On the 3-Colouring Vertex Folkman Number F(2,2,4)

In this note we prove that F (2, 2, 4) = 13.

Complexation in composite solutions of melanin with 2,4,7-trinitrofluorenone

A feasibility of formation of donor-acceptor charge-transfer (CT) complexes between melanin and 2,4,7-trinitrofluorenone (TNF) being good electron acceptor has been studied in solutions by means of the absorption and photoluminescence (PL) spectra. The model of electronic transitions in a melanin-TNF composite solution has been proposed. © 2014 Copyright Taylor & Francis Group, LLC.

Molecular mechanisms of salt effects on carbon nanotube dispersions in an organic solvent (N-methyl-2-pyrrolidone)

We consider the effects of salt (sodium iodide) on pristine carbon nanotube (CNT) dispersions in an organic solvent, N-methyl-2-pyrrolidone (NMP). We investigate the molecular-scale mechanisms of ion interactions with the nanotube surface and we show how the microscopic ion-surface interactions affect the stability of CNT dispersions in NMP. In our study we use a combination of fully atomistic Molecular Dynamics simulations of sodium and iodide ions at the CNT-NMP interface with direct experiments on the CNT dispersions. In the experiments we analyze the effects of salt on the stability of the dispersions by photoluminescence (PL) and optical absorption spectroscopy of the samples as well as by visual inspection. By fully atomistic Molecular Dynamics simulations we investigate the molecular-scale mechanisms of sodium and iodide ion interactions with the nanotube surface. Our simulations reveal that both ions are depleted from the CNT surface in the CNT-NMP dispersions mainly due to the two reasons: (1) there is a high energy penalty for the ion partial desolvation at the CNT surface; (2) NMP molecules form a dense solvation layer at the CNT surface that prevents ions to come close to the CNT surface. As a result, an increase of the salt concentration increases the "osmotic" stress in the CNT-NMP system and, thus, decreases the stability of the CNT dispersions in NMP. Direct experiments confirm the simulation results: addition of NaI salt into the NMP dispersions of pristine CNTs leads to precipitation of CNTs (bundle formation) even at very small salt concentration (∼10 -3 mol L -1). In line with the simulation predictions, the effect increases with the increase of the salt concentration. Overall, our results show that dissolved salt ions have strong effects on the stability of CNT dispersions. Therefore, it is possible to stimulate the bundle formation in the CNT-NMP dispersions and regulate the overall concentration of nanotubes in the dispersions by changing the NaI concentration in the solvent. © 2012 The Royal Society of Chemistry.

Polarization insensitive in-fiber mode-locker based on carbon nanotube with N-methyl-2-pryrrolidone solvent filled fiber microchamber

We report an in-fiber laser mode locker based on carbon nanotube with n-methyl-2-pryrrolidone solvent filled in-fiber microchamber. Symmetrically femtosecond laser fabricated in-fiber microchamber with randomly oriented nanotubes assures polarization insensitive oscillation of laser mode locking. The proposed and demonstrated passively mode locked fiber laser shows higher energy soliton output. The laser has an output power of ∼29 mW (corresponding to 11 nJ energy). It shows stable soliton output with a repetition rate of ∼2.3 MHz and pulse width of ∼3.37 ps. © 2012 American Institute of Physics.

Fiber laser mode locked by carbon nanotubes-N-methyl-2-pryrrolidone solution in fiber microchannel

We demonstrated an Erbium-doped picosecond fiber laser mode locked by carbon nanotube in N-methyl-2-pryrrolidone solvent in an in-fiber micro-channel. © 2011 Optical Society of America.

Coordination networks of Cu2+ ions with 1,3-bis[2-(4-pyridyl)ethyl]benzene : strong structure-directing role of the counter ion (nitrate, acetate and sulphate), leading to clusters, sheets and chains

Date of Acceptance: 16/10/2015

Coordination networks of Cu2+ ions with 1,3-bis[2-(4-pyridyl)ethyl]benzene : strong structure-directing role of the counter ion (nitrate, acetate and sulphate), leading to clusters, sheets and chains

Date of Acceptance: 16/10/2015

A critical review of both the synthesis approach and the receptor profile of the 8-chloro-1-(2′,4′-dichlorophenyl)-N-piperidin-1-yl-1,4,5,6-tetrahydrobenzo[6,7]cyclohepta[1,2-c]pyrazole-3-carboxamide and analogue derivatives

We thank European Commission (project “PET BRAIN: Mapping the brain with PET radiolabeled cannabinoid CB1 ligands”; FP7-People-2009-IAPP; Grant Agreement N.25142).

Neue und selektive GSTP1-Inhibitoren mit 1,2,4-Trioxanstruktur als Grundlage für die Entwicklung einer effektiven Tumortherapie

Im Rahmen dieser Arbeit wurden selektive Inhibitoren der Glutathion-Transferase P1 (GSTP1) mit 1,2,4-Trioxanstruktur als potentielle Wirkstoffe gegen multiresistente Tumore synthetisiert. Die Darstellung dieser Substanzen erfolgte über Typ-II-Photooxygenierung allylischer Alkohole mit anschließender Säure-katalysierter Peroxyacetalisierung unter Verwendung von 4-Nitrobenzaldehyd. Über diesen Syntheseweg konnten unterschiedlich substituierte 1,2,4-Trioxane dargestellt werden. Die höchste biologische Aktivität zeigten Verbindungen mit aromatischen Estersubstituenten am 1,2,4-Trioxanring. Es wurde eine Leitstruktur entwickelt, die einen α,β-ungesättigten aromatischen Estersubstituenten in Position 6 des 1,2,4-Trioxangerüsts und in Position 3 einen 4-Nitrophenylsubstituenten aufweist. Die Verbindungen dieser Substanzklasse zeigen Inhibition der GSTP1 im niedrig mikromolaren Bereich. Durch Aktivitätsstudien an den GST-Klassen A und M konnte gezeigt werden, dass die Verbindungen selektiv GSTP1 inhibieren. Nachdem mittels quantitativer PCR 12 Krebszelllinien, die hohe GSTP1-Expressionsniveaus zeigen, identifiziert worden waren, wurde die Aktivität der 1,2,4-Trioxane gegenüber GST, die in Krebszelllysaten vorkommt, nachgewiesen. Die GST in der Brustkrebsepithelzelllinie HBL100 und der Lungenkarzinomzelllinie SK-MES-1 wird durch 1,2,4-Trioxane noch effektiver inhibiert als aufgereinigte GSTP1 (IC50 im nanomolaren Bereich).

CIL I(2): 2.4, 2883 – Bronze lamina with dedication to Castor and Pollux, retrograde text

Photograph

CIL I(2): 2.4, 2965 – Epitaph of Sextus Aemilius Baro, a grain merchant

Squeeze and photograph

CIL I(2): 2.4, 3216 – Funerary (?) inscription for Aula Tetia, priestess of Ceres

Photograph and notes by A.E. Gordon

2-(4-Amino-3-methylphenyl)-5-fluorobenzothiazole is a ligand and shows species-specific partial agonism of the Aryl Hydrocarbon Receptor

2-(4-Amino-3-methylphenyl)-5-fluorobenzothiazole (5F 203) and related compounds are a series of anti-cancer candidate pharmaceuticals (Table 1.), that have been shown to activate the AhR. We show that these compounds are high affinity ligands for the rat AhR, but a quantitative assay for their ability to induce CYP1A1 RNA in H4IIEC3 cells, a measure of activation of the AhR, showed a poor relationship between affinity for the AhR and ability to induce CYP1A1 RNA. 5F 203, an agonist with low potency, was able to antagonise the induction of CYP1A1 RNA by TCDD, while IH 445, a potent agonist, did not antagonise the induction of CYP1A1 RNA by TCDD, and Schild analysis confirmed 5F 203 to be a potent antagonist of the induction of CYP1A1 RNA by TCDD in H4IIEC3 cells. In contrast, several benzothiazoles show potent induction of CYP1A1 RNA in human MCF-7 cells, and 5F 203 is unable to detectably antagonise the induction of CYP1A1 RNA in MCF-7 cells, showing a species difference in antagonism. Evaluation of the antiproliferative activity of benzothiazoles showed that the ability to agonise the AhR correlated with growth inhibition both in H4IIEC3 cells for a variety of benzothiazoles, and between H4IIEC3 and MCF-7 cells for 5F 203, suggesting an important role of agonism of the AhR in the anti-proliferative activity of benzothiazoles.