Understanding the plasmonic properties of dewetting formed Ag nanoparticles for large area solar cell applications

Cataloged from PDF version of article.The effects of substrates with technological interest for solar cell industry are examined on the plasmonic properties of Ag nanoparticles fabricated by dewetting technique. Both surface matching (boundary element) and propagator (finite difference time domain) methods are used in numerical simulations to describe plasmonic properties and to interpret experimental data. The uncertainty on the locations of nanoparticles by the substrate in experiment is explained by the simulations of various Ag nanoparticle configurations. The change in plasmon resonance due to the location of nanoparticles with respect to the substrate, interactions among them, their shapes, and sizes as well as dielectric properties of substrate are discussed theoretically and implications of these for the experiment are deliberated. (C) 2013 Optical Society of Americ

The electrochemistry of iron oxide thin films nanostructured by high ion flux plasma exposure

Photo-electrochemical (PEC) water splitting of hematite photoanodes suffers from low performance and efficiency. One way to increase the performance is to increase the electrochemically active surface area available for the oxygen evolution reaction. In this study, we use high ion flux, low energy helium plasma exposure to nanostructure sputtered iron thin films. Subsequent annealing in air at 645&nbsp;°C leads to the formation of PEC active hematite (α-Fe2O3) phase in these films. The surface area, as derived from electrochemical impedance spectroscopy (EIS), was seen to increase 10–40 times with plasma exposure. The photocurrent density increased by 2–5 times for the plasma exposed films as compared to the unexposed films. However, the less nanostructured film showed a higher photocurrent density. These findings were explained by detailed chemical and structural characterization in combination with electrochemical characterization and attributed to the presence of secondary elements in the film as well as to the presence of secondary iron oxide phases apart from hematite. This work demonstrates the complex effect of plasma exposure on both film morphology and chemical composition of PEC thin films and provides further understanding on how this technique can be used for nanostructuring of other functional films.</p

3,4-ethylenedioxythiophene

Copolymer of 2,5-di(4-methylthiophen-2-yl)-1-(4-nitrophenyl)-1H-pyrrole (MTNP) with 3,4-ethylene dioxythiophene (EDOT) was electro-chemically synthesized and characterized via cyclic voltammetry, Fourier Transform Infrared spectroscopy, Scanning Electron Microscopy, conductivity measurements. Spectroelectrochemical investigations showed that resulting copolymer film has distinct electrochromic properties. It has five different colors (dark purple, red, light grey, green, blue). At the neutral state m due to the pi-pi* transition was found to be 500 mn and E-g was calculated as 1.71 eV Double potential step chronoamperometry experiment shows that copolymer film has good stability, fast switching time (1.1 s) and high optical contrast (30%).Electrochromic device based on P(MTNP-co-EDOT) and PEDOT was constructed and characterized. Oxidized state of the device shows dark purple color with a blue color reduced state. At interval potentials device has good transparency and colors of the device are yellow and grey. Maximum contrast and switching time of the device were measured as 23% and 1.1 s at 650 nm. (C) 2008 Elsevier B.V. All rights reserved

Fine needle aspiration cytology of hepatoblastoma: A report of two cases

BACKGROUND: Hepatoblastoma is the most common primary hepatic tumor in children. The literature contains few examples of fine needle aspiration (FNA) cytology of these tumors. CASES: A 5-month-old and 4-month-old underwent ultrasonography-guided FNA for preoperative investigation of hepatic masses. The smears were stained with May-Grunwald-Giemsa and Papanicolaou stain. Alcohol fixed smears were used for immunocytochemistry. All smears revealed cells with round/oval nuclei, prominent nucleoli and vacuolated cytoplasm, arranged in groups and acinar structures. The groups were embedded in a myxoid stroma. ?-Fetoprotein was positive in all, and vimentin was positive in some tumor cells. The cytologic findings resembled the histologic counterpart in one case, and the other case agreed with the clinical/radiologic prediagnosis. Immunocytochemistry was supportive. CONCLUSION: FNA cytology can be diagnostic in many other childhood tumors as well as hepatoblastomas. Detailed descriptions of cytomorphologic features of hepatoblastoma will help FNA to be used confidently on these tumors

Electrochromic properties of poly (1-(phenyl)-2,5-di(2-thienyl)-1H-pyrrole-co-3,4-ethylenedioxy thiophene) and its application in electrochromic devices

Electrochemical copolymerization of 1-(phenyl)-2,5-di(2-thienyl)-1H-pyrrole (PTP) with 3,4-ethylenedioxy thiophene (EDOT) was carried out in acetonitrile (AN)/NaClO4/LiClO4 (0.1 M) solvent-electrolyte couple via potentiodynamic electrolysis. Characterizations of the resulting copolymer were performed via cyclic voltammetry (CV), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and spectroelectrochemical analysis. Spectroelectrochemical analyses show that the copolymer of PTP with EDOT has an electronic band gap (due to ? to ?* transition) of 1.9 eV at 480 nm, with a claret red in the fully reduced form and a blue color in the fully oxidized form. Via kinetic studies, the optical contrast (?T %) was found to be 8% for P(PTP-co-EDOT). Results showed that the time required to reach 95% of the ultimate transmittance was 1.7 s for the copolymer. The P(PTP-co-EDOT) film was used to construct a dual type polymer electrochromic device (ECDs) with poly(3,4-ethylenedioxy thiophene) (PEDOT). Spectroelectrochemistry, electrochromic switching and open circuit memory of the device were investigated. © 2007 Elsevier B.V. All rights reserved

Fine needle aspiration cytology of hepatoblastoma - A report of two cases

23rd European Congress of Cytology -- SEP 22-25, 1996 -- AARHUS, DENMARKWOS: 000073920000038PubMed ID: 9622712BACKGROUND: Hepatoblastoma is the most common primary hepatic tumor in children. The literature contains few examples of fine needle aspiration (FNA) cytology of these tumors. CASES: A 5-month-old and 4-month-old underwent ultrasonography-guided FNA for preoperative investigation of hepatic masses. The smears were stained with May-Grunwald-Giemsa and Papanicolaou stain. Alcohol-fixed smears were used for immunocytochemistry. All smears revealed cells with round/oval nuclei, prominent nucleoli and vacuolated cytoplasm, arranged in groups and acinar structures. The groups were embedded in a myxoid stroma. alpha-Fetoprotein was positive in all, and vimentin was positive in some tumor cells. The cytologic findings resembled the histologic counterpart in one case, and the other case agreed with the clinical/radiologic prediagnosis. Immunocytochemistry was supportive. CONCLUSION: FNA cytology can be diagnostic in many other childhood tumors as well as hepatoblastomas. Detailed descriptions of cytomorphologic features of hepatoblastoma will help FNA to be used confidently on these tumors

Meropenem versus piperacillin-tazobactam as empiric therapy for febrile neutropenia in pediatric oncology patients

PubMedID: 24969883Background: Infection is a serious cause of mortality in febrile neutropenia of pediatric cancer patients. Recently, monotherapy has replaced the combination therapy in empirical treatment of febrile neutropenia. Since there has been no reported trial comparing the efficacy of meropenem and piperacillin-tazobactam (PIP/TAZ) monotherapies, the present retrospective study was conducted to compare safety and efficacy in febrile neutropenic children with cancer. Materials and Methods: Charts of febrile, neutropenic children hospitalized at our center between March 2008 and April 2011 for hemato-oncological malignancies were reviewed. Patients received PIP/TAZ 360 mg/kg/day or meropenem 60 mg/kg/day intravenously in three divided doses. Duration of fever and neutropenia, absolute neutrophil count, modification, and success rate were compared between the two groups. Resolution of fever without antibiotic change was defined as success and resolution of fever with antibiotic change or death of a patient was defined as failure. Modification was defined as changing the empirical antimicrobial agent during a febrile episode. Results: Two hundred eighty four febrile neutropenic episodes were documented in 136 patients with a median age of 5 years. In 198 episodes meropenem and in 86 episodes PIP/TAZ were used. Duration of fever and neutropenia, neutrophil count, sex, and primary disease were not different between two groups. Success rates and modification rate between two groups showed no significant differences (p>0.05). Overall success rate in the meropenem and PIP/TAZ groups were 92.4% and 91.9% respectively. No serious adverse effects occurred in either of the groups. Conclusions: Meropenem and PIP/TAZ monotherapy are equally safe and effective in the initial treatment of febrile neutropenia in children with cancer