Analysis of Iranian postage stamps belonging to the Qajar dynasty (18th–20th century's) by micro‐PIXE

Eighteen historical Iranian postage stamps belonging to the Qajar dynasty were analyzed by micro‐particle induced X‐ray emission (PIXE) and complementary techniques using Van de Graaff accelerator in the Nuclear Science and Technology Research Institute in Iran. The aim of this study was to determine the elemental composition of different papers and inks of Iranian stamps printed in the Netherlands, Austria, France and Iran. The results obtained in this work show differences between elemental composition of stamps printed in different places and indicate that micro‐PIXE is a suitable technique for this kind of analysis. Copyright © 2009 John Wiley & Sons, Ltd.     

New Anti-Leukemic Effect of Carvacrol and Thymol Combination through Synergistic Induction of Different Cell Death Pathways

Acute myeloid leukemia (AML) is a cancer of the myeloid lineage of blood cells, and treatment for AML is lengthy and can be very expensive. Medicinal plants and their bioactive molecules are potential candidates for improving human health. In this work, we studied the effect of Ptychotis verticillata (PV) essential oil and its derivatives, carvacrol and thymol, in AML cell lines. We demonstrated that a combination of carvacrol and thymol induced tumor cell death with low toxicity on normal cells. Mechanistically, we highlighted that different molecular pathways, including apoptosis, oxidative, reticular stress, autophagy, and necrosis, are implicated in this potential synergistic effect. Using quantitative RT-PCR, Western blotting, and apoptosis inhibitors, we showed that cell death induced by the carvacrol and thymol combination is caspase-dependent in the HL60 cell line and caspase-independent in the other cell lines tested. Further investigations should focus on improving the manufacturing of these compounds and understanding their anti-tumoral mechanisms of action. These efforts will lead to an increase in the efficiency of the oncotherapy strategy regarding AML.     

A non-circular iris localization algorithm using image projection function and gray level statistics

Iris recognition technology identifies an individual from its iris texture with great precision. A typical iris recognition system comprises eye image acquisition, iris segmentation, feature extraction, and matching. However, the system precision greatly depends on accurate iris localization in the segmentation module. In this paper, we propose a reliable iris localization algorithm. First, we locate a coarse eye location in an eye image using integral projection function (IPF). Next, we localize the pupillary boundary in a sub image using a reliable technique based on the histogram-bisection, image statistics, eccentricity, and object geometry. After that, we localize the limbic boundary using a robust scheme based on the radial gradients and an error distance transform. Finally, we regularize the actual iris boundaries using active contours. The proposed algorithm is tested on public iris databases: MMU V1.0, CASIA-IrisV1, and the CASIA-IrisV3-Lamp. Experimental results demonstrate superiority of the proposed algorithm over some of the contemporary techniques.     

Electrochemical behaviour of aldehyde-N-arylhydrazones at platinum electrode and their characterization

A series of chemically and pharmaceutically interesting 2,5-disubstituted-1,3,4-oxadiazoles were efficiently synthesized from the anodic oxidation of aldehyde-N-arylhydrazones at platinum anode by using NaClO₄ as supporting electrolyte in MeOH solution under controlled potential electrolysis at room temperature. The products were characterized by spectroscopic methods and a mechanism was deduced from voltammetry studies. The salient features of this protocol are mild reaction conditions, short reaction time, accelerated rate, high yield and simple work-up procedure.     

Optimal sizes of silica microspheres for linear and nonlinear optical interactions

We investigate theoretically the mode volume (V_eff) and quality factor (Q) of the fundamental whispering gallery mode of a silica microsphere. We determine the optimal sizes of microspheres for linear and nonlinear optical interactions. We find for the latter case that an optimal wavelength exists that corresponds to the low-loss range for silica. For linear optical interactions, the optimal size is found to be relatively insensitive to the choice of wavelength. PACS 42.60.Da     

A solution to an inverse height and level characteristics problem

Given two sequences α and β of positive integers, it is shown that there exists a matrix with level characteristic α and height characteristic β if and only if β strictly majorizes α when reordered in non-increasing order. This generalizes a recently proven result for the case of matrices with simple singular vertices.     

Photocyclization of 1,2-diaryl- and photobicyclization of 1,2,6-triarylpyridinium cations

New 1,2-diaryl- and 1,2,6-triarylpyridinium salts, containing various five- and six-membered heteroaromatic substituents in the 1, 2, and 6-positions of the pyridinium ring, were synthesized. New tetra- and hexacyclic compounds were prepared by photocyclization of the cations of these salts. Photocyclization proceeds through a singlet excited state with nonadiabatic formation of a dihydro intermediate, followed by its oxidative dehydrogenation. The structure and quantum yield of the formation of photoproducts are determined by steric and electronic effects of the substituents, and in bichromophore compounds by the presence of S-S intramolecular interfragment energy transfer.The article is dedicated to the memory of Professor G. N. Dorofeenko.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1509–1518, November, 1984.     

Triazolines 24. Permanganate-catalyzed low temperature thermolysis of 5-(4-pyridyl) substituted 1,2,3-triazolines

Potassium permanganate oxidation of 1-aryl-5-(4-pyridyl)-1,2,3-triazolines I in a benzene-water two-phase system using the phase-transfer catalyst tetrabutylammonium chloride yields the corresponding 1H-1,2,3-tri-azoles II . However, when the reaction is run in a single phase in anhydrous benzene alone, the products are not triazoles, but imines III that can normally be obtained only by high-temperature thermolysis of the tri-azolines. The presence of both potassium permanganate and tetrabutylammonium chloride to yield the benzene soluble tetrabutylammonium permanganate ion pair appears essential for imine formation, although only in catalytic amounts. Thus a reaction pathway is proposed, which involves the initial coordination of the pyridyl nitrogen with the manganese atom of the permanganate ion leading to IV , followed by loss of nitrogen and regeneration of the permanganate ion via the dihydropyridine intermediates, V and VI , to yield the enamine VII , which tautomerizes to the imine III . Supportive evidence for the formation of IV is derived from the failure of 1,5-diaryl- and l-aryl-5-(3-pyridyl)triazolines to yield the respective imines; they lack the structural requirements necessary to comply with the proposed mechanism, and are recovered unchanged. Unlike the high temperature pyrolysis, the permanganate catalyzed low temperature thermolysis reactions provide cleaner products in better yields. Thus, the low temperature thermolysis may afford a route for the synthesis of clean samples of l-arylimino-l-ethyl-4-pyridines, especially when the triazolines are on hand.