323,165 research outputs found
CT-EVALUATION OF MEDIASTINAL LYMPHNODES IN NON-SMALL CELL LUNG CANCER
No full textFor several years the distinction between normal and pathologic lymphnodes was based on the dimensional criteria (radiological diameter more than 1 cm). Computed tomography is valuable for the assessment of hilar and mediastinal lymphnodes. The aim of this study is to report the specificity and the sensitivity of CT in the evaluation of mediastinal lymphnodes in non-small cell lung cancer and to identify the indications for the preoperatory mediastinoscopy. The CT showed low sensitivity and high specificity for the assessment of mediastinal lymphnodes
Determination of the quadratic hyperpolarizability of trans-4-[4-(dimethylamino)styryl]pyridine and 5-dimethylamino-1,10-phenanthroline from solvatochromism of absorption and fluorescence spectra: a comparison with the electric-field-induced second-harmonic generation technique
No full textFor fluorescent compounds, the combined use of absorption and emission solvatochromic data allows to estimate indirectly the cavity radius of the molecule in solution, a very critical parameter in the application of the solvatochromic method for the determination of the quadratic hyperpolarizability β of dipolar molecules. For two test compounds, trans-4-[4-(dimethylamino)styryl]pyridine (DASP) and 5-dimethylamino-1,10-phenanthroline (DAPHEN), the β values so obtained are compared with those obtained by the EFISH (Electric Field Induced Second-Harmonic generation) technique. For DAPHEN, the versatility of the method described in this work in the presence of more than one electronic transition contributing to the non-linear optical response is demonstrated
Extended polymorphism in copper(II) imidazolate polymers: A spectroscopic and XRPD structural study
No full textCopper(II) bisimidazolate affords five different polymorphs; of these, one was structurally characterized 40 years ago by standard single-crystal X-ray diffraction (Jarvis, J. A. J.; Wells, A. F. Acta Crystallogr. 1960, 13, 1027), while the remaining four, selectively prepared as pure polycrystalline phases, have been now studied by X-ray powder diffraction (XRPD) methods. Of the four new (blue, green, olive-green, and pink) phases, three were solved by the ab initio XRPD technique and refined by the Rietveld method, and the fourth phase (pink) could not be structurally characterized. Crystal data for [Cu(imidazolate)2]n: blue phase, a = 27.559(3) Å, c = 5.3870(9) Å, trigonal, R3̄, Z = 54; green phase, a = 21.139(1) Å, b = 19.080(1) Å, c = 9.2842(8) Å, orthorhombic, Ccca, Z = 20; olive-green phase, a = 11.7556(8) Å, b = 23.422(2) Å, c = 9.0727(9) Å, β = 104.993(5)°, monoclinic, C2/c, Z = 12. All polymorphs contain four-coordinate GuN4 chromophores and (N,N′)-exobidentate imidazolate ligands, but show different spectroscopic and structural properties, the latter ranging from 2D to different 3D networks of the PtS, sodalite, and moganite archetypes. The intermediacy of the [Cu(imidazole)2CO3]·H2O species in the synthesis of the blue polymorph has been confirmed by spectroscopic and thermal analyses. FTIR, Raman, and electronic spectra were correlated with the structural features revealed in the present work, and used to gain insight into the coordination geometry of copper(II) ions of the pink polymorph, in addition, the Correct Raman spectrum for copper(II) bisimidazolate, common for all polymorphs, has been definitely determined
Spectrochemical characterization by micro-FTIR spectroscopy of blue pigments in different polychrome works of art
No full textAnalytical examination of blue paint samples, taken from different artworks dating from the second century AD until 1960, was carried out using FTIR microspectroscopy (both in reflection and transmission mode, the latter with the aid of a diamond cell) supported by micro-Raman spectroscopy and SEM observations as well as EDX spectrometry. Pigments examined included azurite, Egyptian blue and ultramarine blue, either natural or artificial. Characteristic spectra for each pigment are presented and an account for the principal differences observed is given. In particular, the FTIR's capability of probing single pigment grains on the surface of paint cross-sections, when integrated with a microscope, brought to light frequency differences and orientation behaviour of the bands of the various minerals used as painting materials. Indeed, a striking effect of shifting and variation of intensity of some of the bands of azurite and Egyptian blue was noted and related to polarization phenomena occurring when the incident light stroke differently oriented faces of the single pigment crystals. The effects of different mineralogical composition of the semi-precious stone lapis-lazuli (from which ultramarine blue is derived) on the appearance of the spectrum of the pigment are also discussed. Finally, a means of distinguishing the natural from the artificial ultramarine blue pigment, on the basis of their FTIR spectra, is proposed
Optimization of an urban particulate matter multi-element analysis method by inductively coupled plasma - Atomic emission spectrometry (ICP-AES)
No full textIn the present work a method for simultaneous metals determination, in urban air particulate matter by ICP-AES has been set up. A large number of elements (18) has been analyzed, including major (Al, Fe, K, and Mg), minor (Na, Ph and Zn) and trace (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Sb, Sr and V) elements. The procedure, consists of microwave sample acidic total digestion by HNO3/HF mixture and subsequent analysis by ICP-AES, using different assemblies depending on sample treatment procedure: a quartz Meinhard nebulizer/cyclonic chamber, if HF excess was eliminated, or a cross-flow nebulizer/plastic Scott chamber, suitable for application with HF. A cyclonic chamber for hydride generation was used for As, Sb and Hg determination. The procedure was tested with Standard Reference Materials 1648 NIST Urban Particulate Matter and Certified Reference Material No8 NIES "Vehicle Exhaust Particulates". Two sampling supports, quartz fibre and polycarbonate filters, have been examined in order to find the most suitable i.e. the one characterized by less interference. Some real samples of urban air particulate matter, TSP, PM10 and PM2.5 fractions, collected during an intercomparison campaign promoted by Regione Lombardia, have been analyzed with the procedure developed
INFRARED SPECULAR REFLECTION SPECTRA OF COPPER-ZINC PHOSPHATE-GLASSES
No full textCopper-zinc phosphate glasses of composition xZnO-yCuO-zP2O5, with (x + y)/z varying between 1 and 2, have been synthesized and examined in the 2000-400 cm-1 range by infrared specular reflection spectroscopy. This technique has proved to be a useful tool to characterize the short-range structure of the phosphate matrix in these glasses
Synthesis and spectroscopic and NLO properties of "push-pull" structures incorporating the inductive electron-withdrawing pentafluorophenyl group
No full textA series of push-pull mols., each incorporating a pentafluorophenyl ring as an inductive accepting group, has been synthesized. The nonlinear optical properties of these compds. were measured in soln. by EFISH (operating at 1907 nm) and in the solid state by the Kurtz powder technique (at 1907 nm). Values of μβ, the product of the mol. dipole moment and its first-order hyperpolarizability, of up to 200 × 10-48 esu were obtained
J-AGGREGATES GRANTING GIANT SECOND-ORDER NLO RESPONSES IN SELF-ASSEMBLED HYBRID INORGANIC-ORGANIC MATERIALS
No full text[Cu(imidazole)2(CO3)]*H2O: An intermediate in the formation of the copper bis-imidazolate polymer (blue phase)
No full textThe crystal structure of [Cu(Him)2(CO3)].H2O, determined from conventional X-ray powder diffraction methods, allowed to clarify, on the basis of a structural interpretation of the chemical transformation, the role of the title compound in the formation of the blue phase of Cu(im)2 [Cu(Him)(2)(CO3)].H2O is triclinic, P-1; a = 8.8565(7), b = 8.9579(5), c = 8.3705(6) Angstrom, alpha = 105.728(4)°, beta = 105.318(3)°, gamma = 114.369(4)°; final R-wp, R-p and R-F agreement factors, for 4700 data collected in the 11-105° range, are 0.053, 0.036 and 0.078, respectively
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