A low perfusion rate microreactor for continuous monitoring of enzyme characteristics: application to glucose oxidase

This report describes a versatile and robust microreactor for bioactive proteins physically immobilized on a polyether sulfone filter. The potential of the reactor is illustrated with glucose oxidase immobilized on a filter with a cut-off value of 30 kDa. A flow-injection system was used to deliver the reactants and the device was linked on-line to an electrochemical detector. The microreactor was used for on-line preparation of apoglucose oxidase in strong acid and its subsequent reactivation with flavin adenine dinucleotide. In addition we describe a miniaturized version of the microreactor used to assess several characteristics of femtomole to attomole amounts of glucose oxidase. A low negative potential over the electrodes was used when ferrocene was the mediator in combination with horseradish peroxidase, ensuring the absence of oxidation of electro-active compounds in biological fluids. A low backpressure at very low flow rates is an advantage, which increases the sensitivity. A variety of further applications of the microreactor are suggested

Stripping the Boss : The Powerful Role of Humor in the Egyptian Revolution 2011

The Egyptian Revolution 2011 has shaken the Arab world and stirred up Middle-East politics. Moreover, it caused a rush in political science and the neighboring disciplines, which had not predicted an event like this and now have troubles explaining it. While many things can be learned from the popular uprising, and from the limitations of previous scholarship, our focus will be on a moral resource, which has occasionally been noticed, but not sufficiently explored: the role of humor in keeping up the spirit of the Revolution. For eighteen days, protestors persevered at Liberation Square in Central Cairo, the epicenter of resistance; at times a few dozens, at times hundreds of thousands. What they did was to fight the terror of the regime, which reached absurd peaks during those days, with humor – successfully. We offer a social-functionalist account of the uprising, which includes behavioral as well as cultural levels of analysis, and illuminates how humorous means helped to achieve deadly serious goals. By reconstructing how Egyptians laughed themselves into democracy, we outline a social psychology of resistance, which uses humor both as a sword and a shield.Peer reviewe

Design and synthesis of novel pyrrolo[2,3-b]pyridine derivatives targeting V600EBRAF

Several pyrrolo[2,3-b]pyridine-based B-RAF inhibitors are well known and some of them are currently FDA approved as anticancer agents. Based on the structure of these FDA approved V600E B-RAF inhibitors, two series of pyrrolo[2,3-b]pyridine scaffold were designed and synthesized in attempt to develop new potent V600E B-RAF inhibitors. The 38 synthesized compounds were biologically evaluated for their V600E B-RAF inhibitory effect at single dose (10 μM). Compounds with high percent inhibition were tested to determine their IC 50 over V600E B-RAF. Compounds 34e and 35 showed the highest inhibitory effect with IC 50 values of 0.085 µM and 0.080 µM, respectively. Headed for excessive biological evaluation, the synthesized derivatives were tested over sixty diverse human cancer cell lines. Only compound 35 emerged as a potent cytotoxic agent against different panel of human cancer cell lines

Structural optimization of imidazothiazole derivatives affords a new promising series as B-Raf V600E inhibitors; synthesis, in vitro assay and in silico screening

BRAF mutation is commonly known in a number of human cancer types. It is counted as a potential component in treating cancer. In this study, based on structural optimization of previously reported inhibitors (3-fluro substituted derivatives of imidazo[2,1-b]thiazole-based scaffold), we designed and synthesized sixteen new imidazo[2,1-b]thiazole derivatives with m-nitrophenyl group at position 6. The electron withdrawing properties was reserved while the polarity was modified compared to previously synthesized compounds (-F). Furthermore, the new substituted group (-NO 2) provided an additional H-bond acceptor(s) which may bind with the target enzyme through additional interaction(s). In vitro cytotoxicity evaluation was performed against human cancer cell line (A375). In addition, in vitro enzyme assay was performed against mutated B-Raf (B-Raf V600E). Compounds 13a, 13g and 13f showed highest activity on mutated B-Raf with IC 50 0.021, 0.035 and 0.020 µM. All target compounds were tested for in vitro cytotoxicity against NCI 60 cell lines. Compounds 13a and 13g were selected for 5 doses test mode. Moreover, in silico molecular simulation was explored in order to explore the possible interactions between the designed compounds and the B-Raf V600E active site

Design, synthesis, and biological evaluation of novel imidazole derivatives possessing terminal sulphonamides as potential BRAFV600E inhibitors

BRAF V600E mutation has been detected in various malignant tumours. Developing of potent BRAF V600E inhibitors is considered a leading step in the way to cure different cancer types. In the current work, a series of 38 4-(1H-imidazol-5-yl)pyridin-2-amine derivatives was designed and synthesized using Dabrafenib as a lead compound for structural-guided optimization. The target compounds were evaluated as potential anticancer agents against NCI 60 human cancer cell lines. In 5-dose testing mode, two compounds 14h and 16e were tested to determine their IC 50 values over each of the 60 cell lines. The selected candidates exhibited promising activity with mean IC 50 values of 2.4 µM and 3.6 µM, respectively. Melanoma cancer cell lines exhibited the highest sensitivity after the treatment with the tested compounds 14h and 16e. The mean IC 50 values of compounds 14h and 16e against Melanoma cancer cell lines are 1.8 µM and 1.88 µM, respectively. In addition, BRAF V600E kinase inhibitory activity was determined for each derivative. Compounds 15i, 15j, 16a, and 16d were the most potent inhibitors against BRAF V600E with IC 50 76 nM, 32 nM, 35 nM, and 68 nM. The newly developed compounds represent a therapeutically promising approach for the treating various cancer types

Design, synthesis, and anticancer activity of imidazo[2,1-b]oxazole-based RAF kinase inhibitors

In the present work, a novel series of B-RAF kinase inhibitors having imidazo[2,1-b]oxazole scaffold was designed and synthesized based on the structures of the well-known B-RAF inhibitors. The twenty two final compounds were tested over A375 and SKMEL28 cell lines to determine the primary cytotoxic activity of these compounds, and their activities were compared with that of sorafenib as a standard. Compounds 11c, 11e, 11o, 11q, 11r, and 11u exhibited higher cellular activity compared to sorafenib with IC 50 values of 7.25, 8.03, 9.81, 8.47, 4.70, and 9.04 µM, respectively and 10.38 µM for sorafenib. In addition, the target compounds were screened for their anticancer activity by the NCI-60 cell line assay. Compounds 11v and 11u were the most active compounds with percent inhibition reached 95.99% for 11v and 87.03% for 11u over K562 cell line at 10 µM concentration. Compound 11v was selected for 5-dose test mode. Furthermore, the kinase inhibitory activities of 11a, 11c, 11e, 11i, 11o, 11q, 11r, 11u, and 11v were determined against wild-type B-RAF, V600E-B-RAF, and RAF1. Compound 11o was the most potent against V600E-B-RAF with IC 50 34 nM followed by 11q and 11u with IC 50 92 and 93 nM, respectively

Modification of imidazothiazole derivatives gives promising activity in B-Raf kinase enzyme inhibition; synthesis, in vitro studies and molecular docking

B-Raf mutation was identified as a key target in cancer treatment. Based on structural features of dabrafenib (potent FDA approved B-Raf inhibitor), the design of new NH2-based imidazothiazole derivatives was carried out affording new highly potent derivatives of imidazothiazole-based scaffold with amino substitution on the terminal phenyl ring as well as side chain with sulfonamide group and terminal substituted phenyl ring. In vitro enzyme assay was investigated against V600E B-Raf kinase. Compounds 10l, 10n and 10o showed higher inhibitory activities (IC50 = 1.20, 4.31 and 6.21 nM, respectively). In vitro cytotoxicity evaluation was assessed against NCI-60 cell lines. Most of tested derivatives showed cytotoxic activities against melanoma cell line. Compound 10k exhibited most potent activity (IC50 = 2.68 µM). Molecular docking study revealed that the new designed derivatives preserved the same binding mode of dabrafenib with V600E B-Raf active site. It was investigated that the new modification in the synthesized derivatives (substituted with NH2) had a significant inhibitory activity towards V600E B-Raf. This core scaffold is considered a key compound for further structural and molecular optimization

The Influence of Microstructure on the Passive Layer Chemistry and Corrosion Resistance for Some Titanium-Based Alloys

The effect of microstructure and chemistry on the kinetics of passive layer growth and passivity breakdown of some Ti-based alloys, namely Ti-6Al-4V, Ti-6Al-7Nb and TC21 alloys, was studied. The rate of pitting corrosion was evaluated using cyclic polarization measurements. Chronoamperometry was applied to assess the passive layer growth kinetics and breakdown. Microstructure influence on the uniform corrosion rate of these alloys was also investigated employing dynamic electrochemical impedance spectroscopy (DEIS). Corrosion studies were performed in 0.9% NaCl solution at 37 °C, and the obtained results were compared with ultrapure Ti (99.99%). The different phases of the microstructure were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Chemical composition and chemistry of the corroded surfaces were studied using X-ray photoelectron spectroscopy (XPS) analysis. For all studied alloys, the microstructure consisted of α matrix, which was strengthened by β phase. The highest and the lowest values of the β phase’s volume fraction were recorded for TC21 and Ti-Al-Nb alloys, respectively. The susceptibility of the investigated alloys toward pitting corrosion was enhanced following the sequence: Ti-6Al-7Nb < Ti-6Al-4V << TC21. Ti-6Al-7Nb alloy recorded the lowest pitting corrosion resistance (Rpit) among studied alloys, approaching that of pure Ti. The obvious changes in the microstructure of these alloys, together with XPS findings, were adopted to interpret the pronounced variation in the corrosion behavior of these materials

Design, synthesis and anti-inflammatory activity of imidazol-5-yl pyridine derivatives as p38α/MAPK14 inhibitor

P38α/MAPK14 is intracellular signalling regulator involved in biosynthesis of inflammatory mediator cytokines (TNF-α, IL-1, IL-6, and IL-1b), which induce the production of inflammatory proteins (iNOS, NF-kB, and COX-2). In this study, drug repurposing strategies were followed to repositioning of a series of B-RAF V600E imidazol-5-yl pyridine inhibitors to inhibit P38α kinase. A group 25 reported P38α kinase inhibitors were used to build a pharmacophore model for mapping the target compounds and proving their affinity for binding in P38α active site. Target compounds were evaluated for their potency against P38α kinase, compounds 11a and 11d were the most potent inhibitors (IC 50 = 47 nM and 45 nM, respectively). In addition, compound 11d effectively inhibited the production of proinflammatory cytokines TNF-α, 1L-6, and 1L-1β in LPS-induced RAW 264.7 macrophages with IC 50 values of 78.03 nM, 17.6 µM and 82.15 nM, respectively. The target compounds were tested for their anti-inflammatory activity by detecting the reduction of Nitric oxide (NO) and prostaglandin (PGE2) production in LPS-stimulated RAW 264.7 macrophages. Compound 11d exhibited satisfied inhibitory activity of the production of PGE2 and NO with IC 50 values of 0.29 µM and 0.61 µM, respectively. Molecular dynamics simulations of the most potent inhibitor 11d were carried out to illustrate its conformational stability in the binding site of P38α kinase