bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular Dynamics Study of Oxygen Permeation in PFSA Ionomer on the Pt Catalyst Surface
Authors: Sakai Kiminori , Tokumasu Takashi
Published: October 2011

In polymer electrolyte membrane fuel cell (PEFC) cathode catalyst layer, PFSA ionomer with which the catalyst is covered is very important on the point of transferring protons to the catalytic surface on the cathode side. On the other hand, it is said that an ionomer interferes with oxygen permeation to the catalytic surface. The mechanism of oxygen permeation through an ionomer was not analyzed in detail because it is too small to research by experiment. Moreover molecular dynamics simulation of the catalyst layer and oxygen permeability has not yet studied. In this research, we constructed the system of ionomer on the platinum surface by using molecular dynamics study, and studied about the effect of the water content of the ionomer on the structure of the ionomer and permeability of the oxygen molecule.
Analysis of Proton and Water Transfer in PFSA Membrane by Molecular Dynamics Simulation
Authors: Mabuchi Takuya , Tokumasu Takashi
Published: October 2011

Protons transfer in polyelectrolyte membrane by both Vehicle and Grotthus mechanisms. This study describes the property of proton and water transfer in perfluorosulfonic acid (PFSA) membrane using molecular dynamics (MD) simulation in view of both Vehicle and Grotthus mechanisms. To treat Grotthus mechanism, Empirical Valence Bond (EVB) method was introduced to MD simulation. The potential energy barrier of proton hopping in EVB method was adjusted to the computational result of Density Functional Theory (DFT) to replicate the experimental value of diffusion coefficient of oxonium ions in water. The parameter for the simulation of PFSA membrane was water contents λ, which is defined as the ratio of water molecules and oxonium ions to sulfo groups, SO3-, obtained byλ=NH2O,H3O+/NSO3-. The structure of water and PFSA membrane was analyzed by Radial Distribution Function (RDF) and diffusion coefficient of proton was found out from Mean Square Displacement (MSD).
Proton Conduction Characteristics in Radiation-Grafted Polymer Electrolyte Membranes Based on Perfluorinated and Aromatic Hydrocarbon Polymers
Authors: Sawada Shin-ichi , Maekawa Yasunari
Published: October 2011

For understanding the relationship between the proton conductivity, and structures of polymer electrolyte membranes (PEMs), we compared proton conduction characteristics in two different types of radiation-grafted PEMs; those based on crosslinked-poly(tetrafluoroethylene) (cPTFE) and poly(etheretherketone) (PEEK). The conductivity showed different dependency on ion exchange capacity (IEC) in cPTFE and PEEK PEMs; namely, the PEEK PEMs showed higher conductivity at a low IEC region, while the cPTFE PEM showed higher conductivity at a high IEC region. The conduction behavior was clearly elucidated by taking into account the self-diffusion coefficient of protons, DP. At a high IEC region, the cPTFE PEMs absorbed more water than the PEEK PEMs to weaken the attractive coulombic interactions between protons and sulfonic acid groups, increasing the DP. In contrast, at a low IEC region, a large amounts of PTFE crystallites possibly deteriorated the connectivity of hydrophilic proton transport pathways, lowering the DP of the cPTFE PEMs.
Ionic-Crosslinked Interpenetrating Polymer Network (IPN) Membranes for Anhydrous High Temperature Polymer Electrolyte Fuel Cells Based on PFSA Ionomer and Functionalized Polysiloxane
Authors: Zhu Xiaobing , Martin Zulima , Clark Kyle T. , Brecht Tobias , Potrekar Ravindra A. , Burgess Sean , Kerr John B.
Published: October 2011

To minimize humidity dependence and enhance temperature tolerance, anhydrous Polymer Electrolyte Membranes (PEM) are desired to allow fuel cells to operate with conductivities as high as 0.1S/cm at temperatures up to 120oC. Heterocyclic molecules such as imidazole and triazole, similar to water, assist proton conduction due to self-dissociation. By doping into perfluorosulfonic acid (PFSA) ionomer, it could assist proton conducting through Grotthus mechanism, but with potential leaching issues under open circumstance. In this paper, the synthesis of siloxane tethered imidazole or 1,2,4-triazole is described, as is their in-situ polymerization by acidic catalysis with PFSA ionomers. Optically homogeneous membranes were obtained from these procedures. The dry membrane conductivity approaches 10-3S/cm, but doping with 30wt.% phosphoric acid shows conductivity of 10-1S/cm at 120oC under dry conditions. The crosslinked interpenetrating polymer network (IPN) membranes, were characterized by microscopy, by analytical, electrochemical, thermal/mechanical, and physicochemical means, and tested for durability in the presence of Fenton reagent.
Renewing Accelerated Stress Tests Correlated to Actual Deterioration in Proton Exchange Membrane Fuel Cells to Evaluate the Durability of Perfluorinated and Hydrocarbon Proton Exchange Membranes
Authors: Nomura Yoshihiro , Hiramitsu Yusuke , Yamashita Shotaro , Yamaguchi Yuya , Kobayashi Kenji , Hori Michio
Published: October 2011

Accelerated stress tests for evaluation of durability of perfluorinated and hydrocarbon proton exchange membranes (PFSA and HC-PEM) in proton exchange membrane fuel cells (PEMFCs) were examined. At the open circuit voltage(OCV) and relative humidity (RH) cycles, HC-PEM sometimes showed exceeding durability compared to PFSA. Power generation and OCV tests in high cell temperature, high anode humidity and low cathode humidity conditions were examined in order to accelerate. The cells were diagnosed and the drain analysis were performed. Post-test analysis included micro mechanical strength testing and EPMA measurement of MEA.
Analysis of Kinetics of Oxygen Reduction Reaction in Alkaline Solution by Scanning Electrochemical Microscopy
Authors: Teranishi Rie , Higuchi Eiji , Chiku Masanobu , Inoue Hiroshi
Published: October 2011

Kinetics of oxygen reduction reaction (ORR) at some electrocatalysts in alkaline solution was investigated by scanning electrochemical microscopy (SECM). Oxygen was reduced at a substrate (ORR catalyst) electrode and transient oxidation currents of a product, HO2-, were detected at an ultramicro electrode (UME) as the probe which was positioned at parallel to substrate. The transient oxidation currents at the UME for the Ag, Au and Ni(OH)2 substrates were different from each other. Theoretical transient oxidation currents of HO2- were fitted to the experimental data to evaluate the rate constants of three elementary reactions. The mechanism of ORR at each electrocatalyst was discussed based on the rate constants.
Activity and Durability of Pd Core/Pt Shell-Loaded Carbon Black as the Cathode Catalyst in PEFC
Authors: Sakai Ryotaro , Chiku Masanobu , Higuchi Eiji , Inoue Hiroshi
Published: October 2011

Pd nanoparticles with mean sizes less than 5 nm were prepared with and without stabilizer by using CO as a reducing agent, and used for preparing Pd core/Pt shell-loaded carbon black (Ptx/Pd/CB). The acitivity and durability of the Ptx/Pd/CB as the cathode catalyst in polymer electrolyte fuel cells (PEFCs) were evaluated. The Ptx/Pd/CB prepared from Pd nanoparticles without stabilizer had much higher mass activity than the Ptx/Pd/CB catalysts prepared from Pd nanoparticles including polyvinylpyrrolidone as a stabilizer and commercial Pt/CB. The durability of the Ptx/Pd/CB prepared from Pd nanoparticles without stabilizer was almost equivalent or superior to the commercial Pt/CB.
PAN Based Carbon Nanofibers as an Active ORR Catalyst for DMFC
Authors: Nakagawa Nobuyoshi , Ali Abdelkareem Mohammad , Takino Daiki , Ishikawa Takayuki , Tsujiguchi Takuya
Published: October 2011

Polyacrylonitrile (PAN) based carbon nanofibers containing different proportions of transition metals in the form of metal phthalocyanine, MPc, where, M is Co and Fe, have been prepared by electrospinning and their activities for oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR) in acidic media were investigated. Field emission electron microscope (FE-SEM), transition electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV) were carried out to investigate the surface morphology, composition, and catalytic activity. The ORR activity significantly increased with the addition of the transition metals, and also increased the pyridine N content. The highest ORR activity was obtained for CoPc PAN nanofibers at 900 oC, this would be related to the balance between electrical conductivity and pyridine N content. FePc PAN based carbon nanofibers at 900 oC showed a high stability and ORR activity comparable to that of the commercial Pt/C catalyst while FePc PAN nanofibers has no MOR activity.
Oxygen Reduction Activity of Pyrolyzed Polyanilines Studied by 15N Solid-State NMR and XPS with Principal Component Analysis
Authors: Kuroki Shigeki , Nabae Yuta , Kakimoto Masa-aki , Miyata Seizo
Published: October 2011

15N labeled polyaniline is prepared as a precursor of N-doped carbon catalysts and is pyrolyzed at several different temperatures in a nitrogen atmosphere. The oxygen reduction reaction is evaluated by rotating disk electrode experiments, and solid-state 15N NMR and XPS spectra of the samples are measured. The relationship between oxygen reduction activity and the chemical structure, combined with principal component analysis is discussed. Using principal component analysis of the XPS and 15N solid-state NMR spectra, it is found that most pyridinic, graphitic, and pyridinium-like or pyrrolic nitrogen atoms in the samples are not related to oxygen reduction reaction. However, the samples which contain a larger proportion of some particular type of pyridinic nitrogen atoms show a higher activity for the oxygen reduction reaction.
Electrocatalytic Ethanol Oxidation Reaction at Rh and SnO2 Monolayer-Modified Pt Electrodes
Authors: Haze Akinori , Chiku Masanobu , Higuchi Eiji , Inoue Hiroshi
Published: October 2011

Rh or/and Sn oxide monolayers were deposited on a Pt polycrystalline plate (Pt/Rh, Pt/SnO2, Pt/Rh/SnO2) by the H-underpotential deposition method. The coverage of Rh and SnO2 for each electrode was electrochemically evaluated. The oxidation current density of ethanol at 0.6 V vs. RHE for the Pt/SnO2 and Pt/Rh/SnO2 electrodes was ca. 8 times as high as that for the Pt and Pt/Rh electrodes. Thein-situ infrared reflection absorption spectroscopy exhibited the Pt/Rh electrode did not improve the activity for ethanol oxidation reaction (EOR), but improved the selectivity of CO2 production. On the other hand, at the Pt/SnO2 electrode, CO2 was scarcely formed, while the formation of acetic acid was significantly accelerated. At the Pt/Rh/SnO2 electrode, acetic acid and CO2 were formed. In this case, not only the EOR activity but also the selectivity of CO2 production were improved.
Oxygen Reduction Reaction Activity of Shape Controlled Pt Catalysts
Authors: Toge Akihide , Yokono Takashi , Saito Morihiro , Daimon Hideo , Tasaka Akimasa , Inaba Minoru
Published: October 2011

In order to clarify the effect of surface atomic structure on oxygen reduction reaction (ORR) activity for Pt/C catalysts, cubic and cuboctahedral Pt nanoparticles (NPs) colloidal solutions were prepared from K2PtCl4 solutions using sodium polyacrylate (PAA) as a capping reagent, and furthermore the shape-controlled Pt NPs were deposited on a Ketjen Black support. The cubic and cuboctahedral Pt/C catalysts (Ptcubic/C and Ptcuboctahedral/C) gave characteristic H2 absorption/desorption peaks in the CV curves attributed to their crystal facets. The Ptcuboctahedral/C having the (100) and (111) faces showed higher ORR activity than a commercially available polycrystalline Pt/C and the Ptcubic/C composed of mainly (100) facet.
Functionalized Metal Oxides for PEMFC Applications
Authors: Cozzi Dafne , De Bonis Catia , D'Epifanio Alessandra , Mecheri Barbara , Felice Valeria , Tavares Ana , Licoccia Silvia
Published: October 2011

A synthetic strategy for the surface functionalization of ZrO2 nanoparticles was developed to obtain ceramic materials with improved proton conductivity to be used as fillers in proton conducting membranes for fuel cell applications. The procedure consisted in condensation of the oxide surface hydroxyl groups with 3-mercaptopropyltrimethoxy silane, followed by oxidation of the thiol group into sulfonic acid. The morphology, chemical structure and composition of the functionalized oxide were investigated by differential thermal analysis (DTA), Fourier Transform Infrared Spectroscopy (FT-IR) and Field Emission Scanning Electron Microscopy (FE-SEM). Thermal analysis demonstrated the good thermal and hydrothermal stability of this new material. The proton transport features of the oxide were investigated by measuring ion exchange capacity (IEC) and proton conductivity (σ), demonstrating that the surface functionalization procedure enhanced the proton transport feature of zirconium oxide.
Electrochemical Performance of Polymer Electrolyte Fuel Cells Using Carbon-Free SnO2-Supported Pt Electrocatalysts
Authors: Kanda Kohei , Hayashi Shingo , Takasaki Fumiaki , Noda Zhi Yun , Taniguchi Shunsuke , Shiratori Yusuke , Hayashi A. , Sasaki Kazunari
Published: October 2011

Carbon black is commonly used as an electrocatalyst support material in polymer electrolyte fuel cells (PEFCs). However, during the fuel cell start-stop cycles, carbon is known to be oxidized electrochemically. In the present study, SnO2 has been selected as a candidate for the support material, and the relation between SnO2 preparation conditions and electrochemical properties is analyzed.
Development of Non-Precious Metal Catalysts for Oxygen Reduction Reaction in Fuel Cells with High Activity and Stability
Authors: Li Xuguang , Popov Branko N.
Published: October 2011

Non-precious metal catalysts (NPMCs) with high activity and stability are developed for oxygen reduction reaction (ORR) in alkaline membrane fuel cell (AMFC). A variety of important parameters determining the performance of AMFC are systematically investigated, including the ratio of catalyst to ionomer at cathode, the flow rates of oxygen and air, and the fuel cell operating temperatures. An optimum catalyst/ionomer ratio range of 7:3 to 8:2 was found for the NPMC-based cathode in both H2/O2 and H2/air cases. The operating temperature was demonstrated to play the crucial role in determining the AMFC performances.
Age-Related Differences in Doctor-Patient Interaction and Patient Satisfaction
Authors: Peck B. Mitchell
Published: October 2011

Background. Relatively little is known about patient characteristics associated with doctor-patient interaction style and satisfaction with the medical visit.Objective. The primary study objectives are to assess: whether doctors interact in a more or less patient-centered style with elderly patients and whether patient age moderates the relationship between interaction style and satisfaction, that is, whether elderly patients are more or less satisfied with patient-centered medical encounters.Methods. We collected pre- and post-visit questionnaire data from 177 patients at a large family medicine clinic. We audiotaped the encounters between doctors and patients. Patient-centered interaction style was measured from coding from the audiotapes of the doctor-patient interactions. Patient satisfaction was measured using the Patient Satisfaction Questionnaire.Results. We found physicians were more likely to have patient-centered encounters with patients over age 65. We also found patient age moderated the association between interaction style and patient satisfaction: older patients were more satisfied with patient-centered encounters.Conclusion. Patient age is associated with style of interaction, which is, in turn, associated with patient satisfaction. Understanding the factors and processes by which doctors and patients interact has the potential to improve many facets of health care delivery.
Unital Compact Homomorphisms between Extended Analytic Lipschitz Algebras
Authors: Alimohammadi Davood , Mayghani Maliheh
Published: October 2011

Let X and K be compact plane sets with K⊆X. We define A(X, K) = {f ∈ C(X) : f|K ∈ A(K)}, where A(K) = {g ∈ C(X) : g is analytic on int(K)}. For α ∈ (0,1], we define Lip(X, K, α) = {f ∈ C(X) : pα,K(f) = sup{|f(z) − f(w)|/|z − w|α   :   z, w ∈ K, z ≠ w} < ∞} and LipA(X, K, α) = A(X, K)∩Lip(X, K, α). It is known that LipA(X, K, α) is a natural Banach function algebra on X under the norm | | f | |Lip(X,K,α) = | | f | |X + pα,K(f), where | | f | |X = sup {|f(x)| : x ∈ X}. These algebras are called extended analytic Lipschitz algebras. In this paper we study unital homomorphisms from natural Banach function subalgebras of LipA(X1, K1, α1) to natural Banach function subalgebras of LipA(X2, K2, α2) and investigate necessary and sufficient conditions for which these homomorphisms are compact. We also determine the spectrum of unital compact endomorphisms of LipA(X, K, α).
Panic Attack during Elective Gastrointestinal Endoscopy
Authors: Mitsonis Charalampos , Dimopoulos Nikolaos , Zavrou Marianna , Psarra Vassiliki , Giofkos Christos , Fiorakis Christos , Dimitriadis Athanasios , Valavanis Dimitrios , Vousoura Eleni , Zervas Iannis , Papavassiliou Efstathios
Published: October 2011

Background. Esophagogastroduodenoscopy (EGD) and colonoscopy (CS) can evoke anxiety, embarrassment, and discomfort. These concerns can culminate in panic attacks, which may traumatize patients and significantly decrease their compliance to the procedure. The objective of this study was to evaluate the relationship between preendoscopic anxiety and the possibility of a panic attack during an elective gastrointestinal endoscopy (EGE).Methods. The study population comprised of 79 Greek outpatients. The examination was carried out without the use of conscious sedation. Patients' anxiety levels were assessed before the procedure using the Greek version of the Spielberger State-Trait Anxiety Inventory (STAI-Y).Results. Seventy-nine patients were enrolled: 45 EGD and 34 CS. Females had higher state and trait anxiety levels than males (48.14 7.94 versus 44.17 7.43, ; and 43.68 6.95 versus 39.86 7.46, ). Patients who experienced panic attack had significantly higher levels of both trait and state anxiety, compared to those who were panic-free. There was no significant relationship between panic attacks and sex or type of procedure.Conclusions. Patients who experience panic attacks during endoscopic procedures appear to have significantly higher anxiety levels before the procedure. Administering the STAI questionnaire prior to the endoscopy seems to be a useful screening method for vulnerable patients.
The Dystrophin‐Glycoprotein Complex in the Prevention of Muscle Damage
Authors: Gumerson Jessica D. , Michele Daniel E.
Published: October 2011

Muscular dystrophies are genetically diverse but share common phenotypic features of muscle weakness, degeneration, and progressive decline in muscle function. Previous work has focused on understanding how disruptions in the dystrophin‐glycoprotein complex result in muscular dystrophy, supporting a hypothesis that the muscle sarcolemma is fragile and susceptible to contraction‐induced injury in multiple forms of dystrophy. Although benign in healthy muscle, contractions in dystrophic muscle may contribute to a higher degree of muscle damage which eventually overwhelms muscle regeneration capacity. While increased susceptibility of muscle to mechanical injury is thought to be an important contributor to disease pathology, it is becoming clear that not all DGC‐associated diseases share this supposed hallmark feature. This paper outlines experimental support for a function of the DGC in preventing muscle damage and examines the evidence that supports novel functions for this complex in muscle that when impaired, may contribute to the pathogenesis of muscular dystrophy.
Micropapillary Variant of Urothelial Carcinoma
Authors: Kwon Ghee Young , Ro Jae Y.
Published: October 2011

Micropapillary carcinoma (MPC) of urinary tract is an uncommon variant of urothelial carcinoma with significant diagnostic and prognostic implications. Though MPC shows characteristic microscopic features, there exists interobserver variability and also it needs to be differentiated from the metastasis from other organs. The prognosis is generally poor, depending on the proportion of the micropapillary component in some reports. Early cystectomy in cases with only lamina propria invasion may be indicated according to recent studies. This review outlines the general features of this entity and briefly comments on the controversies and the recent development.
Mechanical Properties of Chitosan-Starch Composite Filled Hydroxyapatite Micro- and Nanopowders
Authors: Ai Jafar , Rezaei-Tavirani Mostafa , Biazar Esmaeil , Heidari K Saeed , Jahandideh Rahim
Published: October 2011

Hydroxyapatite is a biocompatible ceramic and reinforcing material for bone implantations. In this study, Starch-chitosan hydrogel was produced using the oxidation of starch solution and subsequently cross-linked with chitosan via reductive alkylation method (weight ratio (starch/chitosan): 0.38). The hydroxyapatite micropowders and nanopowders synthesized by sol-gel method (10, 20, 30, 40 %W) were composited to hydrogels and were investigated by mechanical analysis. The results of SEM images and Zetasizer experiments for synthesized nanopowders showed an average size of 100 nm. The nanoparticles distributed as uniform in the chitosan-starch film. The tensile modulus increased for composites containing hydroxyapatite nano-(size particle: 100 nanometer) powders than composites containing micro-(size particle: 100 micrometer) powders. The swelling percentage decreased for samples containing hydroxyapatite nanopowder than the micropowders. These nanocomposites could be applied for hard-tissue engineering.
Pyrolytic Characteristics and Kinetics of Phragmites australis
Authors: Zhao Hui , Yan Huaxiao , Zhang Congwang , Liu Xiaodong , Xue Yanhui , Qiao Yingyun , Tian Yuanyu , Qin Song
Published: October 2011

The pyrolytic kinetics of Phragmites australis was investigated using thermogravimetric analysis (TGA) method with linear temperature programming process under an inert atmosphere. Kinetic expressions for the degradation rate in devolatilization and combustion steps have been obtained for P. australis with Dollimore method. The values of apparent activation energy, the most probable mechanism functions, and the corresponding preexponential factor were determined. The results show that the model agrees well with the experimental data and provide useful information for the design of pyrolytic processing system using P. australis as feedstock to produce biofuel.
Atypical Mycobacterial Infection Presenting as Persistent Skin Lesion in a Patient with Ulcerative Colitis
Authors: Bamias Giorgos , Daikos George L. , Siakavellas Spyros I. , Kaltsa Garyfallia , Smilakou Stavroula , Katsogridakis Ioannis , Vafiadis-Zouboulis Irene , Ladas Spiros D.
Published: October 2011

Immunosuppressive drugs are commonly used for the treatment of inflammatory bowel disease. Patients receiving immunosuppressants are susceptible to a variety of infections with opportunistic pathogens. We present a case of skin infection withMycobacterium chelonaein a 60-year-old Caucasian woman with ulcerative colitis who had been treated with corticosteroids and azathioprine. The disease manifested with fever and rash involving the right leg. Infliximab was administered due to a presumptive diagnosis of pyoderma gangrenosum, leading to worsening of the clinical syndrome and admission to our hospital. Routine cultures from various sites were all negative. However, Ziehl-Neelsen staining of pus from the lesions revealed acid-fast bacilli, and culture yielded a rapidly growing mycobacterium further identified asM. chelonae. The patient responded to a clarithromycin-based regimen. Clinicians should be aware of skin lesions caused by atypical mycobacteria in immunocompromised patients with inflammatory bowel disease. Furthermore, they should be able to thoroughly investigate and promptly treat these conditions.
Immunogenicity of a Recombinant Influenza Virus Bearing Both the CD4+ and CD8+ T Cell Epitopes of Ovalbumin
Authors: Garulli Bruno , Di Mario Giuseppina , Sciaraffia Ester , Kawaoka Yoshihiro , Castrucci Maria R.
Published: October 2011

Recombinant influenza viruses that bear the single immunodominant CD8+ T cell epitope OVA257−264 or the CD4+ T cell epitope OVA323−339 of the model antigen ovalbumin (OVA) have been useful tools in immunology. Here, we generated a recombinant influenza virus, WSN‐OVAI/II, that bears both OVA‐specific CD8+ and CD4+ epitopes on its hemagglutinin molecule. Live and heat‐inactivated WSN‐OVAI/II viruses were efficiently presented by dendritic cells in vitro to OT‐I TCR transgenic CD8+ T cells and OT‐II TCR transgenic CD4+ T cells. In vivo, WSN‐OVAI/II virus was attenuated in virulence, highly immunogenic, and protected mice from B16‐OVA tumor challenge in a prophylactic model of vaccination. Thus, WSN‐OVAI/II virus represents an additional tool, along with OVA TCR transgenic mice, for further studies on T cell responses and may be of value in vaccine design.
Toxicity of Volatile Methylated Species of Bismuth, Arsenic, Tin, and Mercury in Mammalian CellsIn Vitro
Authors: Dopp E. , von Recklinghausen U. , Hippler J. , Diaz-Bone R. A. , Richard J. , Zimmermann U. , Rettenmeier A. W. , Hirner A. V.
Published: October 2011

The biochemical transformation of mercury, tin, arsenic and bismuth through formation of volatile alkylated species performs a fundamental role in determining the environmental processing of these elements. While the toxicity of inorganic forms of most of these compounds are well documented (e.g., arsenic, mercury) and some of them are of relatively low toxicity (e.g., tin, bismuth), the more lipid-soluble organometals can be highly toxic. In the present study we investigated the cyto- and genotoxicity of five volatile metal(loid) compounds: trimethylbismuth, dimethylarsenic iodide, trimethylarsine, tetramethyltin, and dimethylmercury. As far as we know, this is the first study investigating the toxicity of volatile metal(loid) compoundsin vitro. Our results showed that dimethylmercury was most toxic to all three used cell lines (CHO-9 cells, CaCo, Hep-G2) followed by dimethylarsenic iodide. Tetramethyltin was the least toxic compound; however, the toxicity was also dependend upon the cell type. Human colon cells (CaCo) were most susceptible to the toxicity of the volatile compounds compared to the other cell lines. We conclude from our study that volatile metal(loid) compounds can be toxic to mammalian cells already at very low concentrations but the toxicity depends upon the metal(loid) species and the exposed cell type.
Tumor-to-Tumor Metastasis to Chromophobe Renal Cell Carcinoma: A First Report
Authors: Shin Toshitaka , Kan Tomoko , Sato Fuminori , Mimata Hiromitsu
Published: October 2011

Tumor-to-tumor metastasis is a rare phenomenon. From our review of the international literature, around 150 cases have been reported since it was first documented by Campbel in 1868. Renal clear cell carcinoma is well known to be the most common recipient of tumor-to-tumor metastasis in all tumors. However, renal chromophobe cell carcinoma has not been reported to be a recipient. Here, we report a first case of colorectal carcinoma metastatic to chromophobe renal cell carcinoma.
Role of Signaling Transduction Pathways in Development of Castration-Resistant Prostate Cancer
Authors: Inoue Takahiro , Ogawa Osamu
Published: October 2011

Almost all patients who succumb to prostate cancer die of metastatic castration-resistant disease. Although docetaxel is the standard treatment for this disease and is associated with modest prolongation of survival, there is an urgent need for novel treatments for castration-resistant prostate cancer (CRPC). Great advances in our understanding of the biological and molecular mechanisms of prostate cancer progression have resulted in many clinical trials of numerous targeted therapies. In this paper, we review mechanisms of CRPC development, with particular focus on recent advances in the understanding of specific intracellular signaling pathways participating in the proliferation of CRPC cells.
Synthesis, Crystal Structure, and Spectra Properties of the Cadmium (II) Complex with Bis(N-allylbenzimidazol-2-ylmethyl)benzylamine
Authors: Wu Huilu , Yuan Jingkun , Bai Ying , Kou Fan , Jia Fei , Liu Bin
Published: October 2011

A novel complex of cadmium (II) picrate (pic) with V-shaped ligand bis(N-allylbenzimidazol-2-ylmethyl)benzylamine (babb), with composition [Cd(babb)2](pic)2, was synthesized and characterized by elemental analyses and electrical conductivity, IR, and UV/visible spectra. The crystal structure of the complex has been determined by the single-crystal X-ray diffraction. In the complex, the coordination sphere around Cd (II) is distorted octahedral, six nitrogen atoms involved in coordination afforded by two tridentate ligand babb. Moreover, The DNA-binding properties of the ligand babb and Cd (II) complex were investigated by spectrophotometric methods and viscosity measurements, and the results suggest that they bind to DNA via an intercalation binding mode, and the Cd (II) complex shows higher affinity than the ligand.
Aviation Fueling: A Cleaner, Greener Approach
Authors: Hendricks Robert C. , Bushnell Dennis M. , Shouse Dale T.
Published: October 2011

Projected growth of aviation depends on fueling where specific needs must be met. Safety is paramount, and along with political, social, environmental, and legacy transport systems requirements, alternate aviation fueling becomes an opportunity of enormous proportions. Biofuels—sourced from halophytes, algae, cyanobacteria, and “weeds” using wastelands, waste water, and seawater—have the capacity to be drop-in fuel replacements for petroleum fuels. Biojet fuels from such sources solve the aviation CO2emissions issue and do not compete with food or freshwater needs. They are not detrimental to the social or environmental fabric and use the existing fuels infrastructure. Cost and sustainable supply remain the major impediments to alternate fuels. Halophytes are the near-term solution to biomass/biofuels capacity at reasonable costs; they simply involve more farming, at usual farming costs. Biofuels represent a win-win approach, proffering as they do—at least the ones we are studying—massive capacity, climate neutral-to-some sequestration, and ultimately, reasonable costs.
Synthesis of the Nakanishi Ring-Locked Retinoid
Authors: Côté Jamie B. , Quach Tan D. , Demenev Andrey P. , Garvey David S. , Berman Judd M.
Published: October 2011

An optimized synthetic route to prepare ring-locked retinoid 1a has been developed. We fully describe a purification protocol that provides isomerically pure 1a in support of on-going proof of concept studies for the development of therapeutic agents to treat human ADRP. Additionally, we have found that isomerically pure 1a can be stored in amber vials under argon at −20°C for use over time (up to six months) without degradation. Thus, enabling 1a to be an accessible and valuable biological tool.
Epithelial Cell Coculture Models for Studying Infectious Diseases: Benefits and Limitations
Authors: Duell Benjamin L. , Cripps Allan W. , Schembri Mark A. , Ulett Glen C.
Published: October 2011

Countless in vitro cell culture models based on the use of epithelial cell types of single lineages have been characterized and have provided insight into the mechanisms of infection for various microbial pathogens. Diverse culture models based on disease‐relevant mucosal epithelial cell types derived from gastrointestinal, genitourinary, and pulmonary organ systems have delineated many key host‐pathogen interactions that underlie viral, parasitic, and bacterial disease pathogenesis. An alternative to single lineage epithelial cell monoculture, which offers more flexibility and can overcome some of the limitations of epithelial cell culture models based on only single cell types, is coculture of epithelial cells with other host cell types. Various coculture models have been described, which incorporate epithelial cell types in culture combination with a wide range of other cell types including neutrophils, eosinophils, monocytes, and lymphocytes. This paper will summarize current models of epithelial cell coculture and will discuss the benefits and limitations of epithelial cell coculture for studying host‐pathogen dynamics in infectious diseases.
β-Cell Generation: Can Rodent Studies Be Translated to Humans?
Authors: Carlotti Françoise , Zaldumbide Arnaud , Ellenbroek Johanne H. , Spijker H. Siebe , Hoeben Rob C. , de Koning Eelco J.
Published: October 2011

β-cell replacement by allogeneic islet transplantation is a promising approach for patients with type 1 diabetes, but the shortage of organ donors requires new sources ofβcells. Islet regenerationin vivoand generation ofβ-cellsex vivofollowed by transplantation represent attractive therapeutic alternatives to restore theβ-cell mass. In this paper, we discuss different postnatal cell types that have been envisaged as potential sources for futureβ-cell replacement therapy. The ultimate goal being translation to the clinic, a particular attention is given to the discrepancies between findings from studies performed in rodents (bothex vivoon primary cells andin vivoon animal models), when compared with clinical data and studies performed on human cells.
Refinements of the Lower Bounds of the Jensen Functional
Authors: Franjić Iva , Khalid Sadia , Pečarić Josip
Published: October 2011

The lower bounds of the functional defined as the difference of the right‐hand and the left‐hand side of the Jensen
inequality are studied. Refinements of some previously known results are given by applying results from the theory of majorization. Furthermore, some interesting special cases are considered.
Low-Complexity, Distributed Characterization of Interferers in Wireless Networks
Authors: Kapnadak Vibhav , Senel Murat , Coyle Edward J.
Published: October 2011

We consider a large-scale wireless network that uses sensors along its edge to estimate the characteristics of interference from neighboring networks or devices. Each sensor makes a noisy measurement of the received signal strength (RSS) from an interferer, compares its measurement to a threshold, and then transmits the resulting bit to a cluster head (CH) over a noisy communication channel. The CH computes the maximum likelihood estimate (MLE) of the distance to the interferer using these noise-corrupted bits. We propose and justify a low-complexity threshold design technique in which the sensors use nonidentical thresholds to generate their bits. This produces a dithering effect that provides better performance than previous techniques that use different non-identical thresholds or the case in which all the sensor motes use an identical non-optimal threshold. Our proposed technique is also shown (a) to be of low complexity compared to previous non-identical threshold approaches and (b) to provide performance that is very close to that obtained when all sensors use the identical, but unknown, optimal threshold. We derive the Cramér-Rao bound (CRB) and also show that the MLE using our dithered thresholds is asymptotically both efficient and consistent. Simulations are used to verify these theoretical results.
H∞ Neural‐Network‐Based Discrete‐Time Fuzzy Control of Continuous‐Time Nonlinear Systems with Dither
Authors: Tsai Zhi-Ren , Hwang Jiing-Dong
Published: October 2011

This study presents an effective approach to stabilizing a continuous‐time (CT) nonlinear system using dithers and a discrete‐time (DT) fuzzy controller. A CT nonlinear system is first discretized to a DT nonlinear system. Then, a Neural‐Network (NN) system is established to approximate a DT nonlinear system. Next, a Linear Difference Inclusion state‐space representation is established for the dynamics of the NN system. Subsequently, a Takagi‐Sugeno DT fuzzy controller is designed to stabilize this NN system. If the DT fuzzy controller cannot stabilize the NN system, a dither, as an auxiliary of the controller, is simultaneously introduced to stabilize the closed‐loop CT nonlinear system by using the Simplex optimization and the linear matrix inequality method. This dither can be injected into the original CT nonlinear system by the proposed injecting procedure, and this NN system is established to approximate this dithered system. When the discretized frequency or sampling frequency of the CT system is sufficiently high, the DT system can maintain the dynamic of the CT system. We can design the sampling frequency, so the trajectory of the DT system and the relaxed CT system can be made as close as desired.
Chronic Rhinosinusitis in Children
Authors: Ramadan Hassan H.
Published: October 2011

Rhinosinusitis is a very common disease worldwide and specifically in the US population. It is a common disease in children but may be underdiagnosed. Several reasons may account to the disease being missed in children. The symptoms in children are limited and can be very similar to the common cold or allergic symptoms. Cough and nasal discharge may be the only symptoms present in children. A high index of suspicion is necessary to make the diagnosis of rhinosinusitis in these children. The majority of those children are treated medically. Only a few number will require surgical intervention when medical treatment fails. Complications of rhinosinusitis, even though rare, can carry a high morbidity and mortality rate.
Follicular Proinflammatory Cytokines and Chemokines as Markers of IVF Success
Authors: Sarapik Aili , Velthut Agne , Haller-Kikkatalo Kadri , Faure Gilbert C. , Béné Marie-Christine , de Carvalho Bittencourt Marcelo , Massin Frédéric , Uibo Raivo , Salumets Andres
Published: October 2011

Cytokines are key modulators of the immune system and also contribute to regulation of the ovarian cycle. In this study, Bender MedSystems FlowCytomix technology was used to analyze follicular cytokines (proinflammatory: IL-1β, IL-6, IL-18, IFN-γ, IFN-α, TNF-α, IL-12, and IL-23;, and anti-inflammatory: G-CSF), chemokines (MIP-1α, MIP-1β, MCP-1, RANTES, and IL-8), and other biomarkers (sAPO-1/Fas, CD44(v6)) in 153 women undergoingin vitrofertilization (IVF). Cytokine origin was studied by mRNA analysis of granulosa cells. Higher follicular MIP-1αand CD44(v6) were found to correlate with polycystic ovary syndrome, IL-23, INF-γ, and TNF-αwith endometriosis, higher CD44(v6) but lower IL-βand INF-αcorrelated with tubal factor infertility, and lower levels of IL-18 and CD44(v6) characterized unexplained infertility. IL-12 positively correlated with oocyte fertilization and embryo development, while increased IL-18, IL-8, and MIP-1βwere associated with successful IVF-induced pregnancy.
Adenosine and Immune Imbalance in Visceral Leishmaniasis: The Possible Role of Ectonucleotidases
Authors: Paletta-Silva Rafael , Meyer-Fernandes José Roberto
Published: October 2011

Visceral leishmaniasis (VL) is the most severe form of leishmaniasis and is responsible for mostLeishmania-associated deaths. VL represents a serious public health problem that affects many countries. The immune response in leishmaniasis is very complex and is poorly understood. The Th1 versus Th2 paradigm does not appear to be so clear in visceral leishmaniasis, suggesting that other immunosuppressive or immune-evasion mechanisms contribute to the pathogenesis of VL. It has been demonstrated that generation of adenosine, a potent endogenous immunosuppressant, by extracellular enzymes capable to hydrolyze adenosine tri-nucleotide (ATP) at the site of infection, can lead to immune impairment and contribute to leishmaniasis progression. In this regard, this paper discusses the unique features in VL immunopathogenesis, including a possible role for ectonucleotidases in leishmaniasis.
Noble Metal Nanoparticles Applications in Cancer
Authors: Conde João , Doria Gonçalo , Baptista Pedro
Published: October 2011

Nanotechnology has prompted new and improved materials for biomedical applications with particular emphasis in therapy and diagnostics. Special interest has been directed at providing enhanced molecular therapeutics for cancer, where conventional approaches do not effectively differentiate between cancerous and normal cells; that is, they lack specificity. This normally causes systemic toxicity and severe and adverse side effects with concomitant loss of quality of life. Because of their small size, nanoparticles can readily interact with biomolecules both at surface and inside cells, yielding better signals and target specificity for diagnostics and therapeutics. This way, a variety of nanoparticles with the possibility of diversified modification with biomolecules have been investigated for biomedical applications including their use in highly sensitive imaging assays, thermal ablation, and radiotherapy enhancement as well as drug and gene delivery and silencing. Here, we review the available noble metal nanoparticles for cancer therapy, with particular focus on those already being translated into clinical settings.
Stochastic Stabilization of Nonholonomic Mobile Robot with Heading‐Angle‐Dependent Disturbance
Authors: Wu Zhao Jing , Liu Yong Hui
Published: October 2011

The problem of exponential stabilization for nonholonomic mobile robot with dependent stochastic disturbance of heading angle is considered in this paper. An integrator backstepping controller based on state‐scaling method is designed such that the state of the closed‐loop system, starting from a nonzero initial heading angle, is regulated to the origin with exponential rate in almost surely sense. For zero initial heading angle, a controller is designed such that the heading angle is driven away from zero while the position variables are bounded in a neighborhood of the origin. Combing the above two cases results in a switching controller such that for any initial condition the configuration of the robot can be regulated to the origin with exponential rate. The efficiency of the proposed method is demonstrated by a detailed simulation.
Removal of Nonmyrmecochorous Seeds by Ants: Role of Ants in Cattle Grasslands
Authors: Escobar-Ramírez Selene , Duque Sebastián , Henao Natalia , Hurtado-Giraldo Alejandra , Armbrecht Inge
Published: October 2011

Livestock production models prevailing in Colombian Andes are simplified treeless pastures for extensive ranching, with the consequent reduction of environmental services, such as seed dispersal, due to lack of primary dispersers, scarcity of adequate sites for seedling establishment and competition with grasses. This study evaluated if, in these harsh environments, ants can promote the colonization of arboreal species through directed dispersion of seeds towards the nests. Ten seeds of each species were offered to ants in six grazing pastures. Ants removed 25% of the seeds (1827) in 48 hours. Preference for arillated and small-to-medium sized seeds, such asPithecellobium dulce, andGuazuma ulmifolia, was observed.Cyphomyrmex major, Ectatomma ruidum, Solenopsis geminataandAtta cephaloteswere the key ant species in seed removal. It was concluded that functional ant groups present in the pastures could contribute to secondary dispersion of seeds with potential for restoration.
Rhein Induces Apoptosis in Human Breast Cancer Cells
Authors: Chang Ching-Yao , Chan Hong-Lin , Lin Hui-Yi , Way Tzong-Der , Kao Ming-Ching , Song Ming-Zhang , Lin Ying-Ju , Lin Cheng-Wen
Published: October 2011

Human breast cancers cells overexpressing HER2/neuare more aggressive tumors with poor prognosis, and resistance to chemotherapy. This study investigates antiproliferation effects of anthraquinone derivatives of rhubarb root on human breast cancer cells. Of 7 anthraquinone derivatives, only rhein showed antiproliferative and apoptotic effects on both HER2-overexpressing MCF-7 (MCF-7/HER2) and control vector MCF-7 (MCF-7/VEC) cells. Rhein induced dose- and time-dependent manners increase in caspase-9-mediated apoptosis correlating with activation of ROS-mediated activation of NF-κB- and p53-signaling pathways in both cell types. Therefore, this study highlighted rhein as processing anti-proliferative activity against HER2 overexpression or HER2-basal expression in breast cancer cells and playing important roles in apoptotic induction of human breast cancer cells.
Resuscitating Wild-Type p53 Expression by Disrupting Ceramide Glycosylation: A Novel Approach to Target Mutant p53 Tumors
Authors: Liu Yong-Yu
Published: October 2011

Mutant p53 is frequently detected in cancers in which p53 has lost its ability in tumor suppression and gained function in promoting tumor progression. Restoration of p53 functions by replacement of wild-type p53 and inhibition of its degradation or increment of its transcriptional activity has been applied to the prevention and treatment of cancers. Recent evidence indicates that disrupting ceramide glycosylation can resuscitate wild-type p53 expression and p53-dependent apoptosis in mutant p53 tumors. A posttranscriptional process that can turn on wild-type p53 expression and abrogate mutant p53 may provide a new strategy to eradicate mutant p53 cancers. Cancer Res; 71(20); 6295–9. ©2011 AACR.
Vitamin E δ-Tocotrienol Augments the Antitumor Activity of Gemcitabine and Suppresses Constitutive NF-κB Activation in Pancreatic Cancer
Authors: Husain Kazim , Francois Rony A. , Yamauchi Teruo , Perez Marta , Sebti Said M. , Malafa Mokenge P.
Published: October 2011

The NF-κB transcription factor functions as a crucial regulator of cell survival and chemoresistance in pancreatic cancer. Recent studies suggest that tocotrienols, which are the unsaturated forms of vitamin E, are a promising class of anticancer compounds that inhibit the growth and survival of many cancer cells, including pancreatic cancer. Here, we show that tocotrienols inhibited NF-κB activity and the survival of human pancreatic cancer cells in vitro and in vivo. Importantly, we found the bioactivity of the four natural tocotrienol compounds (α-, β-, δ-, and γ-tocotrienol) to be directly related to their ability to suppress NF-κB activity in vitro and in vivo. The most bioactive tocotrienol for pancreatic cancer, δ-tocotrienol, significantly enhanced the efficacy of gemcitabine to inhibit pancreatic cancer growth and survival in vitro and in vivo. Moreover, we found that δ-tocotrienol augmentation of gemcitabine activity in pancreatic cancer cells and tumors is associated with significant suppression of NF-κB activity and the expression of NF-κB transcriptional targets (Bcl-XL, X-linked inhibitor of apoptosis, and survivin). Our study represents the first comprehensive preclinical evaluation of the activity of natural vitamin E compounds in pancreatic cancer. Given these results, we are conducting a phase I trial of δ-tocotrienol in patients with pancreatic cancer using pancreatic tumor cell survival and NF-κB signaling components as intermediate biomarkers. Our data also support future clinical investigation of δ-tocotrienol to augment gemcitabine activity in pancreatic cancer. Mol Cancer Ther; 10(12); 2363–72. ©2011 AACR.