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981.
Bahadori F Topçu G Boğa M Türkekul A Kolak U Kartal M 《Natural product communications》2012,7(6):731-734
A new indole alkaloid, 11-hydroxypolyneuridine, was isolated from Vinca major subsp. major L. and the known indole alkaloids vallesiachotamine and isovallesiachotamine from Vinca minor L. This is the first report on the alkaloids of both Vinca species growing in Turkey; vallesiachotamine and isovallesiachotamine were isolated from a Vinca species for the first time. V. minor may be considered as a new source for these two alkaloids due to their occurrence in high amount in the aerial parts of the plant. The alkaloid extracts of the two Vinca species were found to have high lipid peroxidation inhibitory and DPPH radical scavenging activities. Anticholinesterase activity of the extracts was also very strong. 相似文献
982.
Zolfigol Mohammad Ali Khazaei Ardeshir Mokhlesi Mohammad Zare Abdolkarim Safaiee Maliheh Derakhshan‐Panah Fatemeh Keypour Hassan Ali Dehghani‐Firouzabadi Ahmad Merajoddin Maria 《中国化学》2012,30(2):345-352
Aluminum chloride (AlCl3) efficiently catalyzes one‐pot multicomponent condensation of enolizable ketones or alkyl acetoacetates with aldehydes, acetonitrile and acetyl chloride to afford β‐acetamido ketone or ester derivatives in high to excellent yields and in relatively short reaction times. Moreover, by this synthetic method, some novel β‐acetamido ketones and esters (i.e. one complex structure) are prepared. 相似文献
983.
Seyed Mojtaba Taghizadeh Yadollah YaminiMohammad Hosein Naeeni Fatemeh MohamadniaReza Sardeh Moghadam 《Polymer Testing》2012,31(2):297-303
A simple and efficient method based on hollow fiber protected headspace liquid-phase in conjunction with high performance liquid chromatography has been introduced for extraction and determination of three residual monomers (2-ethylhexyl acrylate (EHA), vinyl acetate (VA), glycidyl methacrylate (GM)) in polymer latex. Using this methodology, the analytes of interest extracted from a sample are led into organic solvent located inside the porous hollow fiber membrane. Initially, several experimental parameters were controlled and optimized and the optimum conditions were reached with 8 cm neatly cut hollow fibers containing heptanol, which were exposed to the headspace of a 12 mL sample solution containing 20% (w/v) NaCl thermostated at 110 °C and stirred at 800 rpm for 20 min. Finally, 20 μL of the extraction solution was withdrawn into a syringe and injected into HPLC for analysis. The calibration curves were linear (r2 ≥ 0.994) over the concentration range of 0.05-10 mg L−1 for VA and 0.02-10 mg L−1 for other analytes. The relative standard deviation (RSD%) for three-replicate extractions and measurements was below 8.6%. The limits of detection of this method for quantitative determination of the analytes were found within the range of 0.005 to 0.011 mg kg−1 with the enrichment factors within the 5-164 range. The method was successfully applied for determination of residual monomers in polymer latex. 相似文献
984.
Ali Reza Keshtkar Fatemeh Kafshgari Mohammad Ali Mousavian 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(2):501-512
Simultaneous biosorption of uranium(VI) and nickel(II) ions onto Ca-pretreated Cystoseira indica biomass was studied and compared with single uranium or nickel biosorption in a fixed-bed column. Results of single biosorption
showed the breakthrough and exhaustion time increase with the increase of the flow rate and inlet metal concentration for
both metal ions. Also, it was observed that there was an optimum flow rate of 1.4 mL min−1 (surface loading of 0.792 cm min−1) for both metal ions in the column. Results from both single and binary systems showed the adsorption capacity of C. indica for both metal ions increases with the increasing inlet concentration of each component and C. indica had a stronger affinity for uranium than nickel ions. The binary system results showed that the presence of the second component
affected the adsorption of the first one by C. indica so the antagonistic action was observed. Also, the inhibitory effect of uranium ions on the nickel adsorption was greater
than nickel ions on the uranium adsorption. The uranium and nickel breakthrough curves under different conditions were described
by the Thomas, Yoon-Nelson and Yan models. Among these models, the Yan model appeared to describe the experimental results
better. 相似文献
985.
Ahmad Shaabani Fatemeh Hajishaabanha Hamid Mofakham Mojtaba Mahyari Bagher Lali 《Helvetica chimica acta》2012,95(2):246-254
A novel and efficient isocyanide‐based multicomponent reaction between alkyl or aryl isocyanides 1 , 2,3‐diaminomaleonitrile ( 2 ), naphthalene‐2,3‐diamines ( 6 ) or benzene‐1,2‐diamine ( 9 ), and 3‐oxopentanedioic acid ( 3 ) or Meldrum's acid ( 4 ) or ketones 7 was developed for the ecologic synthesis, at room temperature under mild conditions, of 1,6‐dihydropyrazine‐2,3‐dicarbonitriles 5a – 5f in H2O without using any catalyst, and of 3,4‐dihydrobenzo[g]quinoxalin‐2‐amine and 3,4‐dihydro‐3,3‐dimethyl‐quinoxalin‐2‐amine derivatives 8a – 8g and 10a – 10e , respectively, in the presence of a catalytic amount of p‐toluenesulfonic acid (TsOH) in EtOH, in good to excellent yields (Scheme 1). 相似文献
986.
The longest path problem is a well-known NP-hard problem and so far it has been solved polynomially only for a few classes of graphs. In this paper, we give a linear-time algorithm for finding a longest path between any two given vertices in a rectangular grid graph. 相似文献
987.
One-pot, three-component coupling reactions of indole, aromatic aldehydes, and heteroaryl amines under solvent-free conditions lead to the formation of the corresponding novel 3-[(N-heteroaryl)(aryl)methyl]indoles in moderate to high yields. The key features of this multi-component reaction are the simple reaction procedure, no organic solvent or acid catalyst, and easy product separation without further purification. 相似文献
988.
Amir Reza Jalilian Hassan Yousefnia Samaneh Zolghadri Mohammad Reza Khoshdel Fatemeh Bolourinovin Ali Rahiminejad 《Journal of Radioanalytical and Nuclear Chemistry》2010,284(1):49-54
[67Ga]-ethylenecysteamine cysteine ([67Ga]ECC) was prepared using freshly prepared [67Ga]GaCl3 and ethylenecysteamine cysteine (ECC) for 30 min at 90 °C (radiochemical purity ≈97 ± 0.88% ITLC, specific activity: 210 ± 5 GBq/mM).
Stability of the complex was checked in human serum for 24 h at 37 °C. Partition co-efficient of the tracer in octanol:saline
mixture was determined (log P; 0.8). The biodistribution of the radiolabeled compound in vital organs of wild-type rats were compared with that of free
Ga3+ cation up to 48 h. Initial biodistribution results showed significant kidney excretion of the tracer comparable to that of
homologous 99mTc compound. 相似文献
989.
Keivan Majidzadeh-A Vahid Khalaj Davami Fatemeh Hemayatkar Mahdi Barkhordari Farzaneh Adeli Ahmad Fereidoun Mahboudi 《Applied biochemistry and biotechnology》2010,162(7):2037-2048
Human tissue plasminogen activator (t-PA) plays a pivotal role in the treatment of acute myocardial infarction, ischemic stroke,
and deep vein thrombosis. It has the benefit of generating no adverse effects such as fibrinogen depletion, systemic hemorrhage,
and immunologic reactions. Human t-PA is a serine-protease enzyme containing 527 amino acid residues in five structural domains.
The correct folding of t-PA requires the correct pairing of 17 disulfide bridges in the molecule. A gene encoding full-length
human t-PA was cloned into pPICZαA expression vector downstream of alcohol oxidase promoter and α-mating signal sequence from
Saccharomyces cerevisiae and flush with the kex2 cleavage site to express the protein with a native N terminus. The methylotrophic yeast, Pichia pastoris GS115 strain, was transformed with this cassette, and methanol utilizing (mut+) transformants were selected for production
and secretion of human t-PA into culture media. SDS–PAGE and Western blot analysis showed the expressed bands of t-PA protein.
Zymography test indicated suitable folding and proper function of the expressed recombinant human t-PA in conversion of plasminogen
to plasmin and gelatin lysis. Amidolytic activity test showed the amidolytic activity of 1,650 IU/ml. The results of this
study concluded that P. pastoris methylotrophic yeast can be a suitable alternative for mammalian and prokaryotic expression systems to produce t-PA. 相似文献
990.
Pure tin dioxide (SnO2) nanoparticles were synthesized via thermolysis of tin phthalate and tin oxalate in the presence of oleic acid (OA) as solvent. Oleic acid (OA) was employed as an organic solvent, which can be applied to control particle growth and to stabilize the particles. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) spectroscopy. The orthorhombic phase SnO2 nanoparticles with average size about 12 nm were synthesized through thermolysis of tin phthalate in the presence of oleic acid. 相似文献