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Using the mass spectrometric and double oven technique, the gallium cyanide molecule was identified and its atomization energy was determined: D0° (GaCN)=312.5 ± 1.4 kcal/mole. Upper limits for the atomization energies of GaN(g) and Ga2N(g) also were established.

The energy balance between heat excess and 4 He in the gas phase has been found to be reasonably satisfied even if the low levels of 4 He do not give the necessary confidence to state definitely that we are dealing with the fusion of deuterons to give 4 He. In the melted cathode, the data of which are reported, no 4 He was found at the achieved sensitivity. X-ray film, positioned at 50 mm from the cell, roughly gave the image of the cathode through spots. Extended considerations have been made to explain this evidence on the basis of the bundle nature of the cathode. From these considerations, the energy of the radiation and the total energy associated to it have been estimated, as 89 keV and 12 kJ, respectively. This value is ∼ 0.5% of the energy measured by calorimetry in the same interval of time. The highest values of energy and excess power are 8.3 MJ and 10 W, respectively.

Aim: The lack of sensitivity of chronic myeloid leukemia (CML) stem cells to imatinib mesylate (IM) commonly leads to drug dose escalation or early disease relapses when therapy is stopped. Here, we report that packaging of IM into a biodegradable carrier based on polyelectrolyte microcapsules increases drug retention and antitumor activity in CML stem cells, also improving the ex vivo purging of malignant progenitors from patient autografts. Materials & methods: Microparticles/capsules were obtained by layer-by-layer (LbL) self-assembly of oppositely charged polyelectrolyte multilayers on removable calcium carbonate (CaCO3) templates and loaded with or without IM. A leukemic cell line (KU812) and CD34+ cells freshly isolated from healthy donors or CML patients were tested. Results & discussion: Polyelectrolyte microcapsules (PMCs) with an average diameter of 3 µm, fluorescently labelled multilayers sensitive to the action of intracellular proteases and 95–99% encapsulation efficiency of IM, were prepared. Cell uptake efficiency of such biodegradable carriers was quantified in KU812, leukemic and normal CD34+ stem cells (range: 70–85%), and empty PMCs did not impact cell viability. IM-loaded PMCs selectively targeted CML cells, by promoting apoptosis at doses that exert only cytostatic effects by IM alone. More importantly, residual CML cells from patient leukapheresis products were reduced or eliminated more efficiently by using IM-loaded PMCs compared with freely soluble IM, with a purging efficiency of several logs. No adverse effects on normal CD34+ stem-cell survival and their clonogenic potential was noticed in long-term cultures of hematopoietic progenitors in vitro. Conclusion: This pilot study provides the proof-of-principle for the clinical application of biodegradable IM-loaded PMC as feasible, safe and effective ex vivo purging agents to target CML stem cells, in order to improve transplant outcome of resistant/relapsed patients or reduce IM dose escalation.

In this contribution we report on the preparation and characterisation of both 2,5-di-(9,9-dimethylfluoren-2-yl)-3,4-dihexyl-thiophene-1,1-dioxide and the corresponding polymer with longer alkyl substituents at 9 fluorene position. Optical and structural characterisations performed on both crystalline and amorphous films showed noticeable luminescence properties depending on the molecular aggregation. Both polymer and oligomer based LEDs showed external efficiency of more than 10−1%.

In this paper we report results obtained in the fabrication and use of novel coded diffractive nano-optics that, beyond focusing, can perform new optical functions. In particular, the intensity of light in the space beyond the optical elements can be redistributed with almost complete freedom. These novel X-ray optical elements have been tested and found to perform multi-focusing in single or multiple focal planes and beam shaping of a generic monochromatic beam into a desired continuous geometrical pattern. Already available extreme ultraviolet and X-ray sources are suitable as ideal sources for such diffractive optical elements. Their new optical functions have been tested in differential interference contrast microscopy and we suggest their use also in maskless lithography and chemical vapour deposition induced by extreme ultraviolet and X-ray radiation.

The high-temperature microfluidic lithography was studied. A simple approach to improve the performance of microfluidic lithography, which does not act on the increase in the difference between the pressure that drives the capillary motion, but on the temperature-controlled reduction of the polymer viscosity was presented. It was shown that high-temperature micro-molding in capillaries (MIMIC) is very flexible and straightforward method to improve the throughput of lithography.

We have studied the emission spectra of spin-coated films of a novel soluble substituted quinque-thiophene under nanoseconds pulsed excitation. The photoluminescence spectra show a clear line narrowing, ascribed to amplified spontaneous emission assisted by waveguiding inside the film slab, for excitation energy fluence above $0.8\phantom{\rule{0.3em}{0ex}}\mathrm{mJ}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}2}$. We employed our oligothiophene as active medium for a fully organic distributed feedback (DFB) resonator on a flexible transparent substrate of poly(dimethylsiloxane) (PDMS). The DFB has been fabricated by replica molding from a master grating realized by electron-beam lithography, and subsequent spin coating of the active material on the patterned side of PDMS. It shows a clear DFB emission at about $603\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ of linewidth $0.8\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$.

The "rigid-core" material 3,5-dimethyl-2,3'-bis(3-methylthiophene)-dithieno[3,2-b:',3'-d]thiophene-4,4-dioxide (DTTOMe4) has the highest photoluminescence ever reported for thiophene-based molecules in the solid state. We report the structure of this material, determined directly from powder X-ray diffraction data using the Genetic Algorithm method for structure solution, followed by Rietveld refinement, and the structural properties are discussed in relation to the structures of the corresponding subsystems DTTO and DTTOMe. While the crystal structures of the latter compounds contain cofacial dimers, the crystal structure of DTTOMe4 comprises layers of molecules aligned in an antiparallel fashion. Intermediate neglect of differential overlap with single configuration interaction (INDO/SCI) calculations on the intermolecular interactions in the three crystal structures show that the different solid-state photoluminescence efficiencies of DTTOMe4, DTTOMe, and DTTO cannot be correlated with the different types of dipole-dipole alignment in the solid state. Instead, photoluminescence efficiencies correlate well with the rate of formation of nonradiatively decaying charge-transfer pairs upon photoexcitation. Because of larger intermolecular distances in DTTOMe4, the photoluminescence is less effectively quenched by charge-transfer processes than in DTTOMe and DTTO.

We demonstrate bright and efficient spin-coated yellow organic light emitting diodes (OLEDs) employing as active medium a novel thiophene-based compound, in which the conventional linear structure of the oligothiophenes has been replaced by a branched benzo[ b ]thiophene-based structure. Such a structure, combined with the oxygen functionalization of the core-thienyl sulphur atom and the cyclohexyl substitution of the lateral thienyl rings, allowed us to obtain a brightness up to 10,500 cd/m 2 and an external quantum efficiency up to 0.48%, which are the highest values so far obtained by substituted oligothiophene-based compounds.

The aim of this paper is to demonstrate that efficient fiber-waveguide optical coupling can be achieved using a multilevel phase diffractive element (PDE) fabricated directly on the top of the fiber by means of e-beam lithography. The diffractive phase element is calculated to focus and reshape the gaussian symmetric beam exiting a single-mode fiber into a desired asymmetric intensity distribution at the waveguide input plane. Phase modulation is obtained by multilevel profiling a polymeric material coated on the top of the fiber by means of a specific fabrication process including e-beam lithography and chemical etching. Experimental results obtained for fiber-waveguide coupling with a 20-µm diameter diffractive element are also presented.

Sub micron patterning of the conjugated polymer, poly-[2-methoxy-5-(2′-ethyl-hexiloxy)-p-phenylenevinylene] (MEH-PPV) has been achieved by high-temperature soft lithography. The process has been carried out by placing a spin-coated polymer film in conformal contact with elastomeric replicas of master structures fabricated by electron beam lithography. The system is then heated to decrease the polymer viscosity, allowing the pattern transfer with resolution down to 300 nm. The well-preserved photoluminescence spectrum and efficiency of the emissive polymer clearly indicate that high-temperature soft lithography can be successfully applied for the one-step realization of organic-based devices.

We show how colour tunability (including white) can be achieved by controlling non-radiative intermolecular energy transfer from the donor to the acceptor in binary blends of oligomeric compounds. Blends of different concentrations of a novel functionalized thiophene-based oligomer and a low-molar-mass diamine derivative (N, N'-diphenyl-N, N'-bis(3-methylphenyl)-1,1'-biphenyl-4.4'diamine) are used to tune both the photoluminescence and the electroluminescence (EL) from red to blue, including balanced white, according to the standards of the Commission Internationale de l'Eclairage. The single-active-layer light-emitting devices, realized by spin-coating, exhibit good EL performance. In particular, the white-emitting device shows an EL efficiency of 5 x 10(-1) cd A(-1) and a luminance of more than 180 cd m(-2).

We report on white electroluminescence (EL) emission from a single-layer light-emitting diode based on a binary blend of organic soluble blue-emitting molecules, i.e., a diamine derivative and a substituted thiophene-1,1-dioxide. Weakly voltage-dependent white color, of coordinates (0.39, 0.40) according to the standard of the Commission Internationale de l’Eclairage, is obtained from the superposition of the blue emission from the donor and a low-energy peak due to a charge-transfer complex between the two molecules (exciplex). The EL spectrum is broader and more structured than the photoluminescence one: this could be due to the activation of exciplexes with different conformations as inferred from quantum-chemistry calculations.

A new class of oligothiophenes is realized by replacing the conventional linear structure with a branched benzo[b]thiophene-based structure (see Figure). These compounds are used as active materials in light-emitting diodes exhibiting record luminances up to 10 500 cd m–2 (see inset). Optical measurements and theoretical calculations show these performances are mainly to the distorted molecular structure

Balanced white electroluminescence (EL) emission from binary organic blends was achieved via intermolecular down-convertion processes: the exciplex and the Foerster transfer mechanisms. This was obtained by combining a low electronic affinity (EA) molecule, a diamine derivative (TPD), with two high electronic affinity substituted oligothiophenes having high and low ionization potential (IP), respectively. Both the energy down-convertion mechanisms were exploited in two single active-layer organic light emitting devices, showing stable white emission, independent of the applied voltage.

We report on the lasing properties of spin coated films formed by a novel soluble substituted oligothiophene. The molecule shows a high gain cross section (6×10 -16 cm 2 ) and a low threshold (20 μJ cm -2 ) for line narrowing The laser shows single-mode TEM 00 emission tunable from yellow to red, over 37 nm, with a low pump threshold as low as 10 μJ cm -2 and an external efficiency up to 1.7%. These results are among the best so far reported for organic lasers.