealing temperature from 8 nm at 25 ℃ down to 5 nm at 800 ℃. Field emission scanning electron microscope （FE-SEM） analysis and atomic force microscope （AFM） images revealed that BST thin films had mesoporous and nanocrystafiine structure with average grain size of 3Onm at 600 ℃. Based on Brunauer-Emmett-Teller （BET） analysis, the synthesized BST showed mesoporous structure containing nnres with needle, and nlate shanes and BET surface area in the range of 49-32 m^2/g at 500-800℃

关键词： Barium strontium titanate Room temperature Sol-gel chemistry Nanostructure

Interpreting genotype × environment interactions for grain yield of rainfed durum wheat in Iran

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The Crop Journal 2015年第6期3卷 526-535页

作者： reza mohammadi Ezatollah Farshadfar Ahmed Amri Campus of Agriculture and Natural Resources Razi University Dryland Agricultural Research Institute (DARI) AREEO Sararood branch International Center for Agricultural Research in the Dry Areas (ICARDA)

Clustering genotype × environment(GE) interactions and understanding the causes of GE interactions are among the most important tasks in crop breeding programs. Pattern analysis(cluster and ordination techniques) was applied to analyze GE interactions for grain yield of 24 durum wheat(Triticum turgidum L. var. durum) genotypes(breeding lines and old and new cultivars) along with a popular bread wheat(Triticum aestivum) cultivar grown in 21 different rainfed environments during the 2010–2013 cropping seasons. To investigate the causes of GE interaction, several genotypic and environmental covariables were used. In a combined ANOVA, environment was the predominant source of variation,accounting for 81.2% of the total sum of squares(TSS), and the remaining TSS due to the GE interaction effect was almost seven times that of the genetic effect. Cluster analysis separated the environments into four groups with similar discriminating ability among genotypes, and genotypes into five groups with similar patterns in yield *** analysis confirmed two major environmental clusters(cold and warm), and allowed the discrimination and characterization of genotype adaptation. Within the cold-environment cluster, several subclusters were identified. The breeding lines were most adapted to moderate and warm environments, whereas the old varieties were adapted to cold environments. The results indicated that winter rainfall and plant height were among the environmental and genotypic covariables, respectively, that contributed most to GE interaction for grain yield in rainfed durum wheat.

关键词： Durum wheat Classification Ordination analysis Environmental covariables

In-situ solvothermal processing of polycaprolactone/hydroxyapatite nanocomposites with enhanced mechanical and biological performance for bone tissue engineering

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Bioactive Materials 2017年第3期2卷 146-155页

作者： Saeed Moeini Mohammad reza mohammadi Abdolreza Simchi Department of Materials Science and Engineering Sharif University of TechnologyTehranIran Institute for Nanoscience and Nanotechnology Sharif University of TechnologyTehranIran

The interest in biodegradable polymer-matrix nanocomposites with bone regeneration potential has been increasing in recent *** the present work,a solvothermal process is introduced to prepare hydroxyapatite(HA)nanorod-reinforced polycaprolactone in-situ.A non-aqueous polymer solution containing calcium and phosphorous precursors is prepared and processed in a closed autoclave at different temperatures in the range of 60-150℃.Hydroxyapatite nanorods with varying aspect ratios are formed depending on the processing temperature.X-ray diffraction analysis and field-emission scanning electron microscopy indicate that the HA nanorods are ***-dispersive Xray spectroscopy and Fourier transform infrared spectrometry determine that the ratio of calcium to phosphorous increases as the processing temperature *** evaluate the effect of in-situ processing on the mechanical properties of the nanocomposites,highly porous scaffolds(>90%)containing HA nanorods are prepared by employing freeze drying and salt leaching *** is shown that the elastic modulus and strength of the nanocomposites prepared by the in-situ method is superior(~15%)to those of the ex-situ samples(blended HA nanorods with the polymer solution).The enhanced bone regeneration potential of the nanocomposites is shown via an in vitro bioactivity assay in a saturated simulated body *** improved cell viability and proliferation is also shown by employing(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide)(MTT)assay in human osteosarcoma cell *** prepared scaffolds with in vitro regeneration capacity could be potentially useful for orthopaedic applications and maxillofacial surgery.

关键词： Nanocomposite Polycaprolactone Hydroxyapatite Mechanical property Cytotoxicity

Template-based growth of titanium dioxide nanorods by a particulate sol-electrophoretic deposition process

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Particuology 2011年第2期9卷 161-169页

作者： Mohammad reza mohammadi Farideh Ordikhani Derek J.Fray Farzad Khomamizadeh Department of Materials Science & Engineering Sharif University of Technology Department of Materials Science & Metallurgy University of Cambridge

TiO2 nanorods have been successfully grown into a track-etched polycarbonate （PC） membrane by a particulate sol-electrophoretic deposition from an aqueous medium. The prepared sols had a narrow particle size distribution around 17 nm and excellent stability against aging, with zeta potentials in the range of 47-50 mV at pH 2. It was found that TiO2 nanorods were grown from dilute aqueous sol with a low, 0.1-M concentration. Fourier transform infrared spectroscopy （FT-IR） analysis confirmed that a full conversion of titanium isopropoxide was obtained by hydrolysis, resulting in the formation of TiO2 particles. X-ray diffraction （XRD） results revealed that TiO2 nanorods dried at 100℃ were a mixture of anatase and brookite phases, whereas they were a mixture of anatase and futile structures at 500℃. Moreover, the rutile content of the TiO2 nanorods was higher than that of TiO2 powders. Transmission electron microscope （TEM） images confirmed that TiO2 nanorods had a smooth morphology and longi- tudinal uniformity in diameter. Field emission scanning electron microscope （FE-SEM） images showed that TiO2 nanorods grown by sol-electrophoresis from the dilute aqueous sol had a dense structure with a uniform diameter of 200 rim, containing small particles with an average size of 15 nm. Simultaneous differential thermal （SDT） analysis verified that individual TiO2 nanorods, grown into a PC template, were obtained after annealing at 500℃. Based on kinetic studies, it was found that uniform TiO2 nanorods with high-quality morphology were obtained under optimum conditions at an applied potential of 0.3 V/cm and a deposition time of 60 min.

关键词： Nanorod Crystal morphology Electrophoretic deposition Sol-electrophoresisTitanium dioxide

Field evaluation of durum wheat landraces for prevailing abiotic and biotic stresses in highland rainfed regions of Iran

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The Crop Journal 2015年第5期3卷 423-433页

作者： reza mohammadi Behzad Sadeghzadeh Hasan Ahmadi Nowzar Bahrami Ahmed Amri Dryland Agricultural Research Institute (DARI) Center of Agricultural Research and Natural Resources International Center for Agricultural Research in the Dry Areas (ICARDA)

Biotic and abiotic stresses are major limiting factors for high crop productivity worldwide. A landrace collection consisting of 380 durum wheat(Triticum turgidum L. var. durum) entries originating in several countries along with four check varieties were evaluated for biotic stresses:yellow rust(Puccinia striiformis Westendorf f. sp. tritici) and wheat stem sawfly(WSS) Cephus cinctus Norton(Hymenoptera: Cephidae), and abiotic stresses: cold and drought. The main objectives were to(i) quantify phenotypic diversity and identify variation in the durum wheat landraces for the different stresses and(ii) characterize the agronomic profiles of landraces in reaction to the stresses. Significant changes in reactions of landraces to stresses were *** resistant to each stress were identified and agronomically *** reduction due to the stresses varied from 11.4%(yellow rust) to 21.6%(cold stress) for 1000-kernel weight(TKW) and from 19.9(yellow rust) to 91.9%(cold stress) for grain yield. Landraces from Asia and Europe showed enhanced genetic potential for both grain yield and cold tolerance under highland rainfed conditions of Iran. The findings showed that TKW and yield productivity could be used to assess the response of durum wheat landraces to different stresses. In conclusion, landraces showed high levels of resistance to both biotic and abiotic stresses, and selected landraces can serve in durum wheat breeding for adaptation to cold and drought-prone environments.

关键词： Durum wheat Landraces Biotic and abiotic stresses

Effect of post-harvest UV-C irradiation and calcium chloride on enzymatic activity and decay of tomato(Lycopersicon esculentum L.)fruit during storage

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Journal of Integrative Agriculture 2017年第9期16卷 2093-2100页

作者： Saeideh Mansourbahmani Behzad Ghareyazie Sepideh Kalatejari reza Salehi mohammadi Vahid Zarinnia Department of Horticultural Sciences Science and Research BranchIslamic Azad UniversityTehran ***Iran Agriculture Biotechnology Research Institute of Iran(ABRII)/Agricultural Research Education and Extension Organization(AREEO)Karaj ***Iran Department of Horticultural Sciences University of TehranKaraj ***Iran

Tomato is one of the extensively consumed vegetable crops worldwide. The regular consumption of tomato decreases the incidence of chronic degenerative diseases such as certain types of cancer and cardiovascular diseases. The objective of this study was to find an appropriate method that not only reduces tomatoes decay, but also maintains its post-harvest quality. A factorial experiment based on randomized complete block design with three replications was conducted to evaluate effects of ultraviolet（UV）-C and CaCl_2 applications on tomato during storage. The traits studied included ethylene, polygalacturonase（PG） activity, pectin methyl esterase（PME） activity, firmness, total phenol content, and fungal-induced decay were measured weekly during 35 days of storage. Both UV-C and CaCl_2 treatments had positive effects on tomato quality as compared to control treatment. The 3 and 4.5 k J m^（-2） levels of UV-C and 2% CaCl_2 had positive effects on quality characteristics, respectivly. Fruits treated by UV-C and CaCl_2 had higher phenol and firmness, and less PME activity, PG activity, ethylene production, and decay than the control fruits. In conclusion, increasing in storage duration significantly affected the fruits quality by increasing in ethylene, PME activity, PG activity, decay and decreasing the phenol content and firmness. But UV-C and CaCl_2 led to significant decrease in this adverse impact relative to control treatment.

关键词： CaCl_2 ethylene production firmness PG PME phenol

Nano TiO_2 as a heterogeneous catalyst in an efficient one-pot three-component Mannich synthesis of β-aminocarbonyls

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Chinese Chemical Letters 2011年第10期22卷 1203-1206页

作者： M.Z.Kassaee reza mohammadi Hassan Masrouri Farnaz Movahedi Department of Chemistry Tarbiat Modares UniversityP.O.Box 14155-4838TehranIran

TiO_2 nanoparticles（TiO_2 NPs） worked as an efficient heterogeneous catalyst in a one-pot,three-component,and solvent free Mannich reaction;producing variousβ-aminocarbonyls in good yields,and with good *** catalyst was easily separated from the reaction mixture and was recycled four times with no significant loss of its catalytic activity.

关键词： TiO_2 nanoparticles Heterogeneous catalyst Mannich reaction β-Aminocarbonyls Solvent-free

Rank correlation among different statistical models in ranking of winter wheat genotypes'

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The Crop Journal 2014年第Z1期2卷 154-163页

作者： Mozaffar Roostaei reza mohammadi Ahmed Amri Dryland Agricultural Research Institute (DARI) International Center for Agricultural Research in the Dry Areas (ICARDA)

Several statistical methods have been developed for analyzing genotype×environment(GE)interactions in crop breeding programs to identify genotypes with high yield and stability *** statistical methods,including joint regression analysis(JRA),additive mean effects and multiplicative interaction(AMMI)analysis,genotype plus GE interaction(GGE)biplot analysis,and yield–stability(YSi)statistic were used to evaluate GE interaction in20 winter wheat genotypes grown in 24 environments in *** main objective was to evaluate the rank correlations among the four statistical methods in genotype rankings for yield,stability and yield–*** kinds of genotypic ranks(yield ranks,stability ranks,and yield–stability ranks)were determined with each *** results indicated the presence of GE interaction,suggesting the need for stability *** respect to yield,the genotype rankings by the GGE biplot and AMMI analysis were significantly correlated(P<0.01).For stability ranking,the rank correlations ranged from 0.53(GGE–YSi;P<0.05)to0.97(JRA–YSi;P<0.01).AMMI distance(AMMID)was highly correlated(P<0.01)with variance of regression deviation(S2di)in JRA(r=0.83)and Shukla stability variance(σ2)in YSi(r=0.86),indicating that these stability indices can be used *** correlation was found between yield ranks and stability ranks(AMMID,S2di,σ2,and GGE stability index),indicating that they measure static stability and accordingly could be used if selection is based primarily on *** yield–stability,rank correlation coefficients among the statistical methods varied from 0.64(JRA–YSi;P<0.01)to 0.89(AMMI–YSi;P<0.01),indicating that AMMI and YSi were closely associated in the genotype ranking for integrating yield with stability *** on the results,it can be concluded that YSi was closely correlated with(i)JRA in ranking genotypes for stability and(ii)AMMI for integrating yield and stability.

关键词： GE interaction Statistical models Rank correlation Winter wheat

Solvent extraction of rubidium from gold waste using conventional SX and new CFE methods

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Rare Metals 2015年第11期34卷 818-828页

作者： Mohammad reza Tavakoli mohammadi Seyed Mohammad Javad Koleini Sepideh Javanshir Hossein Abolghasemi Mahmoud Abdollahy Mineral Processing Department Tarbiat Modares University Mining Engineering Department University of Birjand Oil and Gas Center of Excellence School of Chemical Engineering College of Engineering University of Tehran

Solvent extraction（SX） of rubidium（Rb） from leaching filtrate of gold waste（GW） in Mouteh Processing Plant by 18-crown-6（18C6） was studied. High potential of new column flotoextraction（CFE） method in extraction of Rb from dilute solutions was also demonstrated. First, the factors affecting SX of Rb from a synthetic rubidium sulfate solution(containing 100 mg·L-1Rb) were identified.0.05 mol·L-118C6 in kerosene, 0.02 mol·L-1picric acid in aqueous phase, aqueous to organic（A/O） ratio of 1, p H7 and mixing time of 15 min are the optimum values for affective factors. The three-stage precipitation with sodium carbonate, p H adjustment with sulfuric acid and two-stage evaporation and crystallization were conducted to purify the leaching from impurities such as Fe, Al, Mn, Ca and especially competing cations of K and Na. Almost complete extraction of Rb and K from final filtrate containing 0.08 mol·L-1picric acid was performed using 0.2 mol·L-118C6 in kerosene. The Rb and K strippings of 99.12 % and 9.93 %, respectively, are obtained with 2 mol·L-1nitric acid with A/O ratio of 2. Finally, the performance comparison of the CFE and SX methods in similar conditionsshows increased extraction of K and Rb by 16 % and 5 %,respectively, using CFE method.

关键词： Rubidium Gold waste Solvent extraction Column flot