bluuebunny/crossref_metadata_2025 huggingface dataset:
AQUIVION{trade mark, serif} -- The Short-Side-Chain and Low-EW PFSA for Next-Generation PEFCs Expands Production and Utilization
Authors: Gebert Matthias , Ghielmi A. , Merlo L. , Corasaniti M. , Arcella V.
Published: May 2010

MEA producers enjoy benefits from the short side chain when using the various AQUIVION{trade mark, serif} PFSA ionomer membrane and dispersion grades. Both are vital for the manufacturing of Polymer Electrolyte Fuel Cell (PEFC) stacks as well as other applications such as gas humidifiers and filtration devices. AQUIVION{trade mark, serif}'s portfolio of improved physical characteristics is described in this article and can be a strong leverage to (i) cost reduction through a reduced amount of active cell area required to realize the desired target power and (ii) reduction in system size and complexity, especially with regard to a reduced or eliminated gas humidification.
Enhancement of Durability and Performance in Direct Methanol Fuel Cell by a Microporous Layer with Ultra-Small Pores
Authors: Chin Xing-Guo , Yan Pa-Yu , Wang C-P.
Published: May 2010

In this work, we modified the anode MPL structure design for MEA operated with high MeOH concentration feedstock with an aim to reduce MeOH crossover and, as a consequence, to enhance stability during continuous operation. The results showed that twice reduced voltage decay rate of MEA during continuous operation in constant current mode(3A) compared with commercial GDL-based MEA was done by creating ultra-small(<5 µm) and uniform distributed pores in MPL. Extra-small pore was created by applying high pressure as well as high temperature to MPL during the fabrication process. The enhancement of power density at low temperature (40°) with lowering MeOH crossover compared with commercial GDL based MEA was also demonstrated. The maximum power density of 105 mW/cm2 at low temperature(40°) and 140 mW/cm2 at high temperature(60°) under high MeOH concentration feedstock were achieved with ultra-small pores MPL as anode diffusion media. Furthermore, the durability test of DMFC after 1000hr operation demonstrates that the DMFC with extra-small pore MPL as anode diffusion media exhibits very good stability. The voltage decay was smaller than 20% compared with the initial voltage.
Integrated Coal Gasification and Solid Oxide Fuel Cell Systems for Centralized Power Generation
Authors: Ghezel-Ayagh Hossein , Way Richard , Huang Peng , Walzak Jim , Jolly Stephen , Patel Dilip , Lukas Mike , Willman Carl , Davis Keith , Stauffer David , Vaysman Vladimir , Borglum Brian , Tang Eric , Pastula Michael , Petri Randy
Published: May 2010

FuelCell Energy is developing solid oxide fuel cell (SOFC) systems and technology for very efficient, economically viable, coal-to-electricity power plants utilizing synthesis gas (syngas) from a coal gasifier. One of the key objectives is implementation of an innovative system concept in design of a multi-MW power plant to achieve an electrical efficiency exceeding 50% based on the higher heating value (HHV) of coal, exclusive of power requirements for CO2 compression. The system is also designed to remove at least ninety percent of carbon in the syngas, for sequestration as CO2. Combined with CO2 separation technology, the Integrated Gasification Fuel Cell (IGFC) power plant is expected to achieve near-zero emissions to the environment. Development of this technology will significantly advance the nation's energy security and independence interests (through effective utilization of the nation's vast coal reserves), address pollution and greenhouse gas concerns, and help enhance the nation's economic growth.
Carbon Dioxide Reforming of Methane on Ni-ceria-based Oxide Cermet Anode for Practical Size Solid Oxide Fuel Cells
Authors: Kawano Mitsunobu , Yoshida Hiroyuki , Hashino Koji , Inagaki Toru
Published: May 2010

Carbon dioxide reforming of methane on Ni-ceria-based oxide cermet anode of practical solid oxide fuel cells was carried out at various temperatures of 750, 700, and 650åC. Electrochemical characterizations and gas analysis results revealed that direct internal carbon dioxide reforming operation was strongly influenced by the operation temperature. Direct internal carbon dioxide reforming operation resulted in sufficient level of conversion for power generation with methane at 750åC, while it gave insufficient level of conversion at 700 and 650åC.
Composite Cathode with Pr Doped Ceria and LNF for SOFCs
Authors: Chiba Reiichi , Komatsu Takeshi , Orui Himeko , Taguchi Hiroaki , Nozawa Kazuhiko , Arai Hajime
Published: May 2010

To improve the performance of our standard cathode consisting of a La(Ni-Fe)O3-Ce(Gd)O2-d active layer and a La(Ni-Fe)O3 current collection layer, we replaced the Ce(Gd)O2-d in the active layer with Pr doped ceria (Ce(Pr)O2-d). We evaluated the cathode performance in terms of its cathode interface resistance, which was greatly improved by this replacement. When X (Pr concentration of the Ce(Pr)O2-d) in Ce1-XPrXO2-d was increased, the interface resistance decreased monotonically and reached a value about one tenth of that for a cathode with Ce(Gd)O2-d. We also investigated the influence of the Ce(Pr)O2-d composition on the high temperature properties including conductivity, thermal expansion coefficient and oxygen nonstoichiometry. The p-type electrical conductivity and oxygen nonstoichiometry increased with the Pr concentration in Ce(Pr)O2-d.
Progress in Development of IT-SOFC Based on Lanthanum Gallate Electrolyte
Authors: Eto Hiroyuki , Akbay Taner , Hirata Katsuya , Sato Motoki , Inagaki Toru , Nishiwaki Futoshi
Published: May 2010

Mitsubishi Materials Corporation and The Kansai Electric Power Co., Inc. are developing highly efficient units based on intermediate-temperature solid oxide fuel cells for stationary power generation applications. The use of high oxide ion conducting electrolyte made up of strontium, magnesium and cobalt doped lanthanum gallate (LSGMC) help realize the intermediate-temperature operation between 600{degree sign}C and 800{degree sign}C. An improved 10 kW-class CHP system based on LSGMC electrolyte was subjected to a second time long term stability test for over 3,000 hrs. No significant voltage degradation was observed when the output power was slightly reduced during the second long term stability test of the 10kW CHP system. In addition, scale-up of cells were achieved by doubling the active surface area. 170mm diameter cells were manufactured and successfully tested in high power density modules.
Effects of Impurities on the Degradation of SOFC Stacks
Authors: Horita Teruhisa , Kishimoto Haruo , Yamaji Katsuhiko , Brito Manuel E. , Yokokawa Harumi
Published: May 2010

Effects of impurities on the degradation of SOFC components were examined at 5 different stacks. Several kinds of impurities (such as Na, Al, Si, P, S, Cr, and Sr) were detected at each component after long-term operation of stacks (2000-10000 hours operation). The concentration levels of impurities were analyzed at each cell component by secondary ion mass spectrometry (SIMS) in the order of magnitudes of ppm in weight. Several kinds of degradation phenomena were observed at cell components associated to impurities. Some degradation mechanisms were considered at the electrode/electrolyte interfaces.
Dense Protective Coatings for SOFC Interconnect Deposited by Spray Pyrolysis
Authors: Xie Yongsong , Qu Wei , Yao Baisheng , Shaigan Nima , Rose Lars
Published: May 2010

Spray pyrolysis deposition is a cost-effective process to deposit films of a wide variety of materials, especially solid oxides. In this study, spray pyrolysis deposition was used to deposit 2-3 μm thick Mn1.5Co1.5O4 spinel and Ta2O5-doped CeO2 on a ferritic stainless steel as protective coatings on SOFC interconnect. The coated samples were exposed to air at 1000oC to study the diffusion and oxidation behaviours. Characterization results indicated that the coatings are dense, have good adhesion to the substrate, and are stable and effective to prevent Cr outward diffusion at the high temperature.
Overview of SOFC Anode Interactions with Coal Gas Impurities
Authors: Marina Olga A. , Pederson Larry , Gemmen Randy , Gerdes Kirk , Finklea Harry , Celik Ismail
Published: May 2010

An overview of the results of SOFC anode interactions with phosphorus, arsenic, selenium, sulfur, antimony, and hydrogen chloride as single contaminants or in combinations is discussed. Tests were performed using both anode- and electrolyte-supported cells in synthetic and actual coal gas for periods greater than 1000 hours. Post-test analyses were performed to identify reaction products formed and their distribution, and compared to phases expected from thermochemical modeling. The ultimate purpose of this work is to establish maximum permissible concentrations for impurities in coal gas, to aid in the selection of appropriate coal gas clean-up technologies.
Direct Fuel Cell Stack Module Evolution
Authors: Farooque Mohammad , Leo Anthony , Pawlaczyk R. , Rauseo Anthony , Venkataraman Ramakrishnan
Published: May 2010

The direct carbonate fuel cell (DFC®) power plant is an emerging high efficiency, ultra-clean electric power generation system utilizing a variety of gaseous, liquid, and solid carbonaceous fuels. The power-producing block of this system is the carbonate fuel cell stack. One of its key characteristics is the ability to generate electricity directly from a hydrocarbon fuel, by reforming the fuel inside the fuel cell to produce hydrogen. FCE has placed approximately 75 units ranging from 250kW to 2.4 MW around the world, achieving an electric efficiency of 45 to 49%. FCE currently has 50 MW/year manufacturing capacity, and plans are in place to increase production capacity as demand increases from domestic and Asian markets. The manufacturing cost has been improved through implementing lean manufacturing, process improvements, and strategic sourcing for vendor purchased items. The stack output has been increased from 250kW to 350 kW. An overall stack cost reduction of ~50% has been achieved over the past five years. Concerted efforts to improve performance, lower cost and increase service life are continuing. This paper will describe FCE's DFC stack technology evolution in advancing output and lowering manufacturing cost.
Carbonate Fuel Cell Application for Synergistic Power Generation and Carbon Dioxide Capture
Authors: Ghezel-Ayagh Hossein , Farooque Mohammad , Patel Dilip , Sanderson Robert
Published: May 2010

FuelCell Energy, Inc. (FCE) has developed novel system concepts for separation of carbon dioxide from greenhouse gas emission sources, using Direct FuelCell® (DFC®) technology. DFC is based on carbonate fuel cells featuring internal reforming. The unique chemistry of carbonate fuel cells offers an innovative approach for separation of CO2 from fossil-fuel power plant exhaust streams (flue gases). DFC-based CO2 separation systems are suitable for many types of coal-based power plants, from existing pulverized coal (PC) plants to future integrated gasification combined cycle (IGCC) plants. The carbonate fuel cell system also produces electric power at high efficiency. Cost of electricity (COE) analysis of the DFC system suggests that the simultaneous generation of power and CO2 capture is an attractive scenario for re-powering the existing coal-fueled power plants.
Recent Developments of Semi-fuel Cells for Powering Underwater Sensors and Platforms
Authors: Cardenas-Valencia Andres M. , Short R. Timothy , Adornato Lori , Langebrake Larry
Published: May 2010

This paper studies two novel galvanic cells and postulates their use in underwater power applications. One couples Aluminum to sodium peroxide (Al-Na2O2) and the other to a chlorinated halamine (Al-C3N3Cl3O3). Experimental results show that the chemistries are indeed capable of providing good specific energies. The results from small cells showed an specific energy (SE) of 200 Wh/kg, (~ 300 Wh/kg, if the packaging is not considered) for the Al-halamine cell. The SE of Al-alkali perox¬ide was found to be approximately 230 Wh/kg (460 Wh/kg, considering only active materials). Interestingly, latest results indicate that it is possible to increase the current of a given cell by using high surface area electrodes. Results using high surface area, porous, foam-like materials are estimated and show promising results their use in semi-fuel cell schemes (SE on the order of 0.5 kWh/Kg).
Design and Initial Flight Tests of a Hydrogen Fuel Cell Powered Unmanned Air Vehicle (UAV)
Authors: Ward Thomas A. , Jenal Norhisyam
Published: May 2010

A fuel cell powered unmanned air vehicle (UAV) named Kenyalang-1 was designed, built, and flight-tested at the Universiti Teknologi MARA (UiTM) in Shah Alam, Malaysia. The UAV is propeller-driven by a DC brushless motor, powered by a 500 W proton exchange membrane (PEM) hydrogen fuel cell. The objective was to demonstrate the design and technological challenges involved and determine the relative merits or shortcomings that fuel cell electrically-powered propulsion systems have over conventional systems. This paper describes the UAV design (airframe, propulsion, and avionics) and measured performance during initial flight tests. The results of this analysis will be used to improve the UAV and power plant system for future production models.
Fuel Cells as Tactical Auxiliary Power in Military Vehicles
Authors: Andrukaitis Ed
Published: May 2010

An integration of a PEM fuel cell for on-board auxiliary power of a military vehicle was demonstrated. If fuel (hydrogen) storage methods are properly implemented, a fuel cell is potentially the lightest and most energy efficient electrical power source in this application as part of a hybrid power system. The need for mobile auxiliary power units (APUs) is widespread in the military where communications and reconnaissance systems are operational while the vehicle engine is not running. Current drawbacks with present battery systems are that they do not run as long as desired. Diesel generators give off undesirable, detectable emissions such as noise, heat, vibrations and particulate matter, making its operation around personnel problematic. A full scale integration of fuel cells into a military vehicle is challenging given the availability of space, but the design goal performances were achieved in this demonstration.
Case Studies on the Cost Efficiency of a Hybrid Fuel Cell - Water Electrolyzer System Used to Level Daytime and Nighttime Power Consumption
Authors: Matsuzaki Harumi
Published: May 2010

The present paper evaluated the cost efficiency of the hybrid fuel cell (FC) - water electrolyzer (WE) system by reviewing several case studies with different values of FC efficiency ηFC, WE efficiency ηWE, the pay-per-use price in the nighttime hours and the same price in the daytime hours. The results showed that the cost efficiency of a hybrid FC-WE system with the present track record of ηFC of 0.5 and ηWE of 0.9 was held in some companies with the pay-per-use prices of electrical power of the summer period and that if it was assumed that the daytime hours (12 hours) was equal to the nighttime hours (12 hours), the cost efficiency of this system was held in all companies shown in this paper.
Development of Sensors and Sensing Technology for Hydrogen Fuel Cell Vehicle Applications
Authors: Brosha Eric L. , Sekhar Praveen K. , Mukundan Rangachary , Williamson Todd , Garzon Fernando H. , Woo Leta Y. , Glass Robert S.
Published: May 2010

In this work, we present recent progress in our work to develop new sensors and sensing technology for future hydrogen powered fuel cell vehicles. The first device is an electrochemical mixed potential sensor based on an indium-tin oxide/YSZ/Pt configuration prototype fabricated using commercial ceramic sensor manufacturing methods. This sensor has been designed to detect hydrogen in air and may serve in safety systems for vehicles or as a component of hydrogen infrastructure. The second device relies on a swept frequency acoustic method to non-invasively determine the state of charge of a hydride material contained within a sealed storage system.
Co-Production of Renewable Hydrogen and Electricity: Technology Development and Demonstration
Authors: Patel Pinakin , Lipp Ludwig , Jahnke Fred , Heydorn Ed , Abdallah Tarek , Holcomb Frank
Published: May 2010

Co-production of renewable hydrogen, electricity and heat (CHHP) using internal-reforming, high-temperature fuel cells offers a potentially attractive option for the hydrogen infrastructure. The multiple co-products enhance the overall value proposition and help to mitigate the stranded assets issue. High temperature fuel cell (DFC®) systems produce their own hydrogen internally using a synergistic system integration approach. When the excess hydrogen is separated, a submegawatt co-production plant (called DFC-H2®) can co-produce 125 kg/day of hydrogen and 250 kW of power, with a combined hydrogen, power and heat efficiency of 80-85% and ultra-low emissions. A proof-of-concept co-production plant using conventional separation technology has been operated for >8,500 hours at FCE. Electrochemical Hydrogen Separation (EHS) systems, currently under development at FCE, can separate the excess hydrogen produced in the DFC® system with relatively lower energy consumption.
Development of a Highly Integrated Micro Fuel Processor Based on Methanol Steam Reforming for a HT-PEM Fuel Cell with an Electric Power Output of 30 W
Authors: Wichmann Daniel , Engelhardt Philip , Wruck Roland , Lucka Klaus , Köhne Heinrich
Published: May 2010

Within the scope of a German cooperative project a consortium with partners from industry and academia develops a Reformed Methanol Fuel Cell System (RMFC) on the basis of a HT-PEM fuel cell with an electric power output of 30 W. The fuel cell system is used as a hybrid system with an accumulator as an energy supply for golf-caddies. The Steam Reforming of Methanol (SRM) is applied for hydrogen production in a micro-structured reactor which is built on the basis of thin hydroformed metal sheets. An innovative heat exchanger design allows the integration of all relevant fuel processing steps (catalytic combustion, vaporization, reforming, heat exchange) into a single component and also the integration with the HT-PEM fuel cell as such. The fuel processor was tested with different types of catalysts (base metal, precious metal). It turns out that among the catalysts tested a precious metal catalyst has the best stability and performance.
The dual-specificity MAP kinase phosphatases: critical roles in development and cancer
Authors: Bermudez O. , Pagès G. , Gimond C.
Published: May 2010

Intracellular signaling by mitogen-activated protein (MAP) kinases (MAPK) is involved in many cellular responses and in the regulation of various physiological and pathological conditions. Tight control of the localization and duration of extracellular-regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK), or p38 MAPK activity is thus a fundamental aspect of cell biology. Several members of the dual-specificity phosphatase (DUSPs) family are able to dephosphorylate MAPK isoforms with different specificity, cellular, and tissue localization. Understanding how these phosphatases are themselves regulated during development or in physiological and pathological conditions is therefore fundamental. Over the years, gene deletion and knockdown studies have completed initial in vitro studies and shed a new light on the global and specific roles of DUSPs in vivo. Whereas DUSP1, DUSP2, and DUSP10 appear as crucial players in the regulation of immune responses, other members of the family, like the ERK-specific DUSP6, were shown to play a major role in development. Recent findings on the involvement of DUSPs in cancer progression and resistance will also be discussed.
Circulating signals as critical regulators of autonomic state—central roles for the subfornical organ
Authors: Smith Pauline M. , Ferguson Alastair V.
Published: May 2010

To maintain homeostasis autonomic control centers in the hypothalamus and medulla must respond appropriately to both external and internal stimuli. Although protected behind the blood-brain barrier, neurons in these autonomic control centers are known to be influenced by changing levels of important signaling molecules in the systemic circulation (e.g., osmolarity, glucose concentrations, and regulatory peptides). The subfornical organ belongs to a group of specialized central nervous system structures, the circumventricular organs, which are characterized by the lack of the normal blood-brain barrier, such that circulating lipophobic substances may act on neurons within this region and via well-documented efferent neural projections to hypothalamic autonomic control centers, influence autonomic function. This review focuses on the role of the subfornical organ in sensing peripheral signals and transmitting this information to autonomic control centers in the hypothalamus.
Maternal perinatal undernutrition programs a “brown-like” phenotype of gonadal white fat in male rat at weaning
Authors: Delahaye Fabien , Lukaszewski Marie-Amélie , Wattez Jean-Sébastien , Cisse Ouma , Dutriez-Casteloot Isabelle , Fajardy Isabelle , Montel Valérie , Dickes-Coopman Anne , Laborie Christine , Lesage Jean , Breton Christophe , Vieau Didier
Published: May 2010

Several studies indicate that maternal undernutrition sensitizes the offspring to the development of metabolic disorders, such as obesity. Using a model of perinatal maternal 50% food-restricted diet (FR50), we recently reported that rat neonates from undernourished mothers exhibit decreased leptin plasma levels associated with alterations of hypothalamic proopiomelanocortin system. The present study aimed at examining the consequences of FR50 on the brain-adipose axis in male rat neonates. Using quantitative RT-PCR array containing 84 obesity-related genes, we demonstrated that most of the genes involved in energy metabolism regulation are expressed in rat gonadal white adipose tissue (WAT) and are sensitive to maternal perinatal undernutrition (MPU). In contrast, hypothalamic gene expression was not substantially affected by MPU. Gene expression of uncoupling protein 1 (UCP1), a marker of brown adipocytes, showed an almost 400-fold stimulation in postnatal day 21 (PND21) FR50 animals, suggesting that their gonadal WAT possesses a brown-like phenotype. This was confirmed by histological and immunoshistochemical procedures, which demonstrated that PND21 FR50 gonadal adipocytes are multilocular, resembling those present in interscapular brown adipose tissue, and exhibit an overexpression of UCP1 and neuropeptide Y (NPY) at the protein level. Control animals contained almost exclusively “classical” unilocular white adipocytes that did not show high UCP1 and NPY labeling. After weaning, FR50 animals exhibited a transient hyperphagia that was associated with the disappearance of brown-like fat pads in PND30 WAT. Our results demonstrate that MPU delays the maturation of gonadal WAT during critical developmental time windows, suggesting that it could have long-term consequences on body weight regulation in the offspring.
Bioimpedance spectroscopy for the estimation of body fluid volumes in mice
Authors: Chapman M. E. , Hu L. , Plato C. F. , Kohan D. E.
Published: May 2010

Conventional indicator dilution techniques for measuring body fluid volume are laborious, expensive, and highly invasive. Bioimpedance spectroscopy (BIS) may be a useful alternative due to being rapid, minimally invasive, and allowing repeated measurements. BIS has not been reported in mice; hence we examined how well BIS estimates body fluid volume in mice. Using C57/Bl6 mice, the BIS system demonstrated <5% intermouse variation in total body water (TBW) and extracellular (ECFV) and intracellular fluid volume (ICFV) between animals of similar body weight. TBW, ECFV, and ICFV differed between heavier male and lighter female mice; however, the ratio of TBW, ECFV, and ICFV to body weight did not differ between mice and corresponded closely to values in the literature. Furthermore, repeat measurements over 1 wk demonstrated <5% intramouse variation. Default resistance coefficients used by the BIS system, defined for rats, produced body composition values for TBW that exceeded body weight in mice. Therefore, body composition was measured in mice using a range of resistance coefficients. Resistance values at 10% of those defined for rats provided TBW, ECFV, and ICFV ratios to body weight that were similar to those obtained by conventional isotope dilution. Further evaluation of the sensitivity of the BIS system was determined by its ability to detect volume changes after saline infusion; saline provided the predicted changes in compartmental fluid volumes. In summary, BIS is a noninvasive and accurate method for the estimation of body composition in mice. The ability to perform serial measurements will be a useful tool for future studies.
Afferent arteriolar vasodilator effect of adenosine predominantly involves adenosine A2Breceptor activation
Authors: Feng Ming-Guo , Navar L. Gabriel
Published: May 2010

Adenosine is an important paracrine agent regulating renal vascular tone via adenosine A1and A2receptors. While A2Breceptor message and protein have been localized to preglomerular vessels, functional evidence on the role of A2Breceptors in mediating the vasodilator action of adenosine on afferent arterioles is not available. The present study determined the role of A2Breceptors in mediating the afferent arteriolar dilation and compared the effects of A2Band A2Areceptor blockade on afferent arterioles. We used the rat in vitro blood-perfused juxtamedullary nephron technique combined with videomicroscopy. Single afferent arterioles of Sprague-Dawley rats were visualized and superfused with solutions containing adenosine or adenosine A2receptor agonist (CV-1808) along with adenosine A2Band A2Areceptor blockers. Adenosine (10 μmol/l) caused modest constriction and subsequent superfusion with SCH-58261 (SCH), an A2Areceptor blocker, at concentrations up 10 μmol/l elicited only slight additional decreases in afferent arteriolar diameter with maximum effect at a concentration of 1 μmol/l (−11.0 ± 2.5%, n = 6, P < 0.05). However, superfusion of adenosine-treated vessels with MRS-1754 (MRS), an A2Breceptor blocker, elicited greater decreases in afferent arteriolar diameter (−26.0 ± 4.7%, n = 5, P < 0.01). SCH did not significantly augment the adenosine-mediated afferent constriction elicited by MRS; however, adding MRS after SCH caused further significant vasoconstriction. Superfusion with CV-1808 dilated afferent arterioles (17.2 ± 2.4%, n = 6, P < 0.01). This effect was markedly attenuated by MRS (−22.6 ± 2.0%, n = 5, P < 0.01) but only slightly reduced by SCH (−9.0 ± 1.1%, n = 5, P < 0.05) and completely prevented by adding MRS after SCH (−24.7 ± 1.8%, n = 5, P < 0.01). These results indicate that, while both A2Aand A2Breceptors are functionally expressed in juxtamedullary afferent arterioles, the powerful vasodilating action of adenosine predominantly involves A2Breceptor activation, which counteracts A1receptor-mediated vasoconstriction.
Regulation of the creatine transporter by AMP-activated protein kinase in kidney epithelial cells
Authors: Li Hui , Thali Ramon F. , Smolak Christy , Gong Fan , Alzamora Rodrigo , Wallimann Theo , Scholz Roland , Pastor-Soler Núria M. , Neumann Dietbert , Hallows Kenneth R.
Published: May 2010

The metabolic sensor AMP-activated protein kinase (AMPK) regulates several transport proteins, potentially coupling transport activity to cellular stress and energy levels. The creatine transporter (CRT; SLC6A8) mediates creatine uptake into several cell types, including kidney epithelial cells, where it has been proposed that CRT is important for reclamation of filtered creatine, a process critical for total body creatine homeostasis. Creatine and phosphocreatine provide an intracellular, high-energy phosphate-buffering system essential for maintaining ATP supply in tissues with high energy demands. To test our hypothesis that CRT is regulated by AMPK in the kidney, we examined CRT and AMPK distribution in the kidney and the regulation of CRT by AMPK in cells. By immunofluorescence staining, we detected CRT at the apical pole in a polarized mouse S3 proximal tubule cell line and in native rat kidney proximal tubules, a distribution overlapping with AMPK. Two-electrode voltage-clamp (TEV) measurements of Na+-dependent creatine uptake into CRT-expressing Xenopus laevis oocytes demonstrated that AMPK inhibited CRT via a reduction in its Michaelis-Menten Vmaxparameter. [14C]creatine uptake and apical surface biotinylation measurements in polarized S3 cells demonstrated parallel reductions in creatine influx and CRT apical membrane expression after AMPK activation with the AMP-mimetic compound 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside. In oocyte TEV experiments, rapamycin and the AMPK activator 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranosyl 5′-monophosphate (ZMP) inhibited CRT currents, but there was no additive inhibition of CRT by ZMP, suggesting that AMPK may inhibit CRT indirectly via the mammalian target of rapamycin pathway. We conclude that AMPK inhibits apical membrane CRT expression in kidney proximal tubule cells, which could be important in reducing cellular energy expenditure and unnecessary creatine reabsorption under conditions of local and whole body metabolic stress.
The role of epigenetics in the pathology of diabetic complications
Authors: Villeneuve Louisa M. , Natarajan Rama
Published: May 2010

Diabetes is associated with significantly accelerated rates of several debilitating microvascular complications such as nephropathy, retinopathy, and neuropathy, and macrovascular complications such as atherosclerosis and stroke. While several studies have been devoted to the evaluation of genetic factors related to type 1 and type 2 diabetes and associated complications, much less is known about epigenetic changes that occur without alterations in the DNA sequence. Environmental factors and nutrition have been implicated in diabetes and can also affect epigenetic states. Exciting research has shown that epigenetic changes in chromatin can affect gene transcription in response to environmental stimuli, and changes in key chromatin histone methylation patterns have been noted under diabetic conditions. Reports also suggest that epigenetics may be involved in the phenomenon of metabolic memory observed in clinic trials and animal studies. Further exploration into epigenetic mechanisms can yield new insights into the pathogenesis of diabetes and its complications and uncover potential therapeutic targets and treatment options to prevent the continued development of diabetic complications even after glucose control has been achieved.
Prolactin and dopamine 1-like receptor interaction in renal proximal tubular cells
Authors: Crambert Susanne , Sjöberg Agneta , Eklöf Ann-Christine , Ibarra Fernando , Holtbäck Ulla
Published: May 2010

Prolactin is a natriuretic hormone and acts by inhibiting the activity of renal tubular Na+-K+-ATPase activity. These effects require an intact renal dopamine system. Here, we have studied by which mechanism prolactin and dopamine interact in Sprague-Dawley rat renal tissue. Na+-K+-ATPase activity was measured as ouabain-sensitive ATP hydrolysis in microdissected renal proximal tubular segments. Intracellular signaling pathways were studied by a variety of different techniques, including Western blotting using phosphospecific antibodies, immunoprecipitation, and biotinylation assays. We found that dopamine and prolactin regulated Na+-K+-ATPase activity via similar signaling pathways, including protein kinase A, protein kinase C, and phosphoinositide 3-kinase activation. The cross talk between prolactin and dopamine 1-like receptors was explained by a heterologous recruitment of dopamine 1-like receptors to the plasma membrane in renal proximal tubular cells. Prolactin had no effect on Na+-K+-ATPase activity in spontaneously hypertensive rats, a rat strain with a blunted response to dopamine. These results further emphasize the central role of the renal dopamine system in the interactive regulation of renal tubular salt balance.
Expression of adrenomedullin 2/intermedin, a possible reno-protective peptide, is decreased in the kidneys of rats with hypertension or renal failure
Authors: Hirose Takuo , Totsune Kazuhito , Mori Nobuyoshi , Mori Takefumi , Morimoto Ryo , Metoki Hirohito , Asayama Kei , Kikuya Masahiro , Ohkubo Takayoshi , Kohzuki Masahiro , Takahashi Kazuhiro , Imai Yutaka
Published: May 2010

Adrenomedullin 2/intermedin (AM2/IMD) is a potent vasodilator peptide with organ-protective effects and is abundantly expressed in the kidney. We examined the expression of AM2/IMD in the kidneys of rats with hypertension or chronic renal impairment using quantitative RT-PCR, radioimmunoassay, and immunohistochemistry. Kidneys of 8-wk-old male spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats were dissected into inner medulla, outer medulla, cortex, and glomerulus fractions. A rat renal impairment model was prepared by 5/6 nephrectomy in WKY rats. AM2/IMD mRNA levels were the highest in the cortex among four renal portions, and significantly lower in SHR than WKY rats in all renal portions. In the remnant kidneys of 5/6 nephrectomized rats, AM2/IMD mRNA levels were significantly decreased on days 3 and 56, whereas mRNA levels of calcitonin receptor-like receptor, receptor activity-modifying proteins-1 and -2, which form receptor for AM and AM2/IMD, were increased, compared with that in sham-operated rats. AM mRNA levels were decreased on day 3, but increased on day 56, after nephrectomy. Decreased immunoreactive AM2/IMD levels in the remnant kidneys of 5/6 nephrectomized rats on day 56 were confirmed by radioimmunoassay. The renal tubules were immunostained with anti-AM2/IMD antibody, with a decreased AM2/IMD immunostaining found in proximal tubular cells of 5/6 nephrectomized rats compared with sham-operated rats. In conclusion, intrarenal AM2/IMD expression is decreased in SHR and 5/6 nephrectomized rats. Given the organ-protective effects of AM2/IMD, the downregulation of AM2/IMD as an endogenous regulatory peptide may have a role in the progression of renal impairment.
Gamma Band Unit Activity and Population Responses in the Pedunculopontine Nucleus
Authors: Simon Christen , Kezunovic Nebojsa , Ye Meijun , Hyde James , Hayar A. , Williams D. K. , Garcia-Rill E.
Published: May 2010

The pedunculopontine nucleus (PPN) is involved in the activated states of waking and paradoxical sleep, forming part of the reticular activating system (RAS). The studies described tested the hypothesis that single unit and/or population responses of PPN neurons are capable of generating gamma band frequency activity. Whole cell patch clamp recordings (immersion chamber) and population responses (interface chamber) were conducted on 9- to 20-day-old rat brain stem slices. Regardless of cell type (I, II, or III) or type of response to the nonselective cholinergic receptor agonist carbachol (excitation, inhibition, biphasic), almost all PPN neurons fired at gamma band frequency, but no higher, when subjected to depolarizing steps (50 ± 2 Hz, mean ± SE). Nonaccommodating neurons fired at 18–100 Hz throughout depolarizing steps, while most accommodating neurons exhibited gamma band frequency of action potentials followed by gamma band membrane oscillations. These oscillations were blocked by the sodium channel blocker tetrodotoxin (TTX), suggesting that at least some are mediated by sodium currents. Population responses in the PPN showed that carbachol induced peaks of activation in the theta and gamma range, while glutamatergic receptor agonists induced overall increases in activity at theta and gamma frequencies, although in differing patterns. Gamma band activity appears to be a part of the intrinsic membrane properties of PPN neurons, and the population as a whole generates different patterns of gamma band activity under the influence of specific transmitters. Given sufficient excitation, the PPN may impart gamma band activation on its targets.
Impaired Interlimb Coordination of Voluntary Leg Movements in Poststroke Hemiparesis
Authors: Tseng Shih-Chiao , Morton Susanne M.
Published: May 2010

Appropriate interlimb coordination of the lower extremities is particularly important for a variety of functional human motor behaviors such as jumping, kicking a ball, or simply walking. Specific interlimb coordination patterns may be especially impaired after a lesion to the motor system such as stroke, yet this has not been thoroughly examined to date. The purpose of this study was to investigate the motor deficits in individuals with chronic stroke and hemiparesis when performing unilateral versus bilateral inphase versus bilateral antiphase voluntary cyclic ankle movements. We recorded ankle angular trajectories and muscle activity from the dorsiflexors and plantarflexors and compared these between subjects with stroke and a group of healthy age-matched control subjects. Results showed clear abnormalities in both the kinematics and EMG of the stroke subjects, with significant movement degradation during the antiphase task compared with either the unilateral or the inphase task. The abnormalities included prolonged cycle durations, reduced ankle excursions, decreased agonist EMG bursts, and reduced EMG modulation across movement phases. By comparison, the control group showed nearly identical performance across all task conditions. These findings suggest that stroke involving the corticospinal system projection to the leg specifically impairs one or more components of the neural circuitry involved in lower extremity interlimb coordination. The express susceptibility of the antiphase pattern to exaggerated motor deficits could contribute to functional deficits in a number of antiphase leg movement tasks, including walking.
The Amblyopic Deficit and Its Relationship to Geniculo-Cortical Processing Streams
Authors: Hess Robert F. , Thompson Benjamin , Gole Glen A. , Mullen Kathy T.
Published: May 2010

Amblyopia or lazy eye is the most common cause of uniocular blindness in adults and is caused by a disruption to normal visual development as a consequence of unmatched inputs from the two eyes in early life, arising from a turned eye (strabismus), unequal refractive error (anisometropia), or form deprivation (e.g., cataract). Using high-field functional magnetic resonance imaging in a group of human adults with amblyopia, we previously demonstrated that reduced responses are observable at a thalamic level, that of the lateral geniculate nucleus (LGN). Here we investigate the selectivity of this deficit by using chromatic and achromatic stimuli that are designed to bias stimulation to one or other of the three ascending pathways (the parvocellular, magnocellular, and koniocellular). We find the greatest LGN deficit is for stimuli modulated along the chromatic, L/M cone opponent axis of color space, suggesting a selective loss of parvocellular function in the LGN. We also demonstrate a cortical deficit that involves all the visual areas studied (V1, V2, V3, VP, V3A, V4), and we find this is greatest for the two chromatic responses (S cone opponent and L/M cone opponent) versus the achromatic response, as might be expected from a loss of segregation of chromatic pathways in the cortex.
Insulin Promotes Survival of Amyloid-Beta Oligomers Neuroblastoma Damaged Cells via Caspase 9 Inhibition and Hsp70 Upregulation
Authors: Di Carlo M. , Picone P. , Carrotta R. , Giacomazza D. , San Biagio P. L.
Published: May 2010

Alzheimer's disease (AD) and type 2 diabetes are connected in a way that is still not completely understood, but insulin resistance has been implicated as a risk factor for developing AD. Here we show an evidence that insulin is capable of reducing cytotoxicity induced by Amyloid-beta peptides (A-beta) in its oligomeric form in a dose-dependent manner. By TUNEL and biochemical assays we demonstrate that the recovery of the cell viability is obtained by inhibition of intrinsic apoptotic program, triggered by A-beta and involving caspase 9 and 3 activation. A protective role of insulin on mitochondrial damage is also shown by using Mito-red vital dye. Furthermore, A-beta activates the stress inducible Hsp70 protein in LAN5 cells and an overexpression is detectable after the addition of insulin, suggesting that this major induction is the necessary condition to activate a cell survival program. Together, these results may provide opportunities for the design of preventive and therapeutic strategies against AD.
Dielectrophoresis: A Review of Applications for Stem Cell Research
Authors: Pethig Ronald , Menachery Anoop , Pells Steve , De Sousa Paul
Published: May 2010

Dielectrophoresis can discriminate distinct cellular identities in heterogeneous populations, and monitor cell state changes associated with activation and clonal expansion, apoptosis, and necrosis, without the need for biochemical labels. Demonstrated capabilities include the enrichment of haematopoetic stem cells from bone marrow and peripheral blood, and adult stem cells from adipose tissue. Recent research suggests that this technique can predict the ultimate fate of neural stem cells after differentiationbeforethe appearance of specific cell-surface proteins. This review summarises the properties of cells that contribute to their dielectrophoretic behaviour, and their relevance to stem cell research and translational applications.
Autocrine, Not Paracrine, Interferon-Gamma Gene Delivery Enhances Ex Vivo Antigen-Specific Cytotoxic T Lymphocyte Stimulation and Killing
Authors: Zhang Dazhi , Liu Yong , Shi Min , You Chang Xuan , Cao Maohua , Luo Rong Cheng , Hermonat Paul L.
Published: May 2010

The adoptive transfer of antigen-specific cytotoxic T lymphocytes (CTL) shows promise in the treatment of cancer and infectious diseases. We utilize adeno-associated virus-(AAV-) based antigen gene-loaded dendritic cells (DCs) to stimulate such antigen-specific CTL. Yet further improvements in CTL stimulation and killing may result by gene delivery of various Th1-response interferons/cytokines, such as interferonγ(IFN-γ), as the delivered gene can continuously produce that interferon. However which immune cell type should optimally express IFN-γis unclear as the phenotypes of both DC and T cells are enhanced by it. Here, we used AAV to compare and contrast IFN-γgene delivery into DC or T cells, and versus the addition of exogenous IFN-γ, for stimulating carcinoembryonic antigen-(CEA-) specific CTL. It was found that AAV/IFN-γdelivery into T cells (autocrine) resulted in T cell populations with the highest CD8(+)/CD4(+) ratio, highest IFN-γ(+)/IL-4(+) ratio, highest CD69(+),CD8(+) levels, and lowest CD4(+)/CD25(+) levels, all consistent with the strongest Th1 response. Most importantly, AAV/IFN-γtransduction of T cells resulted in antigen-specific T cell populations with the highest killing capabilities, 49% above other treatments. These data strongly suggest that AAV/IFN-γautocrine gene delivery into T cells is worthy of further study towards maximizing the generation of antigen-specific anticancer CTL killers.
Stability of a Mixed Type Functional Equation on Multi-Banach Spaces: A Fixed Point Approach
Authors: Wang Liguang , Liu Bo , Bai Ran
Published: May 2010

Using fixed point methods, we prove the Hyers-Ulam-Rassias stability of a mixed type functional equation on multi-Banach spaces.
Vascularized Fibula Grafts for Reconstruction of Bone Defects after Resection of Bone Sarcomas
Authors: Petersen Michael Mørk , Hovgaard Dorrit , Elberg Jens Jørgen , Rechnitzer Catherine , Daugaard Søren , Muhic Aida
Published: May 2010

We evaluated the results of limb-sparing surgery and reconstruction of bone defects with vascularized fibula grafts in 8 consecutive patients (mean age at operation 13.6 years (range 4.1–24.2 years), female/male = 6/2) with bone sarcomas (BS) (osteosarcoma/Ewing's sarcoma/chondrosarcoma= 4/3/1) operated on form 2000 to 2006. The bone defects reconstructed were proximal femoral diaphysis and epiphysis (n=2), humeral diaphysis (n=2), humeral proximal diaphysis and epiphysis (n=1), femoral diaphysis (n=1), ulnar diaphysis (n=1), and tibial diaphysis (n=1). One patient with Ewing's sarcoma had an early hip disarticulation, developed multiple metastases, and died 9 months after the operation. The remaining patients (n=7) are all alive 50 months (range 26–75 months) after surgery. During the follow-up the following major complications were seen: 1-2 fractures (n=4), pseudarthrosis (n=2), and hip dislocation (n=1). Limb-sparing surgery with reconstruction of bone defects using vascularized fibular grafts in BS cases is feasible with acceptable clinical results, but fractures should be expected in many patients.
Mitoxantrone Loaded Superparamagnetic Nanoparticles for Drug Targeting: A Versatile and Sensitive Method for Quantification of Drug Enrichment in Rabbit Tissues Using HPLC-UV
Authors: Tietze Rainer , Schreiber Eveline , Lyer Stefan , Alexiou Christoph
Published: May 2010

In medicine, superparamagnetic nanoparticles bound to chemotherapeutics are currently investigated for their feasibility in local tumor therapy. After intraarterial application, these particles can be accumulated in the targeted area by an external magnetic field to increase the drug concentration in the region of interest (Magnetic-Drug-Targeting). We here present an analytical method (HPLC-UV), to detect pure or ferrofluid-bound mitoxantrone in a complex matrix even in trace amounts in order to perform biodistribution studies. Mitoxantrone could be extracted in high yields from different tissues. Recovery of mitoxantrone in liver tissue (5000 ng/g) was76±2%. The limit of quantification of mitoxantrone standard was 10 ng/mL±12%. Validation criteria such as linearity, precision, and stability were evaluated in ranges achieving the FDA requirements. As shown for pilot samples, biodistribution studies can easily be performed after application of pure or ferrofluid-bound mitoxantrone.
Comparative Proteomic Analysis of Proteins Involved in the Tumorigenic Process of Seminal Vesicle Carcinoma in Transgenic Mice
Authors: Chang Wei-Chao , Chou Chuan-Kai , Tsou Chih-Chiang , Li Sheng-Hsiang , Chen Chein-Hung , Zhuo Yu-Xing , Hsu Wen-Lian , Chen Chung-Hsuan
Published: May 2010

We studied the seminal vesicle secretion (SVS) of transgenic mice by using one-dimensional gel electrophoresis combined with LTQ-FT ICR MS analysis to explore protein expression profiles. Using unique peptide numbers as a cut-off criterion, 79 proteins were identified with high confidence in the SVS proteome. Label-free quantitative analysis was performed by using the IDEAL_Q software program. Furthermore, western blot assays were performed to validate the expression of seminal vesicle proteins. Sulfhydryl oxidase 1, glia-derived nexin, SVS1, SVS3, and SVS6 showed overexpression in SVS during cancer development. With high sequence similarity to human semenogelin, SVS2 is the most abundance protein in SVS and is dramatically decreased during the tumorigenic process. Our results indicate that these protein candidates could serve as potential targets for monitoring seminal vesicle carcinoma. Moreover, this information can provide clues for investigating seminal vesicle secretion-containing seminal plasma for related human diseases.