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31.
Antimicrobial activities and biofilm-formation preventive properties of Mentha piperita and Cuminum cyminum essential oils and chlorhexidine were assessed against Streptococcus mutans and Streptococcus pyogenes. Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analysis led to the identification of 26 and 32 compounds in the essential oils of M. piperita and C. cyminum, respectively. Minimal bactericidal concentrations (MBC) of the oils and chlorhexidine and microbial decimal reduction time (D value) were determined. Antibacterial and in vivo biofilm preventive efficacies of all the concentrations of M. piperita oil were significantly (p<0.001) higher. The biofilm inhibitory properties in planktonic cultures were in M. piperita > chlorhexidine > C. cyminum order. In vivo experiments conducted on male and female volunteers who brushed with essential oil blended toothpastes indicated that lower concentrations of the oils, in particular the M. piperita oil, were significantly higher (p<0.001) and effective during the course of the study as compared to chlorhexidine. In conclusion, there may be a potential role for essential oils in the development of novel anticaries treatments. 相似文献
32.
Iraj Mohammadpoor-Baltork Majid Moghadam Shahram TangestaninejadValiollah Mirkhani Seyedeh Fatemeh Hojati 《Polyhedron》2008
12-Tungstophosphoric acid (TPA) supported on silica, activated carbon and poly(4-styrylmethyl)pyridinium chloride (PMP) were found to be highly efficient catalysts for the synthesis of oxazolines, imidazolines and thiazolines from the condensation of various nitriles with aminoalcohols, ethylenediamine and cisteamine, respectively. In the case of oxazolines, dicyanobenzenes were selectively converted to mono- and bis-oxazolines in the presence of these catalysts. In the reaction of dicyanobenzenes with ethylenediamine, only mono-imidazolines were produced and the remaining cyano group did not react even with long reaction times. In the case of thiazolines, only bis-thiazolines were produced in the reaction of dicyanobenzenes with cysteamine. Furthermore, these catalysts could be recovered and reused without significant loss of their activities. 相似文献
33.
Seied M. Pourmortazavi Iraj Kohsari Seiedeh S. Hajimirsadeghi 《Central European Journal of Chemistry》2009,7(1):74-78
The present study concerns the electrochemical synthesis of basic copper carbonate nanoparticles by oxidation of metallic
copper on the anode in an aqueous bicarbonate solution. This simple and one-step preparation can be considered as green synthesis.
The scanning electron microscopy (SEM) analysis indicates that average particle size of the product is in the range of about
70 nm. On the other hand, basic copper carbonate micro-powder has been prepared, by mixing solutions of copper(II) sulphate
and sodiu bicarbonate. The SEM analysis showed that the size of particles prepared in the same way is in the range of about
1 μm. In another part of this study, the thermal decomposition of micro and nanoparticles of copper carbonate produced by
various methods was studied in air using TG-DTA techniques. The results of thermal study show that the decomposition of both
samples occurs in single step. Also, the TG-DTA analysis of the nanoparticles indicates that the main thermal degradation
occurs in the temperature range of 245–315°C. However, microparticles of Cu(OH)2 · CuCO3 decomposed endothermally in the temperature range of 230–330°C.
相似文献
34.
Khodabakhsh Niknam Seyed Mehdi Razavian Mohammah Ali Zolfigol Iraj Mohammahpoor‐Baltork 《Journal of heterocyclic chemistry》2006,43(1):199-202
35.
Anwar Gavili Taghi Dallali Isfahani Fatemeh Zabihi Iraj Hadi 《Heat and Mass Transfer》2013,49(10):1433-1445
The heat transfer and fluid flow behavior of water based Al2O3 nanofluids are numerically investigated inside a two-sided lid-driven differentially heated rectangular cavity. Physical properties which have major effects on the heat transfer of nanofluids such as viscosity and thermal conductivity are experimentally investigated and correlated and subsequently used as input data in the numerical simulation. Transport equations are numerically solved with finite volume approach using SIMPLEC algorithm. It was found that not only the thermal conductivity but also the viscosity of nanofluids has a key role in the heat transfer of nanofluids. The results show that at low Reynolds number, increasing the volume fraction of nanoparticles increases the viscosity and has a deteriorating effect on the heat transfer of nanofluids. At high Reynolds number, the increase in the viscosity is compensated by force convection and the increase in the volume fraction of nanoparticles which results in an increase in heat transfer is in coincidence with experimental results. 相似文献
36.
J–V characteristics and efficiency as a function of active region thickness of the p-i-n intermediate band solar cells have been calculated. We compared the maximum efficiency point of three different cells made of well-known materials. Each cell includes a different size of quantum dot in the i-region that causes different intermediate band position. Numerical optimizations have been done by adjusting parameters such as the combination of band gap, mismatch as well as the specific structure of the cell. In addition, it is illustrated that the maximum efficiency point increases with increasing the incident light concentration in the radiative limit. This article considered that using light concentrators can be useful to enhance the efficiency of the solar cell with respect to manufacturing and cost improvements. 相似文献
37.
Abdollahi A Hassani A Ghosta Y Bernousi I Meshkatalsadat MH Shabani R Ziaee SM 《Natural product research》2012,26(1):77-83
The effects of postharvest spraying of essential oils from sweet basil (Ocimum basilicum), fennel (Foeniculum vulgare), summer savory (Satureja hortensis) and thyme (Thymus vulgaris) on fungal decay and quality parameters of the 'Thompson seedless' table grape stored at 0?±?1°C for 60 days were evaluated. Results showed that the essential oils, especially of thyme and fennel, have a good inhibitory effect on the development of fungal decay in Thompson table grapes. In addition, essential oils reduced weight loss, berry and rachis browning and had no considerable adverse effect on the flavour of the fruits. GC-MS analysis showed that the main compounds identified in sweet basil, fennel, summer savory and thyme oils are linalool (65.25%), trans-anethole (64.72%), carvacrol (54.14%) and β-ocimene (12.62%), respectively. Therefore, these essential oils have good potential for use as an alternative to synthetic fungicides for the preservation and storage of table grapes. 相似文献
38.
M Araghi V Mirkhani M Moghadam S Tangestaninejad I Mohammdpoor-Baltork 《Dalton transactions (Cambridge, England : 2003)》2012,41(38):11745-11752
New hybrid complexes based on covalent interaction between 5,10,15,20-tetrakis(4-aminophenyl)porphyrinatozinc(ii) and 5,10,15,20-tetrakis(4-aminophenyl)porphyrinatotin(iv) chloride, and a Lindqvist-type polyoxometalate, Mo(6)O(19)(2-), were prepared. These new porphyrin-polyoxometalate hybrid materials were characterized by (1)H NMR, FT IR and UV-Vis spectroscopic methods and cyclic voltammetry. These spectro- and electrochemical studies provided several spectral data for synthesis of these compounds. Cyclic voltammetry showed the influence of the polyoxometalate on the redox process of the porphyrin ring. The catalytic activity of tin(iv)porphyrin-hexamolybdate hybrid material was investigated in the acetylation of alcohols and phenols with acetic anhydride. The reusability of this catalyst was also investigated. 相似文献
39.
Ashengroph M Nahvi I Zarkesh-Esfahani H Momenbeik F 《Applied biochemistry and biotechnology》2012,166(1):1-12
To screen strains of halotolerant or halophile bacteria which are able to convert isoeugenol to vanillin, 36 different strains
of bacteria isolated from the salty environments in Iran were investigated. During growth on isoeugenol, a moderately halotolerant
Gram-negative coccobacil showed capability of converting isoeugenol to vanillin. Based on morphological, physiological, and
phylogenetic studies, strain CSW4 was classified as a bacterium belonging to the genus Psychrobacter. The bioconversion products were confirmed by thin-layer chromatography, high-performance liquid chromatography, and spectral
data obtained from UV/Vis spectroscopy, FTIR, and mass-spectroscopy. Using growing cells, vanillin reached its maximum level
of 88.18 mg L−1 after 24 h of reaction time in the presence of 1 g L−1 isoeugenol, resulting in a molar yield of 10.2%. The use of resting cells led to the optimal yield of vanillin (16.4%) which
was obtained after 18-h reaction using 1 g L−1 isoeugenol and 3.1 g of dry weight of cells per liter harvested at the end of the exponential growth phase. To improve vanillin
yield, the effect of substrate concentration on vanillin production under resting cells conditions was also investigated.
Using 10 g L−1 isoeugenol, the maximal vanillin concentration (1.28 g L−1) was achieved after a 48-h reaction, without further optimization. The present study brings the first evidence for biotransformation
of isoeugenol to vanillin in the genus Psychrobacter. 相似文献
40.
Maryam YadegariMajid Moghadam Shahram TangestaninejadValiollah Mirkhani Iraj Mohammadpoor-Baltork 《Polyhedron》2012,31(1):332-338
In the present work, highly efficient trimethylsilylation of alcohols and phenols with hexamethyldisilazane (HMDS) catalyzed by high-valent [TiIV(salophen)(OTf)2] is reported. Under these conditions, primary, secondary and tertiary alcohols as well as phenols were silylated in short reaction times and high yields. It is noteworthy that this method can be used for chemoselective silylation of primary alcohols in the presence of secondary and tertiary alcohols and phenols. The catalyst was reused several times without loss of its catalytic activity. 相似文献