bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel Anti-Cancer, Anti-Bacterial Coatings for Biomaterial Applications: Selenium Nanoclusters
Authors: Tran Phong Anh , Taylor Erik , Sarin Love , Hurt Robert H. , Webster Thomas J 
Published: February 2010

AbstractTwo common problems with implantation after cancerous tumor resection are cancer recurrence and bacteria infection at the implant site. Tumor resection surgery sometimes can not remove all the cancerous cells, thus, cancer can return after implantation. In addition, bacteria infection is one of the leading causes of implant failure. Therefore, it is desirable to have anti-cancer and anti-bacterial molecules which both rapidly (for anti-infection purposes) and continuously (for anti-cancer purposes) are available at the implant site following implantation. Therefore, the objective of the present in vitro study was to create a multi-functional coating for anti-cancer and anti-bacterial orthopedic implant applications. Elemental selenium was chosen as the biologically active agent in this effort because of its known chemopreventive and anti-bacterial properties. To achieve that objective, titanium (Ti), a conventional orthopedic implant material was coated with selenium (Se) nanoclusters. Different coating densities were achieved by varying Se concentration in the reaction mixture. Titanium substrates coated with Se nanoclusters were shown to enhance healthy osteoblast (bone-forming cell) and inhibit cancerous osteoblast proliferation in co-culture experiments. Functions of S. epidermidis (one of the leading bacteria that infect implants) were inhibited on Ti coated with Se-nanoclusters compared to uncoated materials. Thus, this study provided for the first time a coating material (selenium nanoclusters) to the biomaterials’ community to promote healthy bone cells’ functions, inhibit cancer growth and prevent bacteria infection.
Assessment of Nanomodified Endotracheal Tubes in a Bench Top Airway Model
Authors: Machado Mary C. , Chang Daniel , Webster Thomas J , Tarquinio Keiko M 
Published: February 2010

AbstractVentilator associated pneumonia (VAP) is a serious and costly clinical problem. Specifically, receiving mechanical ventilation over 24 hours increases the risk of VAP and is associated with high morbidity, mortality and medical costs. This complication is especially hard to diagnose in children because of non-specific clinical signs and lack of established diagnostic methods. Cost effective endotracheal tubes (ETTs) that are resistant to bacterial infection would be essential tools for the prevention of VAP. In addition to their bacterial resistance, ETT with magnetic nanoparticles could aid in the diagnosis of VAP allowing physicians to locate infections with greater accuracy. The objective of this study was twofold, first to develop strategies to decrease bacterial adhesion on nano-rough ETT and secondly to develop better methods to assessin vitrobacterial adhesion or biofilm formation on ETT. In preliminary tests, nanomodified polyvinyl chloride (PVC) ETTs has been shown to be effective at reducing bacterial colonization. This study also sought to evaluate the bacterial resistance of these ETTs more effectively by creating a bench top airway model, which can create a similar environment to the flow system that ETTs are exposed toin vivo. The airway model designed to test ETTs has two Plexiglas chambers representing the oropharynx and the lungs, a tube representing the trachea and finally an intricate pumping system to the oropharynx with bacteria flow and to the lung with simulated compliance and resistance. ETTs were connected to a ventilator and passing the oropharynx into the trachea and observed under the mechanical ventilation and continuous bacterial flow system. In addition, the study examined dual gas flow conditions and their effect on bacterial growth of ETT. In no less than three separate trials in the airway chamber, each ETT will be tested for its effectiveness at the reduction of bacterial growth within the airway by sampling from both lung and oropharynx chambers during continuous operation. Special attention will be given to the long-term effects on the ETT by including a study that lasts longer than ten days. Both the bacterial proliferation in the two chambers and on the ETT itself will be carefully analyzed. This specialized testing should yield valuable information on the efficacy of nanomodified ETT in airway conditions and will provide further evidence to determine if nanomodified ETTs are a valid solution to VAP.
Phosphorescent White OLEDs for Solid-state Lighting
Authors: Xia Sean , Levermore Peter , Adamovich Vadim , Lin Chun , Kwong Raymond C. , Weaver Michael S. , Brown Julie J. 
Published: February 2010

AbstractWhite OLEDs (WOLEDTMs) fabricated using energy efficient phosphorescent OLED (PHOLEDTM) technology open up exciting new ways to develop efficient white lighting. WOLEDs have the potential to transform the lighting industry. In this presentation, phosphorescent WOLEDs with high conductivity transport layers will be discussed. White light can be generated by partial energy transfer from blue to green and red. Single WOLED stacks are demonstrated that match the Energy Star® lighting color criteria for 2700K and 3000K with high efficiency (˜80 lm/W) and high color rendering indices (˜80). Both devices had operational lifetimes (LT70%) over 30,000 hours measured from an initial luminance of 1,000 cd/m2. Different techniques to improve optical outcoupling will also be discussed.
An Improved Triple-Tandem Organic Solar Cell
Authors: Zhao Dewei , Sun Xiao Wei , Ke Lin , Tan Swee Tiam 
Published: February 2010

AbstractWe present an efficient polymer-small molecule triple-tandem organic solar cell (OSC), consisting of poly(3-hexylthiophene) (P3HT) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C61 (PCBM) bulk heterojunction as the first and second cells, and small molecules copper phthalocyanine (CuPc) and fullerene (C60) as the third cell on top. These sub-cells are connected by an intermediate layer of Al(1 nm)/MoO3(15 nm), which appears to be highly transparent, structurally smooth, and electrically functional. Compared to our previous all polymer triple-tandem organic solar cells (2.03%), this polymer-small molecule triple-tandem organic solar cell achieves an improved power conversion efficiency of 2.18% with a short-circuit current density (Jsc) = 3.02 mA/cm2, open-circuit voltage (Voc) = 1.51 V, and fill factor (FF) = 47.7% under simulated solar irradiation of 100 mW/cm2 (AM1.5G), which can be attributed to the increased photocurrent generation in the third cell since the third cell has the complementary absorption with two bottom cells despite a slightly reduced Voc.
Area-scaling of Organic Solar Cells and Integrated Modules
Authors: Choi Seungkeun , Potscavage William J , Kippelen Bernard 
Published: February 2010

AbstractWe report on the improved performance of large-area organic solar cells and modules by integrating metal grids directly with the indium tin oxide (ITO), thereby reducing the series resistance contribution from the ITO. Devices with different areas (0.1, 7, and 36.4 cm2) were prepared to study the area-dependency of the organic solar cells based on pentacene and C60 heterojunctions. Modules were prepared in which four individual cells (7 cm2) were connected in series and parallel. For the series connected modules, VOC scales linearly with the number of cells while parallel connected modules exhibited multiplied current density as expected.
UV-Vis. Spectroelectrochemical Study on Electron Blocking and Trapping Behaviors in Conducting Polymer Bilayers with Diphenylamine End Groups
Authors: Li Yunfeng , Tin Chin-Che , Cammarata Vince 
Published: February 2010

AbstractSpectroelectrochemistry was used to study the electron trapping and rectifying behavior in several diphenylamine endgroup polymeric bilayers. Various combinations of the following monomers were pairwise sequentially electropolymerized onto ITO transparent electrodes: FD, DNTD, DPTD and Cl4DPTD. Poly(FD) is a p-type material while poly(DNTD), poly(DPTD) and poly(Cl4DPTD) are bipolar materials being both n-type and p-type. Bilayers of ITO|poly(FD)|poly (DNTD) or ITO|poly (FD)|poly (DPTD), block electrons from reducing the outer layer even at -1.0 V vs Ag/AgCl, yet holes effectively oxidize both layers. The LUMO differences between poly(DNTD) and poly(Cl4DPTD) or poly(DPTD) and poly(Cl4DPTD) provide a large enough electronic barrier that electron trapping can occur between these n-type materials. The visible spectra results imply that these polymers, poly(DPTD) or poly(Cl4DPTD) can be used as photovoltaic materials.
Hydrogen adsorption calculations in expanded graphite and amorphous carbons
Authors: Peng Lujian , Morris James Robert 
Published: February 2010

AbstractThis paper uses an efficient and accurate approach to estimate the hydrogen physical adsorption in various carbon structures. By comparing with previous Grand Canonical Monte Carlo (GCMC) and other methods on expanded graphite, the introduced method is shown to be accurate, but the calculation is much faster and more intuitive. Our preliminary results in amorphous carbons show high hydrogen uptake close to 0.8% at 300 K and moderate pressure.
In-situ TEM Observation for Reaction Mechanism in MgH2 Hydrogen Storage Material
Authors: Ono Akifumi , Isobe Shigehito , Wang Yongming , Hashimoto Naoyuki , Ohnuki Somei 
Published: February 2010

AbstractIn-situ observation on the catalytic effect of Nb2O5 in MgH2 was carried out by using transmission electron microscopy (TEM). We prepared two kinds of samples, because we tried to observe the reaction from two kinds of viewpoints. MgH2 catalyzed with 1 mol% of Nb2O5 was prepared for an overall viewpoint on the desorption process of MgH2 with catalyst by conventional TEM. The dehydrogenation of the 1 mol% sample started at 150 °C and Mg nano-size particles were formed. However, Nb2O5 was not confirmed in diffraction patterns and images, because it was highly dispersed by ball-milled. So MgH2 catalyzed with 10 mol% of Nb2O5 was prepared for local viewpoint to focus the boundary between the catalyst and the Mg phase by high voltage electron micro scope (HVEM). The sample mixed in mortar was prepared for this, because it was difficult to find the boundary in the sample ball-milled. The high resolution images of the 10 mol% sample revealed that the dehydrogenation started from the interface of MgH2 and Nb2O5. The result suggested that the dehydrogenation could proceed with hydrogen diffusion from MgH2 phase to the interface between Mg and Nb2O5.
In-situ TEM Observation for Reaction of LiH with NH3 by Means of Environmental Cell
Authors: Hirasawa Hiroko , Isobe Shigehito , Wang Yongming , Yamamoto Hikaru , Miyaoka Hiroki , Hashimoto Naoyuki , Ohnuki Somei , Ichikawa Takayuki , Kojima Yoshitsugu 
Published: February 2010

AbstractIn-situ observation of the reaction between light weight hydride LiH and NH3 gas was performed by means of TEM (Transmission Electron Microscopy) with an environmental cell. This environmental cell was designed for the observation of the gas-solid reaction under 0 ∼ 0.2 MPa gas atmosphere at 20 ∼ 150 °C. It has been confirmed a volume expansion and generation of LiNH2, that is the reaction between LiH and NH3. Moreover, it was revealed that LiNH2 was generated at the surface of LiH particle at first process of the reactions.
In-situ Kinetics Studies on Hydrogenation of Transition Metal (=Ti, Fe) Doped Mg Films
Authors: Tan Zhuopeng , Heilweil Edwin J. , Bendersky Leonid 
Published: February 2010

AbstractIn this paper we report on kinetics studies of the growth rates of a hydride phase during the metal-hydride phase transformation of Mg films doped with transition metals (=Ti, Fe). Infrared emission imaging of wedge-shaped thin films during hydrogen loading reveals different effects of Ti and Fe additives on Mg hydride growth rates. Compared to hydrogenation of pure Mg, Ti addition (atomic fraction 1.6 % and 2.3 %) does not increase the Mg hydride growth rate. However, this doping results in the formation of a thicker hydride layer residing on top of the films. The hydrogenation rate is increased by an order of magnitude for addition of atomic fraction 3.1 % of Fe and the thickness of Mg hydride layer is more than twice that of the hydride layer during hydrogenation of pure Mg. Results obtained here can be used to guide powder design for hydrogen storage applications.
Phase Transformation from Mg to MgH2 Studied by SEM Metallography
Authors: Montone Amelia , Aurora Annalisa , Mirabile Gattia Daniele , Vittori Antisari Marco 
Published: February 2010

AbstractMetallographic information has been used to support the kinetic analysis and the relative experimental findings in the phase transformation from Mg to MgH2, by absorption of hydrogen gas. In particular the method provides detailed information on the role of localized features like catalyst particles and defects present in the sample, which is obtained from ball milled MgH2 enriched with 5wt% Fe. In this work we have compared the kinetics of the hydrogenation reaction carried out at two different temperatures while keeping constant the thermodynamic force driving the reaction. This last was achieved by carefully controlling the hydrogen gas pressure. Despite this fact, the sample microstructure shows a marked effect of the temperature on the nucleation mechanism. In particular we have noticed that the density of sites active for nucleation is higher at lower temperature.Instant nucleation deduced by the kinetic analysis was confirmed by comparing the microstructure of samples at different reaction stages.
In-situ Raman study of the thermal decomposition of LiBH4
Authors: Reed Daniel , Book David 
Published: February 2010

AbstractWith relatively high gravimetric and volumetric hydrogen storage capacities, borohydrides have attracted interest as potential hydrogen storage media. Lithium borohydride has a maximum theoretical gravimetric hydrogen storage density of 18.4 wt%, and has been shown to be reversible when heated to 600°C in 350 bar hydrogen1. It is hoped that a greater understanding of the decomposition and reformation mechanisms, may lead to the development of LiBH4-based materials that can absorb and desorb hydrogen under less extreme conditions. However, these studies have proved a challenge: currently most in-situ investigations have used x-ray diffraction or neutron diffraction however these cannot readily give information on non-crystalline or liquid phases. The preparation of samples measured ex-situ via XRD, NMR2 and Raman3 have shown the reaction products and stable intermediates during the thermal decomposition, however, it is very difficult to detect short lived intermediate (or byproduct) species. Raman spectroscopy has the advantages that: materials with only short-range order can be analysed; and by focusing the laser on regions in a sample the reaction path can be monitored with changing temperature with a rapid scan rate.After heating lithium borohydride through its phase change and melting point, shifts in peak position and peak width were observed, which agreed with other studies4. A sample was also heated to 500°C (under 1 bar Ar) to decompose the sample. A number of intermediates and reaction products have been predicted and observed ex situ. This work shows the in situ formation of lithium dodecaborane (Li2B12H12) and amorphous boron from liquid lithium borohydride. It is therefore possible to determine at what temperatures certain intermediates and products form.
Enhancement of TiO2 Photocatalytic Activity by N- Doping Using the Gas Phase Impregnation Method
Authors: Li Chennan , Srinivasan Sesha , Kislov Nikolai , Schmidt Mark , Stefanakos Lee , Goswami Yogi 
Published: February 2010

AbstractThis paper investigated an inexpensive way to improve the overall photocatalytic activity of TiO2 by N- doping using anhydrous ammonia as the nitrogen source. Doping amount could be further optimized by controlling the reaction time. Experiments showed that photocatalytic effect has one threshold concentration. Lower or higher reaction will decrease the photocatalytic efficiency. Experiments showed that the suitable reaction temperature should be lower than 650oC.
Environmental Friendly and Highly Regioselective Oxybromination in An Aqueous System Using SBA-15 Supported Sulfated Zirconia Catalyst
Authors: Ai-Jan Chen , Xiao-Rong Chen , Mou Chung-Yuan 
Published: February 2010

AbstractBrominated aromatic compounds have been widely used in synthetic organic chemistry for themanufacturing of many bulk and fine chemicals. In contrast to direct bromination by toxic elemental bromine or HBr, we developed an environmentally friendly system for oxybromination using hydrogen peroxide and ammonium bromide in the aqueous phase under mild temperature and near neutral conditions over a SBA-15 supported sulfated zirconia (SZ) catalyst. The ready availability of the catalyst and the nearly neutral aqueous solution are the salutary features of this approach. Bromination of aromatics with electron-withdrawing group took place readily, and bromoproducts were produced in moderate to excellent yields. A good to excellent para-selectivity was observed. The SZ/SBA-15 catalyst may be re-used several times without substantial loss of activity.We also studied the catalytic activity of SZ which were supported on mesoporous SBA-15 silica or mesoporous SZ. On bromination silica supported sulfated zirconia (SZ/SBA-15) showed much better catalytic ability for bromination then self-supported SZ (m-SZ). Furthermore, we found the catalytic activity of SZ decreased as the calcinations temperature increased. The good catalytic performance of the SZ/SBA-15 materials was attributed to the well dispersed of sulfate groups to give sulfated silica-zirconia of with (1) very good redox property and (2) high strength and high density of acid sites.
γ-Al2O3 Thin Films Catalyst Model Support Preparation on β-NiAl(110) Alloy
Authors: Zhang Zhongfan , Li Long , Shah Malay , Wen Jianguo , Yang Judith C 
Published: February 2010

AbstractLow temperature oxidation of NiAl(110) alloy has been studied with surface characterization methods and cross-section TEM. Our work demonstrated thin and high quality single crystal γ-Al2O3(111) films have grown heteroepitaxially on NiAl(110) alloy. The orientation relationship of metal/oxide is NiAl(110) || γ-A12O3(111)and NiAl(211)∥γ-Al2O3(311) with very slight lattice mismatch. Al cation outward diffusion dominates during this low temperature oxidation confirmed by EELS mapping along interface.
Twisted Nanostructures of 2H-MoS2 Slabs
Authors: Ramos Manuel , Ferrer Domingo A. , José-Yacamán Miguel , Berhault Gilles , Torres Brenda , Chianelli Russell r. 
Published: February 2010

AbstractIn the last decades, HRTEM approach has been quite fruitful to study structural characteristics of layered transition metal sulfide (LTMS) catalytic materials since providing direct local information about the structural organization of this quite important class of catalysts at the nanoscale level. However, up to now, HRTEM observations of some common localized structural organization like honeycomb-like structures have remained unexplained. In the present study, a structural model corresponding to stacked 2H-MoS2 slabs twisted along their basal direction is proposed to explain honeycomb like-structures observed by HRTEM. This model is based on a comparison between experimental and simulated images of 2H-MoS2 catalysts promoted with cobalt. The resulting Density of States (DOS) of the twisted structure was then calculated.
Bimetallic Nanoparticles of PtCu and PtNi; Synthesis and CO Oxidation Catalysis
Authors: Yamamoto Takao A. , Nakagawa Takashi , Seino Satoshi , Nitani Hiroaki 
Published: February 2010

AbstractBimetallic nanoparticles of PtCu and PtNi supported on iron oxide particles were synthesized by a new method employing a 4.8-MeV electron beam as a trigger for reduction of their aqueous ions, and their CO oxidation catalysis was evaluated to find activities enhanced by the alloying. Sample materials of PtCu (PtNi) bimetallic grains supported on γ-Fe2O3 particles were synthesized by irradiating with the electron beam a glass vial containing precursors in an aqueous solution. The vial contains aqueous ions of platinum and copper (nickel) and γ-Fe2O3 particles of average size of 30 nm. The irradiation induces water radiolysis generating reducing species, such as hydrated electrons, and metallic nanograins are formed and stabilized on the support material. The irradiation was finished in several seconds without using any organic solvent and any surfactant. The average grain sizes observed with a TEM were around 3 nm in diameter. XRD patterns of PtCu samples exhibited the FCC structure with peak shifts obeying the Vegard’s law at low Cu concentrations. X-ray absorption spectra measured at edges of the constituent elements indicated that Pt is in the metallic state and coordinates certainly with Cu or Ni. Catalytic activity of CO oxidation of the material was evaluated by measuring residual CO contents in air in contact with the sample material by using a gas-chromatograph. The activities of the PtCu and PtNi samples were higher than that of monolithic Pt on γ-Fe2O3. The correlation between the atomic structure in these nanograins and their activities was investigated, which indicated that the random alloy enhances the activity. These bimetallic nanoparticles are expected as catalysts for preferential oxidation of CO in hydrogen gas fed to fuel cells.
Preparation of Platinum Nanoparticles Using Linear Polyethyleneimine as a Stabilizer by Liquid-phase Reduction Method
Authors: Imai Takanori , Abe Yoshimoto , Nishio Keishi , Tamura Ryuji , Shibata Hirobumi , Kineri Tohru , Gunji Takahiro 
Published: February 2010

AbstractPlatinum nanoparticles stabilized by linear polyethyleneimine were prepared by the liquid-phase reduction of chloroplatinic(IV) acid with sodium borohydride. The particle sizes were 3.26 nm and 1.76 nm when the molecular weights of linear polyethyleneimine were 25000 and 2150, respectively. These nanoparticles were well-dispersed in water in the range of pH 1-6. Branched polyethyleneimine also provided nanoparticles that dispersed in water in the range of pH 0-8. Linear poly(ethyleneimine-co-N-methylethyleneimine) gave nanoparticles that dispersed in water in the range of pH 0-10. The dispersibility of the nanoparticles decreased with increasing content of the N-methyl group.