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91.
We investigate unconditional security for message authentication protocols that are designed using two-channel cryptography. (Two-channel cryptography employs a broadband, insecure wireless channel and an authenticated, narrow-band manual channel at the same time.) We study both noninteractive message authentication protocols (NIMAPs) and interactive message authentication protocols (IMAPs) in this setting. First, we provide a new proof of nonexistence of nontrivial unconditionally secure NIMAPs. This proof consists of a combinatorial counting argument and is much shorter than the previous proof by Wang and Safavi-Naini, which was based on probability distribution arguments. We also prove a new result which holds in a weakened attack model. Further, we propose a generalization of an unconditionally secure 3-round IMAP due to Naor, Segev and Smith. The IMAP is based on two ?-Δ universal hash families. With a careful choice of parameters, our scheme improves that of Naor et al. Our scheme is very close to optimal for most parameter situations of practical interest. Finally, a variation of the 3-round IMAP is presented, in which only one hash family is required.  相似文献   
92.
The adsorption of the dyes Acid Red 114 and Reactive Black 5 in aqueous solutions on polyhydroxyl dendrimer magnetic nanoparticles (Fe3O4@SiO2‐TRIS) was studied in a batch system. The Fe3O4@SiO2‐TRIS NPs were characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, and transmission electron microscopy. Experiments were performed under different conditions such as the initial dye concentration, adsorbent dose, and pH. The pseudo‐second‐order model provided a very good fit for the two anionic dyes. The Langmuir and Freundlich adsorption models were used to describe the equilibrium isotherms at different temperatures, and the former agreed very well with the experimental data. However, the adsorption capacity of Fe3O4@SiO2‐TRIS NPs was reduced during surface modification, which could be due to the dye occupying the binding sites of the dendrimer. Thermodynamic parameters, namely the change in free energy (ΔG0), enthalpy (ΔH0), and entropy (ΔS0), were also determined.  相似文献   
93.
Structural Chemistry - In the present study, an asymmetric tetradentate NOON Schiff base ligand 2,2′-((4-methyl-1,2-phenylene)bis(nitrilomethylylidene))bis(4-chlorophenol) (H2L) was...  相似文献   
94.
Construction and feature of a nanocomposite modified carbon paste electrode for aluminum(III) ion determination based on N,N′-dipyridoxyl (1,2-cyclohexanediamine) (PYCA) as a novel selector material will be covered by this paper. The optimum composition, Nernstian slope/linear range/detection limit in the forms of calibration graph, response time, utilizable pH range, repeatability and precision of measurements of the aluminum(III) ion using the new fabricated Al3+-CPE was evaluated. The optimal composition which performed over Al+3 ion concentration range 1.0 × 10?8 mol L?1–1.0 × 10?1 mol L?1 with near-Nernstian slope equal 20.9 ± 0.2 mV decade?1 and low detection limit about 5.0 × 10?9 mol L?1, was formed of ionophore (PYCA 3 %), binder (paraffin oil 30 %), modifier [multi-wall carbon nanotubes (MWCNTs) 1 %] & [Nanosilica (NS) 0.5 %], and inert matrix (graphite powder 65.5). The request time to give rise Nernstian response of electrode for concentrations from 1.0 × 10?8 mol L?1 to 1.0 × 10?1 mol L?1 of Al3+ ion solution was estimated about ~6 s. The new Al3+-CPE was applied in pH range 2.0–5.0 with no consequential change in potential response. To verify the selectivity of electrode toward aluminum(III) ion in the presence of different metallic cations, matched potential method was used. The obtain results in analytical applications reflect the excellent ability of this electrode to play the role as endpoint indicator electrode in both titration and direct potentiometric measurements.  相似文献   
95.
Micromeria persica Boiss. is medicinal and aromatic plant, belonging to the Lamiaceae family. The chemical composition of the essential oils (EOs) from aerial parts of M. persica were extracted using hydro-distillation method and analysed using GC and GC–MS. Fifty-two compounds were identified in the EOs of aerial parts of M. persica. The main chemical compositions were n-hexadecanoic acid (14.9%), thymol (9.5%), linoleic acid (8.0%), carvacrol (5.6%), (E)-nerolidol (5.5%), linolenic acid (5.5%), α-cadinol (2.7%), linalool (2.7%), borneol (2.6%), caryophyllene oxide (2.3%) and pulegone (2.0%). Presence of borneol, thymol, carvacrol and pulegone suggests the potential of this plant as a flavouring source in the food industry, being used in perfumery and cosmetics industry, vitamin E synthesis and exhibit strong fungicidal, antibacterial and antimicrobial activities.  相似文献   
96.
Lagoecia cuminoides L. belongs to the family of Umbelliferae (Apiaceae), and known also as common wild cumin. The aerial parts of L. cuminoides were collected at the flowering stage and dried, then the methanolic extract was analyzed for polyphenol compounds identified by HPLC-DAD and antioxidant activity (DPPH(2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay). It was found that the predominant phenolic constituents were chlorogenic acid, hesperidin, rosmarinic acid, hesperetin and vanillin. The antioxidant activity of methanolic extract from L. cuminoides was found 1597 μg/mL in DPPH scavenging assay. There is no strict positive relationship between the polyphenolic content and antioxidant activity of extracts.  相似文献   
97.
Single crystal viscoplasticity, with a regularization technique for the power law, is presented and implemented into a discontinuous Galerkin (DG) framework. Although single crystal plasticity has been extensively studied, its examination with the regularization method in combination with a DG formulation leads to a numerically efficient and robust model. The performance of the DG framework in crystal viscoplasticity is shown by an example. (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   
98.
New Schiff base complexes of zinc(II), copper(II), nickel(II), and vanadium(IV) were synthesized using the Schiff base ligand formed by the condensation of 2-aminoethanethiol and 2-hydroxy-1-naphthaldehyde. The tetradentate Schiff base ligand N,N´-(3,4-dithiahexane-1,6-diyl)bis(2-hydroxy-1-naphthaleneimine), containing a disulfide bond, was coordinated to the metal(II) ions through the two azomethine nitrogen atoms and two deprotonated phenolic oxygens of two different ligands which was connected to each other by sulfur-sulfur bond. The molar conductivity values of complexes in DMSO solvent implied the presence of nonelectrolyte species. The fluorescence properties of the Schiff base ligand and its complexes were studied in dimethylsulfoxide. The Schiff base ligand and its complexes were characterized by FT-IR, 1H NMR, UV/Vis spectroscopies, elemental analysis, and conductometry. The crystal structure of tetradentate Schiff base ligand was characterized by single crystal X-ray diffraction. The Schiff base ligand was contained disulfide bond. Furthermore, the binding interaction of these complexes with calf thymus DNA (CT-DNA) was investigated by different methods.  相似文献   
99.

Here, the synthesis of photochromic hydrogen bond-assembled [2]rotaxanes using bis-fumarate as a thread for the first time is reported. In fact, photochromic 1,3-diazabicyclo[3.1.0]hex-3-ene moieties were used as stoppers and two-atom spacers managed good binding sites for the tetralactam macrocycles in clipping reactions. Moreover, the yields of photochromic [2]rotaxanes highly depended on the NO2 substituent stoppers. While the thread with a para –NO2 substituent as stopper units was shown to be an excellent template for the synthesis of photochromic [2]rotaxanes. The structures of the [2]rotaxanes are established clearly in solution by chemical shifts of the 1H 13C NMR signals and UV–Vis spectra. A pronounced bathochromic shift was occurred in the excitation wavelength of photochoromic [2]rotaxanes compared with the absorption band of photochromic threads. Therefore, these organizations can be applied in light-driven molecular switches and motors. The reversible transformation of trans and cis geometric photoisomers under UV radiation was identified. In other efforts, the possibility of the process of trans to cis interconversion of the fumarate linker under UV irradiation has been examined computationally and it has appeared that it may cause the transverse of the bis-fumarate linker inside the tetralactam macrocycle to some extent.

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100.
ABSTRACT

The growth of cancer is still the focus of many research works in the scientific community. So far, various models have been introduced to analyse the behaviour of cancers, including the mathematical growth models such as Logistic, Gompertz and Bertalany. Despite the advances in the analysis of the cancer behaviour, the lack of definitive treatment of cancer disease indicates the need for new perspectives which are supported by more biological background. Recently, a model has been proposed, in which, the tumour growth is interpreted as the outcome of the competition of healthy and cancer cells over the available oxygen, nutrients and space. We have modified this model in order to provide the necessary preparations for wider use of the model in growth rate, growth curve and growth prediction of tumours. Meanwhile, the model is performed on some experimental data to show its capabilities.  相似文献   
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