Synthesis and biological evaluation of 5-methyl-4-phenyl thiazole derivatives as anticancer agents

Abstract

New N-(5-methyl-4-phenylthiazol-2-yl)-2-(substituted thio)acetamides were synthesized and studied for their anticancer activity. The title compounds were procured by reacting 2-chloro-N-(5-methyl-4-phenylthiazol-2-yl)acetamide with some mercapto derivatives. The structural elucidation of the compounds was performed by ¹H-NMR, ¹³C-NMR and LC-MS/MS spectral data and elemental analyses. The synthesized compounds were investigated for their antitumor activities against A549 human lung adenocarcinoma cells and NIH/3T3 mouse embryoblast cell line for determining their selective cytotoxicity. 2-[(1-methyl-1H-tetrazol-5-yl)thio]-N-(5-methyl-4-phenylthiazol-2-yl)acetamide (4c) showed high selectivity, and whose IC₅₀ value was determined as 23.30?±?0.35?µM and >1000?µM against A549 human lung adenocarcinoma cells and NIH/3T3 mouse embryoblast cell lines, respectively. 2-[(1-Methyl-1H-imidazol-2-yl)thio]-N-(5-methyl-4-phenyl thiazol-2-yl)acetamide (4a) and 2-[(1-Methyl-1H-tetrazol-5-yl)thio]-N-(5-methyl-4-phenyl thiazol-2-yl)acetamide (4c) exhibited the highest apoptosis percentage among those tested, but not as high as the standard, cisplatin.     

Magnetoresistance near the metal-insulator transition of Cd0.99Mn0.01Se

At 0.5 ≤ T ≤ 4.2 K samples of Cd_0.99Mn_0.01Se which are near the metal-insulator transition exhibit a large positive magnetoresistance (MR) in fields H ∽ 10 k0e. The effect is accompanied by an increase in the Hall coefficient and a decrease in the Hall mobility. At the lowest temperatures and for fields well above 10 k0e a small negative MR is observed. The positive MR is tentatively attributed to an increase in the screening radius r_s, which leads to enhanced Coulomb-potential fluctuations.     

Measurement of compound-nucleus lifetime by X-ray spectroscopy in the 106Cd(p,p')106Cd reaction

A new method for measuring compound-nucleus lifetimes in the range of 10^?18–10^?16 s is presented. The method is based on the comparison between the known lifetime of an atomic excited state used as a reference and the nuclear delay time to be measured. On-line coincidences performed between the nuclear reaction products and the emitted X-rays enable the selection of the atomic vacancies decaying during the compound stage of the nuclear interaction. The main characteristics of this technique are illustrated by measurements of lifetimes of the ¹⁰⁷In compound nucleus excited at 13.6 and 15.6 MeV in the ¹⁰⁶Cd(p, p')¹⁰⁶Cd reaction. They are found in agreement with statistical model calculations. The spurious effect associated with decay by internal conversion of final states populated by the competitive (p, n) reaction is emphasized.     

Approximation algorithm for minimizing total latency in machine scheduling with deliveries

We study the problem of minimizing total latency in machine scheduling with deliveries, which is defined as follows. There is a set of n jobs to be processed by a single machine at a plant, where job J_i is associated with its processing time and a customer i located at location i to which the job is to be delivered. In addition, there is a single uncapacitated delivery vehicle available. All jobs (vehicle) are available for processing (delivery) at time 0. Our aim is to determine the sequence in which the jobs should be processed in the plant, the departure times of the vehicle from the plant, and the routing of the vehicle, so as to minimize the total latency (job delivery time). We present a 6e16.309691-approximation algorithm for the problem.     

A tournament approach to pattern avoiding matrices

We consider the following Turán-type problem: given a fixed tournament H, what is the least integer t = t(n,H) so that adding t edges to any n-vertex tournament, results in a digraph containing a copy of H. Similarly, what is the least integer t = t(T _n ,H) so that adding t edges to the n-vertex transitive tournament, results in a digraph containing a copy of H. Besides proving several results on these problems, our main contributions are the following:

• Pach and Tardos conjectured that if M is an acyclic 0/1 matrix, then any n × n matrix with n(log n) ^O(1) entries equal to 1 contains the pattern M. We show that this conjecture is equivalent to the assertion that t(T _n ,H) = n(log n) ^O(1) if and only if H belongs to a certain (natural) family of tournaments.
• We propose an approach for determining if t(n,H) = n(log n) ^O(1). This approach combines expansion in sparse graphs, together with certain structural characterizations of H-free tournaments. Our result opens the door for using structural graph theoretic tools in order to settle the Pach–Tardos conjecture.

     

Optical AND gate based on soliton interaction in a fiber Bragg grating

Using computer simulations, we demonstrate an optical cascadable AND gate based on soliton interaction in a fiber Bragg grating. A single soliton that is launched into the device is backreflected. When two solitons are launched, one of the solitons is transmitted while the other is backreflected. The time delay between the solitons may be few times longer than the duration of the solitons. We show that the interaction causes an increase in the frequency of one of the solitons that enables its transmission through the grating bandgap.     

Temperature Integration: An efficient procedure for calculation of free energy differences

We propose a method, Temperature Integration, which allows an efficient calculation of free energy differences between two systems of interest, with the same degrees of freedom, which may have rough energy landscapes. The method is based on calculating, for each single system, the difference between the values of lnZ$lnZ$ at two temperatures, using a Parallel Tempering procedure. If our two systems of interest have the same phase space volume, they have the same values of lnZ$lnZ$ at high-T$T$, and we can obtain the free energy difference between them, using the two single-system calculations described above. If the phase space volume of a system is known, our method can be used to calculate its absolute (versus relative) free energy as well. We apply our method and demonstrate its efficiency on a “toy model” of hard rods on a 1-dimensional ring.     

Avoider–Enforcer games played on edge disjoint hypergraphs

We analyze Avoider–Enforcer games played on edge disjoint hypergraphs, providing an analog of the classic and well known game Box, due to Chvátal and Erd?s. We consider both strict and monotone versions of Avoider–Enforcer games, and for each version we give a sufficient condition to win for each player. We also present applications of our results to several general Avoider–Enforcer games.     

Experimental observation of self-accelerating beams in quadratic nonlinear media

We present the experimental observation of 1D and 2D self-accelerating nonlinear beams in quadratic media, which are also the first nonlinear self-accelerating beams in any symmetric nonlinearity. Notably, we show that the intensity peaks of the first and second harmonics are asynchronous with respect to one another, but the coupled harmonics exhibit joint acceleration within the nonlinear medium. Finally, we demonstrate the impact of self-healing effects on the jointly accelerating first and second harmonics.     

Self-similar amplification in fiber Bragg gratings written in fiber amplifiers

We show, by using numerical simulations, that self-similar pulses with a duration on the order of few nanoseconds and an energy on the order of 10?μJ can be obtained at the output of a fiber Bragg grating (FBG) written in a fiber amplifier. The evolution of the amplified pulses is determined by the combined effect of Kerr nonlinearity, normal-dispersion, gain, and gain saturation, which limit the pulse energy. The output pulse mainly depends on the initial pulse energy rather than on the initial pulse profile. The reduced group velocity in FBGs can significantly increase the total gain for a given amplifier length. Hence we find that the proposed amplification scheme can be highly advantageous for amplification of nanosecond-scale pulses in fiber amplifiers.