Effects of silver nanoparticles towards the efficiency of organic solar cells

We report an alternative approach to enhance the optical and electrical performance of a vanadyl 2,9,16,23-tetraphenoxy-29H,31H-phthalocyanine:poly(3hexylthiophene) (VOPcPhO:P3HT) blending system by integrating plasmonic spherical silver into an active layer of organic solar cells. Studies of the influence of the size distribution and optical properties of the silver nanoparticles were carried out using UV–Vis spectroscopy and field emission scanning electron microscopy, respectively. Electrical characteristics with and without the presence of metallic nanostructures were analyzed using J–V characteristics to observe the plasmonic effects on the performance in the VOPcPhO:P3HT organic solar cells.     

Positive-ion mass spectra and collision-induced dissociation of some 2,3-didehydro amino acids

The positive-ion mass spectra of a number of didehydro amino acids, ionized by electron impact and/or thermospray, and collision-induced dissociation spectra taken at collision energies of a few electron volts and keV have been performed on multiple quadrupole and reversed geometry sector instruments. Observed differences in the mass spectra and in the fragmentation patterns are explained in terms of different isomeric structures, different internal excitation energies and different ion transit times between the ion source and the collision cell. Molecular ions of unhydrated amino acids are efficiently formed both by electron impact and thermospray, whilst molecular ions of the hydrated compounds are formed more efficiently by the latter technique. The present investigation demonstrates that the use of different ionization techniques combined with mass spectrometry/mass spectrometry measurements at different collision energies yields a wealth of information relevant to structural characterization of this important class of molecules.     

The Effect of Hemodialysis on Voice: An Acoustic Analysis

Because respiration is part of the well-coordinated process necessary for phonation, this study was conducted with the purpose of analyzing the effect of chronic hemodialysis on voice characteristics of patients with chronic renal failure. A total of 57 patients were recruited for the study, including 31 males and 26 females ranging in age from 16 to 85 years. Patients underwent evaluation of their voice directly before and after hemodialysis using the Kay Elemetric VISI Pitch (Model 330; Kay Elemetric Corporation, Lincoln Park, New Jersey). The vocal acoustic parameters studied include habitual pitch, pitch range, relative average perturbation, shimmer, noise-to-harmonic ratio, voice turbulence index, maximum phonation time, and voice energy. The data were analyzed using the paired t-test for the total sample and the nonparametric test for the female and male subgroups. The total sample analysis showed a statistically significant increase in the habitual pitch after the hemodialyis (p < 0.05), with a borderline increase in the pitch range and maximum phonation time (p < 0.10). In the female group, there was a statistically significant increase in the habitual pitch and a borderline increase in the relative average perturbation. In the male group, there was a significant increase in the habitual pitch with a borderline increase in maximum phonation time. Discussion of the after-mentioned results is presented.     

Photostablity and amplified spontaneous emission in dye-activated new organic-inorganic hybrid material

This paper reports on the lasing action of some dyes (pyrromethene 597, pyrromethene 567 and Rhodamin B) incorporated into a new organic-inorganic hybrid material. The amplified spontaneous emission (ASE) was studied under 532 nm, laser excitation in transverse pumping configuration for the prepared rod samples. The influence of the dye concentration on the amplified spontaneous emission peak wavelengths, the output energies, the gain and the energy conversion efficiencies were studied. Relatively high efficiencies (up to ∼64%) were obtained with good photostabilities where a decrease to ∼30% of the initial amplified spontaneous emission output energy were observed after pumping by 60,000 shots at relatively high repetition rate (10 Hz) and energy (15 mJ).     

Proteomic analysis of pancreatic ductal carcinoma cells treated with 5-aza-2'-deoxycytidine

A pancreatic adenocarcinoma cell line (PaCa44), which contains, among other alterations, a methylated p16 promoter, was treated with a chemoterapeutic agent, 5-aza-2'-deoxycytidine (DAC), in order to evaluate the effect of this drug on cell growth and protein expression. Cell proliferation was strongly inhibited by a 24 h DAC treatment and this inhibition lasted for at least 10 days. Master maps of control and treated PaCa44 cells were generated by analysis with the PDQuest software. The comparison between such maps showed up- and downregulation of 45 polypeptide chains, of which 32 were downregulated and 13 upregulated, out of a total of 700 spots detected by a medium-sensitivity stain, micellar Coomassie Brilliant Blue. Fingerprinting by mass spectrometry analysis enabled the identification of 36 of these spots. Among the major changes in DAC-treated cells: cofilin and profilin 1 are silenced; coactosin, peptidyl-propyl cis-trans isomerase A and cystatin B are decreased by 22, 16- and 15-fold, respectively; stress-70 protein, superoxide dismutase and protein disulfide isomerase A3 are increased by 13-, 11-, and 5-fold, respectively. The significance of some of these major changes is discussed.     

Investigating the reaction of a number of gel electrophoresis cross-linkers with beta-lactoglobulin by matrix assisted laser desorption/ionization-mass spectrometry

A number of cross-linkers that are commonly used in polyacrylamide gels have been incubated with bovine beta-lactoglobulin B and the resulting reaction mixtures were examined by matrix assisted laser desorption/ionization-mass spectrometry. At concentrations of 0.1, 1, and 20 mM of each cross-linker incubated for 1 h with 50 pmol/microL of the protein, a reactivity scale can be expressed as polyethylene glycol diacrylate > N,N'-bisacrylylcystamine > bisacrylyl piperazine > N,N'-methylenebisacrylamide > N,N'-diallyltartardiamide (PEGDA>BAC>BAP>Bis>DATD). Relatively short incubation times indicated one of the five Cys residues as the target of reaction, which was confirmed by post-source decay measurements. Longer incubation times (24 h) with bisacrylamide extended the reaction to all five Cys residues and a number of Lys residues. A second consequence of longer reaction time is the involvement of both terminals of the cross-linker in the observed reaction. This experimental evidence is the first to demonstrate a different reactivity of both ends of one of the most commonly used cross-linkers. Investigation of solutions containing a cross-linker and acrylamide monomers provided useful information on the competition between the two identities for reaction with the protein. Possible implications of these experimental observations for isoelectric focusing separations in polyacrylamide gels are discussed.