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991.
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
992.
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
993.
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
994.
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
995.
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
996.
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
997.
The present work is motivated by the desire to obtain numerical solution to a quasilinear parabolic inverse problem. The solution
is presented by means of the method of lines. Method of lines is an alternative computational approach which involves making
an approximation to the space derivatives and reducing the problem to a system of ordinary differential equations in the variable
time, then a proper initial value problem solver can be used to solve this ordinary differential equations system. Some numerical
examples and also comparison with finite difference methods will be investigated to confirm the efficiency of this procedure. 相似文献
998.
We study spin dependent transport through a magnetic bilayer graphene nanojunction configured as a two-dimensional normal/ferromagnetic/normal structure where the gate voltage is applied on the layers of ferromagnetic graphene. Based on the four-band Hamiltonian, conductance is calculated by using the Landauer-Buttiker formula at zero temperature. For a parallel configuration of the ferromagnetic layers of bilayer graphene, the energy band structure is metallic and spin polarization reaches its maximum value close to the resonant states, while for an antiparallel configuration the nanojunction behaves as a semiconductor and there is no spin filtering. As a result, a huge magnetoresistance is achievable by altering the configurations of ferromagnetic graphene around the band gap. 相似文献
999.
Nanocellulose (NC) materials have some unique properties, which make them attractive as organic or inorganic supports for catalytic applications. Nanocatalysts with diameters of less than 100 nm are difficult to separate from the reaction mixture, therefore, magnetic nanoparticles (MNPs) were used as catalysts to overcome this problem. Fe3O4@NCs/BF0.2 as a green, bio‐based, eco‐friendly, and recyclable catalyst was synthesized and characterized using fourier‐transform infrared spectroscopy (FT‐IR), vibrating sample magnetometer (VSM), X‐ray diffraction (XRD), X‐ray fluorescence (XRF), Brunauer–Emmett–Teller (BET), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and thermal gravimetric analysis (TGA) techniques. Fe3O4@NCs/BF0.2 was employed for the synthesis of 2,3‐dihydro‐1H‐perimidine derivatives via a reaction of 1,8‐diaminonaphthalene with various aldehydes at room temperature under solvent‐free conditions. The present procedure offers several advantages including a short reaction time, excellent yields, easy separation of catalyst, and environmental friendliness. 相似文献
1000.
Silica-supported boron trifluoride (BF3·SiO2) is an efficient, readily available, and reusable catalyst for the synthesis of 14-aryl or alkyl-14H-dibenzo[a,j]xanthenes by condensation of 2-naphthol and aldehydes. This reaction under heating or sonication conditions is very simple, affording good to excellent yields of products. 相似文献