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101.
Ali Mehri Sahar Mohammadpour Lashkari 《The European Physical Journal B - Condensed Matter and Complex Systems》2016,89(11):241
Complex structure of human language enables us to exchange very complicated information. This communication system obeys some common nonlinear statistical regularities. We investigate four important long-range features of human language. We perform our calculations for adopted works of seven famous litterateurs. Zipf’s law and Heaps’ law, which imply well-known power-law behaviors, are established in human language, showing a qualitative inverse relation with each other. Furthermore, the informational content associated with the words ordering, is measured by using an entropic metric. We also calculate fractal dimension of words in the text by using box counting method. The fractal dimension of each word, that is a positive value less than or equal to one, exhibits its spatial distribution in the text. Generally, we can claim that the Human language follows the mentioned power-law regularities. Power-law relations imply the existence of long-range correlations between the word types, to convey an especial idea. 相似文献
102.
Maryam Nourisefat Farhad Panahi Marzieh Nabipour Sahar Heidari Ali Khalafi-Nezhad 《Journal of the Iranian Chemical Society》2016,13(10):1853-1865
l-Cysteine-functionalized magnetic nanoparticles (LCMNP) were introduced as an efficient and magnetically separable organocatalyst for the synthesis of 9-(1H-indol-3-yl) xanthen-4-(9H)-one derivatives. This class of compounds was synthesized via a one-pot three-component coupling reaction of 2-hydroxybenzaldehyde, dimedone, and indole in the presence of catalytic amount of LCMNP under mild and green conditions. High yields, short reaction time, easy workup, using environmental friendly conditions, and magnetic reusable catalyst are the advantages of this synthetic methodology. The LCMNP catalyst was reusable in this reaction at least for 6 times without significant decreasing in its catalytic activity. 相似文献
103.
Helwa Amira A. Gedawy Ehab M. Abou-Seri Sahar M. Taher Azza T. El-Ansary Afaf K. 《Research on Chemical Intermediates》2018,44(4):2685-2702
Research on Chemical Intermediates - New series of pyrimidinone-5-carbonitriles 3a–i, 4a–e, 5a–c, 6 and 7 have been synthesized and explored for their activities as anticancer,... 相似文献
104.
105.
Micro- and nano-structural analyses of damage in bone 总被引:4,自引:0,他引:4
Skeletal fractures represent a significant medical and economic burden for our society. In the US alone, age-related hip, spine, and wrist fractures accounted for more than $17 billion in direct health care costs in 2001. Moreover, skeletal fractures are not limited to the elderly; stress fractures and impact/trauma-related fractures are a significant problem in younger people also. Gaining insight into the mechanisms of fracture and how these mechanisms are modulated by intrinsic as well as extrinsic factors may improve the ability to define fracture risk and develop and assess preventative therapies for skeletal fractures. Insight into failure mechanisms of bone, particularly at the ultrastructural-level, is facilitated by the development of improved means of defining and measuring tissue quality. Included in these means are microscopic and spectroscopic techniques for the direct observation of crack initiation, crack propagation, and fracture behavior. In this review, we discuss microscopic and spectroscopic techniques, including laser scanning confocal microscopy (LSCM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopic imaging for visually observing microdamage in bone, and the current understanding of damage mechanisms derived from these techniques. 相似文献
106.
Ring‐Opening Copolymerization of Maleic Anhydride with Functional Epoxides: Poly(propylene fumarate) Analogues Capable of Post‐Polymerization Modification 下载免费PDF全文
Yusheng Chen Dr. James A. Wilson Shannon R. Petersen Derek Luong Dr. Sahar Sallam Jialin Mao Prof. Chrys Wesdemiotis Prof. Matthew L. Becker 《Angewandte Chemie (International ed. in English)》2018,57(39):12759-12764
Three functional epoxides were copolymerized with maleic anhydride to yield degradable poly(propylene fumarate) analogues. The polymers were modified post‐polymerization and post‐printing with either click‐type addition reactions or UV deprotection to either attach bioactive species or increase the hydrophilicity. Successful dye attachment, induced wettability, and improved cell spreading show the viability of these analogues in biomaterials applications. 相似文献
107.
Jahan Bakhsh Raoof Abolfazl Kiani Reza Ojani Roudabeh Valiollahi Sahar Rashid-Nadimi 《Journal of Solid State Electrochemistry》2010,14(7):1171-1176
Gold nanoparticles (GNs) could be efficiently immobilized on binary mixed self-assembled monolayers (SAMs) on a gold surface
composed of 1,6-hexanedithiol and 1-octanethiol (nano-Au/SAMs gold electrode). This GN chemically modified electrode was used
for electrochemical determination of ascorbic acid (AA) and dopamine (DA) in aqueous media. The result showed that the GN-modified
electrode could clearly resolve the oxidation peaks of AA and DA, with a peak-to-peak separation (∆E
p) of 110 mV enabling determination of AA and DA in the presence of each other. The linear analytical curves were obtained
in the ranges of 0.3–1.4 mM for AA and 0.2–1.2 mM for DA concentrations using differential pulse voltammetry. The detection
limits (3σ) were 9.0 × 10−5 M for AA and 9.0 × 10−5 M for DA. 相似文献
108.
The electrodes (anode and cathode) have an important role in the efficiency of a microbial fuel cell (MFC), as they can determine the rate of charge transfer in an electrochemical process. In this study, nanoporous gold electrode, prepared from commercially available gold-made compact disk, is utilized as the anode in a two-chamber MFC. The performance of nanoporous gold electrode in the MFC is compared with that of gold film, carbon felt and acid-heat-treated carbon felt electrodes which are usually employed as the anode in the MFCs. Electrochemical surface area of nanoporous gold electrode exhibits a 7.96-fold increase rather than gold film electrode. Scanning electron microscopy analysis also indicates the homogeneous biofilm is formed on the surface of nanoporous gold electrode, while the biofilm formed at the surface of acid-heat-treated carbon felt electrode shows rough structure. Electrochemical studies show although modifications applied on carbon felt electrodes improve its performance, nanoporous gold electrode, due to its structure and better electrochemical properties, acts more efficiently as the MFC’s anode. The maximum power density produced by nanoporous gold anode is 4.71 mW m?2 at current density of 16.00 mA m?2, while this value for acid-heat-treated carbon felt anode is 3.551 mW m?2 at current density of 9.58 mA m?2. 相似文献
109.
Sahar A. El-Molla Laila I. Ali Nabil H. Amin Anwer A. Ebrahim Hala R. Mahmoud 《Chemical Papers》2012,66(8):722-732
The effects of Ag-doping on the physico-chemical, spectral, surface, and catalytic properties of the FeMgO system with various Fe2O3 loadings were investigated. The dopant (Ag) molar ratio varied between 0.01 % and 0.05 %. The techniques employed for characterisation of catalysts were TG/DTG, XRD, ESR, N2 adsorption at ?196°C, and catalytic decomposition of H2O2 at 25?C35°C. The results obtained revealed that the investigated catalysts consisted of nanosized MgO as the major phase, apart from the MgFe2O4 and/or Fe3O4 phases. ESR result of the FeMgO system revealed the presence of paramagnetic species as a result of Ag-doping. The textural properties including SBET, porosity and St were modified by Ag-doping. The doping process with Ag-species improved the catalytic activity of the FeMgO system. Increasing the calcination temperature from 400°C to 800°C increased the catalytic activity (k*30 °C) of 0.05 AgFeMgO in H2O2 decomposition by 21.2 times. 相似文献
110.
Electrochemistry and electrogenerated chemiluminescence of 3,6-di(spirobifluorene)-N-phenylcarbazole
Rashidnadimi S Hung TH Wong KT Bard AJ 《Journal of the American Chemical Society》2008,130(2):634-639
We report here the electrochemistry, luminescence, and electrogenerated chemiluminescence (ECL) of 3,6-dispirobifluorene-N-phenylcarbazole (DSBFNPC). DSBFNPC contains two spirobifluorene groups covalently attached to the N-phenylcarbazole core. The optimized geometry as determined from semiempirical MNDO calculations shows that the phenyl group is twisted 89 degrees from the plane of central carbazole, indicating a lack of electron delocalization between these groups. However, the two fluorene rings of each spirobifluorene group are twisted 58 degrees relative to each other and two spirobifluorene groups are twisted 64 degrees from the N-phenylcarbazole ring, suggesting some charge delocalization among these groups. The cyclic voltammetry of this compound shows two reversible oxidation waves (assigned to the formation of the cation and dication) and a two-electron reduction wave that becomes reversible at higher scan rates (assigned to formation of anion). Digital simulations were carried out to obtain details of the electrochemical processes, and electrochemical behavior was compared to that of phenylcarbazole (PC). Upon cycling between the oxidation and reduction waves, ECL is produced by radical ion annihilation. The photophysical properties of DSBFNPC show a strong resemblance to the parent compound, PC, and the ECL spectrum produced via radical ion annihilation shows good agreement with the fluorescence emission spectrum of DSBFNPC. 相似文献