bluuebunny/crossref_metadata_2025 huggingface dataset:
An Electrochemical Model of a Solid Oxide Fuel Cell Using Experimental Data for Validation of Material Properties
Authors: DiGiuseppe Gianfranco
Published: December 2010

This paper reports an electrochemical model of a Solid Oxide Fuel Cell where the model is compared against experimental data using the results from a button cell electrical test. The model fits the experimental data reasonably well using material properties found in the literature. Some of the material properties were used as fitted parameters to improve the fit, and their values compared with reported measured values. Further, cell polarization losses are explored to determine which one influences the voltage-current density characteristics the most. In comparing the material properties found in the literature with the one appropriate for the model curve fit to the experimental results, some discrepancies were observed. Hence, a better methodology is needed to understand the actual cell behavior and where improvements are needed. The method developed here is very useful for a commercial supplier of Solid Oxide Fuel Cells where button cells taken from a batch can be used to determine how good the cells are before they are installed in a stack.
Modeling the Effects of Gas Channel Flooding on the Voltage-Current Characteristics of PEM Fuel Cell
Authors: Wong K. H. , Loo K. H. , Lai Y. M. , Tan Siew-Chong , Tse Chi K.
Published: December 2010

It has been reported recently that water flooding in the gas channel (GC) has significant effects on the voltage-current characteristics of a proton exchange membrane (PEM) fuel cell. However, the theoretical treatment of these effects on the fuel cell performance is still preliminary. A one-dimensional fuel cell model including the effects of two-phase flow in the GC is proposed to investigate the influences of inlet conditions on the water distribution in fuel cell and its performance by means of coupling the GC and membrane electrode assembly (MEA) modeling domains. The model predicts that the GC conditions, which are closely correlated to the inlet conditions, significantly affect the liquid water saturation level in the MEA. An increase in the inlet air pressure or humidification level leads to more severe water flooding, while an increase in the inlet air flow rate helps mitigating the water flooding. The simulated voltage-current characteristics under various inlet conditions are verified against experimental data and simulation results of a published computational fluids dynamics (CFD) model. They indicate that the relative humidity and stoichiometry of inlet air are crucial to the fuel cell performance, particularly at high current densities, due to their influences on the liquid water distribution in the fuel cell. The correlations between the inlet conditions and the fuel cell performance are addressed in the proposed model through a more accurate treatment of two-phase water transport in the cathodic MEA and GC. These are important for appropriate water management in fuel cells.
Development of In-Situ Mechanical Testing Method for SOFC Components
Authors: Watanabe Satoshi , Sato Kazuhisa , Takeyama Yohei , Iguchi Fumitada , Yashiro Keiji , Hashida Toshiyuki , Mizusaki Junichiro , Kawada Tatsuya
Published: December 2010

For the commercialization of solid oxide fuel cell (SOFC), in addition to the electrical reliability, it is also important to ensure the mechanical reliability of SOFC. Thus, the establishment of a suitable mechanical testing method under various temperatures and oxygen partial pressure conditions is a prerequisite for the development of reliable SOFCs. This paper presents the experimental results of the investigation of elastic modulus and fracture strength on the SOFC components under reducing conditions. An in-situ mechanical testing method was developed in order to investigate the elastic modulus and fracture strength of solid oxide fuel cells components under high oxidizing/reducing environments. The elastic modulus was shown to change under reducing condition, and the behavior was most likely due to non-stoichiometry. It was demonstrated that the in-situ mechanical testing method enabled us to estimate the internal stress in the SOFC cell and stack.
Operation of a Solid Oxide Fuel Cell on Biodiesel With a Partial Oxidation Reformer
Authors: Siefert Nicholas , Shekhawat Dushyant , Gemmen Randall , Robey Edward , Bergen Richard , Haynes Daniel , Moore Kevin , Williams Mark , Smith Mark
Published: December 2010

The National Energy Technology Laboratory’s Office of Research & Development (NETL/ORD) has successfully demonstrated the operation of a solid oxide fuel cell (SOFC) using reformed biodiesel. The biodiesel for the project was produced and characterized by West Virginia State University (WVSU). This project had two main aspects: 1) demonstrate a catalyst formulation on monolith for biodiesel fuel reforming; and 2) establish SOFC stack test stand capabilities. Both aspects have been completed successfully. For the first aspect, in–house patented catalyst specifications were developed, fabricated and tested. Parametric reforming studies of biofuels provided data on fuel composition, catalyst degradation, syngas composition, and operating parameters required for successful reforming and integration with the SOFC test stand. For the second aspect, a stack test fixture (STF) for standardized testing, developed by Pacific Northwest National Laboratory (PNNL) and Lawrence Berkeley National Laboratory (LBNL) for the Solid Energy Conversion Alliance (SECA) Program, was engineered and constructed at NETL. To facilitate the demonstration of the STF, NETL employed H.C. Starck Ceramics GmbH & Co. (Germany) anode supported solid oxide cells. In addition, anode supported cells, SS441 end plates, and cell frames were transferred from PNNL to NETL. The stack assembly and conditioning procedures, including stack welding and sealing, contact paste application, binder burn-out, seal-setting, hot standby, and other stack assembly and conditioning methods were transferred to NETL. In the future, fuel cell stacks provided by SECA or other developers could be tested at the STF to validate SOFC performance on various fuels. The STF operated on hydrogen for over 1000 hrs before switching over to reformed biodiesel for 100 hrs of operation. Combining these first two aspects led to demonstrating the biodiesel syngas in the STF. A reformer was built and used to convert 0.5 ml/min of biodiesel into mostly hydrogen and carbon monoxide (syngas.) The syngas was fed to the STF and fuel cell stack. The results presented in this experimental report document one of the first times a SOFC has been operated on syngas from reformed biodiesel.
Degradation Issues in Solid Oxide Cells During High Temperature Electrolysis
Authors: Sohal M. S. , O’Brien J. E. , Stoots C. M. , Sharma V. I. , Yildiz B. , Virkar A.
Published: December 2010

Idaho National Laboratory (INL) is performing high-temperature electrolysis (HTE) research to generate hydrogen using solid oxide electrolysis cells (SOECs). The project goals are to address the technical and degradation issues associated with the SOECs. This paper provides a summary of ongoing INL and INL-sponsored activities aimed at addressing SOEC degradation. These activities include stack testing, post-test examination, degradation modeling, and issues that need to be addressed in the future. Major degradation issues relating to solid oxide fuel cells (SOFC) are relatively better understood than those for SOECs. Some of the degradation mechanisms in SOFCs include contact problems between adjacent cell components, microstructural deterioration (coarsening) of the porous electrodes, and blocking of the reaction sites within the electrodes. Contact problems include delamination of an electrode from the electrolyte, growth of a poorly (electronically) conducting oxide layer between the metallic interconnect plates and the electrodes, and lack of contact between the interconnect and the electrode. INL’s test results on HTE using solid oxide cells do not provide clear evidence as to whether different events lead to similar or drastically different electrochemical degradation mechanisms. Post-test examination of the SOECs showed that the hydrogen electrode and interconnect get partially oxidized and become nonconductive. This is most likely caused by the hydrogen stream composition and flow rate during cooldown. The oxygen electrode side of the stacks seemed to be responsible for the observed degradation because of large areas of electrode delamination. Based on the oxygen electrode appearance, the degradation of these stacks was largely controlled by the oxygen electrode delamination rate. Virkar et al. [19–22] have developed a SOEC model based on concepts in local thermodynamic equilibrium in systems otherwise in global thermodynamic nonequilibrium. This model is under continued development. It shows that electronic conduction through the electrolyte, however small, must be taken into account for determining local oxygen chemical potential within the electrolyte. The chemical potential within the electrolyte may lie out of bounds in relation to values at the electrodes in the electrolyzer mode. Under certain conditions, high pressures can develop in the electrolyte just under the oxygen electrode (anode)/electrolyte interface, leading to electrode delamination. This theory is being further refined and tested by introducing some electronic conduction in the electrolyte.
Measurement of Water Content Distribution in Catalyst Coated Membrane at Water Permeation Condition by Magnetic Resonance Imaging
Authors: Suzuki Takahiro , Tabuchi Yuichiro , Tsushima Shohji , Hirai Shuichiro , Aotani Koichiro , Kubo Norio
Published: December 2010

Through-plane water content distribution in a polymer electrolyte membrane (PEM) and water flux across the membrane were measured under different water permeation conditions using magnetic resonance imaging (MRI) and a dew point measurement system. We placed the PEM by itself or as a catalyst coated membrane (CCM) in an experimental cell, and we subjected them to several water permeation conditions that had different water activities across the membrane. We compared the water content distribution and water flux of samples, and the results showed the membranes exhibited different water content distribution between the PEM and the CCM. The differences suggest that the rate-determining process of the water transport phenomena across the membrane, which are diffusion through the membrane and interfacial transport across the membrane-gas interface, changed according to whether the membrane is used by itself or as a CCM.
Effect of Cathode Functional Layer on the Electrical Performance of Tubular Solid Oxide Fuel Cell
Authors: Prakash Deep , Lenka Raja K. , Sahu A. K. , Patro P. K. , Sinha P. K. , Suri A. K.
Published: December 2010

Development of technology related to solid oxide fuel cells at Materials Group, BARC includes synthesis of materials viz. lanthanum strontium manganite (LSM), yttria stabilized zirconia (YSZ), NiO etc. using chemical methods followed by shaping components and integrating into single cells. The indigenously prepared materials are converted to single cells for studies on material characterization and cell performances. This paper presents results of studies on electrical performances of tubular solid oxide fuel cell under hydrogen and oxygen atmospheres and correlates them with the use of cathode functional layers. Studies on symmetrical cells comprising of YSZ electrolyte sandwiched between cathode layers were carried out using electrical impedance spectroscopy (EIS). The EIS results exhibit improvement of area specific resistance (ASR) on incorporation of functional layers. Based on EIS data, double functional layers with varying compositions were incorporated in button cells as well as tubular single cells. Two types of tubular cells were fabricated, electrolyte supported and cathode supported. The electrolyte supported tubular cells were fabricated by making one-end closed tubes of YSZ, followed by coating with porous LSM inside and porous NiO-YSZ layer outside the tubes. On the other hand, tubular cathode supported cells were fabricated by one-end closed porous LSM tubes, followed by subsequent coatings of electrolyte and anode. The cells were characterized for electrical performance from 800 to 1000°C. Electrical power output from electrolyte supported cells with cathode functional layers increased from 300 mW per cell to 500 mW per cell. On the other hand, cathode supported cells exhibited improvement in ASR from ∼ 2 Ωcm2 to < 1 Ωcm2. The results were correlated with microstructure, area of triple phase boundaries and catalytic activity of cathode.
Tunable Field Control Over the Binding Energy of Single Dopants by a Charged Vacancy in GaAs
Authors: Lee D. H. , Gupta J. A.
Published: December 2010

Tuning Semiconductor Dopants

Dopants in semiconductors can alter their conductivity or introduce spin centers that alter their magnetic properties. Generally, the charge state of a dopant and field it creates are fixed.
Lee and Gupta
(p.
1807
, published online 9 December) studied Mn dopants in GaAs with a low-temperature scanning tunneling microscope (STM). Using the STM to position As vacancies at different distances from the Mn dopants revealed that the As vacancy tuned the local electrostatic field of the dopant.
Decreased Clearance of CNS β-Amyloid in Alzheimer’s Disease
Authors: Mawuenyega Kwasi G. , Sigurdson Wendy , Ovod Vitaliy , Munsell Ling , Kasten Tom , Morris John C. , Yarasheski Kevin E. , Bateman Randall J.
Published: December 2010

Alzheimer’s disease is associated with reduced β-amyloid clearance from the brain
Maternal Plasma DNA Sequencing Reveals the Genome-Wide Genetic and Mutational Profile of the Fetus
Authors: Lo Y. M. Dennis , Chan K. C. Allen , Sun Hao , Chen Eric Z. , Jiang Peiyong , Lun Fiona M. F. , Zheng Yama W. , Leung Tak Y. , Lau Tze K. , Cantor Charles R. , Chiu Rossa W. K.
Published: December 2010

Sequencing plasma DNA from a pregnant woman permits genome-wide scanning for the mutational status of the fetus prenatally and noninvasively.
Influence of thePhotorhabdus luminescensPhosphomannose Isomerase Gene,manA, on Mannose Utilization, Exopolysaccharide Structure, and Biofilm Formation
Authors: Amos Matthew R. , Sanchez-Contreras Maria , Jackson Robert W. , Muñoz-Berbel Xavier , Ciche Todd A. , Yang Guowei , Cooper Richard M. , Waterfield Nicholas R.
Published: December 2010

Extracellular polysaccharide (EPS) is produced by diverse bacterial pathogens and fulfills assorted roles, including providing a structural matrix for biofilm formation and more specific functions in virulence, such as protection against immune defenses. We report here the first investigation of some of the genes important for biofilm formation inPhotorhabdus luminescensand demonstrate the key role of the phosphomannose isomerase gene,manA, in the structure of functional EPS. Phenotypic analyses of amanA-deficient mutant showed the importance of EPS in motility, insect virulence, and biofilm formation on abiotic surfaces as well as the requirement of this gene for the use of mannose as the sole carbon source. Conversely, this defect had no apparent impact on symbiosis with the heterorhabditid nematode vector. A more detailed analysis of biofilm formation revealed that themanAmutant was able to attach to surfaces with the same efficiency as that of the wild-type strain but could not develop the more extended biofilm matrix structures. A compositional analysis ofP. luminescensEPS reveals how themanAmutation has a major effect on the formation of a complete, branched EPS.
Spatial distribution and morphology of shoots in the variant crown form of Rhododendron reticulatum
Authors: Yoshimura Kenichi
Published: December 2010

Rhododendron reticulatum D. Don ex G.Don is a common understory shrub in western Japan that exhibits highly plastic crown architecture and occurs in various light environments. I investigated how functional differentiation and spatial distribution of long and short shoots contribute to the plasticity of crown architecture of R. reticulatum. Crown form was derived from the crown depth/width ratio. Crown depth/width ratio was higher in sun-lit crowns. In crowns with higher depth/width ratio, long shoots were distributed in upper positions of the crown. Long shoots grew vertically and horizontally. In crowns with lower depth/width ratio, long shoots were arranged in the outer position of the crown and grew outward. Within neighboring shoots, long shoots had less mass than their paired short shoots. Results suggest that long shoots of R. reticulatum function to expand the crown and to reduce leaf overlap in multilayer crowns, which are found in high-light environments, while both long and short shoots function to minimize leaf overlap in monolayer crowns, which are found in shaded environments. Plasticity of crown architecture by altering shoot position and shoot morphology allows growth under various light environments in the forest understory.
Total phenolics and individual phenolic acids vary with light environment inLindera benzoin
Authors: Ingersoll Christine M. , Niesenbaum Richard A. , Weigle Caitlin E. , Lehman Julia H.
Published: December 2010

The understory shrub Lindera benzoin L. experiences lower rates of herbivory in sun environments than in shade environments. The production of secondary metabolites (e.g., phenolic compounds with known plant defense properties) is one likely contributor to these observed differences in herbivory. This work determined the total phenolic content as well as the concentrations of several individual phenolic acids in L. benzoin leaves found in sun and shade habitats. Total phenolic concentrations were determined to be higher in leaves from sun plants than in those from shade plants (47.5 ± 2.4 vs. 28.6 ± 1.3 gallic acid equivalents, respectively). High-performance liquid chromatography with diode array detection was used to separate and quantify several individual phenolic acids, and specific compounds were identified based on their retention times and ultraviolet spectra. The concentrations of vanillic, chlorogenic, p-coumaric, and ferulic acids were shown to be statistically higher in leaves from sun plants than in those from shade plants (P < 0.05), whereas 2,5-dihydroxybenzoic acid and caffeic acid were not significantly different in L. benzoin leaves from sun versus shade habitats.
Energy-level crossing of atomic hydrogen spin states
Authors: Weil John A. , Wong Brian C.S.
Published: December 2010

Atomic hydrogen 1H0 has four spin states. It is not well known that the upper two, in its electronic ground state, cross at a sufficiently high externally applied magnetic field Bx (ca. 17 T). The magnetic resonance spectra show particular effects in the crossing region. In the present work, we predict the relevant field-swept spectra at selected fixed frequencies, for 1H0 encapsulated in crystalline alpha-quartz powder, using the known spin Hamiltonian parameters derived from single-crystal EPR measurements. It was found that there is a 5 GHz frequency region in which spectral effects from the crossing can be observed.
Temperatures in the upper mesosphere and lower thermosphere from OSIRIS observations of O2 A-band emission spectra
Authors: Sheese P. E. , Llewellyn E. J. , Gattinger R. L. , Bourassa A. E. , Degenstein D. A. , Lloyd N. D. , McDade I. C.
Published: December 2010

Temperatures in the mesosphere – lower thermosphere region (MLT) have been derived from the Optical Spectrograph and InfraRed Imaging System (OSIRIS) observations of O2 A-band (b1Σ g+ –X3Σ g– )O–O emission spectra. The observed OSIRIS spectra are inverted pixel by pixel, producing inverted volume emission rate spectra at altitudes between 90 and 110 km, which are compared to modelled temperature dependent O2 A-band spectra. The estimated accuracy of the retrieved temperatures is approximately ±2 K near 90 km and up to ±6 K at higher altitudes. The developed temperature retrieval technique is presented, and some initial retrieval results are briefly discussed.
An improved one-pot cost-effective synthesis of N,N-disubstituted carbamoyl halides and derivatives
Authors: Adeppa K. , Rupainwar D. C. , Misra Krishna
Published: December 2010

A convenient one-pot procedure is reported for preparing N,N-disubstituted carbamoyl chlorides by using chlorocarbonylsulfenyl chloride as a carbonylating agent. It comprises the reaction of secondary amines with chlorocarbonylsulfenyl chloride in the presence of an aprotic organic solvent to produce the corresponding N,N-disubstituted carbamoyl halides. Insertion of the carbonyl group without using phosgene is the novelty of this method.
Fabrication of boron carbonitride (BCN) nanotubes and giant fullerene cages
Authors: Sun Guifang , Gao Faming , Hou Li
Published: December 2010

Boron carbonitride (BCN) nanotubes have been successfully prepared using NH4Cl, KBH4, and ZnBr2 as the reactants at 480 °C for 12 h by a new benzene-thermal approach in a N2 atmosphere. As its by-product, a new form of carbon regular hexagonal nanocages are observed. The samples are characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), transmission electron diffraction (TED), electron energy loss spectroscopy (EELS), and high-resolution transmission electron microscopy (HRTEM). The prepared nanotubes have uniform outer diameters in the range of 150 to 500 nm and a length of up to several micrometerss. The novel carbon hexagonal nanocages have a typical size ranging from 100 nm to 1.5 µm, which could be the giant fullerene cages of [Formula: see text] (N = 17∼148). So, high fullerenes are observed for the first time. The influences of reaction temperature and ZnBr2 on products and the formation mechanism of BCN nanotubes are discussed.
MODAL DYNAMICS APPROXIMATIONS OF CANTILEVERS UNDER PARTIAL FOLLOWER LOAD
Authors: SOPHIANOPOULOS D. S. , KATSAMAGOU S. , KEFOU N.
Published: December 2010

Presented herein is a modified Galerkin discretization procedure for determining the qualitative dynamic behavior of elastic cantilevers with internal damping under partial follower step loading at their tips. For this strong nonlinear nonconservative system, the scheme proposed makes use of basic functions that are a product of nonlinear corrections of approximate linear shape functions. These corrected modes are computed in a way that all the nonlinear nonhomogeneous boundary conditions of the actual problem are satisfied throughout the motion. Numerical results obtained using a two-mode approach are found to be in very good qualitative agreement with the finite element results presented in the literature, not only in the vicinity of the critical states, but also in remote unstable domains. The effect of variation of initial conditions is also investigated and the advantages of the proposed procedure compared with conventional ones are discussed. Further research is required for establishing its capabilities and the range of its applicability for a broader class of nonconservative dynamic problems.
QUASI-SOLID-STATE DYE-SENSITIZED SOLAR CELLS WITH A HIGH MOLECULAR GEL POLYMER ELECTROLYTE BASED ON PEO/P(VDF-HFP)
Authors: ZHANG D. W. , LI X. D. , HUANG S. M. , WANG Z. A. , SHI J. H. , SUN Z. , YIN X. J.
Published: December 2010

Quasi-solid-state dye-sensitized solar cells were fabricated using a high molecular polymer redox electrolyte. Poly(ethylene oxide) (PEO) and Poly(vinylidenefluoride-co-hexafluoropropylene) (P(VDF-HFP)) were used to form a stable quasi-solid structure and a three-dimensional gel polymer network structure. The polymer electrolytes were composed of LiI , I2 , and DMPII in the mixture of propylene carbonate (PC) and γ-butyrolactone (GBL) with different volume ratios. A metal-free organic dye (indoline dye D102) was used as a sensitizer. The ionic conductivity of the gel polymer electrolytes was measured with Electrochemical Impedance Spectroscopy (EIS). The dependence of the ionic conductivity on the volume ratio of PC to GBL was investigated. The volume ratio of the mix solvent, weight ratio of PEO/P(VDF-HFP), and the weight ratio of TiO2 fillers were optimized. The optimized quasi-solid-state cell exhibited an efficiency of 5.49% at full sunlight (air mass 1.5, 60 mW/cm2) irradiation.
NANOMECHANICAL PROPERTIES OF A Sn–Ag–Cu SOLDER REINFORCED WITH Ni-COATED CARBON NANOTUBES
Authors: HAN Y. D. , JING H. Y. , NAI S. M. L. , XU L. Y. , TAN C. M. , WEI J.
Published: December 2010

In the present study, 0.05 wt.% of Ni -coated multi-walled carbon nanotubes ( Ni -CNTs) were successfully incorporated into the 95.8Sn–3.5Ag–0.7Cu solder using the powder metallurgy technique, to synthesize a new lead-free composite solder. Its mechanical property (in terms of hardness) was investigated at room temperature using the nanoindentation method. The results revealed that the nanoindentation hardness increased by 14.3% with the incorporation of 0.05 wt.% of Ni -coated CNTs. This observation is in good agreement with the microhardness test results. Moreover, the addition of Ni -CNTs improved the creep resistance of the composite solder. The test results established that nanotechnology coupled with composite technology in electronics solders can result in the enhancement of mechanical properties. These advanced interconnect materials will thus benefit the microelectronics assembly and packaging industry.
NANOSCALE ARRAYS IN LITHIUM NIOBATE FABRICATED BY INTERFERENCE LITHOGRAPHY AND DRY ETCHING
Authors: SI G. Y. , DANNER A. J. , TENG J. H. , ANG S. S. , CHEW A. B. , DOGHECHE E.
Published: December 2010

Channel waveguides have been fabricated in x-cut lithium niobate (LiNbO3) by proton exchange (PE) method and optically measured. The thickness and the optical constants of the thin PE layer were characterized using a prism coupling technique. The PE area was plasma etched and a 2.775-μm total etching depth was achieved. The measured average etching rate is 92.5 nm/min. One- and two-dimensional dense arrays of LiNbO3 nanostructures have also been fabricated by using interference lithography (IL) and inductively coupled plasma reactive ion etching (ICP-RIE) techniques.
NONEQUILIBRIUM GREEN'S FUNCTION BASED QUANTUM TRANSPORT SIMULATION FOR STRAINED-ENGINEERED NANOSCALE TRANSISTORS IN THE PRESENCE OF ELECTRON–PHONON INTERACTIONS
Authors: MAITI T. K. , MAITI C. K.
Published: December 2010

Based on ab initio formulation and using nonequilibrium Green's function (NEGF) formalism, electronic transport in the presence of electron–phonon interactions in strained-engineered nanoscale transistors is presented. Ab initio methods are applied to treat the metal/semiconductor interface properly. NEGF formalism is applied as quantum transport and phonon scattering are the dominant factors in devices under realistic operating voltages. Local self-energy functions for electron–phonon scattering have been obtained using deformation potential theory. This approach is applied to the study of electronic transport in strain-engineered nanowire transistors. Electron–phonon interactions on broadening of local density of states are also reported.
PULSED LASER ANNEALING OF ULTRA-SHALLOW JUNCTIONS IN SILICON–GERMANIUM
Authors: TAN L. S. , TAN J. Y. , BEGUM A. , HONG M. H. , DU A. Y. , BHAT M. , WANG X. C.
Published: December 2010

The effect of laser energy fluence and substrate heating on the annealing of boron-implanted silicon–germanium epitaxial layers on silicon was investigated. By making use of the difference in the melting points of silicon–germanium and silicon, a process window in the laser energy fluence can be found such that the meltdepth was confined within the silicon–germanium. Pre-heating of the substrate to 300°C was done to reduce the laser fluence required and improve the surface morphology. Cross-sectional transmission electron microscopy showed that there were no end-of-range defects due to ion implantation at the silicon–germanium/silicon interface after the laser annealing.
PROFILES OPTIMIZATION AND CHARACTERIZATIONS OF 1D AND 2D PLASMONIC CRYSTALS
Authors: KANG HUSEN KARTASASMITA , WONG CHEE CHEONG , ROMANATO FILIPPO
Published: December 2010

Surface plasmon polariton is surface electromagnetic waves that propagate parallel along a metal/dielectric interface through a 1D or 2D periodic structures. Since the polaritons wave is confined at interface, the surface plasma polariton (SPP) is very sensitive to any changes on this boundary that directly change the effective refractive index of the system. This enables us to do some variations to control the SPP, i.e., modifying the metallic nanostructure of the plasmonic crystal (PCL) to vary the effective refractive index. Interference lithography has been widely used to produce different orders of periodic/array of nanostructures. It also has been used as the most economist and efficient way to provide 1D and 2D plasmonic crystals over large area. However, this method suffers from nonlinear processes involved in the manufacture of nominally sinusoidal surface relief diffraction gratings that can introduce distortions. Such distortions may dramatically affect both the specular reflectivity and diffracted efficiencies from plasmonic crystals. Therefore, the quality of surface profile and some geometrical parameters need to be controlled in order to optimize the coupling condition. This will lead us to the understanding of the fundamental geometrical contribution to obtain the field enhancement and variety of profile qualities.
THE JANUS-FACED E-VALUES OF HMMER2: EXTREME VALUE DISTRIBUTION OR LOGISTIC FUNCTION?
Authors: WONG WING-CHEONG , MAURER-STROH SEBASTIAN , EISENHABER FRANK
Published: December 2010

E-value guided extrapolation of protein domain annotation from libraries such as Pfam with the HMMER suite is indispensable for hypothesizing about the function of experimentally uncharacterized protein sequences. Since the recent release of HMMER3 does not supersede all functions of HMMER2, the latter will remain relevant for ongoing research as well as for the evaluation of annotations that reside in databases and in the literature. In HMMER2, the E-value is computed from the score via a logistic function or via a domain model-specific extreme value distribution (EVD); the lower of the two is returned as E-value for the domain hit in the query sequence. We find that, for thousands of domain models, this treatment results in switching from the EVD to the statistical model with the logistic function when scores grow (for Pfam release 23, 99% in the global mode and 75% in the fragment mode). If the score corresponding to the breakpoint results in an E-value above a user-defined threshold (e.g. 0.1), a critical score region with conflicting E-values from the logistic function (below the threshold) and from EVD (above the threshold) does exist. Thus, this switch will affect E-value guided annotation decisions in an automated mode. To emphasize, switching in the fragment mode is of no practical relevance since it occurs only at E-values far below 0.1. Unfortunately, a critical score region does exist for 185 domain models in the hmmpfam and 1,748 domain models in the hmmsearch global-search mode. For 145 out the respective 185 models, the critical score region is indeed populated by actual sequences. In total, 24.4% of their hits have a logistic function-derived E-value < 0.1 when the EVD provides an E-value > 0.1. We provide examples of false annotations and critically discuss the appropriateness of a logistic function as alternative to the EVD.
Evidence of porphyrin monoanion by simple spectrophotometric titration in dimethyl sulfoxide
Authors: Prashanthi Suthari , Hemant Kumar P. , Siva Doddi , Bangal Prakriti R.
Published: December 2010

We present a simple spectrophotometric titration to illustrate the existence of stable porphyrin monoanion in dimethyl sulfoxide by tetrabutylammonium hydroxide towards justifying the term 'free-acid porphyrin' for metal-free porphyrin.
Relationship between structure and photoactivity of porphyrins derived from protoporphyrin IX
Authors: Uchoa Adjaci F. , Oliveira Carla S. , Baptista Mauricio S.
Published: December 2010

Protoporphyrin (Pp IX) derivatives were prepared to study the relationship between photosensitizer structure and photoactivity, with an emphasis on understanding the role of membrane interactions in the efficiency of photosensitizers used in photodynamic therapy (PDT). The synthetic strategies described here aimed at changing protoporphyrin periferic groups, varying overall charge and oil/water partition, while maintaining their photochemical properties. Three synthetic routes were used: (1) modification of Pp IX at positions 31and 81by addition of alkyl amine groups of different lengths (compounds 2–5), (2) change of Pp IX at positions 133and 173, generating alkyl amines (compounds 6 and 7, a phosphate amine (compound 8, and quarternary ammonium compounds (compounds 9 and 10), and (3) amine-alkylation of Hematoporphyrin IX (Hp IX) at positions 31, 81, 133and 173(compound 12). Strategy 1 leads to hydrophobic compounds with low photocytotoxicity. Strategy 2 leads to compounds 6–10 that have high levels of binding/incorporation in vesicles, mitochondria and cells, which are indicative of high bioavailability. Addition of the phosphate group (compound 8), generates an anionic compound that has low liposome and cell incorporation, plus low photocytotoxicity. Compound 12 has intermediate incorporation and photocytotoxic properties. Compound modification is also associated with changes in their sub-cellular localization: 30% of 8 (anionic) is found in mitochondria as compared to 95% of compound 10 (cationic). Photocytotoxicity was shown to be highly correlated with membrane affinity, which depends on the asymmetrical and amphiphilic characters of sens, as well as with sub-cellular localization.
CUSTOMER ROLES IN INNOVATIONS
Authors: ÖBERG CHRISTINA
Published: December 2010

The purpose of this paper is to discuss and classify the roles of customers in innovations. In literature on innovations, customers have been increasingly emphasised as a source for innovations and also in how they help develop ideas in their early phases. This paper exemplifies various customer roles in innovations through three case studies. These describe the customer as initiator, as co-producer and as inspiration for business development. Through using role theory to discuss customers in innovations, it becomes explicit how customers may play their traditional roles, add roles or transfer to new roles beyond the scope of being a customer. Furthermore, the paper shows that customer roles change during the innovation process from added or transferred towards more traditional ones.
R&D STRATEGIES AND FIRM INNOVATIVE PERFORMANCE: A PANEL DATA ANALYSIS
Authors: CRUZ-CÁZARES CLAUDIO , BAYONA-SÁEZ CRISTINA , GARCÍA-MARCO TERESA
Published: December 2010

The aim of this research is to ascertain the effects of the different R&D strategies (RDSs) — defined as make, buy and make-buy — on firm innovative performance. In order to evaluate RDSs effects in a broader sense, and looking for robust results, we consider different measures of product and/or process innovations as indicators of firm innovative performance. Using panel data models for a sample of 1478 Spanish manufacturing firms during the period 1992–2005, we observe that all RDSs produce a positive influence over all innovation outputs, although the impact is greater for the make-buy strategy and lower for the buy strategy. These effects are conditional on temporality since the greatest impact occurs one year later and that in the second year is reduced to half. Results show that the buy strategy seems to have only short-term effects, whereas the make-buy effects are greater and last longer. In addition, we find empirical support for our proposed argument that RDS effects on firm innovativeness are moderated by technological intensity level.
INNOVATION MANAGEMENT CHALLENGES OF A SYSTEM INTEGRATOR IN INNOVATION NETWORKS
Authors: PAASI JAAKKO , VALKOKARI KATRI , RANTALA TUIJA , HYTÖNEN HENRI , NYSTÉN-HAARALA SOILI , HUHTILAINEN LAURA
Published: December 2010

The paper describes findings from a multiple case study about the innovation management challenges of a system integrator (SI) whose operation is characterized by a high demand of innovation and whose focus of integration capabilities is, accordingly, changing from component assembly to knowledge integration. The study involved six diverse case firms, and it applied the methodology of qualitative research. Innovation networks orchestrated by the SI were categorized, according to the way in which knowledge and intellectual property (IP) were explored and exploited in the network, to sourcing (transaction) and co-creation types of networks. The research question of the study was, what aspects of sourcing networks and of co-creation networks support or hinder networked innovation from the viewpoint of a SI and innovation management? After iteratively addressing the lessons learned from literature and empirical case findings, sets of supporting and hindering aspects were presented as implications of the study.
CUSTOMER VALUE PROPOSITIONS IN THE CONTEXT OF TECHNOLOGY COMMERCIALIZATION
Authors: WOUTERS MARC
Published: December 2010

Many larger, technology incumbent companies involve smaller, high-tech entrepreneurial firms in their innovation processes by outsourcing the development of new products, services, and processes. These R&D firms face the challenge of profitable technology commercialization. In this context, we study the use of customer value propositions and agreements based on these. The problem is that it is not clear how such propositions can be structured under considerable uncertainty. Real options logic seems to lend itself, in principle, to structuring value propositions. However, recent studies have discussed the organizational challenges of applying real options. Hence, we specifically investigate under what conditions real options logic can be an adequate base for the development of the value proposition of a small high-tech entrepreneurial supplier cooperating with a large-scale incumbent firm to develop new technology. We provide empirical support based on two case studies. Ideas for future research conclude this paper.
Altered dipeptidyl peptidase-4 activity during the progression of hyperinsulinemic obesity and islet atrophy in spontaneously late-stage type 2 diabetic rats
Authors: Kirino Yasushi , Sato Youichi , Kamimoto Takayuki , Kawazoe Kazuyoshi , Minakuchi Kazuo
Published: December 2010

Altered dipeptidyl peptidase-4 (DPP4) activity during the progression of late-stage type 2 diabetes was measured in Otsuka Long-Evans Tokushima fatty (OLETF) rats. Compared with OLETF rats subjected to 30% food restriction, food-satiated OLETF rats exhibited spontaneous hyperphagic obesity, insulin resistance, hyperglycemia, hyperinsulinemia, and increased plasma DPP4 activity during the early phase of the experiment (up to ∼30 wk). Subsequently, their plasma DPP4 activity as well as their body weight, body fat, and plasma insulin concentration declined to control levels during the late phase, resulting in excessive polyuria, proteinuria, dyslipidemia, pancreatic islet atrophy, hypoinsulinemia, and diabetes, which changed from insulin-resistant diabetes to hypoinsulinemic diabetes secondary to progressive islet insufficiency, and their fasting blood glucose level remained high. Since plasma DPP4 activity demonstrated significant positive correlations with body weight and the fasting plasma insulin level but not with the fasting blood glucose level during the late stage of diabetes, body fat and fasting plasma insulin levels may be useful factors for predicting the control of plasma DPP4 activity. In contrast, pancreatic DPP4 activity was significantly increased, and the expression of pancreatic insulin was significantly reduced in late-stage diabetic OLETF rats, suggesting that a relationship exists between the activation of pancreatic DPP4 and insulin depletion in pancreatic islet atrophy. In conclusion, it is suggested that plasma DPP4 activity changes in accordance with the progression of hyperinsulinemic obesity and pancreatic islet atrophy. DPP4 activity may play an important role in insulin homeostasis.
Inhibition of intestinal biotin absorption by chronic alcohol feeding: cellular and molecular mechanisms
Authors: Subramanya Sandeep B. , Subramanian Veedamali S. , Kumar Jeyan S. , Hoiness Robert , Said Hamid M.
Published: December 2010

The water-soluble vitamin biotin is essential for normal cellular functions and its deficiency leads to a variety of clinical abnormalities. Mammals obtain biotin from exogenous sources via intestinal absorption, a process mediated by the sodium-dependent multivitamin transporter (SMVT). Chronic alcohol use in humans is associated with a significant reduction in plasma biotin levels, and animal studies have shown inhibition in intestinal biotin absorption by chronic alcohol feeding. Little, however, is known about the cellular and molecular mechanisms involved in the inhibition in intestinal biotin transport by chronic alcohol use. These mechanisms were investigated in this study by using rats and transgenic mice carrying the human full-length SLC5A6 5′-regulatory region chronically fed alcohol liquid diets; human intestinal epithelial Caco-2 cells chronically exposed to alcohol were also used as models. The results showed chronic alcohol feeding of rats to lead to a significant inhibition in carrier-mediated biotin transport events across jejunal brush border and basolateral membrane domains. This inhibition was associated with a significant reduction in level of expression of the SMVT protein, mRNA, and heterogenous nuclear RNA. Chronic alcohol feeding also inhibited carrier-mediated biotin uptake in rat colon. Studies with transgenic mice confirmed the above findings and further showed chronic alcohol feeding significantly inhibited the activity of SLC5A6 5′-regulatory region. Finally, chronic exposure of Caco-2 cells to alcohol led to a significant decrease in the activity of both promoters P1 and P2 of the human SLC5A6 gene. These studies identify for the first time the cellular and molecular parameters of the intestinal biotin absorptive processes that are affected by chronic alcohol feeding.
Trimethylangelicin reduces IL-8 transcription and potentiates CFTR function
Authors: Tamanini Anna , Borgatti Monica , Finotti Alessia , Piccagli Laura , Bezzerri Valentino , Favia Maria , Guerra Lorenzo , Lampronti Ilaria , Bianchi Nicoletta , Dall'Acqua Francesco , Vedaldi Daniela , Salvador Alessia , Fabbri Enrica , Mancini Irene , Nicolis Elena , Casavola Valeria , Cabrini Giulio , Gambari Roberto
Published: December 2010

Chronic inflammatory response in the airway tract of patients affected by cystic fibrosis is characterized by an excessive recruitment of neutrophils to the bronchial lumina, driven by the chemokine interleukin (IL)-8. We previously found that 5-methoxypsoralen reduces Pseudomonas aeruginosa -dependent IL-8 transcription in bronchial epithelial cell lines, with an IC50 of 10 μM (Nicolis E, Lampronti I, Dechecchi MC, Borgatti M, Tamanini A, Bezzerri V, Bianchi N, Mazzon M, Mancini I, Giri MG, Rizzotti P, Gambari R, Cabrini G. Int Immunopharmacol 9: 1411–1422, 2009). Here, we extended the investigation to analogs of 5-methoxypsoralen, and we found that the most potent effect is obtained with 4,6,4′-trimethylangelicin (TMA), which inhibits P. aeruginosa -dependent IL-8 transcription at nanomolar concentration in IB3–1, CuFi-1, CFBE41o−, and Calu-3 bronchial epithelial cell lines. Analysis of phosphoproteins involved in proinflammatory transmembrane signaling evidenced that TMA reduces the phosphorylation of ribosomal S6 kinase-1 and AKT2/3, which we found indeed involved in P. aeruginosa -dependent activation of IL-8 gene transcription by testing the effect of pharmacological inhibitors. In addition, we found a docking site of TMA into NF-κB by in silico analysis, whereas inhibition of the NF-κB/DNA interactions in vitro by EMSA was observed at high concentrations (10 mM TMA). To further understand whether NF-κB pathway should be considered a target of TMA, chromatin immunoprecipitation was performed, and we observed that TMA (100 nM) preincubated in whole living cells reduced the interaction of NF-κB with the promoter of IL-8 gene. These results suggest that TMA could inhibit IL-8 gene transcription mainly by intervening on driving the recruitment of activated transcription factors on IL-8 gene promoter, as demonstrated here for NF-κB. Although the complete understanding of the mechanism of action of TMA deserves further investigation, an activity of TMA on phosphorylating pathways was already demonstrated by our study. Finally, since psoralens have been shown to potentiate cystic fibrosis transmembrane conductance regulator (CFTR)-mediated chloride transport, TMA was tested and found to potentiate CFTR-dependent chloride efflux. In conclusion, TMA is a dual-acting compound reducing excessive IL-8 expression and potentiating CFTR function.
EphrinB2 induces pelvic-urethra reflex potentiation via Src kinase-dependent tyrosine phosphorylation of NR2B
Authors: Wu Hsi-Chin , Chang Chao-Hsiang , Peng Hsien-Yu , Chen Gin-Den , Lai Cheng-Yuang , Hsieh Ming-Chun , Lin Tzer-Bin
Published: December 2010

Recently, the role of EphB receptor (EphBR) tyrosine kinase and their ephrinB ligands in pain-related neural plasticity at the spinal cord level have been identified. To test whether Src-family tyrosine kinase-dependent glutamatergic N-methyl-d-aspartate receptor NR2B subunit phosphorylation underlies lumbosacral spinal EphBR activation to mediate pelvic-urethra reflex potentiation, we recorded external urethra sphincter electromyogram reflex activity and analyzed protein expression in the lumbosacral (L6-S2) dorsal horn in response to intrathecal ephrinB2 injections. When compared with vehicle solution, exogenous ephrinB2 (5 μg/rat it)-induced reflex potentiation, in associated with phosphorylation of EphB1/2, Src-family kinase, NR2B Y1336 and Y1472 tyrosine residues. Both intrathecal EphB1 and EphB2 immunoglobulin fusion protein (both 10 μg/rat it) prevented ephrinB2-dependent reflex potentiation, as well as protein phosphorylation. Pretreatment with PP2 (50 μM, 10 μl it), an Src-family kinase antagonist, reversed the reflex potentiation, as well as Src kinase and NR2B phosphorylation. Together, these results suggest the ephrinB2-dependent EphBR activation, which subsequently provokes Src kinase-mediated N-methyl-d-aspartate receptor NR2B phosphorylation in the lumbosacral dorsal horn, is crucial for the induction of spinal reflex potentiation contributing to the development of visceral pain and/or hyperalgesia in the pelvic area.