bluuebunny/crossref_metadata_2025 huggingface dataset:
A Herpes Simplex Virus Vector System for Expression of Complex Cellular cDNA Libraries
Authors: Wolfe Darren , Craft April M. , Cohen Justus B. , Glorioso Joseph C.
Published: May 2010

Viral vector-based gene expression libraries from normal or diseased tissues offer opportunities to interrogate cellular functions that influence or participate directly in specific biological processes. Here we report the creation and characterization of a herpes simplex virus (HSV)-based expression library consisting of cDNAs derived from PC12 pheochromocytoma cells. A replication-defective HSV vector backbone was engineered to contain both a bacterial artificial chromosome (BAC) and the Invitrogen
in vitro
Gateway recombination system, creating DBAC-GW. A cDNA library was produced and transferred into the DBAC-GW genome by
in vitro
recombination and selection in bacteria to produce DBAC-L. DBAC-L contained at least 15,000 unique cDNAs, as shown by DNA array analysis of PCR-amplified cDNA inserts, representing a wide range of cancer- and neuron-related cellular functions. Transfection of the recombinant DBAC-L DNA into complementing animal cells produced more than 1 million DBAC-L virus particles representing the library genes. By microarray analysis of vector-infected cells, we observed that individual members of this vector population expressed unique PC12 cDNA-derived mRNA, demonstrating the power of this system to transfer and express a variety of gene activities. We discuss the potential utility of this and similarly derived expression libraries for genome-wide approaches to identify cellular functions that participate in complex host-pathogen interactions or processes related to disease and to cell growth and development.
Functional Analysis of the Influenza Virus H5N1 Nucleoprotein Tail Loop Reveals Amino Acids That Are Crucial for Oligomerization and Ribonucleoprotein Activities
Authors: Chan Wai-Hon , Ng Andy Ka-Leung , Robb Nicole C. , Lam Mandy Ka-Han , Chan Paul Kay-Sheung , Au Shannon Wing-Ngor , Wang Jia-Huai , Fodor Ervin , Shaw Pang-Chui
Published: May 2010

Homo-oligomerization of the nucleoprotein (NP) of influenza A virus is crucial for providing a major structural framework for the assembly of viral ribonucleoprotein (RNP) particles. The nucleoprotein is also essential for transcription and replication during the virus life cycle. In the H5N1 NP structure, the tail loop region is important for NP to form oligomers. Here, by an RNP reconstitution assay, we identified eight NP mutants that had different degrees of defects in forming functional RNPs, with the RNP activities of four mutants being totally abolished (E339A, V408S P410S, R416A, and L418S P419S mutants) and the RNP activities of the other four mutants being more than 50% decreased (R267A, I406S, R422A, and E449A mutants). Further characterization by static light scattering showed that the totally defective protein variants existed as monomers
in vitro
, deviating from the trimeric/oligomeric form of wild-type NP. The I406S, R422A, and E449A variants existed as a mixture of unstable oligomers, thus resulting in a reduction of RNP activity. Although the R267A variant existed as a monomer
in vitro
, it resumed an oligomeric form upon the addition of RNA and retained a certain degree of RNP activity. Our data suggest that there are three factors that govern the NP oligomerization event: (i) interaction between the tail loop and the insertion groove, (ii) maintenance of the tail loop conformation, and (iii) stabilization of the NP homo-oligomer. The work presented here provides information for the design of NP inhibitors for combating influenza virus infection.
HIV-2 Genetic Evolution in Patients with Advanced Disease Is Faster than That in Matched HIV-1 Patients
Authors: Skar Helena , Borrego Pedro , Wallstrom Timothy C. , Mild Mattias , Marcelino José Maria , Barroso Helena , Taveira Nuno , Leitner Thomas , Albert Jan
Published: May 2010

The objective of this study was to estimate and compare the evolutionary rates of HIV-2 and HIV-1. Two HIV-2 data sets from patients with advanced disease were compared to matched HIV-1 data sets. The estimated mean evolutionary rate of HIV-2 was significantly higher than the estimated rate of HIV-1, both in the gp125 and in the V3 region of the
env
gene. In addition, the rate of synonymous substitutions in gp125 was significantly higher for HIV-2 than for HIV-1, possibly indicating a shorter generation time or higher mutation rate of HIV-2. Thus, the lower virulence of HIV-2 does not appear to translate into a lower rate of evolution.
A Spread-Deficient Cytomegalovirus for Assessment of First-Target Cells in Vaccination
Authors: Mohr Christian Andreas , Arapovic Jurica , Mühlbach Hermine , Panzer Marc , Weyn Annelies , Dölken Lars , Krmpotic Astrid , Voehringer David , Ruzsics Zsolt , Koszinowski Ulrich , Sacher Torsten
Published: May 2010

Human cytomegalovirus (HCMV) is a human pathogen that causes severe disease primarily in the immunocompromised or immunologically immature individual. To date, no vaccine is available. We describe use of a spread-deficient murine CMV (MCMV) as a novel approach for betaherpesvirus vaccination. To generate a spread-deficient MCMV, the conserved, essential gene
M94
was deleted. Immunization with MCMV-Δ
M94
is apathogenic and protective against wild-type challenge even in highly susceptible IFNαβR
−/−
mice. MCMV-Δ
M94
was able to induce a robust CD4
+
and CD8
+
T-cell response as well as a neutralizing antibody response comparable to that induced by wild-type infection. Endothelial cells were identified as activators of CD8
+
T cells
in vivo
. Thus, the vaccination with a spread-deficient betaherpesvirus is a safe and protective strategy and allows the linkage between cell tropism and immunogenicity. Furthermore, genomes of MCMV-
ΔM94
were present in lungs 12 months after infection, revealing first-target cells as sites of genome maintenance.
Contemporary Japanese view of life and death as depicted in the filmDepartures(Okuribito)
Authors: Asai Atsushi , Fukuyama Miki , Kobayashi Yasunori
Published: May 2010

Through films, we can see many aspects of a country and its times: culture, morality and religion, and views on life and death. The best films can both entertain audiences and provide viewers with opportunities to think about fundamental human problems. In this article, we useDepartures(Okuribito) to examine the contemporary Japanese view of life and death. All sorts of deaths are depicted and each scene provides an insight into the contemporary Japanese view of death. We use the medium of film to consider the issue of death: what death is, the relationship that exists between life and death, and how the impurity and dignity of the dead are recognised by contemporary Japanese people. The ritual of ‘encoffinment’ will also be discussed, and what it suggests and reveals about Japanese views on what happens to a person when they die, and what requirements exist for someone to be able to depart from this world to the afterlife. The view of death depicted inDeparturesis thought to accept and even hope for a worldview that postulates continuity between life and death, wherein not only the soul but also personal individuality continues on as it existed in life. The rite of encoffinment is required to relieve the family's grief as well as to wipe away the impurity of the dead. The Japanese traditional view that the ‘dead are impure’ seems to die hard. It is also suggested that complicated and ambivalent attitudes towards the dead exist among contemporary Japanese people.
A Nonparametric Approach to Generating Inseason Forecasts of Salmon Returns
Authors: Noakes D. J.
Published: May 2010

Variations in the size and timing of salmon runs have frustrated attempts to develop models for updating forecasts of returns inseason. The relationship between run size and inseason predictor variables is often nonlinear and changes over time. The nature of these nonlinearities is generally not known and analysts have elected to approximate observed patterns in the data with ad hoc parametric models. Although conceptually attractive, the performance of these models is frequently degraded by their inflexibility and failure to satisfy key model assumptions. In this paper, nonparametric probability density estimation techniques are employed to calculate the total run size conditional on the observed inseason data. Unlike the parametric techniques, the nonparametric approach allows the data to speak for themselves instead of having to merely conform to some arbitrary mathematical model. The approach is easily adapted to handle information from either terminal or guantlet fisheries and can be generalized to compute conditional expectations of various quantities of interest including run size, run timing, or both. Weekly estimates of the number of sockeye salmon (Oncorhynchus nerka) returning to the Skeena River, British Columbia, are employed to demonstrate the performance of the model.
Characterization of Patches Along Transects Using High-Resolution 70-kHz Integrated Acoustic Data
Authors: Nero R. W. , Magnuson J. J.
Published: May 2010

A patch recognition algorithm was applied to high-resolution (1 m vertical and 25 m horizontal) daytime sonar date collected from a 20-km-length transect to a depth of 200 m. The transect was oriented perpendicular to the Gulf Stream frontal zone, 105 km east–northeast ENE of Cape Hatteras, North Carolina, on August 8 1985. An adaptive high-pass filter was used to identify patches of high-intensity echo strengths. For a broad based averaging "window size" of 13 m deep by 1.4 km long and an echo strength threshold of 1.4 × integrated echo units patches resemble fine-scale features of the original echogram. A discrimination of patches using sonar statistics from within the patches gave good separation of slope water patches from patches belonging to four other water masses Slope water patches were characteristically small and of low mean scattering. Large but infrequent targets were present In the Gulf Stream, by contrast, patches contained more uniformly distributed targets with a higher mean scattering The observed correlation between echo patches, biological structures, and oceanographic features suggests that the measurement of echo statistics and our patch recognition techniques produce biologically meaningful parameters.
Plasma Cortisol Changes in Seawater-Adapted Mummichogs (Fundulus heteroclitus) Exposed to Ammonia
Authors: Spotte Stephen , Anderson Gary
Published: May 2010

Seawater-adapted mummichogs (Fundulus heteroclitus) were exposed to total NH4-N concentrations of 1, 2, 5, 10, 25, 50, 100, 150, and 200 mg/L for periods of 2, 4, 8, 12, 18, 24, 36, and 48 h. Afterward, the fish were captured quickly and anesthetized with MS-222 before blood was collected. The concentration of total NH4-N and duration of exposure accounted for, respectively, ~35 and <4% of the observed increase in plasma cortisol. The effective concentration (the concentration of total NH4-N inducing a mean cortisol response two standard deviations above the mean of the controls) was 47.14 mg/L, corresponding with a mean cortisol level of 13.44 μg/dL. Test concentrations of NH3-N were calculated from total NH4-N, pH, salinity, and temperature (constant at 20 °C), and the effects of both forms of ammonia on plasma cortisol concentration were compared. Significance was not detected at p < 0.05, demonstrating that total NH4-N and NH3-N explained the observed changes in cortisol levels similarly. Mean cortisol concentrations of mummichogs anesthetized and sampled in the field were comparable with published values and did not differ significantly from the mean value of captive control fish sampled after the same length of time in MS-222 (p < 0.05).
Comparison of Allozyme and Mitochondrial DNA Variation in Populations of Walleye,Stizostedion vitreum
Authors: Ward Robert D. , Billington Neil , Hebert Paul D. N.
Published: May 2010

Twelve populations of walleye (Stizostedion vitreum) from the Great Lakes and three populations from northern Manitoba were screened for allozyme and mitochondrial DNA (mtDNA) variation. Nine enzyme loci known to show genetic variation were screened in all fish: five of them (Prot-4, Prot-2, Mdh-3, Idh-1, Adh) showed appreciable polymorphism. MtDNA was examined in all fish using six endonucleases that detected polymorphic sites and a further 13 endonucleases that detected only monomorphic sites. Only one of the allozyme loci (Prot-4) showed evidence of geographic patterning of allele frequencies. By contrast, the mtDNA haplotypes showed clear geographic variation. The proportion of total genetic diversity attributable to population differentiation (Gst) was three to five times greater for mtDNA than for the allozymes. Gst values for organelle genes are expected on theoretical grounds to be greater than for nuclear genes, and this expected difference may be enhanced in walleye because of the likelihood that, in this species, male-mediated gene flow exceeds that of females. The distributions of mtDNA haplotypes and estimated divergence times are consistent with the derivation of extant walleye populations from three different glacial refugia.
Spawning Dynamics of Golf of St. Lawrence Herring (Clupea harengus)
Authors: Lambert Timothy C. , Messieh Shoukry N.
Published: May 2010

Mean day of arrival of spawning herring (Clupea harengus) in the Gulf of St. Lawrence was calculated for different length groups by region and season. During the spawning season of both spring and autumn groups, herring arrived and deposited eggs on spawning grounds in decreasing order of age and length. Spawning bed surveys at two locations confirmed batch depositions of eggs which were correlated with the presence of dominant age-classes within the spawning population. Due to limitations of the port sampling procedure for collection of biological information routinely used in herring stock assessment, some length groups were underrepresented. This could result in the underestimation of the abundance of recruiting year-classes.
Comparative Vulnerability of Three Esocids to Largemouth Bass (Micropterus salmoides) predation
Authors: Wahl David H. , Stein Roy A.
Published: May 2010

We compared vulnerability among tiger muskellunge (Esox masquinongy × E. lucius) (TM), northern pike (E. lucius) (NP), and muskellunge (E. masquinongy) (M) to predation by largemouth bass (Micropterus salmoides). Equal numbers (about 25/ha) and sizes (either 145, 180, or 205 mm) of each esocid taxa were stocked into three reservoirs (40–89 ha) during 3 yr (five stockings total). Tiger muskellunge were significantly more susceptible to predation ([Formula: see text], range 1–53% mortality) than muskellunge ([Formula: see text], range 2–26%); northern pike were intermediate in susceptibility ([Formula: see text], range 2–35%). Esocid size influenced predation rates for all taxa; losses to predation by largemouth bass decreased from an average of 31% at 145 mm to 2% at 205 mm. Pond experiments (N = 7) provided results similar to reservoirs: TM>NP>M. In laboratory pools with simulated vegetation (N = 106 experiments), susceptibility to predation among esocids did not differ. Dispersal rates by esocids were similar in reservoirs and all taxa preferred vegetated habitats. However, differential habitat selection may partially explain why tiger muskellunge are more vulnerable to largemouth bass predation, as they spent more time in open than vegetated habitats in both pond and pool experiments than either of the parent species. For all taxa, stocking lengths [Formula: see text] in fall will increase survival by reducing predatory losses.
Freezing Resistance in Some Northern Populations of Pacific Herring, Clupea harengus pallasi
Authors: Raymond James A.
Published: May 2010

Pacific herring, Clupea harengus pallasi, were collected at three locations in Alaska and Japan in winter and spring to determine their degree of freezing resistance. Herring collected from waters whose temperatures ranged between 4.7 and −1.4 °C showed serum freezing points between −1.22 and −1.40°C. All freezing points were below those expected from measurements of serum osmolality, indicating that a noncolligative antifreeze was present that added between 0.28 and 0.61° to the freezing point depression. In addition, osmotically active substances other than sodium chloride contributed to the freezing point depression. in some of the samples.
Utility of Similarity Dendrograms in Stock Composition Analysis
Authors: Wood Chris C.
Published: May 2010

Similarity dendrograms are useful for revealing clustering patterns among reference stocks used in stock composition analysis. Simulations with simple mixtures of known composition indicate that clustering patterns based on genetic differences among reference stocks have a greater influence on the reliability of maximum likelihood estimates of mixture composition than either the number of reference stocks in the analysis or the size of the mixture samples. Estimated proportions for reference stocks that form tight ("problem") clusters in a similarity dendrogram tend to be biased and this bias increases as the overall proportion contributed by the problem-cluster stocks increases. Accuracy and precision can be improved dramatically by summing estimated proportions within problem clusters to estimate their overall contribution to the mixture. Adding reference stocks not present in the mixture has little effect on the reliability of stock composition estimates unless the additional stock forms a problem cluster in the similarity dendrogram. Four different measures of the degree of difference between reference stocks were evaluated for their ability to predict clustering sequences for improving estimates of mixture contributions by problem-cluster stocks.
Size Structure of a Lake Trout (Salvelinus namaycush) Population an Arctic Lake: Influence of Angling and Implications for Fish Community Structure
Authors: McDonald Michael E. , Hershey Anne E.
Published: May 2010

The lake trout (Salvelinus namaycush) population in Toolik Lake in arctic Alaska was assessed by gill net during 1977, prior to exploitation. In 1986 we replicated the gill net study to determine the effects of recent angling pressure on the fish community. Relative composition of the catch varied between samples. Round whitefish (Prosopium cylindraceum), which are not susceptible to angling, made up 42% of the catch in 1986 and 28% in 1977. Significant reductions in the median length and weight of lake trout between the sampling periods were observed. The median size of lake trout in 1986 was below the minimum 1977 reproductive size. Differences in median length and weight of grayling (Thymallus arcticus) and of round whitefish during this period were not significantly different. The condition factor of lake trout was significantly higher in 1986. We suggest that large lake trout in Toolik Lake control salmonid recruitment and determine community structure. With continued fishing pressure further changes in the fish community and lake trophic dynamics may result.
Primary Production in a Tidally Energetic Fjord: Evidence of Seasonal and Inter-annual Tidal Forcing
Authors: Kessler T. A. , Parsons T. R.
Published: May 2010

A long term data set collected from a tidally energetic sill fjord was analyzed for its statistical relationships between primary production indices and several represented environmental variables. The analysis identified variance and covariance structure in these variables implicating changes in water column clarity, in inter-annual variability of phytoplankton carbon uptake rate, and the static stability of basin surface water in phytoplankton standing stock. The biomass–stability relationship was found to be seasonally dependent, with biomass positively correlated with stability in the summer and negatively correlated in the spring/fall, and restricted to waters under the direct mixing influence of the tidal inflow jet. These statistical patterns are discussed in terms of a possible control of primary production by seasonal and inter-annual variations in tidal inflow buoyancy.
Effect of Sea-Age on the Reproductive Potential of Atlantic Salmon (Salmo salar) in Eastern Canada
Authors: Randall R. G.
Published: May 2010

Reproductive potential of Atlantic salmon (Salmo salar), defined as average eggs per fish in the spawning run, varied three-fold both within stocks over time and among stocks from different geographic areas. Eggs per spawner is a function of fecundity, sea-age, proportion of females, and female size; the latter three traits varied significantly among years for salmon in both the Miramichi and Restigouche Rivers, New Brunswick. Because all of the above traits are related to sea-age at maturity, eggs per spawner was significantly correlated with mean sea-age in both rivers (R2 = 0.88 and 0.61, respectively). Among 10 different populations in eastern Canada, reproductive potential was also correlated with sea-age; for mean sea-ages (MSA) ranging from 1.0 to 1.8 yr, reproductive potential (RP) was defined by the power regression: RP = 1831.26 MSA1.30 (R2 = 0.64 P < 0.05). Thus reproductive potential can be estimated for any population for which the sea-age composition of spawners is known. Assuming a target egg deposition rate of 2.4 × 104 eggs per hectare, required spawners varied inversely with reproductive potential among the 10 populations, from five spawners (MSA = 1.75 yr) to 16 spawners (MSA = 1.15 yr) per hectare.
A New Cetacean from the Late Eocene La Meseta Formation Seymour Island, Antarctic Peninsula
Authors: Mitchell Edward D.
Published: May 2010

The new genus and species Llanocetus denticrenatus is described based on a cranial endocast and portion of a dentary fragment bearing two teeth from the Eocene La Meseta Formation, Seymour Island, Antarctic Penninsula. Llanocetus new genus is designated the type genus for the new family Llanocetidae. The Llanocetidae is placed within the new infraorder Crenaticeti, co-ordinate with the new Mysticete infraorder Chaeomysticeti. Llanocetus denticrenatus new species shows relationship with both Archaeoceti and Mysticeti. Revision of archaeocete and mysticete classification includes proposal of the new taxa Kekenodontinae, Mammalodontidae, and the new ranks Protocetoidea, Remingtonocetoidea, Basilosauroidea, and Eschrichtioidea. The endocast shows evidence of intracranial retial hypertrophy, taken as evidence of enhanced diving abilities. The large deeply notched teeth are widely spaced on the lower jaw. I hypothesize that filter feeding in whales arose first in species in which teeth with deep notches, forming widey spaced tubercles, comprised part of a straining apparatus analogous to the serrated teeth of the phocid seal Lobodon carcinophagus.
SOME BIANCHI TYPE-II COSMOLOGICAL MODELS IN LYRA GEOMETRY
Authors: SINGH J. K. , SHARMA N. K.
Published: May 2010

In this work, we have studied the Bianchi type-II anisotropic cosmological models in the theory based on Lyra's geometry in normal gauge in the presence and absence of the magnetic field. The physical and kinematical behaviors of the models have also been discussed.
EMISSIVITY OF NEUTRINOS IN SUPERNOVA IN A LEFT–RIGHT SYMMETRIC MODEL
Authors: GUTIÉRREZ-RODRÍGUEZ A. , TORRES-LOMAS E. , GONZÁLEZ-SÁNCHEZ A.
Published: May 2010

We calculate the emissivity due to neutrino-pair production in e+e- annihilation in the context of a left–right symmetric model in a way that can be used in supernova calculations. We also present some simple estimates which show that such process can act as an efficient energy-loss mechanism in the shocked supernova core. We find that the emissivity is dependent on the mixing angle ϕ of the model in the allowed range for this parameter.
CASIMIR ENERGY CALCULATIONS WITHIN THE FORMALISM OF NONCOMPACT LATTICE QED
Authors: PAVLOVSKY OLEG , ULYBYSHEV MAXIM
Published: May 2010

A new method based on the Monte Carlo calculation on the lattice is proposed for studying the Casimir effect in noncompact lattice QED. As a test of our method, we have studied the standard Casimir problem for the two parallel plane surfaces (mirrors) with the oblique boundary conditions. Physically, these boundary conditions may appear in the problem of modeling the thin material film interactions, and can be generated by the additional Chern–Simons boundary term. This method of boundary condition generation is very suitable — due to its gauge invariance — for the lattice formulation of the Casimir problem.
EXACT NONSPHERICAL RELATIVISTIC STAR
Authors: GHOSH SUSHANT G. , DESHKAR D. W.
Published: May 2010

Einstein's equation with a negative cosmological constant admit solutions which are asymptotically anti-de Sitter. We obtain Vaidya-like solutions to include both a null fluid and a string fluid in nonspherical (plane symmetric and cylindrical symmetric) anti-de Sitter space–times. Assuming that string fluid diffuse, we find analytical solutions to Einstein's field equations. Thus we extend the approach proposed by Glass and Krisch to nonspherical space–times with a negative cosmological constant. Some other exacts solutions are also presented and discussed.
ON THE TWO-LOOP DECOUPLING CORRECTIONS TO τ-LEPTON AND b-QUARK RUNNING MASSES IN THE MSSM
Authors: BEDNYAKOV A. V.
Published: May 2010

Masses of heavy Standard Model (SM) fermions (top-quark, bottom-quark and tau-lepton) play an important role in the analysis of theories beyond the SM. They serve as low-energy input and reduce the parameter space of such theories. In this paper Minimal supersymmetric extension of the SM is considered and two-loop relations between known SM values of fermion masses and running parameters of the MSSM are studied within the effective theory approach. Both b-quark and τ-lepton have the same quantum numbers with respect to SU(2) group and in the MSSM acquire their masses due to interactions with the same Higgs doublet. As a consequence, for large values of tan β parameter corresponding Yukawa couplings also become large and together with tan β can significantly enhance radiative corrections. In the case of b-quark two-loop [Formula: see text] contribution to the relation between running bottom-quark mass in QCD and MSSM is known in literature. This paper is devoted to calculation of the NNLO corrections proportional to Yukawa couplings. For the τ-lepton obtained contribution can be considered as a good approximation to the full two-loop result. For the b-quark numerical analysis given in the paper shows that only the sum of strong and Yukawa corrections can play such a role.
PROSPECTS FOR NEW PHYSICS AT THE LHC
Authors: ELLIS JOHN
Published: May 2010

High-energy collisions at the LHC are now starting. The new physics agenda of the LHC is reviewed, with emphasis on the hunt for the Higgs boson (or whatever replaces it) and supersymmetry. In particular, the prospects for discovering new physics in the 2010-2011 run are discussed.
STAKEHOLDER TREATMENT AMONGST IPOs AND THE ACQUISITION OF RESOURCES FOR ENTREPRENEURIAL VENTURES
Authors: COOMBS JOSEPH E. , HARRISON JEFFREY S.
Published: May 2010

Entrepreneurs bring together the various stakeholders necessary to create new products and services; however, stakeholders face a high level of uncertainty when determining whether to invest their resources in the venture. This paper draws from signaling theory and stakeholder theory to explain how firms that have reputations for outstanding treatment of stakeholders send a signal to potential resource investors that reduces the uncertainty they perceive to be associated with the venture. Perceived uncertainty is reduced because of an enhanced ability to acquire necessary resources, a smaller probability that unexpected events will occur, an increased ability to plan for changes that do occur in the external environment, and the possibility that the strong stakeholder network itself may be a source of sustainable competitive advantage for the firm. While these ideas are applicable to entrepreneurial ventures at many stages, the context examined herein is firms that are preparing for an initial public offering because they have had sufficient time to establish reputations.
QUANTIFICATION OF NEUROTROPHINS IN SKELETAL MUSCLE FOLLOWING NERVE INJURY: COMPARISON BETWEEN SPINAL CORD INJURY AND PERIPHERAL NERVE INJURY
Authors: Morisawa Yasushi , Takayama Shinichiro , Nakamura Masaya , Nakamura Toshiyasu , Ikegami Hiroyasu , Toyama Yoshiaki
Published: May 2010

Purpose: We investigated the kinematics of nerve growth factor (NGF)mRNA and brain-derived neurotrophic factor (BDNF)mRNA in a skeletal muscle following spinal cord and peripheral nerve injuries by utilizing the reverse-transcription polymerase chain reaction/high-performance liquid chromatography (RT-PCR/HPLC) method. Methods: We made mice models of spinal cord transection and sciatic nerve transection, plus sham and control groups. After RNA extraction from gastrocnemius muscle of mice, RT-PCR was done. We measured the levels of NGFmRNA and BDNFmRNA in a skeletal muscle following spinal cord and peripheral nerve injuries by utilizing the RT-PCR/HPLC method. All values are analyzed and graphed as means ±SED. Bonferroni test (Post-hoc test) was used when two values were compared. Differences were considered statistically significant when p < 0.05. Results: According to the wet muscle weight, at day 7, a significant difference was found between the peripheral lesion and control group, and at days 14 and 28, significant differences were found between the spinal and peripheral lesion and control group. According to the NGFmRNA, in the peripheral nerve injury group, the levels increased up to day 28 and when compared with the control group, the levels were significantly higher at days 14 and 28. According to the BDNFmRNA, levels at days 2, 7, 14, and 28 were significantly lower in the spinal cord injury group than in the control group. However, in peripheral nerve injury group, when compared with the control group, the levels significantly increased at days 7, 14, and 28. Conclusion: We clarified marked differences in chronological changes in neurotrophin kinetics in a skeletal muscle between spinal cord injury and peripheral nerve injury.
SHORT-TERM RESULTS OF THE OXFORD UNICOMPARTMENTAL KNEE REPLACEMENT IN PATIENTS LESS THAN SIXTY-FIVE YEARS OF AGE
Authors: Fenichel Itay , Heler Snir , Salai Moshe , Velkes Stieven
Published: May 2010

Our short-term results obtained with the Oxford unicompartmental knee prosthesis for unicompartmental knee arthrosis or AVN (avascular necrosis) in patients younger than 65 years of age are presented. Twenty patients (16 females and 4 males) with 20 prostheses were evaluated. The average age at surgery was 59 years (range 45 to 65 years). The etiology for surgery was osteoarthritis in 18 cases and AVN in two of them. Nineteen prostheses were uni-medial and one uni-lateral. After an average of 38 months, the mean Knee Society Score was excellent with 81.7 (range 29 to 100) points, the mean total WOMAC score was 26 (range 0 to 78), the mean reduced- WOMAC score 7.9 (range 0 to 24), the mean SF12 physical 36.8 (range 19.8 to 56.7), and the mean SF12 mental 47.5 (range 19 to 64). We did not find any significant correlation between the final outcome and the alignment of each component on X-ray. The only statistically significant correlation we could demonstrate was between the alignment of the knee on AP-View and the functional outcome. Three prostheses out of the twenty had to be revised, two of them due to early aseptic loosening of the tibial component and another one because of unexplained pain. Despite the relative high rate of early revisions (15%) in this group, our finding confirm the good results reported in different other studies regarding the success rate of unicompartmental knee replacement in patients under the age of 65 years.
FUZZY LINEAR PROGRAMMING FOR SUPPLY CHAIN PLANNING UNDER UNCERTAINTY
Authors: PEIDRO DAVID , MULA JOSEFA , POLER RAÚL
Published: May 2010

A new fuzzy mathematical programming model for supply chain planning under supply, process and demand uncertainty is proposed in this paper. A tactical supply chain planning problem has been formulated as a fuzzy mixed integer linear programming model where data are ill-known and modeled by fuzzy numbers with modified s-curve membership functions. The fuzzy model provides alternative decision plans to the decision maker (DM) for different degrees of satisfaction. Finally, the proposed model is tested by using data from a real automobile supply chain.
FUZZY MULTICRITERIA ASSIGNMENT FOR NOMINAL CLASSIFICATION: METHODOLOGY AND APPLICATION IN EVALUATION OF GREEK BANK'S ELECTRONIC PAYMENT RETAILERS
Authors: RIGOPOULOS GEORGE , ANAGNOSTOPOULOS KOSTAS
Published: May 2010

This paper presents a novel multicriteria procedure for nominal classification problems. Assignment of an action to a category is based on the comparison between action and category's least typical representative, which is considered as the category inclusion threshold. Evaluation is executed considering performance on evaluation criteria and calculation of a fuzzy inclusion relation for every action, generalizing preference relations model with concordance and nondiscordance concepts as used in ELECTRE methods. An application to a classification problem in banking is also presented in order to demonstrate its applicability to similar problems.
PRIVACY-PRESERVING SVD-BASED COLLABORATIVE FILTERING ON PARTITIONED DATA
Authors: YAKUT IBRAHIM , POLAT HUSEYIN
Published: May 2010

Collaborative filtering (CF) systems are widely employed by many e-commerce sites for providing recommendations to their customers. To recruit new customers, retain the current ones, and gain competitive edge over competing companies, online vendors need to offer accurate predictions efficiently. Therefore, providing precise recommendations efficiently to many users in real time is imperative. Singular value decomposition (SVD) is applied to CF to achieve such goal. SVD-based CF systems offer reliable and accurate predictions when they own large enough data. Data collected for CF purposes, however, might be split between different companies, even competing ones. Some vendors, especially newly established ones, might have problems with available data. To increase mutual advantages, provide richer CF services, and overcome problems caused by inadequate data, companies want to integrate their data. However, due to privacy, legal, and financial reasons, they do not want to combine their data. In this article, we investigate how to provide SVD-based referrals on partitioned (horizontally or vertically) data without greatly jeopardizing data holders' privacy. We conduct real data-based experiments to assess our schemes' overall performance and analyze them in terms of privacy and supplementary costs. Our results show that it is possible to provide accurate SVD-based referrals on integrated data while preserving e-companies' privacy.
The Use of Exergetic Efficiency Rate of Change to Evaluate Fuel Cell Performance
Authors: Williams Mark
Published: May 2010

Fuel cells are electrochemical devices that convert the chemical energy of a chemical reaction directly into electrical energy and heat. The fuel cell is the most efficient means to convert chemical energy to electrical energy. There will always be chemical energy from solar on this planet either from stored energy of coal and petroleum or real time from biomass residues and human wastes. Fuel cells make the energy conversions systems that generate electricity for stationary or transportation applications from primary energy like coal and biomass or energy carriers like hydrogen, respectively, much more efficient.
CFD Performance Study of Planar SOFC using Mixed Hydrogen and Carbon Monoxide as Fuel using STAR-CD
Authors: Ippolito James , Recknagle Kurt
Published: May 2010

Presented is an interesting and substantive paper in the development of effective CFD models. The paper presents a fully three-dimensional, computational fluid dynamics (CFD) study, using STAR-CD, performed for a planar, single-cell, cross-flow type, solid oxide fuel cell. The objective of the study was to investigate the influence of the mixing ratio of hydrogen and carbon monoxide in the fuel on the cell performance of the SOFC over a range of inlet temperatures. The electromotive force of the hydrogen rich fuel gas becomes higher than that of the carbon monoxide rich fuel gas at temperatures well within typical SOFC operating limits and its difference enlarges as the temperature increases. At lower temperatures, the electromotive force of the carbon monoxide rich fuel is higher. In addition, the internal voltage drop in the cell decreases as the fraction of carbon monoxide becomes high [1]. The authors of this paper illustrate this through a number of steady, CFD simulations.
An Equivalent Circuit Model for Gas Diffusion Layers of PEMFC
Authors: Kaewmanee Wattana , Nguyen Dinh An , Hinaje Melika , Thounthong Phatiphat , Davat Bernard
Published: May 2010

This paper presents a new approach to create a circuit model for static operations of the gas diffusion layer of the PEM fuel cell. The model is based on the Stefan-Maxwell equation. The concept of the energy port, which consists of effort and flow variables at the ports, has been used in this work. The model concept is applied on both anode and cathode sides which has 2 and 3 species, respectively. The resulted model consists of the voltage sources and nonlinear resistors which the value are depended on the molar fractions and the mass fluxes. Finally, the model is connected to the equation models of the other parts of the fuel cell and show a good result of V-I characteristics.
Multi-Objective Function Optimization for PEM Fuel Cell System
Authors: Mukhtar Bello , Zaidi Javaid S. , Faqir Naim M.
Published: May 2010

There are numerous design and operating variables that affect the overall performance of a PEM fuel cell system. Many optimization techniques for the PEM fuel cell system have been reported in the literature. However, most of the reported works considered either efficiency or cost as the objective function. But it is known that fuel cell efficiency and cost affect one another. Thus, it has become imperative to consider both efficiency and cost in order to achieve optimal PEM fuel cell system design. In this, paper, a multi-objective problem to optimize the efficiency and cost of a PEM fuel cell system is formulated. The operating variables considered are; stack temperature, current density, system pressure, hydrogen and air flow rates. An optimum operating condition that will produce 5.76 kW at a cost of 521.9298 US$/kW and an efficiency of 52.2 % was obtained.
Experimental Validation on Condensate Removal Capability of PEMFC Stacks
Authors: Scholta Joachim , Häußler Frank , Müller Henriette , Jörissen Ludwig
Published: May 2010

Low temperature PEFC offer a great potential for a broad range of applications. Nonetheless, some developmental issues have remained open so far. One of them is the combination of low pressure drop on one hand and good condensate removal capability on the other hand. In addition to the investigations on condensate removal capability of single straight flow channels [1], in this investigation, data on channels covered with a GDL are reported. The findings are based on in situ tests, which deliver an indirect information on the presence of flooded channels. Serpentine flow fields with high parallelization degree and a cell active area of 100 cm² were used. Specific pressure drop necessary for condensate removal turned out to be comparable, but somewhat lower than expected from ex situ tests. Effects on cell positioning with respect to GDL top/down position show effects dependent on the wetting stage of the GDL.
Numerical Modeling of Two-Phase Behavior in the PEFC Gas Diffusion Layer
Authors: Mukherjee Partha P. , Kang Qinjun , Mukundan Rangachary , Borup Rodney L.
Published: May 2010

A critical performance limitation in the polymer electrolyte fuel cell (PEFC) is attributed to the mass transport loss originating from suboptimal liquid water transport and flooding phenomena. Liquid water can block the porous pathways in the fibrous gas diffusion layer (GDL) and the catalyst layer (CL), thus hindering oxygen transport from the flow field to the electrochemically actives sites in the catalyst layer. The cathode GDL is the component primarily responsible for facilitating gas and liquid transport, therefore plays a major role in determining the water management of a PEFC and hence the mass transport loss. The underlying pore morphology and wetting characteristics have significant influence on the flooding dynamics in the GDL. In this paper, the study of the two-phase behavior and the durability implications due to the wetting characteristics in the carbon paper GDL are presented using a pore-scale modeling framework.
Preparation and Evaluation of a Large Superficial Self-Humidifying Pt-PFSA Composite Membrane for H2/Air PEMFC
Authors: Lü WeiZhong , Liu Zhxiang , Wang Cheng , Zhang Milin , Mao Zongqiang
Published: May 2010

A large superficial (60×60cm) and high performance self-humidifying Pt-PFSA membrane for H2/Air polymer electrolyte membrane (PEM) fuel cells has been developed. The homemade Pt-PSFA composite membrane is prepared with solution-cast method by dispersing Pt black particles into the perfluorosulfonic acid (PFSA) copolymer resin uniformly. Electrochemical performances of the self-humidifying Pt-PFSA membrane and PFSA membrane compared in 150cm2 single cells with 0.6mg/cm2 platinum loading. The results indicated that Pt distribution in the Pt-PFSA composite membrane and the peak power density of the single cell reached over 37.8W at 60°, 0.05MPa with dry hydrogen and dry Air.
Effects of Platinum Loading on PEFC Power Generation Performance Deterioration by Carbon Monoxide in Hydrogen Fuel
Authors: Hashimasa Yoshiyuki , Matsuda Yoshiyuki , Akai Motoaki
Published: May 2010

Hydrogen for fuel cell vehicles is likely to contain impurities from its production process, and such impurities may poison the fuel cell catalyst, which in turn will deteriorate the power generation performance of the fuel cell especially when the Pt loading is reduced. Effects of anode Pt loading and CO as an impurity on power generation performance were investigated. The test results indicated that the smaller the Pt loading in the anode was, the more rapidly cell voltage declined under the influence of CO contained in the hydrogen. The amount of voltage decrease accelerated as the Pt loading was reduced. With regard to CO and CO2 concentrations in exhaust gas, it was found that when the cell voltage fell and stabilized following the supply of a CO-added hydrogen, a reduction of Pt loading resulted in the lowering of CO concentration and the heightening of CO2 concentration.
Influence of Channel Dimensions on Behavior of a Polymer Electrolyte Membrane Fuel Cell
Authors: Naddaf Maroun , Abboudi Said
Published: May 2010

In this study, we present a fuel cell model that takes into account of the heat and mass transfers in the Membrane Electrolyte Assembly (MEA). The studied model is based on a transient model by combining independent descriptions of heat and mass transfers in the cell with a third description of coupled charge and mass transfers in the electrodes. We used this model with different dimension of the bipolar plate channel to study the effect of the channel dimension on internal heat generation of a polymer electrolyte membrane fuel cell width. Optimum values for each of the dimensions (channel width, land width and channel depth) were obtained. Consequently, their use would lead to improved fuel cell efficiency.
Transport Properties of Hydrogen-Water Vapor Mixture in Fuel Cell Systems
Authors: Huang Peter
Published: May 2010

Knowledge of the transport property of viscosity and thermal conductivity of a hydrogen-water vapor mixture is very important in solving today's engineering problems in fuel cell applications. The properties may be conveniently represented as a function of the quantity of moisture by weight in grams of water per kilogram of dry hydrogen. Values of viscosity and thermal conductivity are calculated for constant pressures of 0.1 MPa, 0.5 MPa and 1 MPa, respectively, on the basis of the equations of state of real gases in the temperature range from 340 K to 500 K and in the range of water vapor concentrations from 10 g H2O/kg dry hydrogen to 105 g H2O/kg dry hydrogen. Useful information obtained indicates that accurate humidity measurements and control are required for the thermal conductivity decreases significantly at a temperature above 120 {degree sign}C and a pressure above 0.1 MPa as water vapor concentration increases.
Stainless Steel Bipolar Plates for PEM Fuel Cell
Authors: Orozco German , Correa Fernando , Arredondo Gerardo
Published: May 2010

The corrosion resistance of several metallic materials was evaluated in the chemical environment encountered in PEM fuel cells. The value of PREN (Pitting Resistance Equivalent Number) was calculated for metallic materials and compared whit the corrosion current. PREN is not useful in bipolar plates research. Merely SS 316 and Inconel 625 are suitable for use as a flow-field plate on the cathodic side of a PEM fuel cell. Inconel 625 has a higher CR, because of its Mo content. The corrosion resistance of AISI 444 is acceptable as material for bipolar plate materials. The corrosion resistance of SS 7222 is higher and cannot been considered as material for bipolar plate materials.
Liquid Holdup in the Bipolar Plate Channels of a PEM Fuel Cell
Authors: Herescu Alexandru , Allen Jeffrey S.
Published: May 2010

Numerical simulations using Surface Evolver are employed to determine the minimum liquid volume (critical volume) necessary to form a plug in a square channel of mixed wettability. The critical volume has direct implications on the water distribution in the flow fields of a PEM fuel cell, as well as on the pumping parasitic power loss. The liquid plug is placed in a channel bend having a contact angle on the GDL wall fixed to 110 and 150 deg. For each considered GDL, the critical volume is determined for different contact angles on the bipolar plate walls, ranging from 50 to 130 deg. The numerical data allows one to determine the liquid holdup in a channel bend of mixed wettability. These correlations can be used as an optimization tool for water management in channels of non-uniform wettability, accounting for the contact angle of the GDL and of the bipolar plate sides, as well as the in-plane geometry (bend dihedral).
Investigation of Local Degradation Effects
Authors: Schulze Mathias , Haug Andrea , Gülzow Erich , Friedrich Andreas
Published: May 2010

Degradation processes in PEFC lead to insufficient life-time which is one of the crucial problems hindering mass market penetration of fuel cells. The degradation rate depends strongly on the operating conditions of fuel cells. Additionally, the operating conditions can vary significantly along the flow path. Therefore, at DLR the degradation processes are investigated with locally resolved in situ methods which are combined with locally resolved ex situ characterizations. The combination of the in situ and ex situ methods allows to quantify and to identify the degradation processes. The new and operated electrode assemblies and their components are investigated with that locally resolved in situ and ex situ methods. This study is focussed on the local degradation effects in the gas diffusion layer as well as in the electrodes.
CO Poisoning of Pt Electrode in PEM-PBI Based Membrane
Authors: Ubong Etim U. , Phillips Diana , Gieseke Matt
Published: May 2010

An experimental evaluation of a PBI membrane was conducted with a 2 and 5 % CO concentration to evaluate its impact on the cell performance. The test conditions consisted of variable temperature and fuel composition at atmospheric pressure. Baseline, pure-hydrogen, tests were conducted prior to CO exposure at each set of temperature studied. Post exposure of the CO-poisoned catalyst to pure hydrogen resulted in a restoration of the catalyst activity and further investigation on this is currently the subject of our ongoing studies. The mechanism resulting in the recovery of the CO-poisoned catalyst activity will be briefly discussed based on the test results.