Uncertainty modeling of carbon nanotube terahertz oscillators

Significant uncertainties have been reported in the material properties of carbon nanotubes. In this paper, a probabilistic approach to take account of these uncertainties is proposed. The probability density function of the natural frequencies is derived in closed-form. The new results are compared with high-fidelity stochastic finite element simulations.     

Some zero-sum constants with weights

For an abelian group G, the Davenport constant D(G) is defined to be the smallest natural number k such that any sequence of k elements in G has a nonempty subsequence whose sum is zero (the identity element). Motivated by some recent developments around the notion of Davenport constant with weights, we study them in some basic cases. We also define a new combinatorial invariant related to (ℤ/nℤ) ^d , more in the spirit of some constants considered by Harborth and others and obtain its exact value in the case of (ℤ/nℤ)² where n is an odd integer.     

An efficient multi-use multi-secret sharing scheme based on hash function

In this work, a renewable, multi-use, multi-secret sharing scheme for general access structure based on the one-way collision resistant hash function is presented in which each participant has to carry only one share. As it applies the collision resistant one-way hash function, the proposed scheme is secure against conspiracy attacks even if the pseudo-secret shares are compromised. Moreover, high complexity operations like modular multiplication, exponentiation and inversion are avoided to increase its efficiency. Finally, in the proposed scheme, both the combiner and the participants can verify the correctness of the information exchanged among themselves.     

Isomeric Effects on Structures and Properties of Polyaminophenols Synthesized in Basic Medium

The oxidative chemical polymerizations of three isomers of aminophenol, ortho, meta, and para (PoAP, PmAP, PpAP) were performed in aqueous NaOH using ammonium persulfate (APS) as oxidant. Solubility tests for the synthesized polymers were performed in various solvents and it was found that all three polymers are soluble in DMSO and DMF. PpAP is soluble in aqueous strong acid, as well as in base, but PoAP is soluble in acid, whereas PmAP is soluble in base. The difference in their solubility is due to their structural difference, which can be supported by the proposed mechanisms of polymerizations. The film casting from the DMF or DMSO solution of PoAP and PpAP is difficult due to the presence of quinone impurity while casting of PmAP film from DMSO solution is possible. The intrinsic viscosities of the polymers were determined from the DMSO solution. The polymers were characterized by UV-VIS, FTIR and¹H-NMR spectroscopy and elemental analyses. From structural analysis, it is found that PoAP and PpAP do not contain π -electron conjugation due to ether linkage in the backbone chain. So, PoAP and PpAP do not show any conductivity like sulfuric acid doped PmAP.     

Efficient and Convenient Methods for Synthesis of Some Phthalazine Derivatives and Their Evaluation of Cytotoxicity

A systematic study of the reaction of 1,4-dihydrazinophthalazine (DHPH) with 1,3-dicarbonyls [viz., acetylacetone (acac), dibenzoylmethane (bzbz), and 1-benzoylacetone (bzac)] varying the reaction conditions was carried out to obtain the phthalazine derivatives (1–4). One-pot reaction of DHPH with acac led to the formation of two compounds 1 and 2, with various factors such as the presence of the acid or base, amount of the acac, time of reflux, and the temperature. The reaction conditions of DHPH with bzbz or bzac are sort of different to isolate the products 3 and 4, respectively. The derivatives (1–4) have been characterized by elemental analyses, ¹H NMR, and electrospray ionization–mass spectrometry (ESIMS) and the cytotoxic activity of the compounds 1–4 was evaluated on HeLa cell line.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Time-delay-induced phase-transition to synchrony in coupled bursting neurons

Signal transmission time delays in a network of nonlinear oscillators are known to be responsible for a variety of interesting dynamic behaviors including phase-flip transitions leading to synchrony or out of synchrony. Here, we uncover that phase-flip transitions are general phenomena and can occur in a network of coupled bursting neurons with a variety of coupling types. The transitions are marked by nonlinear changes in both temporal and phase-space characteristics of the coupled system. We demonstrate these phase-transitions with Hindmarsh-Rose and Leech-Heart interneuron models and discuss the implications of these results in understanding collective dynamics of bursting neurons in the brain.     

Assay of Ivermectin Including Determination and Identification of Its Related Substances in Ivermectin Injectable Product by a Stability-Indicating RP-HPLC Method

Chromatographia - Ivermectin injectable product is widely used as a parasiticide for the treatment and control of internal and external parasites of cattle and swine. A reversed-phase high...