bluuebunny/crossref_metadata_2025 huggingface dataset:
THE sp(3) BRST HAMILTONIAN FORMALISM FOR THE YANG–MILLS FIELDS
Authors: IONESCU CARMEN
Published: May 2008

The paper presents in all its nontrivial details the sp(3) BRST Hamiltonian formalism. It is based on structuring the extended phase space on many levels. In this picture, the standard BRST symmetry appears as being only the first approximation of a generalized symmetry, acting as a horizontal (same level) operator. The gauge-fixing problem is completely solved by formulating a theorem and a general rule which allow the choice of a simple gauge term. As an example, the Hamiltonian sp(3) quantization of the Yang–Mills model is exhaustively presented.
A MEASURE OF ENTANGLEMENT THROUGH QUANTUM TRAJECTORY APPROACH
Authors: HUANG X. L. , WANG L. C. , YI X. X.
Published: May 2008

We propose a measure of entanglement through the quantum trajectory approach. The advantage of this measure is that it can avoid the problem of finding all possible decompositions for mixed states, which is usually complicated. This method can be applied to any physical system whose time evolution is governed by the master equation. As an example, we calculate the entanglement of the following cases: (A) entangled system composed of a pair of two-level atoms coupling to two separate baths and, (B) two entangled modes subjected to two separate baths.
Relations of Water Management and Degradation Processes in PEFC
Authors: Schulze Mathias , Friedrich K. A.
Published: May 2008

The life-time of fuel cells is one of the most critical issues for the commercialization of fuel cells. The decrease of the performance induced by the degradation of the fuel cell components together with failure which yield in the loss of the fuel cell functionality are the processes which limit the fuel cell life-time. The water balance in polymer electrolyte membrane fuel cells (PEFC) is a crucial factor for the electrochemical performance. Therefore, the relation between water management in PEFC and the degradations processes are highly important. Consequently, the interactions between water balance and degradation processes - meaning which degradation processes influence the water balance and which degradation processes are influenced by the water balance - have to be investigated and to be discussed, which are the content of this paper.
The Novel Boltless Stack Assembly and Light weight Stack Configuration
Authors: Kim Sung Han , Jang Jae Hyuk , Cha Hye Yeon , Miesse Craig M. , Lee Hong Ryul , Gil Jae Hyoung , Ku Bo Sung , Jung Chang Ryul , Chae Kyoung Soo , Cha Suk Won , Oh Yong Soo
Published: May 2008

The intrinsic improvement of fuel cell stack design is to minimize the volume and weight of fuel cell and is to maximize energy density. However, the bulky and massive stack is one of the main factors to undermine the chances to realize the higher energy density. Though the using bolts and graphite bipolar plates are common in a conventional stack, it may obstruct realizing a light weight and thinner stack. In this paper, the graphite bipolar plate is substituted with the flexible PCB and lightweight polycarbonate plates are used to separate the reactant gas. By using the plastic material as a separator, an innovative boltless stack assembly is originally possible through an ultrasonic welding. Instead of the bolt, the sharp edge of one plate melts and adjacent cell plates are bonded by the ultrasonic welding, which realizes the boltless and light weight stack assembly.
Exergetic Studies of Intermediate-Temperature, Mixed Ionic-Electronic Conducting Solid Oxide Fuel Cell Electrolytes Using the Wagner Mass Transfer Model
Authors: Williams Mark , Yamaji Katsuhiko , Horita Teruhisa , Sakai N. , Yokokawa Harumi
Published: May 2008

The exergetic and thermal efficiency of various SOFC mixed ionic-electronic conducting (MIEC) intermediate fuel cell electrolytes at various temperatures and electrolyte thicknesses was evaluated. Electrolytes reported on here include: LSGM, YSZ, and GDC (gadolinium doped ceria oxide). Here, results for the hydrogen oxidation reaction are reported. GDC was shown to have a good exergetic efficiency, but only over a very narrow temperature region. The Wagner mass transfer model (MTM) was used to incorporate solid state oxygen ion, hole, and electron conduction effects into a thermodynamic model. The MALT2 data base was used to provide thermodynamic data over the temperatures and compositions of interest. The MTM predicted performance agreed well with the experimental performance. The predicted exergetic performance with the thermodynamic model without the incorporation of the MTM gave higher than experimentally observed results at the higher temperatures for various fuel anodic reactions. A thermodynamically consistent picture of SOFC exergetic performance from the solid state electrochemistry to the macroscopic thermodynamic performance was established.
Sulfur Tolerant Anodes for Solid Oxide Fuel Cells
Authors: Elangovan S , Hartvigsen J , Frost L
Published: May 2008

Conventional solid oxide fuel cells (SOFC) utilize nickel / yttria-stabilized zirconia cermet anodes that are rapidly poisoned by sulfur. Hydrogen sulfide content in the reformate of 2 ppmv (at 1000{degree sign}C) is known to poison the anode. Military fuels, such as JP-8 and JP-5, contain total sulfur levels that far exceed the levels that can damage the typical anode. Typical sulfur levels for these fuels would be 500-600 ppmv for the reformate from a steam reformer and 300-400 ppmv from a partial oxidation reformer. Though most systems utilize a desulfurization step, occasional sulfur slip must be anticipated. Research at Ceramatec, Inc has developed an approach to increasing sulfur tolerance through a combination of material selection and modification.
Volatilization Behavior of Li/Na Carbonate as an Electrolyte in MCFC
Authors: Sugiura Kimihiko , Soga Masatsugu , Yamauchi Makoto , Tanimoto Kazumi
Published: May 2008

We have been elucidating the volatile Li/K electrolyte behavior in MCFC since 2003 using a visualization technique. Regarding the 62Li2CO3/ 38K2CO3 electrolyte, the molten salt is produced as KOH with the water generated with the cell reaction, and K2CO3, which is the volatile matter, is generated as the KOH reacts with CO2 in the anode gas. Conversely, the volatile matter in the cath-ode channel is due to the dispersion of molten salt. In this paper, we aim to elucidate the fundamental electrolyte volatilizing mechanism of 52Li2CO3/ 48Na2CO3 and the influence of the elec-trolyte leakage from the wet seal section on the electrolyte's vola-tile behavior. As a result, the volatile matter Li/Na electrolyte is not observed under the generation mode even as the current density in-creases. However, a large amount of electrolytes that originated in the leakage from the wet seal section are discharged beginning immediately after operation and lasting until about one week later on the Li/Na electrolyte.
Catalysis Studies for H2 Production by Metallic Heat Exchanger-Coated Catalysts
Authors: Shi Yanlong , Van Pelt John , Cross James , Pollica Darryl , O'Brien Christopher , Leshchiner Michael
Published: May 2008

Metallic heat exchanger coated catalyst (MHXCC)-based reformers have been proposed. If successful, the reformers based on this concept are compact in size, with smaller pressure drop, better shock and vibration resistance, quicker startup, faster kinetics, lower operating temperature and longer durability than conventional reformers. In addition, the metallic substrate-coated WGS and PrOx catalysts have some advantages over either pellet-based or ceramic substrate-coated ones for the downstream CO cleanup. In order to develop our next generations of fuel processing systems that have these advantages, a series of works were carried out at Nuvera's micro-reactors for providing the most fundamental data to the design of these kinds of new reformers. Excellent agreement between theoretical and measured equilibrium shows that the reactor setup is suitable for thermodynamic and kinetic studies for MHXCC technology development. Our studies indicate that proper and adequate heating both horizontally from furnace of catalyst bed and vertically from preheat are critical for steam reforming studies using MHXCC-based catalysts. FeCrAlloy is a good substrate for catalyst washcoating, and no catalyst loss was observed for all of the tested catalysts by weight comparisons before and after testing. Methane conversion, kinetics, thermodynamic product distributions are very useful pieces of information for future designs of metal substrate-coated reformers. A power law rate expression accurately models the data for each catalyst. MHXCC technologies developed in the laboratory have been successfully applied to full scale fuel processors for H2 production.
Autothermal Reforming of Jet A-1 and Diesel: General Aspects and Experimental Results
Authors: Pasel Joachim , Latz Jochen , Porš Zdenek , Meißner Jan , Samsun Remzi C. , Tschauder Andreas , Peters Ralf
Published: May 2008

This paper deals with general aspects and experimental results of autothermal reforming of Jet A-1 and Diesel fuel. With that respect, at first a process analysis based on the so called pinch-point methodology compares three different reforming routes, i.e. steam reforming, partial oxidation and autothermal reforming. The analysis is based on the application of a high temperature polymer electrolyte fuel cell (HT-PEFC). Then, specifications of different possible fuels for reforming are given. Their constraints with respect to their suitability for autothermal reforming are discussed. Finally, experiments with respect to the long-term stability of two reforming reactors revealed that it is decisive to posses a highly sophisticated educt and fuel evaporation technology in combination with a homogeneous mixing of the educts. Thereby, very promising long-term stabilities for autothermal reforming of Jet A-1 and Diesel fuel were achieved. E.g., there was 99 % conversion of Jet A-1 at the end of the long-term experiment after 2000 h on stream.
Modeling and Simulating of a PV/H2 Hybrid System for Reducing Load Peaks on an Electrical Grid
Authors: Darras Christophe , Muselli Marc , Poggi Philippe , Cristofari Christian , Le Pivert Xavier
Published: May 2008

The object of the study is to reduce the daily load peaks on an insular electric network (Corsica Island, France) with the help of renewable energy systems. The methodology is based on an energy balance between a PV array, an electrolyzer and fuel cells supplying a seasonal load profile built from electrical network load peaks. This load is supplied firstly by the PV array and the fuel cell produces complementary power when the PV system is deficient. An electrolyzer, using unconsumed PV energy produces hydrogen for the fuel cell. In the present work, at the beginning of the operation, the hydrogen stock is sufficient to satisfy a given number of days corresponding to the system autonomy (Loss of Load probability = 0). The objective was to determine a sizing curve of the hybrid system, in order to obtain in the future the best physical and economical configurations.
Modeling and Simulation of a PEM Fuel Cell System for Aircraft Applications
Authors: Schumann Peter , Graf Christian , Friedrich K. A.
Published: May 2008

A dynamic polymer electrolyte fuel cell system model including reformer, compressor, turbine and balance of pant models as wells as a heuristic control concept has been developed within MATLAB/Simulink. Within this paper emphasis is given to the model validation and dynamic system behavior. In addition the on-board water production and the system water balance were evaluated. The results point out an effective water gain if high effort for cooling is introduced and the load demand is higher than 65% of the nominal fuel cell stack power output. Moreover a response time of approximately 50s regarding load changes was derived from the simulation.
Advancement in Liquid Tin Anode - Solid Oxide Fuel Cell Technology
Authors: Tao Thomas , McPhee William A. , Koslowske Mark T. , Bateman Linda S. , Slaney Mike J. , Bentley Jeff
Published: May 2008

The first Liquid Tin Anode Solid Oxide Fuel Cell (LTA-SOFC) was tested in 1998. Since 1998 the LTA-SOFC has been operated on a range of carbonaceous fuels in the form of gases, liquids and solids. Over this time, several design revisions at the cell, stack and system levels have resulted in multiple technical, performance and commercial milestones, increasing the volumetric and gravimetric power densities. The Gen 3.0 cell and stack (2005-2006) achieved a power density of 40 mW/cm2 by direct JP-8 conversion to electricity. However for mobile/portable applications, compact LTA-SOFC systems are preferred which requires a higher power density. This paper discusses key development areas and performance of the current Gen 3.1 cells/stack which have lead to a 4 times reduction in weight and volume over Gen 3.0. Performance of the Gen 3.1 cell on direct JP-8 conversion with a sulfur content of 1400 ppm shows a power density of 120 mW/cm2 and fuel efficiency over 40%.
Direct Ammonia Borane Alkaline Fuel Cell With In-Situ Electrolyte Replacement
Authors: Cisar Alan , Withers-Kirby Sandra , Heselmeyer Eric
Published: May 2008

An alkaline fuel cell power supply using ammonia borane as fuel was investigated. Ammonia borane was found to have a high energy density when compared to other common fuels, making it an ideal fuel for portable fuel cell technology. Performance of a 10-cell AFC stack operating on ammonia borane was demonstrated with a power density of 315 mW/cm2 achieved at ambient pressure and near ambient temperature. Operating lifetime and fuel utilization were also explored.
Interconnection of Multi-Pad Electrodes by "Controlled Anisotropic Extraneous (CAEx) Deposition" of Electroless NiB Film
Authors: Yokoshima Tokihiko , Yamaji Yasuhiro , Igawa Noboru , Tamura Yuichiro , Kikuchi Katsuya , Nakagawa Hiroshi , Aoyagi Masahiro
Published: May 2008

Interconnection of multi-pad array was developed by using the electroless CAEx deposition of NiB for application to the new flip-chip bonding technology. Behavior of CAEx deposition of Electroless NiB films was depended on pad width and distance between facing pads, and pad with nearer distance and wider pad size was achieved. Practical feasibility of this technique was demonstrated by forming interconnection between pads separated by 5 micrometer and measuring 5 micrometer in both height and width. This method was applied successfully to interconnecting the pads forming an array with a pitch of 20 micrometer.
Chronic treatment with insulin-like growth factor I enhances myocyte contraction by upregulation of Akt-SERCA2a signaling pathway
Authors: Kim Song-Jung , Abdellatif Maha , Koul Sharat , Crystal George J.
Published: May 2008

Chronic treatment with insulin-like growth factor I (IGF-I) improves contractile function in congestive heart failure and ischemic cardiomyopathy. The present study investigated the effect of chronic treatment with IGF-I on intrinsic myocyte function and the role of the phosphatidylinositol (PI)3-kinase-Akt-sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA)2a signaling cascade in these responses. Myocytes were isolated from 23 adult rats and cultured with and without IGF-I (10−6M). After 48 h of treatment, myocyte function was evaluated. IGF-I increased contractile function (percent contraction, 7.7 ± 0.3% vs. 4.5 ± 0.3%; P < 0.01) and accelerated relaxation time (time for 70% relengthening, 81 ± 4 vs. 106 ± 5 ms; P < 0.05) compared with untreated myocytes [control (Con)]. The enhanced function was associated with an increase in Ca2+transients assessed by fura-2 (340/380 nm; IGF-I, 0.42 ± 0.02 vs. Con, 0.25 ± 0.01; P < 0.01). The PI3-kinase inhibitor LY-249002 (10−9M) abolished the enhanced function caused by IGF-I. IGF-I increased both Akt and SERCA2a protein levels 2.5- and 4.8-fold, respectively, compared with those of Con ( P < 0.01); neither phospholamban nor calsequestrin was affected. To evaluate whether the SERCA2a protein was directly mediated by Akt-SERCA2a signaling, IGF-I-induced changes in the SERCA2a protein were compared in myocytes transfected with adenovirus harboring either constitutively active Akt [multiplicity of infection (MOI), 15] or dominant negative Akt (dnAkt; MOI, 15). The ability of IGF-I to upregulate the SERCA2a protein in myocytes transected with active Akt was absent in dnAkt myocytes. Taken together, our findings indicate that chronic treatment with IGF-I enhances intrinsic myocyte function and that this effect is due to an enhancement in intracellular Ca2+handling, secondary to the activation of the PI3-kinase-Akt-SERCA2a signaling cascade.
Persistent alterations in heart rate variability, baroreflex sensitivity, and anxiety-like behaviors during development of heart failure in the rat
Authors: Henze Marcus , Hart Davin , Samarel Allen , Barakat John , Eckert Laurie , Scrogin Karie
Published: May 2008

Depressed heart rate variability and mood are associated with increased mortality in patients with congestive heart failure (CHF). Here autonomic indexes were assessed 3 and 7 wk after left coronary artery ligation in telemetered rats, after which anxiety-like behaviors were assessed in an elevated plus maze. Low frequency (LF) and high frequency (HF) heart rate variability were reduced in CHF rats 3 wk after infarction (LF, 1.60 ± 0.52 vs. 6.97 ± 0.79 ms2; and HF, 1.53 ± 0.39 vs. 6.20 ± 1.01 ms2; P < 0.01). The number of sequences of interbeat intervals that correlated with arterial pressure was decreased in CHF rats at 3 and 7 wk ( week 3, 26.60 ± 10.85 vs. 59.75 ± 11.4 sequences, P < 0.05; and week 7, 20.80 ± 8.97 vs. 65.38 ± 5.89 sequences, P < 0.01). Sequence gain was attenuated in CHF rats by 7 wk (1.34 ± 0.06 vs. 2.70 ± 0.29 ms/mmHg, P < 0.01). Coherence between interbeat interval and mean arterial blood pressure variability in the LF domain was reduced in CHF rats at 3 (0.12 ± 0.03 vs. 0.26 ± 0.05 k2, P < 0.05) and 7 (0.16 ± 0.02 vs. 0.31 ± 0.05 k2, P < 0.05) wk. CHF rats invariably entered the open arm of the elevated plus maze first and spent more time in the open arms (36.0 ± 15% vs. 4.6 ± 1.9%, P < 0.05). CHF rats also showed a tendency to jump head first off the apparatus, whereas controls did not. Together the data indicate that severe autonomic dysfunction is accompanied by escape-seeking behaviors in rats with verified CHF.
Vasopressin regulates the renin-angiotensin-aldosterone system via V1a receptors in macula densa cells
Authors: Aoyagi Toshinori , Izumi Yuichiro , Hiroyama Masami , Matsuzaki Takanobu , Yasuoka Yukiko , Sanbe Atsushi , Miyazaki Hiroki , Fujiwara Yoko , Nakayama Yushi , Kohda Yukimasa , Yamauchi Junji , Inoue Takeaki , Kawahara Katsumasa , Saito Hideyuki , Tomita Kimio , Nonoguchi Hiroshi , Tanoue Akito
Published: May 2008

The neuropeptide hormone arginine-vasopressin (AVP) is well known to exert its antidiuretic effect via the vasopressin V2 receptor (V2R), whereas the role of the vasopressin V1a receptor (V1aR) in the kidney remains to be clarified. Previously, we reported decreased plasma volume and blood pressure in V1a receptor-deficient (V1aR−/−) mice (Koshimizu T, Nasa Y, Tanoue A, Oikawa R, Kawahara Y, Kiyono Y, Adachi T, Tanaka T, Kuwaki T, Mori T. Proc Natl Acad Sci USA 103: 7807–7812, 2006). In this study, we investigated the role of V1aR in urine concentration, renal function, and the renin-angiotensin system (RAS) using V1aR−/−mice. Urine volume of V1aR−/−mice was greater than that of wild-type mice, particularly when water was loaded, while the glomerular filtration rate (GFR), urinary NaCl excretion, AVP-dependent cAMP generation, V2R, and aquaporin 2 (AQP2) expression in the kidney were lower, indicating that the diminished GFR and V2R-AQP2 system led to impaired urinary concentration in V1aR−/−mice. Since the GFR and V2R-AQP2 system are regulated by RAS, we analyzed renin and angiotensin II in V1aR−/−mice and found that the plasma renin and angiotensin II were decreased. The expression of renin in granule cells was decreased in V1aR−/−mice, which led to a decreased level of plasma renin. In addition, the expression of renin stimulators such as neuronal nitric oxide synthase and cyclooxygenase-2 in macula densa (MD) cells, where V1aR was specifically expressed, was decreased in V1aR−/−mice. These data indicate that AVP regulates body fluid homeostasis and GFR via the V1aR in MD cells by activating RAS and subsequently the V2R-AQP2 system.
Radiation-Induced Leiomyosarcoma after Breast Cancer Treatment and TRAM Flap Reconstruction
Authors: Olcina M. , Merck B. , Giménez-Climent M. J. , Almenar S. , Sancho-Merle M. F. , Llopis F. , Vázquez-Albadalejo C.
Published: May 2008

The development of a radiation-induced sarcoma (RIS) in the post mastectomy thoracic treatment volume is an infrequent, but recognized, event. Its frequency is rising in relation with increasing survival of breast cancer patients treated with adjuvant radiation therapy, and is associated with poor prognosis despite treatment. We present a case of leiomyosarcoma in a patient who underwent mastectomy followed by radiotherapy for invasive ductal carcinoma. A delayed TRAM flap reconstruction was performed 10 years after and a rapid growing mass under the reconstructed flap appeared, on routine follow-up, twenty years later. This report analyzes the diagnostic and therapeutic approach of patients with RIS.
Some Characterizations of Open, Closed, and Continuous Mappings
Authors: Noorie Navpreet Singh , Bala Rajni
Published: May 2008

We obtain new characterizations of open maps in terms of closures, of closed maps in terms of interiors, and of continuous maps in terms of interiors. Further open (closed) onto maps
f : X → Y are described in terms of images under f of certain closed (open) sets in X. Continuity of (onto) maps is also characterized in terms of saturated sets.
Erosion-Oxidation Response of Boiler Grade Steels: A Mathematical Investigation
Authors: Das S. K. , Hegde Shubha , Dey P. K. , Mehrotra S. P.
Published: May 2008

A ductile erosion model embodying the mechanisms of erosion involving cutting wear and repeated plastic deformation has been developed to predict erosion rates of boiler grade steels. The issue of erosion-oxidation interaction has also been addressed to further predict the mass loss resulted from this composite mechanism. A deterministic formalism for the kinetics of oxide-scale growth and a probabilistic approach to characterize the material loss are employed to describe simultaneous actions of high-temperature oxidation and mechanical erosion. The model predictions are in good agreement with the published data.
Intracellular Signalling by C‐Peptide
Authors: Hills Claire E. , Brunskill Nigel J.
Published: May 2008

C‐peptide, a cleavage product of the proinsulin molecule, has long been regarded as biologically inert, serving merely as a surrogate marker for insulin release. Recent findings demonstrate both a physiological and protective role of C‐peptide when administered to individuals with type I diabetes. Data indicate that C‐peptide appears to bind in nanomolar concentrations to a cell surface receptor which is most likely to be G‐protein coupled. Binding of C‐peptide initiates multiple cellular effects, evoking a rise in intracellular calcium, increased PI‐3‐kinase activity, stimulation of the Na+/K+ATPase, increased eNOS transcription, and activation of the MAPK signalling pathway. These cell signalling effects have been studied in multiple cell types from multiple tissues. Overall these observations raise the possibility that C‐peptide may serve as a potential therapeutic agent for the treatment or prevention of long‐term complications associated with diabetes.
On Faster Convergent Infinite Series
Authors: Holý Dušan , Matejíčka Ladislav , Pinda Ľudovít
Published: May 2008

Suffcient conditions, necessary conditions for faster convergent infinite series, faster τ‐convergent infinite series are studied. The faster convergence of infinite series of Kummer′s type is proved.
Biomarkers and Mechanisms of FANCD2 Function
Authors: Willers Henning , Kachnic Lisa A. , Luo Chen-Mei , Li Li , Purschke Martin , Borgmann Kerstin , Held Kathryn D. , Powell Simon N.
Published: May 2008

Genetic or epigenetic inactivation of the pathway formed by the Fanconi anemia (FA) and BRCA1 proteins occurs in several cancer types, making the affected tumors potentially hypersensitive to DNA cross‐linkers and other chemotherapeutic agents. It has been proposed that the inability of FA/BRCA‐defective cells to form subnuclear foci of effector proteins, such as FANCD2, can be used as a biomarker to aid individualization of chemotherapy. We show that FANCD2 inactivation not only renders cells sensitive to cross‐links, but also oxidative stress, a common effect of cancer therapeutics. Oxidative stress sensitivity does not correlate with FANCD2 or RAD51 foci formation, but associates with increased γH2AX foci levels and apoptosis. Therefore, FANCD2 may protect cells against cross‐links and oxidative stress through distinct mechanisms, consistent with the growing notion that the pathway is not linear. Our data emphasize the need for multiple biomarkers, such as γH2AX, FANCD2, and RAD51, to capture all pathway activities.
Calcium-Handling Abnormalities Underlying Atrial Arrhythmogenesis and Contractile Dysfunction in Dogs With Congestive Heart Failure
Authors: Yeh Yung-Hsin , Wakili Reza , Qi Xiao-Yan , Chartier Denis , Boknik Peter , Kääb Stefan , Ravens Ursula , Coutu Pierre , Dobrev Dobromir , Nattel Stanley
Published: May 2008

Background—

Congestive heart failure (CHF) is a common cause of atrial fibrillation. Focal sources of unknown mechanism have been described in CHF-related atrial fibrillation. The authors hypothesized that abnormal calcium (Ca
2+
) handling contributes to the CHF-related atrial arrhythmogenic substrate.

Methods and Results—

CHF was induced in dogs by ventricular tachypacing (240 bpm �2 weeks). Cellular Ca
2+
-handling properties and expression/phosphorylation status of key Ca
2+
handling and myofilament proteins were assessed in control and CHF atria. CHF decreased cell shortening but increased left atrial diastolic intracellular Ca
2+
concentration ([Ca
2+
]
i
), [Ca
2+
]
i
transient amplitude, and sarcoplasmic reticulum (SR) Ca
2+
load (caffeine-induced [Ca
2+
]
i
release). SR Ca
2+
overload was associated with spontaneous Ca
2+
transient events and triggered ectopic activity, which was suppressed by the inhibition of SR Ca
2+
release (ryanodine) or Na
+
/Ca
2+
exchange. Mechanisms underlying abnormal SR Ca
2+
handling were then studied. CHF increased atrial action potential duration and action potential voltage clamp showed that CHF-like action potentials enhance Ca
2+
i
loading. CHF increased calmodulin-dependent protein kinase II phosphorylation of phospholamban by 120%, potentially enhancing SR Ca
2+
uptake by reducing phospholamban inhibition of SR Ca
2+
ATPase, but it did not affect phosphorylation of SR Ca
2+
-release channels (RyR2). Total RyR2 and calsequestrin (main SR Ca
2+
-binding protein) expression were significantly reduced, by 65% and 15%, potentially contributing to SR dysfunction. CHF decreased expression of total and protein kinase A–phosphorylated myosin-binding protein C (a key contractile filament regulator) by 27% and 74%, potentially accounting for decreased contractility despite increased Ca
2+
transients. Complex phosphorylation changes were explained by enhanced calmodulin-dependent protein kinase IIδ expression and function and type-1 protein-phosphatase activity but downregulated regulatory protein kinase A subunits.

Conclusions—

CHF causes profound changes in Ca
2+
-handling and -regulatory proteins that produce atrial fibrillation–promoting atrial cardiomyocyte Ca
2+
-handling abnormalities, arrhythmogenic triggered activity, and contractile dysfunction.
Hyperdense Internal Carotid Artery Sign
Authors: Ozdemir Ozcan , Leung Andrew , Bussiére Miguel , Hachinski Vladimir , Pelz David
Published: May 2008

Background and Purpose—

The hyperdense middle cerebral artery sign (HMCAS) is a well-established marker of early ischemia on noncontrast computed tomography of the brain (NCCT). Recently the MCA dot sign has been described and proposed to indicate thrombosis of the M2 or M3 middle cerebral artery branches. The purpose of this study was to define the hyperdense ICA sign (HICAS) and determine its prevalence, diagnostic and prognostic value, and its reliability as a marker for ischemia.

Methods—

Noncontrast computed tomography scans of 71 patients with acute ischemic stroke were analyzed for the presence of a HICAS, HMCAS, or MCA dot sign. For the validation of HICA and HMCA signs on NCCT, 32 of 71 patients who underwent gold standard CT angiography (CTA) before thrombolytic therapy were included in the analysis. The presence of a HICAS was correlated with initial neurological severity and the short and long-term outcomes.

Results—

A HICAS was found in 24% of patients on NCCT. In patients with a HICAS, mean age was 63±17.4 and mean time from symptom onset to CT was 103 minutes. Interobserver agreement was excellent for the HICAS. The HICAS has high specificity (100%) and positive predictive value (100%) in predicting the presence of distal internal carotid artery thrombus on CTA. Patients with a HICAS had a more severe initial neurological deficit and worse prognosis than patients without a HICAS.

Conclusion—

The HICAS is a reliable and a highly specific marker of thromboembolic occlusion of the distal ICA and is associated with severe initial neurological deficit and worse outcome despite thrombolytic therapy.
Impact of Comorbidities on Ischemic Stroke Outcomes in Women
Authors: Bushnell Cheryl D. , Lee Jeanne , Duncan Pamela W. , Newby L. Kristin , Goldstein Larry B.
Published: May 2008

Background and Purpose—

We assessed the association of prestroke comorbidities with long-term stroke outcomes among women with ischemic stroke.

Methods—

Prestroke comorbid conditions in 133 women admitted with acute ischemic stroke were scored with the Charlson Index (CI). We assessed whether the CI and other specific conditions were associated with modified Rankin Score (mRS) at 90 days or more poststroke.

Results—

After adjustment for initial NIHSS and age, higher CI was the sole factor independently associated with poorer 90 day mRS scores. When CI was excluded, coronary disease and diabetes were independently associated with poorer outcome.

Conclusion—

The extent of comorbidities as assessed by the CI is independently associated with 90-day mRS among women with ischemic stroke, but the individual comorbidities of CHD and DM were each associated with functional outcome.
Reperfusion Half-Life
Authors: Merino José G. , Latour Lawrence L. , An Li , Hsia Amie W. , Kang Dong-Wha , Warach Steven
Published: May 2008

Background and Purpose—

We hypothesized that the probability of reperfusion can be modeled by an exponential decay (ie, half-life) function and that this reperfusion half-life is decreased by thrombolytic treatment.

Methods—

Serial perfusion MRI scans were evaluated for evidence of reperfusion in intravenous tissue plasminogen activator-treated (n=45) and untreated (n=103) patients. The cumulative probability of reperfusion for each group was fit with exponential decay functions. The resulting reperfusion half-life (ie, the time it takes half the sample to reperfuse) was calculated.

Results—

In untreated patients, a monoexponential decay function fit the data well (
R
2
=0.95) with a half-life of 29.1 hours. In tissue plasminogen activator-treated patients, the data were best fit with a biexponential decay function (
R
2
=0.99) that had a fast and a slow component. The fast component is attributable to tissue plasminogen activator therapy and has a half-life of 0.71 hours, whereas the slow component was similar to that of the untreated group. Approximately 3.5 hours after the start of treatment, the effect of tissue plasminogen activator on the probability of reperfusion was negligible.

Conclusion—

The probability of reperfusion can be well described by the reperfusion half-life. Determination of the fast component reperfusion half-life may be an approach to compare the relative potency of different thrombolytic agents.
Design and Optimization of Biopolyester Bagasse Fiber Composites
Authors: Hodzic Alma , Coakley Richard , Curro Ray , Berndt Christopher C. , Shanks Robert A.
Published: May 2008

Bagasse fiber, a by-product of the sugar making process, maintains a coherent xylem structure and can offer mechanical reinforcement to composite materials. Biopolyester bagasse composites were prepared with biodegradable matrices polyhydroxylbutyrate (PHB) and its copolymer containing
polyhydroxyvalerate (PHBV). Both biopolymers were reinforced with treated and untreated bagasse fibers, as well as fiber volume fractions involving two fiber lengths. Optimized properties were achieved with PHB-bagasse composite surpassing the PHB flexural strength by 50% and achieving higher
strength and modulus than the standard thermoplastics. The bagasse fibers were cleaned with boiling water and acetone soxhlet extraction to avoid using adhesive chemicals and, therefore, comply with biosafety standards in the packaging industry. A significant improvement in the interfacial
stress transfer between the fiber and the matrix was achieved with the fibers subjected to both washing and acetone treatment. While the crystallization of PHBV was shown to be controllable by processing conditions, it was concluded that no transcrystalline region was formed with this particular
resin in any of the composites. Bagasse was shown to be an effective filler for PHBV; although the results varied somewhat due to the surface treatment of the bagasse fibers. On average, long fiber bagasse composites displayed flexural moduli 33% higher than those of PHBV. Overall, the results
demonstrated the positive potential of bagasse to reinforce both biopolyester matrices.
Towards the Large-Scale Synthesis of Carbon Nanotubes in Fluidised Beds
Authors: Harris A. T. , See C. H. , Liu J. , Dunens O. , Mackenzie K.
Published: May 2008

Carbon nanotubes (CNTs) are a form of crystalline carbon with extraordinary properties, making them valuable in a broad range of applications. However, the lack of suitable large-scale manufacturing techniques, which we define as being of the order 10000 tonnes per annum, continues
to inhibit their widespread use. Of the three established synthesis methods for CNTs: (i) chemical vapour deposition (CVD), (ii) laser ablation, and (iii) arc discharge, CVD techniques show the greatest promise for economically viable, large-scale synthesis. In particular, the fluidised bed
CVD (FBCVD) technique, where the CVD reaction occurs within a fluidised bed of catalyst particles, has the potential to produce high quality CNTs, inexpensively, in large quantities. In this work we report on the development of a catalytic chemical vapour deposition process, using batch fluidised
bed reactors, for the synthesis of straight and spiral carbon nanotubes at pilot scale (up to 1 kg/hr). We believe this to be the first report of the synthesis of spiral carbon nanotubes using fluidised bed CCVD. Iron, nickel and cobalt transition metal catalysts supported on non-porous alumina
substrates were fluidised in a mixture of nitrogen, hydrogen and ethylene at temperatures between 550 and 800 C for between 15 and 90 minutes. Nanotube yield was inferred from thermogravimetric analysis and the quality and size of the CNTs from transmission electron microscopy. Conflicting
information in the literature about the influence of synthesis parameters on CNT properties suggests that further investigation is necessary to understand the synthesis process at a fundamental level, i.e., independent of reactor design and operation.
Polyethyleneimine Modified Biocompatible Poly(N-isopropylacrylamide)-Based Nanogels for Drug Delivery
Authors: Quan Chang-Yun , Wei Hua , Sun Yun-Xia , Cheng Si-Xue , Shen Kun , Gu Zhong-Wei , Zhang Xian-Zheng , Zhuo Ren-Xi
Published: May 2008

A series of biocompatible and stimuli-sensitive poly(N-isopropylacrylamide-co-propyl acrylic acid) (P(NIPAAm-co-PAAc)) nanogels were synthesized by emulsion polymerization. In addition, polyethyleneimine (PEI) was further grafted to modify the PNIPAAm-based nanogels.
The P(NIPAAm-co-PAAc)-g-PEI nanogels exhibited good thermosensitivity as well as pH sensitivity. Transmission electron microscopy (TEM) showed that the P(NIPAAm-co-PAAc)-g-PEI and P(NIPAAm-co-PAAc) nanogels displayed well dispersed spherical morphology. The mean sizes
of the nanogels measured by dynamic light scattering (DLS) were from 100 nm to 500 nm at different temperatures. The cytotoxicity study indicated P(NIPAAm-co-PAAc) nanogels exhibited a better biocompatibility than both PNIPAAm nanogel and P(NIPAAm-co-PAAc)-g-PEI nanogel although
all the three kinds of nanogels did not exhibit apparent cytotoxicity. The drug-loaded nanogels, especially the PEI-grafted nanogels, showed temperature-trigged controlled release behaviors, indicating the potential applications as an intelligent drug delivery system.
Preparation of Rutile and Anatase Phases Titanium Oxide Film by RF Sputtering
Authors: Huang Hong-Hsin , Huang Chia-Chen , Huang Ping-Chih , Yang Cheng-Fu , Hsu Ching-Yun
Published: May 2008

Titanium oxide films were prepared by RF magnetron sputtering onto glass substrates. The effects of RF power and deposition temperature on crystalline structure, morphology and energy gap were investigated, which were analyzed by X-ray diffraction, SEM and UV-Vis spectrometer, respectively.
Results show that rutile phase is the favored structure during deposition. Applying RF power in the range of 50–250 W, the amorphous, rutile, and both rutile and anatase phases TiO2 films were obtained in sequence, while the content of anatase is similar in the range of 34–37%
although the RF power increases. Increasing the deposition temperature, the anatase phase coexists in the rutile phase in the range of 100–200 °C, and the content of anatase increases from 20 to 41% with the deposition temperature. In addition, according to the morphology observation,
the granulous surface is found in rutile phase while facetted surface in anatase phase when titanium oxide films deposited at various RF powers and substrate temperatures. The band gap energy of titanium oxide evaluated from (αhν)1/2 versus energy plots show
that the energy gap decreases with RF power increasing.
Stress and Crystallization of Plasma Enhanced Chemical Vapour Deposition Nanocrystalline Silicon Films
Authors: Milne S. B. , Fu Y. Q. , Luo J. K. , Flewitt A. J. , Pisana S. , Fasoli A. , Milne W. I.
Published: May 2008

Nanocrystalline Si films were prepared with a RF-PECVD system using different SiH4/H2 ratios, plasma powers, substrate temperatures and annealing conditions. The film's intrinsic stress was characterized in relation to the crystallization fraction. Results show
that an increasing H2 gas ratio, plasma power or substrate temperature can shift the growth mechanism across a transition point, past which nanocrystalline Si is dominant in the film structure. The film's intrinsic stress normally peaks during this transition region. Different mechanisms
of stress formation and relaxation during film growth were discussed, including ion bombardment effects, hydrogen induced bond-reconstruction and nanocomposite effects (nanocrystals embedded in an amorphous Si matrix). A three-parameter schematic plot has been proposed which is based on the
results obtained. The film structure and stress are presented in relation to SiH4 gas ratio, plasma power and temperature.
Functional Metal Oxide Coatings by Molecule-Based Thermal and Plasma Chemical Vapor Deposition Techniques
Authors: Mathur S. , Ruegamer T. , Donia N. , Shen H.
Published: May 2008

Deposition of thin films through vaccum processes plays an important role in industrial processing of decorative and functional coatings. Many metal oxides have been prepared as thin films using different techniques, however obtaining compositionally uniform phases with a control over
grain size and distribution remains an enduring challenge. The difficulties are largely related to complex compositions of functional oxide materials, which makes a control over kinetics of nucleation and growth processes rather difficult to control thus resulting in non-uniform material and
inhomogeneous grain size distribution. Application of tailor-made molecular precursors in low pressure or plasma-enhanced chemical vapor deposition (CVD) techniques offers a viable solution for overcoming thermodynamic impediments involved in thin film growth. In this paper molecule-based
CVD of functional coatings is demonstrated for iron oxide (Fe2O3, Fe3O4), vanadium oxide (V2O5, VO2) and hafnium oxide (HfO2) phases followed by the characterization of their microstructural, compositional
and functional properties which support the advantages of chemical design in simplifying deposition processes and optimizing functional behavior.
Diurnal Variation of Convective Activity and Precipitable Water around Ulaanbaator, Mongolia, and the Impact of Soil Moisture on Convective Activity during Nighttime
Authors: Iwasaki Hiroyuki , Nii Tomoki , Sato Tomonori , Kimura Fujio , Nakagawa Kiyotaka , Kaihotsu Ichirow , Koike Toshio
Published: May 2008

The diurnal variations of convective activity and precipitable water were investigated using a C-band airport radar and GPS receivers around Ulaanbaator (UB), Mongolia; this location was considered as an example of an arid region. The convective activity exhibited a pronounced diurnal cycle; it increased rapidly at 1100 local solar time (LST; 0300 UTC), reached the maximum at 1400 LST, and almost disappeared after 1900 LST. On the other hand, no diurnal variation of precipitable water could be observed, which implied that there was no considerable evapotranspiration, and the diurnal variation of the convective activity was irrelevant to the variation of water vapor. The reason why the deep convection could not develop at night is discussed using numerical modeling from the viewpoint of soil moisture. In the moist soil conditions assumed for humid simulations, an increase in the water vapor in the boundary layer due to evapotranspiration led to a potentially unstable condition that was sustained until night. Deep convection was formed at the southern foot of mountains where topographical convergence was expected. On the other hand, in the dry soil conditions assumed for the arid simulations, deep convection did not occur during nighttime even though topographical convergence was expected over the southern foot of the mountains. These features of dry soil conditions were consistent with the results from radar observations around UB. In other words, since the soil around UB is too dry in practice to sustain an unstable condition until night, the deep convection had to decay by night and could not be initiated at night.
Monotone and Conservative Cascade Remapping between Spherical Grids (CaRS): Regular Latitude–Longitude and Cubed-Sphere Grids
Authors: Lauritzen Peter H. , Nair Ramachandran D.
Published: May 2008

A high-order monotone and conservative cascade remapping algorithm between spherical grids (CaRS) is developed. This algorithm is specifically designed to remap between the cubed-sphere and regular latitude–longitude grids. The remapping approach is based on the conservative cascade method in which a two-dimensional remapping problem is split into two one-dimensional problems. This allows for easy implementation of high-order subgrid-cell reconstructions as well as the application of advanced monotone filters. The accuracy of CaRS is assessed by remapping analytic fields from the regular latitude–longitude grid to the cubed-sphere grid. In terms of standard error measures, CaRS is found to be competitive relative to an existing algorithm when regridding from a fine to a coarse grid and more accurate when regridding from a coarse to a fine grid.
The RESPECT approach to tailored telephone education
Authors: Brouse Corey H. , Basch Charles E. , Wolf Randi L.
Published: May 2008

Objective The objective of the RESPECT approach to tailored telephone education (TTE) is described. This approach was shown to be highly effective through a randomized intervention trial for increasing the rate of colorectal cancer (CRC) screening.

Methods At the conclusion of the trial, the investigators identified the main principles that exemplified the TTE. This was accomplished through a review of chart notes and discussion.

Results The concept underlying our TTE approach was RESPECT for the audience, and was based on: (1) Rapport; (2) Educate, but don't overwhelm; (3) Start with people where they are; (4) Philosophical orientation based on a humanistic approach to education; (5) Engagement; (6) Care and show empathy; and (7) Trust.

Conclusions An advantage of using principles of practice is that it may be more feasible to apply general principles than specific activities because they can be adapted to different social contexts and audiences.
Beauty, Art and Theology
Authors: Donagh Enda Mc
Published: May 2008

In this essay the author develops further his ideas on the relation between the arts and theology and on the role of beauty in Christian faith. Beyond the classical doctrines of Creation and Incarnation as foundational to the dialogue between faith and the arts he seeks to integrate the Trinity into the fuller theological discussion of human artistic work. As part of that dialogue he moves from the human values and criteria widely accepted in art-criticism to re-discover the riches of Trinitarian faith.
The Unity of Individual and Ecclesial Graces in the Roles of the Saints
Authors: Sullivan Patricia A.
Published: May 2008

Adequate theological attention is not paid to the unity of charisms given to individuals for their sanctification and charisms given to individuals for the building up of the Church, Karl Rahner wrote. Ecclesiology grounded in theological anthropology remedies this, bringing the neglected saints into renewed and proper focus and showing that their roles of model, companion, and intercessor are intrinsically related and equally important in the life of the Church. Theological de-emphasis of any of these roles can result in anomalies that do not uphold a truly Catholic understanding of sacramentality as manifested in the communion of saints. The Church's essential charismatic dimension is found preeminently in the saints and in the veneration of them.
‘Money itself discriminates’
Authors: Jeffery Patricia , Jeffery Roger
Published: May 2008

Citizenship rights in India are being transformed under economic liberalisation. In this article, we use obstetric crises to provide an entry point to explore recent changes in people's access to health care and their understandings of their civic rights and entitlements. We draw on our research in rural Bijnor district (Uttar Pradesh) between 1982 and 2005. Over this period, the state has increasingly failed to provide a safety net of emergency obstetric care. Poor villagers seeking institutional deliveries in private facilities face either exclusion or indebtedness. Moreover, ‘consumers’ have no capacity to regulate the quality of private health care provision—but nor do the state or civil society organisations. Villagers critique the state's failure to provide the health care that they regard as a citizen's entitlement. Yet the health care market is accorded no greater legitimacy by its ‘customers’. Far from providing opportunities for empowerment, then, changes in health care provision serve to disempower the poor and to reduce the moral authority of both the state and the market.