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201.
Javidi Sarafan Mahnaz Alizadeh Rasool Fattahi Abolfazl Valizadeh Ardalan Mostafa Karimi Nader 《Journal of Thermal Analysis and Calorimetry》2020,141(5):2145-2164
Journal of Thermal Analysis and Calorimetry - Transfer of heat and mass and thermodynamic irreversibilities are investigated in a porous, parallel-plate microreactor in which the working fluid is... 相似文献
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Rasekholghol Ariam Fazaeli Yousef Moradi Dehaghi Shahram Ashtari Parviz 《Journal of Radioanalytical and Nuclear Chemistry》2020,324(2):599-608
Journal of Radioanalytical and Nuclear Chemistry - Radiolabeled fluorescent nanocomposite, 68Ga@CdTeQDs@SH-Propyl@MCM-41, was prepared. The prepared material was characterized using X-ray... 相似文献
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A simple and highly efficient one-pot protocol for the synthesis of novel polysubstituted 1,2-dihydronaphtho[2,1-b] furans has been developed by three-component coupling reaction of 2-aminopyridines, naphthols, and glyoxal in the presence of guanidinium chloride as a polyfunctional organocatalyst under solvent-free conditions. The protocol avoids the use of expensive catalysts, toxic solvents, and chromatographic separation and provides a wide range of novel dihydronaphthofurans in good to excellent yields. 相似文献
206.
Abolfazl Olyaei Mohammad Sadegh Shahsavari Mahdieh Sadeghpour 《Research on Chemical Intermediates》2018,44(2):943-956
An efficient tandem reaction approach is described to prepare novel benzo[f]chromenes from 2,3-dihydroxynaphthalene, malononitrile and aldehydes using 10 mol% guanidine hydrochloride as the catalyst under solvent-free conditions. The method was also extended to the preparation of novel 12H-benzo[5,6]chromeno[2,3-b]pyridines from 2-aminoprop-1-ene-1,1,3-tricarbonitrile instead of malononitrile under the same reaction conditions. The described one-pot three-component reaction is characterized by short reaction times, high-product yield, mild reaction conditions, simple workup procedure, and simple purification. 相似文献
207.
Mina Iranpour Reza Fazaeli Mirabdullah Seyed Sadjadi Mohammad Yousefi 《Russian Journal of Inorganic Chemistry》2018,63(8):1079-1083
This study investigates solvent effect on several electronic structure features, i.e. structural stability, orbital energies, HOMO-LUMO gaps and hardness of an iron aminoborirene complex [(η5-C5H5)(OC)2Fe{μ- BN(SiH3)2C=C}Ph] (closed-isomer) and its isomer the boryl complex [(η5-C5H5)(OC)2FeBN(SiH3)2C≡CPh] (open-isomer) through polarizable continuum model. Results revealed that the closed isomer is less stable than the open isomer, in solvent. Further, influence of the solvent on the frontier orbitals energies, HOMOLUMO gap, electrophilicity and chemical potential energies of the isomers was studied. Thermochemical analysis was conducted to study closed-open equilibrium and thermochemical parameters (ΔG and ΔH) were computed. 相似文献
208.
Mohammad Esmaeil Shahaboddin Khosro Khajeh Abolfazl Golestani 《Applied biochemistry and biotechnology》2018,186(2):358-370
Removal of chondroitin sulfate glycosaminoglycan (GAG) chains with chondroitinase ABC I (chABC I) in CNS injury models promotes both saxon regeneration and plasticity. It has been suggested that direct interaction between an aromatic pair appears to contribute about ??1.3 kcal/mol to the stability of a folded protein, so introducing an aromatic pair by point mutation might increase the enzyme activity and thermal stability as in the case of mesophilic xylanase, although using this approach destabilized T4 lysozyme. In this study, we used site-directed mutagenesis to investigate the effect of new aromatic pairs on activity and stability of chABC I. We replaced Ile295, Ser581, and Gly730 adjacent to pre-existing aromatic residues with Tyr to obtain new aromatic pairs, i.e., Tyr295/His372, Tyr576/Tyr581, and Tyr623/Tyr730. Results showed that Km values of S581Y and G730Y variants decreased relative to wild-type enzyme while their catalytic efficiency (kcat/Km) increased but I295Y variant was inactive. Also, long-term and thermal stability of the active mutants was decreased. Fluorescence and circular dichroism studies showed that these mutations resulted in a more flexible enzyme structures: a finding which was confirmed by thermal and limited proteolytic studies. In conclusion, the activity of chABC I can be improved by introducing appropriate aromatic pairs at the enzyme surface. This approach did not provide any promising results regarding the enzyme stability. 相似文献
209.
Ahmad Mani-Varnosfaderani Atefeh Kanginejad Kambiz Gilany Abolfazl Valadkhani 《Analytica chimica acta》2016
The present work deals with the development of a new baseline correction method based on the comparative learning capabilities of artificial neural networks. The developed method uses the Bayes probability theorem for prevention of the occurrence of the over-fitting and finding a generalized baseline. The developed method has been applied on simulated and real metabolomic gas-chromatography (GC) and Raman data sets. The results revealed that the proposed method can be used to handle different types of baselines with cave, convex, curvelinear, triangular and sinusoidal patterns. For further evaluation of the performances of this method, it has been compared with benchmarking baseline correction methods such as corner-cutting (CC), morphological weighted penalized least squares (MPLS), adaptive iteratively-reweighted penalized least squares (airPLS) and iterative polynomial fitting (iPF). In order to compare the methods, the projected difference resolution (PDR) criterion has been calculated for the data before and after the baseline correction procedure. The calculated values of PDR after the baseline correction using iBRANN, airPLS, MPLS, iPF and CC algorithms for the GC metabolomic data were 4.18, 3.64, 3.88, 1.88 and 3.08, respectively. The obtained results in this work demonstrated that the developed iterative Bayesian regularized neural network (iBRANN) method in this work thoroughly detects the baselines and is superior over the CC, MPLS, airPLS and iPF techniques. A graphical user interface has been developed for the suggested algorithm and can be used for easy implementation of the iBRANN algorithm for the correction of different chromatography, NMR and Raman data sets. 相似文献
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In this investigation, the chemical compositions of berries from sea buckthorn were studied. The amount of ascorbic acid and β-carotene determined by HPLC was 170 mg/100 g FW and 0.20 mg/g FW, respectively. Total phenols, anthocyanins, acidity and total soluble solids (TSS) contents were 247 mg GAE/100 g FW, 3 mg/L (cyanidin-3-glucoside), 5.32% and 13.8%, respectively. Fruit antioxidant activity determined by the ferric reducing ability of plasma (FRAP) method was 24.85 mM Fe/100 g FW. Results confirmed the presence of six dominant fatty acids (determined by GC) in fruit including linoleic (34.2%), palmitoleic (21.37%), palmitic (17.2%), oleic (12.8%), linolenic (5.37%) and stearic acid (1.67%). Five dominant fatty acids of the seeds were linoleic (42.36%), linolenic (21.27%), oleic (21.34%), palmitic (6.54%) and stearic acid (2.54%). The nitrogen content was 3.96%. The P, K, Ca, Mg, Fe, Zn, Mn, Cu, Cd and Cl contents of fruit were 491, 1674, 1290, 990, 291, 29.77, 108.37, 17.87, 0.021 and 2.18 mg/kg DW, respectively. 相似文献