bluuebunny/crossref_metadata_2025 huggingface dataset:
Pharmacokinetic Evaluation of the Penetration of Antituberculosis Agents in Rabbit Pulmonary Lesions
Authors: Kjellsson Maria C. , Via Laura E. , Goh Anne , Weiner Danielle , Low Kang Min , Kern Steven , Pillai Goonaseelan , Barry Clifton E. , Dartois Véronique
Published: October 2011

Standard antituberculosis (anti-TB) therapy requires the use of multiple drugs for a minimum of 6 months, with variable outcomes that are influenced by a number of microbiological, pathological, and clinical factors. This is despite the availability of antibiotics that have good activity against
Mycobacterium tuberculosis in vitro
and favorable pharmacokinetic profiles in plasma. However, little is known about the distribution of widely used antituberculous agents in the pulmonary lesions where the pathogen resides. The rabbit model of TB infection was used to explore the hypothesis that standard drugs have various abilities to penetrate lung tissue and lesions and that adequate drug levels are not consistently reached at the site of infection. Using noncompartmental and population pharmacokinetic approaches, we modeled the rate and extent of distribution of isoniazid, rifampin, pyrazinamide, and moxifloxacin in rabbit lung and lesions. Moxifloxacin reproducibly showed favorable partitioning into lung and granulomas, while the exposure of isoniazid, rifampin, and pyrazinamide in lesions was markedly lower than in plasma. The extent of penetration in lung and lesions followed different trends for each drug. All four agents distributed rapidly from plasma to tissue with equilibration half-lives of less than 1 min to an hour. The models adequately described the plasma concentrations and reasonably captured actual lesion concentrations. Though further refinement is needed to accurately predict the behavior of these drugs in human subjects, our results enable the integration of lesion-specific pharmacokinetic-pharmacodynamic (PK-PD) indices in clinical trial simulations and in
in vitro
PK-PD studies with
M. tuberculosis
.
Phenotypic Changes in Artemisinin-Resistant Plasmodium falciparum Lines
In Vitro
: Evidence for Decreased Sensitivity to Dormancy and Growth Inhibition
Authors: Teuscher Franka , Chen Nanhua , Kyle Dennis E. , Gatton Michelle L. , Cheng Qin
Published: October 2011

The appearance of
Plasmodium falciparum
parasites with decreased
in vivo
sensitivity but no measurable
in vitro
resistance to artemisinin has raised the urgent need to characterize the artemisinin resistance phenotype. Changes in the temporary growth arrest (dormancy) profile of parasites may be one aspect of this phenotype. In this study, we investigated the link between dormancy and resistance, using artelinic acid (AL)-resistant parasites. Our results demonstrate that the AL resistance phenotype has (i) decreased sensitivity of mature-stage parasites, (ii) decreased sensitivity of the ring stage to the induction of dormancy, and (iii) a faster recovery from dormancy.
Composition and Localization of Treponema denticola Outer Membrane Complexes
Authors: Godovikova Valentina , Goetting-Minesky M. Paula , Fenno J. Christopher
Published: October 2011

TheTreponema denticolaouter membrane lipoprotein-protease complex (dentilisin) contributes to periodontal disease by degrading extracellular matrix components and disrupting intercellular host signaling pathways. We recently demonstrated thatprcB, located upstream of and cotranscribed withprcAandprtP, encodes a 22-kDa lipoprotein that interacts with PrtP and is required for its activity. Here we further characterize products of the protease locus and their roles in expression, formation, and localization of outer membrane complexes. PrcB migrates in native gels as part of a >400-kDa complex that includes PrtP and PrcA, as well as the major outer sheath protein Msp. PrcB is detectable as a minor constituent of the purified active protease complex, which was previously reported to consist of only PrtP and auxiliary polypeptides PrcA1 and PrcA2. Though it lacks the canonical ribosome binding site present upstream of bothprcAandprtP, PrcB is present at levels similar to those of PrtP in whole-cell extracts. Immunofluorescence microscopy demonstrated cell surface exposure of the mature forms of PrtP, PrcA1, PrcB, and Msp. The 16-kDa N-terminal acylated fragment of PrtP (predicted to be released during activation of PrtP) was present in cell extracts but was detected neither in the purified active protease complex nor on the cell surface. PrcA2, detectable on the surface of Msp-deficient cells but not that of wild-type cells, coimmunoprecipitated with Msp. Our results indicate that PrcB is a component of the outer membrane lipoprotein protease complex and that Msp and PrcA2 interaction may mediate formation of a very-high-molecular-weight outer membrane complex.
Effectiveness of a multidisciplinary consultation team for cancer pain and palliative care in a large university hospital in the Netherlands
Authors: Jongen Joost L M , Overbeck Anke , Stronks Dirk L , van Zuylen Lia , Booms Monique , Huygen Frank J , van der Rijt Carin C D
Published: October 2011

Background

Multidisciplinary palliative care teams (PCTs) are increasingly employed for cancer patients. However, relatively few studies have prospectively assessed the clinical effectiveness of inpatient PCTs. Our aim was to evaluate the effectiveness of a multidisciplinary PCT for hospitalised cancer patients in a large university hospital in the Netherlands.

Methods

Clinical data and duration of hospitalisation were prospectively collected between January 2007 and December 2008. A group of cancer pain patients from 2006 served as a historical control.

Results

The number of consultations increased from 130 in 2006 to 235 in 2008. The reason for consultation changed from pain in 98% of consultations in 2006 to a diversity of palliative symptoms in 2008. In 2008 a significant decrease in mean pain intensity, including a 70% reduction in severe pain, occurred within 24 h following consultation, although the authors did not demonstrate that the effectiveness of the PCT in 2007 and 2008 surpassed that of routine oncological care including pain control in 2006. Similarly, the median severity for 7 out of 10 items from the Edmonton Symptom Assessment System (ESAS) decreased significantly within 72 h following consultation. The median number of days in hospital for patients for whom the PCT was consulted decreased from 14 days in 2006 to 10 days in 2008.

Conclusions

The authors conclude that a multidisciplinary PCT for clinical cancer patients may have a positive effect on pain, on ESAS symptoms and on duration of hospitalisation.
Quantifying bias in pattern indices extracted from spatially offset landscape samples
Authors: Castilla Guillermo , Linke Julia , McLane Adam J. , McDermid Gregory J.
Published: October 2011

Modern ecological models often account for the influence of the surrounding environment by using landscape pattern indices (LPIs) as measures of landscape structure. Ideally, the landscape samples from which these LPIs are extracted should be centered on the locations where the response variable was measured. However, in situations where this is not possible due to a lack of adequate full-coverage landcover data, the question arises as to what degree this circumstance creates a bias in the value of the LPIs, thereby obscuring their relation with the response variable. To address this question, we extracted four representative LPIs from 30 rectangular (3 × 6 km) landscape samples evenly distributed across a 10 000 km2 boreal forest study area. These rectangles were subjected to systematic displacements across a range of distances (0.5 to 2.5 km) and directions, after which we recomputed the LPIs. We found that a 1 km spatial offset led to an average of 15% deviation of original LPI values. Unfortunately, as the offset increased, the range of resulting deviations also widened, making it difficult to predict this effect. Our findings fill a gap in the literature on landscape pattern analysis and suggest that researchers should avoid LPIs extracted from spatially offset landscape samples.
ASYMPTOTIC SPECTRAL ANALYSIS OF A GENERALIZED N-CUBE BY A QUANTUM PROBABILISTIC METHOD
Authors: KURIHARA JUN , HIBINO YUJI
Published: October 2011

We construct a growing graph such that the Jacobi coefficient of the asymptotic spectral distribution is [Formula: see text]. The distribution is a χ2 distribution with one degree of freedom normalized to have mean 0 and variance 1.
PROBABILITY MEASURES ON ℂ ARISING FROM THE JACOBI–SZEGÖ PARAMETERS FOR CONTINUOUS DUAL HAHN POLYNOMIALS
Authors: ASAI NOBUHIRO
Published: October 2011

In this paper, we shall construct probability measures on ℂ, which can be expressed by the Mellin convolution product of the modified Bessel functions. Our measures on ℂ are related to the Jacobi–Szegö parameters for the continuous dual Hahn polynomials Sn(x2, a, b, c) under the special choice of parameters a, b, c. This paper contains new materials which go further than our previous results in Ref.7. The most interesting thing is that the Mellin convolution of two modified Bessel functions can again be expressed in terms of the modified Bessel functions, by choosing parameters a, b, c appropriately. The origin of our research in this direction goes back to the Bargmann–Fock representation of the classical non-Gaussian random variables.5–8 Our results would have a potential to be related to the higher powers of creation and annihilation operators acting on a new class of interacting Fock spaces.
SRMBUILDER: A USER-FRIENDLY TOOL FOR SELECTED REACTION MONITORING DATA ANALYSIS
Authors: SHENG QUANHU , WU CHAOCHAO , SU ZHIDUAN , ZENG RONG
Published: October 2011

With high sensitivity and reproducibility, selected reaction monitoring (SRM) has become increasingly popular in proteome research for targeted quantification of low abundance proteins and post translational modification. SRM is also well accepted in other mass-spectrometry based research areas such as lipidomics and metabolomics, which necessitates the development of easy-to-use software for both post-acquisition SRM data analysis and quantification result validation. Here, we introduce a software tool SRMBuilder, which can automatically parse SRM data in multiple file formats, assign transitions to compounds, match light/heavy transition/compound pairs and provide a user-friendly graphic interface to manually validate the quantification result at transition/compound/sample level. SRMBuilder will greatly facilitate processing of the post-acquisition data files and validation of quantification result for SRM. The software can be downloaded for free from as part of the software suite ProteomicsTools.
MONIC IDEALS IN A GROUPSEMIRING
Authors: Gupta Vishnu , Chaudhari J. N.
Published: October 2011

In this paper we prove the theorem: An element r ∈ RG is free if and only if r has at least two non zero terms and there does not exist si, ti ∈ RG such that [Formula: see text], a ≠ 0 in R, g ∈ G.
GROUPS WHOSE FINITELY GENERATED SUBGROUPS ARE EITHER PERMUTABLE OR PRONORMAL
Authors: Kurdachenko L. A. , Subbotin I. Ya. , Ermolkevich T. I.
Published: October 2011

In the current article we consider locally finite groups whose finitely generated subgroups are either permutable or pronormal.
EXTENDED RIDGELET TRANSFORM ON DISTRIBUTIONS AND BOEHMIANS
Authors: Roopkumar R.
Published: October 2011

The ridgelet transform is extended to the space of Schwartz distributions and to the space of C∞-Boehmians consistent with the classical Ridgelet transform on the space of square integrable Boehmians. The properties of the ridgelet transform like linearity, injectivity, surjectivity and continuity with respect to two notions of convergence are established. It is also justified that this extended ridgelet transform on C∞-Boehmians properly generalizes the earlier extensions of the ridgelet transform.
Layered security architecture for threat management using multi-agent system
Authors: Gandotra Vandana , Archana Singhal Archana , Bedi Punam
Published: October 2011

The increasing complexity of software systems along with expanding connectivity has necessitated the evolution of an integrated security framework adopting innovative techniques for secure software systems. This paper proposes a layered security architecture for threat management using a multi-agent system to meet the above objective. Layer- 1 of this framework is designed for elicitation of realistic and flawless security requirements. Layer-2 uses a Multi-Agent system planning for avoidance of threats optimally. In this mechanism autonomous agents interact and coordinate with each other to achieve the common goal of software security. An adaptive defense mechanism using Meta-Agents in multi-agent system in conjunction with fuzzy logic to counter the adaptive and compound threats is the responsibility of Layer-3. Guidelines proposed in this paper have augmented this security architecture as a two-fold defensive strategy to ensure that a hacker is not able to tamper data even if they penetrate the periphery defenses. These proactive steps can be implemented during the design and development phases of the software life cycle in an incremental way as per the budget and security requirements of a software project. A case study on internet banking is included in the paper to describe the proposed security framework.
Effect of software evolution on software metrics
Authors: Johari Kalpana , Kaur Arvinder
Published: October 2011

Software needs to evolve in order to be used for a longer period. The changes corresponding to corrective, preventive, adaptive and perfective maintenance leads to software evolution. In this paper we are presenting the results of study conducted on 13 versions of JHot Draw and 16 versions of Rhino released over the period of 10 years. We measured Object Oriented Metrics and studied the changes in the measured values over different releases of two medium sized software developed using Java. We also investigated the applicability of Lehman's Law of Software Evolution on Object Oriented Software Systems using different measures. We found that Lehman's laws related with increasing complexity and continuous growth are supported by the data and computed metrics measure.
Quality-oriented requirements engineering for a data warehouse
Authors: Kumar Manoj , Gosain Anjana , Singh Yogesh
Published: October 2011

Due to the increasing complexity of Data Warehouses (DW), continuous attention must be paid for evaluation of their quality throughout their design and development. DW quality depends on the quality of all requirements, conceptual, logical and physical models used for DW design. Various authors have proposed metrics to assure the quality of conceptual, logical and physical models for DW. However, there is no significant work in the DW literature to assure the quality of a requirements model. A good quality requirements model may lead to a good quality DW. In this paper, we propose a qualityoriented requirements model for a DW. In the proposed model, the notion of perspective is introduced to capture the intention of the agents (stakeholders) associated with their goals. The agent may view a soft goal from two perspectives: decisional and quality perspective. In the former, the agent may refine a soft goal into the goal having well defined criteria for its achievement and termed as decisional goal, whereas in the later the agent may define the various constraint (timing constraint, budgetary constraint etc.) associated with the decisional goals. The agents suggest the decisions for achieving their decisional goals considering these constraints. Thus, the decisional goals and the constraints specified in the decisional and quality perspective respectively should be maintained as meta-data of the DW. In this way, the quality of DW requirements model will be enhanced, which may lead to enhance the quality of conceptual, logical and physical model of DW.
Effectiveness of encapsulation and object-oriented metrics to refactor code and identify error prone classes using bad smells
Authors: Singh Satwinder , Kahlon K. S.
Published: October 2011

To assist maintenance and evolution teams, work needs to be done at the onset of software development. One such facilitation is refactoring the code, making it easier to read, understand and maintain. Refactoring is done by identifying bad smell areas in the code. In this paper, based on empirical analysis, we develop a metrics model to identify smelly classes. The role of two new metrics (encapsulation and information hiding) is also investigated for identifying smelly and faulty classes in software code. This paper first presents a binary statistical analysis of thev relationship between metrics and bad smells, the results of which show a significant relationship. Then, the metrics model (with significant metrics shortlisted from the binary analysis) for bad smell categorization (divided into five categories) is developed. To verify our model, we examine the open source Firefox system, which has a strong industrial usage. The results show that proposed metrics model for bad smell can predict faulty classes with high accuracy, but in the case of the categorized model not all categories of bad smells can adequately identified the faulty and smelly classes. Due to certain limitations of our study more experiments are required to generalize the results of bad smell and faulty class identification in software code.
On-demand time-decaying bloom filters for telemarketer detection
Authors: Bianchi Giuseppe , d'Heureuse Nico , Niccolini Saverio
Published: October 2011

Several traffic monitoring applications may benefit from the availability of efficient mechanisms for approximately tracking smoothed time averages rather than raw counts. This paper provides two contributions in this direction. First, our analysis of Time-decaying Bloom filters, formerly proposed data structures devised to perform approximate Exponentially Weighted Moving Averages on streaming data, reveals two major shortcomings: biased estimation when measurements are read in arbitrary time instants, and slow operation resulting from the need to periodically update all the filter's counters at once. We thus propose a new construction, called On-demand Time-decaying Bloom filter, which relies on a continuous-time operation to overcome the accuracy/performance limitations of the original window-based approach. Second, we show how this new technique can be exploited in thedesign of high performance stream-based monitoring applications, by developing VoIPSTREAM, a proof-of-concept real-time analysis version of a formerly proposed system for telemarketing call detection. Our validation results, carried out over real telephony data, show how VoIPSTREAM closely mimics the feature extraction process and traffic analysis techniques implemented in the offline system, at a significantly higher processing speed, and without requiring any storage of per-user call detail records.
Effects of Inclusions in HSLA Carbon Steel on Pitting Corrosion in CaCl2
Authors: Ziomek-Moroz Margaret , Bullard Sophie , Rozman Kyle , Kruzic Jamie
Published: October 2011

Susceptibility of high strength low alloy steel to localized corrosion was studied in 6.7 M CaCl2 for oil and natural gas drilling applications. Results of the immersion and electrochemical experiments showed that the steel is susceptible to pitting corrosion. Optical microscopy investigations of the polished samples revealed that 10% of the surface area was occupied by defects in the form of pits. The energy dispersive X-ray (EDX) and wavelength dispersive X-ray (WDX) chemical analyses revealed higher concentrations of Mn and S compared to the metal matrix in defected areas. These areas served as the sites for development of corrosion pits during both immersion and electrochemical experiments. The fatigue results of the corroded samples indicate that if the pit was the most significant defect, the fatigue crack initiated and propagated at this site.
Electrodeposition of Novel Precursor Structures for Efficient Copper Indium Gallium Selenide (CIGS) Films
Authors: Aksu Serdar , Lastella Sarah , Kleiman-Shwarsctein Alan , Pinarbasi Mustafa
Published: October 2011

In this study, we present precursor formation techniques for CIGS films, which use multiple electrodeposition steps to form the precursor in the form of stacked layers of electroplated alloy films. The first electrodeposition step consists of electroplating a Cu-In-Ga alloy thin film. Afterwards this layer is combined with other electroplated layers, particularly In-Se and Ga-Se films to minimize or eliminate the need for gaseous species of Se, S and Te in the reaction step. Intentional grading of elemental species throughout the film thicknesses can be achieved in each layer by changing the applied current density or voltage during the electrodeposition steps.
Electrochemical Preparation and Characterization of Cupric Oxide Thin Films
Authors: Dhanasekaran Vickraman , Mahalingam Thaiyan , Chandramohan Rathinam , Chu Jinn Peter
Published: October 2011

The aim of the present study is to investigate the role of pH on the structural, morphological and optical properties of the CuO films. The structural studies revealed that the deposited films are polycrystalline in nature with a cubic structure. The preferential orientation of CuO thin films is found to be along (111) plane. The microstuctural properties such as lattice parameters, crystallite size (D), dislocation density (δ), and microstrain (ε) were calculated. The estimated microstructural parameters revealed that the crystallite size decreases whereas the microstrain increases with increasing solution pH. The surface morphology and elemental analyzes of the films were studied using scanning electron microscopy and energy dispersive analysis by X-rays (EDX), respectively. The topography and surface roughness of the film were studied by atomic force microscopy. The indirect band gap of 1.45 eV is estimated from optical studies and the results are discussed.
Hydrogen Generation by Electrocatalytic Reforming of Ethylene Glycol on a Platinum Electrode
Authors: Spies Kurt , Stuve Eric M.
Published: October 2011

The electrooxidation of ethylene glycol on a Pt/C catalyst was investigated over a range of temperatures (333 - 373 K) using a newly developed high pressure electrochemical reforming reactor. Two distinct oxidation peaks were visible on the positive sweep of the ethylene glycol electrooxidation reaction. The reactor was able to maintain a steady state current over a range of reaction potentials implying a catalytic system for the reforming of ethylene glycol.
Development of Multifunctional Catalysts for Electrooxidation of Organic Fuels
Authors: Kulesza Pawel J. , Barczuk Piotr J
Published: October 2011

This article reports on comprehensive studies of electrooxidation of methyl formate at different catalysts. The influence of the nanostructured palladium on the catalytic properties of platinum and platinum-ruthenium commercial nanoparticles towards electrooxidation of methyl formate is studied. All results are related to the electrooxidation process of formic acid and methanol at the same catalysts.
Model of Performance of a Regenerative Hydrogen Chlorine Fuel Cell for Grid-Scale Electrical Energy Storage
Authors: Rugolo Jason , Huskinson Brian , Aziz Michael J.
Published: October 2011

We develop a model for a regenerative hydrogen-chlorine fuel cell including four voltage loss mechanisms: hydrogen electrode activation, chlorine electrode activation, chlorine electrode mass transport, and ohmic loss through the membrane. The dependencies of each of these losses as a function of two "operating parameters", acid concentration and temperature; and five ``engineering parameters", exchange current densities at both electrodes, membrane thickness, acid diffusion layer thickness, and cell pressure, are explored. By examining this large parameter space, we predict the design target and ultimate limitations to the performance characteristics of this cell. We identify chlorine electrode activation as the dominant contribution to the loss for low current density, high-efficiency operation and membrane resistance as the dominant contribution to the loss at maximum galvanic power density. We conclude that a "dream" cell should be attainable with further research that operates at greater than 90% voltage efficiency at current densities >1A/cm2.
Bevel Edge Treatment for Reduction of Defect Density by Plasma Etch Processes Applied in Silicon Trench Technologies
Authors: Ehrentraut Georg
Published: October 2011

Plasma etch processes in combination with additional process steps in the standard process flow have been developed and implemented in the manufacturing process for semiconductor products utilizing trench technology for successful defect density reduction. The developed methods have resulted in a sustainable reduction of defect density patterns mainly resulting from the formation of Si needles at the wafer edge during single crystal silicon trench etching.
Characterization of Ultrathin PEALD-Grown RuCo Films for Diffusion Barrier and Copper Direct-Plate Applications
Authors: Greenslit Daniel V. , Eisenbraun Eric
Published: October 2011

RuCo films have been grown by plasma enhanced atomic layer deposition (PEALD) and investigated as a novel direct plate liner for advanced copper metallization. The RuCo films were characterized by transmission electron microscope (TEM) and found to form solid solutions, unlike other PEALD-grown mixed-phase direct plate barriers. Electrochemical deposition of copper was carried out on RuCo films with thicknesses from 2 nm to 6 nm and a range of Ru:Co metal ratios. Copper migration through the films was measured by triangle voltage sweep (TVS) testing, and RuCo films <6 nm thick were found to have equivalent diffusion performance as that of PVD TaN. Thicker RuCo films were found to be less robust barriers, and this unusual result is discussed.
Comparative Electrochemical Investigation of Pt, Au and Ti Electrodes on Liquid Crystal Polymer for the Application of Neuromuscular Prostheses
Authors: Mohtashami Saba , Howlader Matiar R. , Doyle Thomas
Published: October 2011

This paper studies the electrochemical impedance of Platinum (Pt), Gold (Au), and Titanium (Ti) deposited on liquid crystal polymer (LCP) to understand charge transfer mechanism of implantable electrodes for neuromuscular electrical stimulation. Electrodes are fabricated through e-beam evaporation and characterized using electrochemical impedance spectroscopy (EIS) and atomic force microscopy (AFM) measurements. A theoretical model is proposed to explain physical functionalities. The results demonstrate as the size of electrodes increases, higher conductivity and double layer capacitance are obtained. In neuromuscular stimulation frequencies, Pt electrodes offer the best conductivity followed by Ti and Au respectively. This material dependence of impedance magnitude is related to the surface morphology of the electrodes and is assessed by AFM. Deposition pressure dependence of Ti electrodes on the impedance is observed due to change of surface roughness and double layer capacitor. This study addresses the interface impedance of implanted electrodes and permits further development of neuromuscular prostheses.
(Invited) Luminescence Properties of Silicon-Rich Silicon Nitride Films and Light Emitting Devices
Authors: Xie Min , Li Dongsheng , Wang Feng , Yang Deren
Published: October 2011

Silicon-rich silicon nitride (SiNX) films have attracted enormous interests due to their promising luminescence properties and well compatibility with current CMOS technique. In this short review, the fabrication process of SiNX was addressed as well as their chemical composition and structure. The optical properties and future applications of the light emitting devices (LEDs) were also discussed. By analyzing the carrier conduction and combination mechanisms, electroluminescence (EL) intensity of LEDs was greatly improved through the following approaches: passivation of the interfacial states between SiNX films and Si substrates through NH3 plasma pre-treatment and post-annealing process; the balance of carrier injection via SiO2 electron accelerating layer; increase of the carrier-injection efficiency and light extraction efficiency and the enhancement of radiative recombination efficiency by surface plasmon.
(Invited) Optical and Structural Properties of Silicon Nanocrystals and Laser-Induced Thermal Effects
Authors: Khriachtchev Leonid
Published: October 2011

Si nanocrystals in silica are attractive for photonic applications. Various optical functions can be realized in this way (for example, light emission). The optical and structural properties of a variety of such materials are described and compared here. It is found that Si nanocrystals with diameters 3-4 nm are not a direct source of the 1.5-eV photoluminescence. Furnace annealing at temperatures up to 1200 °C does not complete the Si SiO2 phase separation, and the suboxide phase and very small Si clusters should be accounted for when discussing light-emission mechanisms. Laser-induced thermal effects on optical and structural properties of free-standing films are described in detail. Laser annealing produces macroscopic Si-SiO2 phase separation and compressive stress on Si nanocrystals. The laser-induced structural changes offer an approach to optical memory with a high data density and superior thermal stability.
Silicon Nanoclusters Embedded into Oxide Host for Non-Volatile Memory Applications
Authors: Khomenkova Larysa , Portier Xavier , Sahu Bhabani , Slaoui Abdelilah , Bonafos Caroline , Schamm-Chardon Sylvie , Carrada Marzia , Gourbilleau Fabrice
Published: October 2011

Non-volatile memory structures with embedded silicon nanoclusters were fabricated by RF magnetron sputtering approach. The capacitance-voltage characteristics of classical SiO2/Si-ncs-SiO2/SiO2 and HfO2/Si-ncs-SiO2/SiO2 structures have been compared. The specific deposition conditions and annealing treatment allowed a large memory window of about 6.8 V at a sweeping voltage of ± 6 V to be achieved. It was observed that the similar memory capacitance can be obtained for classical SiO2/Si-ncs-SiO2/SiO2 structures using multilayer charge storage node. The analysis of microstructural properties of the samples revealed that an annealing at 1000-1100°C results in the formation of crystallized silicon clusters, while the crystallization of HfO2 occurred with a tetragonal phase. It was also revealed that an annealing treatment at 950°C, at which amorphous Si clusters are formed, allowed a highest memory window to be obtained. This result indicates the benefit of low thermal budget treatment for low operating voltage non-volatile memory devices.
The Pt/Ni Modified TiO2 Nanotubes and its Catalytic Activity Toward Glucose
Authors: Mahshid Sahar S. , Mahshid Sara , Ghahremaninezhad Ahmad , Dolati Abolghasem , Ghorbani Mohammad , Luo Shenglian , Yang Lixia , Cai Qingyun
Published: October 2011

The catalytic activity of Pt/Ni/TiO2 nanotubes electrode toward glucose has been studied. Fabrication of Pt/Ni nanostructures was done in a single-bath solution through electrochemical pulse method by changing the deposition potential between -0.3 and -4 V vs. SCE, respectively. The resulting modified electrode represented high conductivity due to the effective presence of metallic components and uniform surface area caused by dispersion of Pt and Ni nanostructures. The scanning electron microscopy images also confirmed that a large amount of metals colonies were well-dispersed at the edge of the TiO2 nanotubes. In addition, the Pt/Ni TiO2 nanotubes modified electrode exhibited an excellent performance in cyclic voltammetry results by changing the concentration of glucose. The proposed electrode had a wide linear range up to 13 mM with the detection sensitivity of 230 μAmM−1 cm−2 respectively. The experiment results also revealed that the electrode exhibited good selectivity with no interference from other oxidable species.
Role of Deposition Potential on the Optical Properties of SnSSe Thin Films
Authors: Mahalingam Thaiyan , Dhanasekaran Vickraman , Ravi Ganesan , Chandramohan Rathinam , Kathalingam Adaikalam , Rhee Jin-Koo
Published: October 2011

SnSSe solid solution thin films were electrosynthesized from an aqueous solution by potentiostatic method. Films were deposited at different potentials in the range of -700 mV to -1000 mV vs SCE. XRD patterns revealed that the deposited films exhibited polycrystalline orthorhombic structure with preferred orientation along (111) crystallographic plane. The optical band gap value was calculated from transmittance and absorption data and the films were found to have direct band gap found to be 1.08 eV-1.25 eV. The refractive index, extinction coefficient, real and imaginary part of dielectric constants and optical conductivity of the SnSSe thin films has been calculated. The value for the refractive index lies between 2.5 and 3.1 and value of extinction coefficient lies between 0.035 and 0.052. Surface morphological studies revealed pellet shaped grains occupying the entire surface of the film distributed homogeneity.
Toward an Electrolytic Micropump Actuator Design with Controlled Cyclic Bubble Growth and Recombination
Authors: Hsu Leejay , Ramunas John , Gonzalez Jason , Santiago Juan , Strickland Daniel G.
Published: October 2011

We here show preliminary work developing a new micropump actuator design with controlled and cyclic electrolytic bubble growth and catalyst-driven recombination. We first present brief experimental data showing design feasibility. We then present an engineering model which predicts pump performance under two regimes: (1) fast bubble recombination, where pump performance is dominated by bubble generation rate and (2) finite bubble recombination, where bubble recombination time is significant. We identify a non-dimensional design parameter related to pump geometry and material-properties as critical to pump performance. In addition, we identify catalyst recombination rate as a key parameter which limits flow rate.
Redox-Induced Actuation of Microcantilevers Modified with Ferrocenylalkanethiolate Self-Assembled Monolayers
Authors: Norman Lana , Dionne Eric R. , Badia Antonella
Published: October 2011

The electrochemically-activated deflection of free-standing microcantilevers has received considerable interest for chemical sensing and nanoactuation. The development and optimization of this type of microcantilever transduction still requires a molecular-level understanding of the surface stress changes that cause the cantilever to bend. We present here the results of an on-going investigation of the electroactuation dynamics of gold-coated microcantilevers modified with model, redox-active ferrocenylalkanethiolate self-assembled monolayers. The microcantilever transducer enables the observation of the electrochemical transformation of the surface-confined ferrocenes to ferroceniums. We find that the ferrocenylalkanethiolate monolayer induces charge-normalized surface stress changes that are at least 10-fold greater than those generated by multilayers of the conducting polymers commonly used for electroactuation. The effects of the electrolyte anion and ferrocene coverage on the magnitude of the surface stress are presented. A physical model to explain the origin of the observed surface stress changes is described
Evaluation of the Corrosion Behavior in the SAE 1018 Carbon Steel Pipelines that Carry Potable Water Applying Acquisition and Data Processing
Authors: Lara Ordaz Herbert , Bolaños Rodríguez Ernesto , Ramírez-Hernández Jose Manuel
Published: October 2011

This work deals with the monitoring of physical variables influencing the corrosion process suffered by SAE 1018 carbon steel pipelines used potable water supply in a region of Hidalgo State, Mexico, by data acquisition card (DAQ) from four sensors: conductivity, pH, chloride concentration, and temperature supported by a graphical user interface through LabView 9.0. The obtained mains results show the potable water is not the cause of the possible faults or cracking in the carbon steel pipelines.
Miniband-Resonant-Tunneling Optoelectronic Device
Authors: Guo Der-Feng
Published: October 2011

The illumination effect on switching performance is presented for a triangular-barrier resonant-tunneling diode (TBRTD). In the structure center of the TBRTD, a delta-doped (d-doped) quantum well is inserted. Owing to the resonant tunneling through the miniband in the quantum well, an N-shaped negative-differential-resistance (NDR) phenomenon is observed in the current-voltage (I-V) characteristics. The device shows a flexible optical function related to the cap-layer conductivity and potential barrier height changeable by incident light.
Critical Analysis of Ion Detection Using Semiconductor Field Effect Devices: Consequences for Chemical and Biomedical Applications
Authors: Nascimento Raphael A. , Mulato Marcelo
Published: October 2011

Biosensors represent a great improvement for medical diagnosis. Miniaturization, cheapness and speed of many diagnostic methods and clinical procedures used every day can be easily adapted. Among the different types of biosensors we highlight the ones based on field effect transistors (FET), more specifically the extended gate field effect transistors (EGFET). This work presents an analysis of the procedures of measurement. Fluorine tin oxide (FTO) thin films were tested as H+ ion sensitive membrane used in the extended gate of an EGFET, which can become a part of a biosensor in the future.
Characteristics of Cubic and Tetragonal PtxFey/C and PtxFexCu/C Catalysts for the O2 Electro-Reduction
Authors: Chen Liang , Bock Christina , MacDougall Barry , Mercier Patrick H. J.
Published: October 2011

Carbon supported Pt based (Pt/C) catalysts are prepared and characterized. Cubic Pt3Fe/C, tetragonal PtFe/C and tetragonal PtxFexCu/C catalysts are made using classical impregnation and subsequent annealing in H2 methods. The catalysts show up to ~ 3 times the mass activity of a Pt/C baseline catalyst. According to Rietveld analyses well ordered catalysts of small lattice constants (e.g., a P4/mmm structure of a = 2.733 and c = 3.712 Aå) can be prepared. The O2 reduction reaction (orr) measurements suggest that the catalytic orr activity is higher (up to 190 %) for tetragonal vs. the cubic alloy catalysts. It is not clear if the experimentally observed higher catalytic activities are due to structural differences and/or difference in catalyst particle size.
NaFePO4 Olivine as Electrode Materials for Electrochemical Cells
Authors: Trottier Julie , Hovington Pierre , Brochu Fernand , Rodrigues Isadora , Zaghib Karim , Mauger Alain , Julien Christian M.
Published: October 2011

Sodium insertion is investigated in sub-micron particles of FePO4 prepared in the olivine structure by chemical delithiation of synthetic LiFePO4 by the bromide route. The electrochemical activity in Na cell is investigated using NaPF6-EC-DEC electrolyte. The structure and composition of the electrode is analyzed as function of the cell potential by means of XRD, SEM and EDX experiments.
Preparation of Silicon Nanostructures for Lithium Ion Battery Anodes
Authors: Mokkelbost Tommy , Fossdal Anita , Dahl Øystein , Martinez Ana Maria , Sheridan Edel , Thomassen Magnus , Vullum Per Erik , Rodahl Silje , Svensson Ann Mari
Published: October 2011

One important challenge, among several others, in using silicon nanostructures as anodes in lithium ion batteries concerns finding cost effective fabrication routes for their connection to a suitable current collector. Here we present synthesis and characterization of silicon nanostructures by plasma enhanced chemical vapor deposition and template assisted electrodeposition on conducting substrates. The two methods give materials with different morphologies. Silicon nanowires were grown by chemical vapor deposition utilizing the gold catalyzed vapor-liquid-solid growth mechanism. A decrease in the nucleation time for silicon wire growth on stainless steel and aluminum substrates was observed with increasing growth temperature and SiH4 pressure. The utilization of plasma enhancement resulted in the formation of silicon thin films. Copper substrates, without diffusion barrier, were found to be unsuitable for gold catalyzed vapor-liquid-solid growth. Silicon films and dots were deposited on copper and copper/gold substrates by template assisted electrochemical deposition in ionic liquids.
A Graphene "MnO2" Hybrid Supercapacitor Based on In Situ Electo-Deposition and Dissolution of "MnO2"
Authors: Perret Philippe G. , Malenfant Patrick R. , Bock Christina , MacDougall Barry
Published: October 2011

The principle of feasibility of a hybrid super-capacitor, based on graphene and the electrochemical deposition and dissolution of "MnO2", is demonstrated. For this system, a composite graphene electrode is used as the capacitive electrode. Graphene is also used in the battery type electrode, where it serves as substrate for the in-situ electrochemical deposition and dissolution of "MnO2". The electrochemical deposition and dissolution reaction provides the bulk of the charge storable in the battery type electrode. The characteristics of the two electrodes are discussed showing that their respective potential windows of stabilities are compatible with the aqueous the electrolyte. Subsequently, two hybrid systems are assembled and subjected to long charge/discharge cycles. One assembly displays an energy density of 34 and 25 Wh kg-1 after the first and 5000th cycle, respectively.
An 11 Electron Redox Couple for Anodic Charge Storage: VB2
Authors: Licht Stuart , Ghosh Susanata , Wang Baohui , Dianlu Jiang , Hettige Chaminda , Lau Jason , Asercion Joe
Published: October 2011

Nanochemical improvements of vanadium diboride are probed to facilitate anodic charge transfer, and an extractable casette chemical recharge concept for this anode is introduced. VB2 releases 11 electrons per molecule, via electrochemical oxidation, at a favorable, electrochemical potential. The discharge voltage is highly level throughout a deep discharge. This unusual multi-electron redox couple provides a charge capacity of 4060 mAh/g, which is greater than other anodes, including more than lithium. Coupled with an air cathode, the VB2 anode has energy capacity among the highest of any electrochemical storage battery or fuel cell. Nanoparticle formation is accomplished with a planetary ball mill media (tungsten carbide) with hardness comparable to that of VB2 (8-9 Mohs2). Mechanochemical synthesized, VB2 nanorods, exhibit higher voltage, sustain higher rate, and depth of discharge than macroscopic VB2.
Anchoring Gold Nanoparticles to Gold Surfaces through Nitroxyl Radicals
Authors: Święch Olga , Kaim Andrzej , Hrynkiewicz-Sudnik Natalia , Palys Barbara , Bilewicz Renata
Published: October 2011

This report describes the interaction of the gold surface with nitroxyl radicals that can be the basis of a new method for binding gold nanoparticles to gold substrates The gold surface is separated from the gold nanoparticle layer by thiolated TEMPO radicals in the sandwich-like system. TEMPO derivatives that separate gold electrode from the layer of gold nanoparticles were oriented either to or from electrode. In both cases however nitroxyl radicals play the role of binding units. The sandwich assemblies of both types were studied by cyclic voltammetry, scanning tunneling microscopy and far-infrared reflectance spectroscopy proving high efficiency of the method since binding of nanoparticles by means of nitroxyl moiety resulted in higher population of nanoparticles at the electrode surface when compared to the conventional dithiol approach.
Cyanide-Treated Fe(III) Porphyrins as an Electrocatalytic Material for Selective H2S Oxidation
Authors: Bennett Jason A. , Neiswonger Marc , Pander James , McKinney Stephanie , Wheeler Christopher
Published: October 2011

Electrodeposited Fe(III) meso-Tetra(4-carboxyphenyl) porphyrin with cyanide ligands coordinated to the central iron ion is being investigated as a possible material capable of selectively oxidizing H2S in the presence of CO and NO in physiologically relevant solutions. Preliminary results suggest this to be a very attractive material as it oxidizes H2S at low potentials while exhibiting minimal activity towards both CO and NO. However certain results suggest that the Fe may not be completely coordinated with cyanide ligands. This may explain the limitations of the material at elevated H2S concentrations and imperfect selectivity over the interfering gases. Additionally, a cathodic-post run treatment is suggested in order to maintain the electrochemical activity of the porphyrin-modified electrode surface by stripping any S0 that deposits on the electrode surface during the H2S oxidation.
Fabrication of Ag Particle with Spin Coating Method for Plasmonic Enhanced Solar Cell Efficiency
Authors: Wu Shich-Chuan , Huang Wen-Hsien , Chen Yen-Yu , Shieh Jia-Min
Published: October 2011

We fabricated thin-ﬁlm hydrogenated amorphous silicon (a-Si:H) solar cell on nano-scale Ag particle modified glass substrate to enhance energy transfer efficiency from plasmonic effect. These Ag particles with nanometer scale are formed by spin-coating method. The energy transfer efficiencies of nano Ag particles modified PIN structure of thin film a-Si:H solar cells are about 9 % higher than that of no Ag modified cell.
Determination of ORR Parameters from Fuel Cell Polarization Data Using Modified Simulated Annealing and Genetic Algorithms
Authors: Watson Mark K.
Published: October 2011

Much of the research currently being performed within the area of PEM fuel cells concerns the development of theoretical models, particularly in terms of catalyst degradation. In order to more effectively apply the results of these theoretical models, improved analysis of existing polarization data has proven useful. This paper will discuss the use of two structured random "walk" analysis algorithms (Simulated Annealing and Genetic), modified to analyze polarization data (normalized with respect to calculated oxygen partial pressure and EPSA). Cathode ORR parameters (such as Tafel slope, exchange current density, or limiting current) were determined using the Tafel Equation. As an indicator of analytical effectiveness, the exchange current density is compared to literature values.
Room Ionic Conduction in Beta Alumina Cell with Nanocomposite Electrodes
Authors: Prokhorov Igor Y. , Radionova Olga I.
Published: October 2011

The effect of the beta alumina electrolyte based nanocomposite electrodes on charge transfer rate was studied at room temperature. Ionic conductivity of cells with conventional or nanocomposite electrodes rises more than twice at the same electrolyte, cell design, and measurement conditions. The concept predicting electrode losses reduction in the electrolyte-based electrodes is proposed.
New Cathode Catalysts for Room Temperature Carbonate Fuel Cells
Authors: Vega Jose A. , Ignatowich Michael , Catanese Michael , Mustain William E.
Published: October 2011

Synthesis of calcium ruthenate pyrochlores was performed using a hydrothermal route. The resulting material was physically characterized by x-ray diffraction, BET gas adsorption and scanning electron microscopy. The use of low concentration KMnO4 (10mM) in the hydrothermal synthesis, in combination with high pH (~14) and moderate temperature (200åC), yielded a highly crystalline, thermally stable Ca2Ru2O7-y pyrochlore. Micron-sized primary particles with a high density of surface nanocrystallites were obtained. The presence of the nanocrystallites gave the pyrochlore a high surface area, 174 m2/g. Thin-film disk electrode experiments showed a slight increase in the kinetic current for O2/CO2 reduction, compared to O2-only reduction. Fuel cell experiments showed a considerable increase in current and open circuit voltage when CO2 is added to the O2 cathode stream, showing high selectivity for carbonate formation.