bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Novel Method for Electrically Modeling of Fuel Cell Using Frequency Response Technology: Executed on a Direct Methanol Fuel Cell
Authors: Wang Yang , Au George , Plichta Edward J. , Zheng Jim P. 
Published: February 2008

In this paper, a novel semi-empirical modeling method to	mathematically derive a nonlinear equivalent circuit from a special group of impedance fuel cell models is proposed.	As an	example, a 5-cm2 direct methanol fuel cell (DMFC) was modeled	by this method. The derived equivalent circuit is composed of	lumped nonlinear resistors, capacitors and an inductor. The nonlinear circuit has an impedance equivalent to the target fuel cell in various operating conditions and provides a good approximation of the static and transient behaviors of the fuel cell. The equivalent circuit fuel cell model was validated by comparing its numerical simulation results with its polarization curve and the dynamic behavior of the target DMFC. These comparisons were performed while the DMFC was operated under square current pulses with different upper and low	current levels.
Moving Boundary Model for the Discharge of a LiCoO2 Electrode
Authors: Zhang Qi , White Ralph E. 
Published: February 2008

A moving boundary model in a spherical LiCoO2 particle is	presented to account for the diffusion controlled phase transition in LiCoO2 solid particles, and this model is incorporated into a porous electrode model for the LiCoO2 electrode. The simulation results agree well with the experimental data of a LiCoO2 electrode. A study of the flux distribution in the porous electrode shows that the phase transition phenomenon in the LiCoO2 particles has a significant effect on the flux distribution by changing the solid phase diffusion resistance in the particles.
Hybrid Electrocatalysts for Degradation Mitigation in PEFCs
Authors: Trogadas Panagiotis , Ramani V. 
Published: February 2008

Pt/C/MnO2 hybrid catalysts were prepared by a wet chemical method. Rotating ring-disk electrode (RRDE) experiments were performed to estimate the amount of hydrogen peroxide (H2O2) formed during the oxygen reduction reaction (ORR) as a function of MnO2 content. Pt/C/ MnO2 (5% by weight of MnO2) hybrid electrocatalysts produced 50% less hydrogen peroxide than the	baseline Pt/C electrocatalyst. The hybrid electrocatalysts were used to prepare membrane electrode assemblies that were tested at 90{degree sign}C and 50% RH at open circuit with pure hydrogen as fuel and air as the oxidant. The concentration of F- in the anode condensate over 24 hours was found to be reduced by a factor of 3-4 when Pt/C/MnO2 replaced Pt/C as the catalyst. Through	cyclic voltammetry and RRDE kinetic studies, the lower ORR activity of the hybrid electrocatalysts was attributed to catalyst treatment with acid during MnO2 introduction.
Dynamic First-Principles Molecular-Scale Model for Solid Oxide Fuel Cells
Authors: Schmidt V. H. 
Published: February 2008

Abstract - This model for voltage V vs. current density i	characteristics applies both to the Solid Oxide Fuel Cell (SOFC) and Solid Oxide Electrolysis Cell (SOEC) modes of	operation. It is based on reaction rates calculated from a molecular-scale model for the physical and chemical processes involved. An expression is obtained for i as a function of activation polarization Vact at either interface. For large applied positive or negative voltage it correctly predicts i to be based respectively on the reverse reaction or forward	reaction attempt rate.	In contrast, the Butler-Volmer i(Vact)	expression incorrectly predicts infinite i for infinite applied voltage. The model expression for V(i) takes open-	circuit emf, activation polarization, concentration polarization, and ohmic polarization into account. Its	predictions agree quite well with experiment results obtained	by another group.
Anode Characterization and SOFC Performance using Ni-YSZ Anodes Formed by Ni Impregnation Methods
Authors: Singh Anand , Krishnan Venkatesan 
Published: February 2008

Impregnation technique has been used to load Ni on to a preformed porous anode matrix. Button cells with YSZ electrolyte	and porous anode matrix (YSZ) have been fabricated by tape casting technique. Performance curves for a cell with 4.25	volume % Ni-YSZ anode, showed that power density increased with temperature and attained a maximum of 30.87mW/cm2 at 900oC, which is low when compared to conventional cells, which have more than 30 volume % Ni incorporated in them. Electrical conductivities of 155 S/cm and 14.7 S/cm were observed at 10.48	and 4.85 volume % Ni loadings respectively which are comparable to values obtained in literature on 30 Vol% NiO-YSZ prepared by ceramic mixing process. One of the reasons for low cell performance is that Ni film formed at such low loadings undergoes sintering and loses connectivity at the operational temperatures. This was revealed by temperature programmed conductivity studies. At loadings above 5%, the Ni film is stable and as such may be considered as anodes for SOFC's.
A Tantalum Oxide Electrode for Electrochemical Ozone Generation
Authors: Kaneda Kazuhiro , Kitsuka Kenta , Nowatari Yuko , Ikematsu Mineo , Iseki Masahiro , Higuchi Tohru , Hattori Takeshi , Tsukamoto Takeyo 
Published: February 2008

An electrode with a tantalum oxide catalyst layer for electrochemical ozone generation was fabricated by sputtering. Its current efficiency for ozone generation is 8% at 10	mA/cm2. Its high value originates from the tantalum oxide band	structure, in which the electronic transfer is possible at a	high energy level.
Corrosion Products Formed on Silver and Copper Plates Exposed in a Volcanic Area
Authors: Watanabe Masamitsu , Handa Takao , Ichino Toshihiro , Kuwaki Nobuo 
Published: February 2008

Corrosion products formed on silver and copper plates exposed in a volcanic area were analyzed to get a better understanding of silver and copper corrosion in harsh environments. Both Ag2S	and AgCl were detected in the X-ray diffraction (XRD) patterns	of silver plates exposed for either 22 or 212 days. Cuprite (Cu2O) and posnjakite (Cu4SO4(OH)6•H2O) were detected in the XRD pattern of a copper plate exposed for 22 days. Brochantite (Cu4SO4(OH)6), antlerite (Cu3SO4(OH)4), and geerite (Cu8S5) were detected as well in that of a copper plate exposed for 212 days. Surface observation revealed that the surface Corrosion products formed on silver and copper plates exposed in a volcanic area were analyzed to get a better understanding of silver and copper corrosion in harsh environments. Both silver sulfide (Ag2S) and silver chloride (AgCl) were detected in the X-ray diffraction (XRD) patterns of silver plates exposed for either 22 or 212 days. Cuprite (Cu2O) and posnjakite (Cu4SO4(OH)6•H2O) were detected in the XRD pattern of a copper plate exposed for 22 days. Brochantite (Cu4SO4(OH) 6), antlerite (Cu3SO4(OH)4), and geerite (Cu8S5) were detected as well in that of a copper plate exposed for 212 days. Surface	observation revealed that the surface morphologies of silver and copper plates exposed for 212 days differed from those exposed for 22 days. Chemical state analysis by X-ray photoelectron spectroscopy showed that sulfur existed mainly as sulfide on the silver plates, while it existed mainly as	sulfate on the copper plates. This agrees well with the XRD results.
Hexavalent Chromium-Free Pre-Treatment for Galvanized Steel
Authors: Hernandez Laura A. , Hernández Luis S. , Miranda J M. , Dominguez Octavio 
Published: February 2008

The corrosion protection provided by an organic inhibitor	containing an alkanolamine salt of a polycarboxilic acid that	is suggested as non-toxic alternative to chromate and phosphate conversion coatings on galvanized steel was studied. Open circuit corrosion potential evolution, linear polarization, potentiodynamic polarization, electrochemical impedance spectroscopy, x-ray diffraction, salt spray (fog) tests and immersion - weight loss tests were used to evaluate the provided protection in a 0.5 M aerated NaCl solution. All tests	gave concordant results, indicating that the chromate-free inhibitor does protect galvanized steel in this environment, even though the provided protection was less than that of the chromate conversion coating. It was observed that after a	moderate initial attack, and except for the phosphated samples, the corrosion rate diminishes due to the appearance and growth of passivating corrosion products layers, mainly con stituted by zinc hydroxychloride (Zn5(OH)8Cl2•H2O) and two varieties of zinc hydroxide.
Review: The Fiber Width of Coalinga Chrysotile: Reduced Respirability due to its Thick Nature in an Aerosol and its ``Ultra-Thin'' Nature in Aqueous Solution (In Vivo)
Authors: Ilgren E. 
Published: February 2008

Deposition of particles in the lung is largely controlled by aerodynamic diameter, and fibers greater than a certain diameter cannot reach the alveoli. Coalinga type chrysotiles form long, thick fibers when aerosolized, which are largely nonrespirable and thus have far less potential to produce disease than true long ``non-Coalinga'' chrysotile fibers that are largely thin and mainly respirable. Increased width and reduced respirability, which was first recognized more than 25 years ago, contribute to its lack of biological activity. There is direct qualitative and quantitative evidence to support the enhanced thickness of Coalinga type chrysotiles in an aerosol and indirect evidence by mass concentration measurements. Coalinga chrysotile fibers in aqueous solution, on the other hand, have greatly reduced width distributions, which reflects the fact that their constituent components are weakly bound ultra thin fibrils. Indirect evidence from surface area measurements supports their extremely thin nature. An important consequence is that regulatory counting methods do not discriminate between Coalinga type chrysotiles and truly pathogenic long typical chrysotile fibers. Until regulatory methods are modified accordingly, the risks attributed to Coalinga type chrysotiles will continue to be grossly overestimated. In litigation, some have claimed that Union Carbide conducted ``secret'' studies that showed Coalinga chrysotile was actually thin and highly respirable in an aerosol. No such studies were ever conducted and these claims were made out of context and are unfounded.
Review: Coalinga Chrysotile: Dissolution, Concentration, Regulation and General Relevance
Authors: Ilgren E. 
Published: February 2008

Coalinga chrysotile's lack of biological activity in animals and humans is due to its amphibole-free nature, short fiber length, and enhanced width, all of which contribute to a greatly reduced bio-persistence. Compared to most other chrysotile types, it has greater solubility and enhanced dissolution, especially the very small percentage of long, thin respirable fibers that reach the alveolar portions of the lung. In consequence, the mineral poses no health threat. The ultra-structural features underlying the susceptibility to dissolution include spiral structures, permanent ledges, an absence of inter- and intra-fibrillar matrix, extremely narrow fibrillar width giving very high surface areas and surface reactivity potentials, and a relatively high number of fibrillar `ends'. Any fibers released from products made from Coalinga type material; including friction products, ceiling tiles, acoustic tiles, shingles, piping and other cement products as well as fireproofing materials, through manipulation will, on aerosolization, show re-aggregation and other properties of the parent fiber. Fiber analysis of any chrysotile containing material has always been problematic because of the fundamental structure of the fibers. Research has shown the need for indirect preparation methods of Coalinga type chrysotiles for risk assessment purposes. Direct preparation methods do not give correct answers and therefore cannot reflect biological potential. Fiber counts made by phase contrast microscopy, for example, will include large numbers of long pseudo-fibers and give results that are very misleading. The true biological nature of short and long Coalinga type chrysotiles can only be predicted using the results of indirect analysis.
In silico discovery of transcription regulatory elements in Plasmodium falciparum
Authors: Young Jason A , Johnson Jeffery R , Benner Chris , Yan S Frank , Chen Kaisheng , Le Roch Karine G , Zhou Yingyao , Winzeler Elizabeth A 
Published: February 2008

Abstract

Background
With the sequence of the Plasmodium falciparum genome and several global mRNA and protein life cycle expression profiling projects now completed, elucidating the underlying networks of transcriptional control important for the progression of the parasite life cycle is highly pertinent to the development of new anti-malarials. To date, relatively little is known regarding the specific mechanisms the parasite employs to regulate gene expression at the mRNA level, with studies of the P. falciparum genome sequence having revealed few cis-regulatory elements and associated transcription factors. Although it is possible the parasite may evoke mechanisms of transcriptional control drastically different from those used by other eukaryotic organisms, the extreme AT-rich nature of P. falciparum intergenic regions (~90% AT) presents significant challenges to in silico cis-regulatory element discovery.

Results
We have developed an algorithm called Gene Enrichment Motif Searching (GEMS) that uses a hypergeometric-based scoring function and a position-weight matrix optimization routine to identify with high-confidence regulatory elements in the nucleotide-biased and repeat sequence-rich P. falciparum genome. When applied to promoter regions of genes contained within 21 co-expression gene clusters generated from P. falciparum life cycle microarray data using the semi-supervised clustering algorithm Ontology-based Pattern Identification, GEMS identified 34 putative cis-regulatory elements associated with a variety of parasite processes including sexual development, cell invasion, antigenic variation and protein biosynthesis. Among these candidates were novel motifs, as well as many of the elements for which biological experimental evidence already exists in the Plasmodium literature. To provide evidence for the biological relevance of a cell invasion-related element predicted by GEMS, reporter gene and electrophoretic mobility shift assays were conducted.

Conclusion
This GEMS analysis demonstrates that in silico regulatory element discovery can be successfully applied to challenging repeat-sequence-rich, base-biased genomes such as that of P. falciparum. The fact that regulatory elements were predicted from a diverse range of functional gene clusters supports the hypothesis that cis-regulatory elements play a role in the transcriptional control of many P. falciparum biological processes. The putative regulatory elements described represent promising candidates for future biological investigation into the underlying transcriptional control mechanisms of gene regulation in malaria parasites.
In vitro activity of tigecycline and comparators against carbapenem-susceptible and resistant Acinetobacter baumannii clinical isolates in Italy
Authors: Mezzatesta Maria Lina , Trovato Giusi , Gona Floriana , Nicolosi Vito Mar , Nicolosi Daria , Carattoli Alessandra , Fadda Giovanni , Nicoletti Giuseppe , Stefani Stefania 
Published: February 2008

Abstract

Background
In a recent multi-centre Italian survey (2003–2004), conducted in 45 laboratories throughout Italy with the aim of monitoring microorganisms responsible for severe infections and their antibiotic resistance, Acinetobacter baumannii was isolated from various wards of 9 hospitals as one of the most frequent pathogens. One hundred and seven clinically significant strains of A. baumannii isolates were included in this study to determine the in vitro activity of tigecycline and comparator agents.

Methods
Tests for the susceptibility to antibiotics were performed by the broth microdilution method as recommended by CLSI guidelines. The following antibiotics were tested: aztreonam, piperacillin/tazobactam, ampicillin/sulbactam, ceftazidime, cefepime, imipenem, meropenem tetracycline, doxycycline, tigecycline, gentamicin, amikacin, ciprofloxacin, colistin, and trimethoprim/sulphametoxazole. The PCR assay was used to determine the presence of OXA, VIM, or IMP genes in the carbapenem resistant strains.

Results

A. baumannii showed widespread resistance to ceftazidime, ciprofloxacin and aztreonam in more than 90% of the strains; resistance to imipenem and meropenem was 50 and 59% respectively, amikacin and gentamicin were both active against about 30% of the strains and colistin about 99%, with only one strain resistant. By comparison with tetracyclines, tigecycline and doxycycline showed a higher activity. In particular, tigecycline showed a MIC90 value of 2 mg/L and our strains displayed a unimodal distribution of susceptibility being indistinctly active against carbapenem-susceptible and resistant strains, these latter possessed OXA-type variant enzymes.

Conclusion
In conclusion, tigecycline had a good activity against the MDR A. baumannii strains while maintaining the same MIC90 of 2 mg/L against the carbapenem-resistant strains.
Dispensable role of Drosophila ortholog of LRRK2 kinase activity in survival of dopaminergic neurons
Authors: Wang Danling , Tang Beisha , Zhao Guohua , Pan Qian , Xia Kun , Bodmer Rolf , Zhang Zhuohua 
Published: February 2008

Abstract

Background
Parkinson's disease (PD) is the most prevalent incurable neurodegenerative movement disorder. Mutations in LRRK2 are associated with both autosomal dominant familial and sporadic forms of PD. LRRK2 encodes a large putative serine/threonine kinase with GTPase activity. Increased LRRK2 kinase activity plays a critical role in pathogenic LRRK2 mutant-induced neurodegeneration in vitro. Little is known about the physiological function of LRRK2.

Results
We have recently identified a Drosophila line with a P-element insertion in an ortholog gene of human LRRK2 (dLRRK). The insertion results in a truncated Drosophila LRRK variant with N-terminal 1290 amino acids but lacking C-terminal kinase domain. The homozygous mutant fly develops normally with normal life span as well as unchanged number and pattern of dopaminergic neurons. However, dLRRK mutant flies were selectively sensitive to hydrogen peroxide induced stress but not to paraquat, rotenone and β-mercaptoethanol induced stresses.

Conclusion
Our results indicate that inactivation of dLRRK kinase activity is not essential for fly development and suggest that inhibition of LRRK activity may serve as a potential treatment of PD. However, dLRRK kinase activity likely plays a role in protecting against oxidative stress.
Key regulatory molecules of cartilage destruction in rheumatoid arthritis: an in vitrostudy
Authors: Andreas Kristin , Lübke Carsten , Häupl Thomas , Dehne Tilo , Morawietz Lars , Ringe Jochen , Kaps Christian , Sittinger Michael 
Published: February 2008

Abstract
Background
Rheumatoid arthritis (RA) is a chronic, inflammatory and systemic autoimmune disease that leads to progressive cartilage destruction. Advances in the treatment of RA-related destruction of cartilage require profound insights into the molecular mechanisms involved in cartilage degradation. Until now, comprehensive data about the molecular RA-related dysfunction of chondrocytes have been limited. Hence, the objective of this study was to establish a standardized in vitro model to profile the key regulatory molecules of RA-related destruction of cartilage that are expressed by human chondrocytes.

Methods
Human chondrocytes were cultured three-dimensionally for 14 days in alginate beads and subsequently stimulated for 48 hours with supernatants from SV40 T-antigen immortalized human synovial fibroblasts (SF) derived from a normal donor (NDSF) and from a patient with RA (RASF), respectively. To identify RA-related factors released from SF, supernatants of RASF and NDSF were analyzed with antibody-based protein membrane arrays. Stimulated cartilage-like cultures were used for subsequent gene expression profiling with oligonucleotide microarrays. Affymetrix GeneChip Operating Software and Robust Multi-array Analysis (RMA) were used to identify differentially expressed genes. Expression of selected genes was verified by real-time RT-PCR.

Results
Antibody-based protein membrane arrays of synovial fibroblast supernatants identified RA-related soluble mediators (IL-6, CCL2, CXCL1–3, CXCL8) released from RASF. Genome-wide microarray analysis of RASF-stimulated chondrocytes disclosed a distinct expression profile related to cartilage destruction involving marker genes of inflammation (adenosine A2A receptor, cyclooxygenase-2), the NF-κB signaling pathway (toll-like receptor 2, spermine synthase, receptor-interacting serine-threonine kinase 2), cytokines/chemokines and receptors (CXCL1–3, CXCL8, CCL20, CXCR4, IL-1β, IL-6), cartilage degradation (matrix metalloproteinase (MMP)-10, MMP-12) and suppressed matrix synthesis (cartilage oligomeric matrix protein, chondroitin sulfate proteoglycan 2).

Conclusion
Differential transcriptome profiling of stimulated human chondrocytes revealed a disturbed catabolic–anabolic homeostasis of chondrocyte function and disclosed relevant pharmacological target genes of cartilage destruction. This study provides comprehensive insight into molecular regulatory processes induced in human chondrocytes during RA-related destruction of cartilage. The established model may serve as a human in vitro disease model of RA-related destruction of cartilage and may help to elucidate the molecular effects of anti-rheumatic drugs on human chondrocyte gene expression.
Common interleukin-6promoter variants associate with the more severe forms of distal interphalangeal osteoarthritis
Authors: Kämäräinen Olli-Pekka , Solovieva Svetlana , Vehmas Tapio , Luoma Katariina , Riihimäki Hilkka , Ala-Kokko Leena , Männikkö Minna , Leino-Arjas Päivi 
Published: February 2008

Abstract
Introduction
The objective of this study was to investigate the relationship of the IL-6 promoter variants G-597A, G-572C and G-174C (rs1800797, rs1800796 and rs1800795, respectively), which have been shown to affect both the transcription and secretion of IL-6, to symptomatic distal interphalangeal (DIP) osteoarthritis (OA).

Methods
A total of 535 women aged 45 to 63 years were included. Radiographs of both hands were taken and each DIP joint was evaluated (grade 0 to 4) for the presence of OA. Information on symptoms (pain, tenderness) in each joint was collected by using a self-administered questionnaire. Symptomatic DIP OA was defined by the presence of both radiographic findings of grade 2 or more and symptoms in at least two DIP joints, and symmetrical DIP OA by the presence of radiographic findings of grade 2 or more in at least one symmetrical pair of DIP joints. Common polymorphic loci in the IL-6 gene were amplified and the promoter haplotypes were reconstructed from genotype data with the PHASE program. Logistic regression analysis was used to examine the association between the IL-6 genotypes/diplotypes and the DIP OA outcome.

Results
The G alleles of two promoter single nucleotide polymorphisms (SNPs) G-597A and G-174C were more common among the subjects with symptomatic DIP OA than among those with no disease (P = 0.020 and 0.024, corrected for multiple testing). In addition, the carriage of at least one G allele in these positions increased the risk of disease (P = 0.006 and P = 0.008, respectively). Carrying a haplotype with the G allele in all three promoter SNPs increased the risk of symptomatic DIP OA more than fourfold (odds ratio (OR) 4.45, P = 0.001). Carriage of the G-G diplotype indicated an increased risk of both symmetrical DIP OA (OR 1.52, 95% confidence interval 1.01 to 2.28) and symptomatic DIP OA (OR 3.67, 95% confidence interval 1.50 to 9.00).

Conclusion
The present study showed that the presence of G alleles at common IL-6 polymorphic promoter loci was associated with the more severe DIP OA outcomes, symmetrical and symptomatic.