bluuebunny/crossref_metadata_2025 huggingface dataset:
Streptococcus anginosusgroup and osteomyelitis: a single centre clinical experience
Authors: Griffin Allen Thomas , Timbrook Tristan , Harting Julie , Christensen Diana
Published: March 2013

Purpose

The Streptococcus anginosus group comprises three species of bacteria classified within the viridans streptococci. This group is known for abscess formation and endocarditis. While a variety of sites in the body claim anginosus streptococci as an agent of infection, osteomyelitis is unusual. The objective of this study was to describe a series of patients with osteomyelitis due to S anginosus group pathogens in terms of demographics, comorbidities, presentation and outcomes.

Study design

We reviewed our database for cases of osteomyelitis caused by S anginosus organisms. Data described included demographics, comorbidities, site of infection, route of infection (haematogenous versus contiguous), laboratory data and course.

Results

11 patients with S anginosus group osteomyelitis were identified. All cases arose from a contiguous anatomical site, with the exception of one haematogenous case. Five instances were related to foot osteomyelitis while three, two and one case, respectively, were related to mandibular, cranial and vertebral osteomyelitis. Seventy-five per cent of patients had associated abscesses. The mean length of antibiotic treatment was 10.9 weeks. One patient failed therapy while four others relapsed.

Conclusions

Osteomyelitis due to the S anginosus group is uncommonly reported. Our case series illustrates the virulence of these organisms in the context of osteomyelitis and the importance of aggressive management.
The effect of walking on cardiorespiratory fitness in adults with knee osteoarthritis
Authors: Larose Joanie , King Judy , Brosseau Lucie , Wells George A. , Reid Robert , Maetzel Andreas , Tugwell Peter , Huijbregts Maria , McCullough Carolyn , Loew Laurianne , Kenny Glen P.
Published: March 2013

Walking programs alone or in combination with behavioral interventions have proven effective at improving quality of life among older adults with osteoarthritis (OA). It is unclear, however, whether the combination of both of these treatments is more effective at improving cardiorespiratory fitness in older adults with knee OA than a walking program alone or than unsupervised self-directed walking. In this study, we assessed cardiorespiratory fitness with 3 programs: a structured supervised community-based aerobic walking program with a behavioral intervention (WB; n = 41); a supervised program of walking only (W; n = 42); and an unsupervised self-directed walking program (n = 32). We measured maximal oxygen uptake (V̇O2peak), exercise test duration, and workload, heart rate, and ventilation at maximum aerobic capacity in older adults with knee OA after 6 months of WB, W, or self-directed walking. Overall, V̇O2peak improved by 4% in female walkers (+0.9 ± 2.5 mL O2·kg−1·min−1; p < 0.001) and 5% in male walkers (+1.3 ± 2.7 mL O2·kg−1·min−1; p < 0.001), and the change in fitness was similar with all 3 walking interventions. In conclusion, low- to moderate-intensity walking may improve and (or) prevent decrements in cardiorespiratory fitness in older adults with OA. This response was comparable in supervised walkers with and without a behavioral intervention and in unsupervised self-directed walkers.
Air–water flow measurements in a flat slope pooled stepped waterway
Authors: Felder S. , Chanson H.
Published: March 2013

Air–water flows on stepped spillways were investigated experimentally in the last decades with a focus on steep slope chutes equipped with flat horizontal steps. Detailed air–water flow properties were recorded herein with three stepped geometries down a slope of θ = 8.9° with: flat horizontal steps, pooled steps, and a combination of flat and pooled steps. The data included the distributions of basic air–water flow properties, as well as the energy dissipation and flow resistance data deduced from the air–water flow measurements. The results on the flat slope showed that the pooled stepped design enabled a greater rate of energy dissipation, but the pooled stepped geometries were affected by some flow instabilities and unsteady flow processes for a range of flow rates.
HHT ANALYSIS OF THE GLOBAL AVERAGE MONTHLY PRECIPITATION DATA
Authors: SHEN SAMUEL S. P. , NEW DAVID , SMITH THOMAS M. , ARKIN PHILLIP A.
Published: March 2013

This paper uses the Hilbert–Huang transform (HHT) method to make time–frequency diagnostic analyses of four monthly time series of the global precipitation: MERG (1900–2008), REOF (1900–2008), GPCP (1979–2009), and CMAP (1979–2009). All these data are the global land and ocean average of precipitation anomalies with respect to the mean of the entire data period. The MERG and REOF are spectral reconstructions based on historical data. The GPCP and CMAP are based on station gauge data and satellite remote sensing data. We have made the following analysis of the four datasets: (a) extract intrinsic mode functions (IMF) by HHT empirical model decomposition (EMD) sifting, (b) calculate the mean frequency and energy of each IMF, (c) calculate the Fourier spectra to compare with the IMF spectral properties, (d) calculate the Hilbert spectra and display the time–frequency variation of the precipitation time series, and (e) calculate the basic statistics of the four datasets, including mean, standard deviation, skewness, kurtosis and inter-correlation among the datasets. Our analysis results indicate the following: (i) IMFs may contain physical signals of MJO (Madden–Julian oscillation), monsoon, annual cycle, and ENSO (El Nino southern oscillation), (ii) Hilbert spectra appears to be an effective tool to display the time-frequency change of a precipitation time series and can help identify critical characteristics for improving data aggregation method and climate models, (iii) among the four datasets, MERG is the smoothest data and has the smallest variance and hence the smallest IMF energies, while the CMAP has the largest, followed by GPCP and REOF, and (iv) the nonlinear and nonstationary annual cycle is the IMF3 for all the four datasets, which is modulated by ENSO signals.
TOTAL ODDS AND OTHER OBJECTIVES FOR CLUSTERING VIA MULTINOMIAL-LOGIT MODEL
Authors: LIPOVETSKY STAN
Published: March 2013

This work considers maximum likelihood objectives for estimating the probability of each multivariate observation's assignment to one particular cluster or to one or more clusters. Combining both objectives yields a maximization of the total probability odds of belonging to one or another cluster. The gradient of the total odds objective can be reduced to the multinomial-logit probabilities leading to a convenient Newton–Raphson clustering procedure presented via an iteratively re-weighted least squares technique. Besides the total odds, several other new objectives are also considered, and numerical examples are discussed.
Evidence of Eocene high-temperature/high-pressure metamorphism of ophiolitic rocks and granitoid intrusion related to Neotethyan subduction processes (Doğanşehir area, SE Anatolia)
Authors: Karaoğlan Fatİh , Parlak Osman , Robertson Alastair , Thöni Martin , Klötzli Urs , Koller Friedrich , Okay Aral İ.
Published: March 2013

New data for regionally important granulite facies metaophiolitic rocks and cross-cutting granitoids rocks are presented and discussed. The high-temperature/high-pressure Berit metaophiolite is cut by unmetamorphosed Eocene (51–45 Ma) granitoid rocks. The highest metamorphic grade occurs in blocks of mafic granulites. Enveloping amphibolite facies rocks reflect retrograde metamorphism related to exhumation. Sm–Nd (pyroxene–garnet–amphibole–whole rock) isochron ages of 52–50 Ma for the granulite facies rocks are interpreted to represent the time of cooling of the granulite facies rocks. The over-riding Malatya metamorphic unit to the north is also intruded by Eocene granitoid rocks. The granulite facies metamorphism of the meta-ophiolitic rocks is inferred to have formed in the roots of an Eocene magmatic arc, with accentuated heat flow being provided by subduction of a spreading ridge, or rupture of the subducting slab. The high-temperature/high-pressure metamorphism was followed by exhumation, as indicated by field structural relations and the evidence of retrograde metamorphism. The Eocene arc magmatism can best be explained by northward subduction of the Southern Neotethys, which persisted after the time of latest Cretaceous regional ophiolite emplacement until the collision of the Eurasian (Anatolian) and Arabian continents during the Early–Mid Miocene. Subsequent Plio-Quaternary left-lateral strike-slip strongly affected the area.

Supplementary-material:

Four supplementary tables giving the whole rock geochemistry of the granitoids, mineral geochemistry of the granulite facies rocks, LA-MC-ICP-MS zircon U–Pb data belonging to granitoids and Sm–Nd data belonging to granulite facies rocks and two documents giving the detailed analytical procedures and detailed petrography of the granitoids are available at
www.geolsoc.org.uk/SUP18588
Development of Highly Active and Durable Pt Core-Shell Catalysts for Polymer Electrolyte Fuel Cells
Authors: Inaba Minoru , Daimon Hideo
Published: March 2013

Reducing the Pt usage by improving the activity of Pt catalysts for oxygen reduction reaction is important for the cost reduction of polymer electrolyte fuel cells. Core-shell catalysts, in which Pt monolayer is deposited on different metal core nanoparticles, are one of the key techniques to improve the mass activity of Pt. We are developing highly active and durable Pt ML core-shell catalysts, especially focusing on Au cores, which have highly electrochemical stability. Here we overview our research results on the core/shell catalysts prepared by the Cu-UPD method, the new method for Pt monolayer formation on Au cores, and the improvement of the stability of Au core nanoparticles.
A Two-Phase Pressure Drop Model Incorporating Local Water Balance and Reactant Consumption in PEM Fuel Cell Gas Channels
Authors: See Evan J. , Kandlikar Satish G
Published: March 2013

A two-phase 1-D pressure drop modeling scheme that incorporates the effect of local channel saturation on flow regime is introduced. The model provides a basis for extending two-phase pressure drop correlations from fundamental studies to more complex conditions within PEMFC reactant channels. The need for additional studies beyond the fundamental level is highlighted and key factors that separate PEMFC reactant channel conditions are explained. A crucial concern in characterizing two-phase flow within PEMFC reactant channels is the local flow pattern transitions throughout the channel. The application of an elemental step-wise calculation scheme approach for the prediction of localized two-phase conditions allows for a more complete prediction of conditions within the channels. Additionally through the application of a control volume approach, the effect of water addition and mass consumption of reactants on pressure drop within PEMFC flow channels is investigated. The resulting modeling scheme shows the relative effects of relaxing several of the common assumptions made when modeling PEMFC reactant channels.
Understanding Mechanism of PTFE Distribution in Fibrous Porous Media
Authors: Inoue Gen , Ishibe Naoyuki , Matsukuma Yosuke , Minemoto Masaki
Published: March 2013

In fibrous porous media, some polymer materials are often used to control of surface property such as making hydrophobic surface and to make another function such as electrolyte. However, all of these polymers are not always distribute in porous media uniformly. The micro pores are blocked with it and it leads to the degradation of mass transfer and heat conduction. In this study, we focused coating and drying process of PTFE treatment to PEFC gas diffusion layer (GDL). By numerical analysis of evaporation and phase change of polymer in GDL, the effect of drying process on polymer distribution and porous property was examined. As a result, the PTFE distribution in the direction of through plane could be controlled by drying condition. These tendencies of experiment and calculation were almost equal to each other qualitatively.
Effect of Channel Materials on the Behavior of Water Droplet Emerging From GDL into PEMFC Gas Channels
Authors: Gopalan Preethi , Kandlikar Satish G
Published: March 2013

Water accumulation in the gas channels of proton exchange membrane fuel cells (PEMFCs) significantly affects the gas diffusion and the overall performance. Hence, understanding the growth and detachment of liquid water droplets from the gas channel becomes critical. In this study, the behavior of liquid water droplets within the gas channel in the presence of air flow (0.2 - 2.4 m/s) is experimentally investigated for different GDL types (MRC105, SGL-25BC, TGP-H-060) and channel wall materials (stainless steel, copper, graphite composite, polycarbonate) that are commercially used in PEMFC for automotive applications. Experimental results were analyzed through Concus-Finn condition using instantaneous dynamic contact angle (IDCA) to determine the filling of the corners with liquid water. It was found that the droplet detachment is influenced by air flow within the channel and the contact angle hysteresis. Air flow produces oscillations in the droplet and changes the IDCA the droplet makes with the sidewalls and hence determines the corner filling.
Effect and Development of Cathode Catalyst on PEFC Cell Performance under Low and High Relative Humidity
Authors: Nakajima Hitoshi , Matsutani Koichi
Published: March 2013

The cell performances under low or high relative humidity were examined for Pt / C or PtCo / C cathode catalysts are investigated. First, to evaluate the effect of the increase of cell temperature (imaging due to the operation of cells), the I-V polarization curves under various cell temperatures at the same humidifier temperature were studied. The degrees of the decrease of cell voltage were almost identical among Pt / C and different cobalt contents of PtCo / C catalysts. To examine the effect the thickness of catalyst layer to the RH dependence of cell performance, both high Pt / C ratio (Pt content =70wt%) catalyst and low Pt / C ratio (Pt content = 20wt%) catalyst were used as cathode material.
Multi-Analytical Study of Gas Diffusion Layer PTFE Content Local Variation
Authors: Reshetenko Tatyana V. , St-Pierre Jean , Bethune Keith P. , Artyushkova Kateryna , Rocheleau Richard , Atanassov Plamen
Published: March 2013

PEMFC GDL materials with different PTFE content (8-35%) were analyzed using three methods: MIP, SEM/image analysis and XPS. PTFE particles from the impregnation suspension (up to 0.5 μm) are segregated within the GDL and only occupy medium size pores (0.4-50 μm). Other pores are unaffected because particles easily move through large pores (50-150 μm) and are geometrically excluded from small pores (0.05-0.4 μm). SEM images were deconvoluted into low and high frequency components. The high frequency component, ascribed to the GDL microstructure, increases with PTFE content and locally provides superhydrophobic properties. This observation was supported by current density distribution measurements at a 0.4 V cell voltage favoring product water formation which were correlated with the high frequency SEM image component. Zones of higher hydrophilicity were also identified and ascribed to partially fluorinated species detected by XPS.
Characterizing Leachant Contaminants from Fuel Cell Assembly Aids, a Prelude to Effects on Performance
Authors: Macomber Clay S. , Christ Jason , Wang Heli , Pivovar Bryan S. , Dinh Huyen N.
Published: March 2013

The role of system contaminants in the performance degradation of Proton Exchange Membrane (PEM) fuel cells has been underappreciated to date. This work seeks to identify potential contaminants derived from balance of plant (BOP) system components with the ultimate goal of tying contaminant exposure to changes in PEMFC performance and durability. After accelerated aging of select assembly aid materials in DI water at 90{degree sign}C, the resulting leachant solutions were qualitatively and quantitatively characterized through a suite of analytical methods for organic and inorganic components. By design, the materials studied fall into a wide range of 'clean' and 'dirty' solutions. Potential routes of entry for species were examined for plausibility of identification, and determination of model compounds. Systematic identification and selection of model compounds provide the basis for in-situ and ex-situ testing to determine the potential degradation mechanisms and effects of these system contaminants on catalysis and membrane performance.
Evaluation of PEMFC System Contaminants on the Performance of Pt Catalyst Via Cyclic Voltammetry
Authors: Wang Heli , Macomber Clay S. , Dinh Huyen N.
Published: March 2013

Using cyclic voltammetry as a quick ex-situ electrochemical screening tool, the impact of the extracted solution and the individual leachable constituents from prospective balance of plant (BOP) component materials on the performance and recoverability of the platinum catalyst were evaluated. Taking an extract from ZytelTM HTN51G35HSLR (PPA) as an example, the major leachable organic components are caprolactam and 1,6 hexanediol. While these organic compounds by themselves do poison the Pt catalyst to some extent, such influence is mostly recoverable by means of potential holding and potential cycling. The extracted solution, however, shows a more drastic poisoning effect and it was not recoverable. Therefore the non-recoverable poisoning effect observed for the extracted solution is not from the two organic species studied. This demonstrates the complexity of such a contaminant study. Inorganic compounds that are known poisons like sulfur even in very low concentrations, may have a more dominant effect on the Pt catalyst and the recoverability.
Dynamic Analysis and Diagnostics of a High Temperature PEM Fuel Cell Stack
Authors: Zhu Ying , Zhu Wenhua H. , Tatarchuk Bruce J.
Published: March 2013

In this work, impedance measurement was performed on a high temperature PEM fuel cell stack module consisting of 65 planar single cells. Pure hydrogen and ambient air were supplied into the stack. The impedance data of the stack were collected under varying loads at 160ºC. However, temperature variations and gradient existed over the whole stack during the measurement. The impedance measurement was then repeated under the same operating conditions to collect the second set of data. An unexpected increase of cell impedance was observed. An EC diagram was derived to simulate the impedance data of the stack module. The electronic auxiliaries and temperature profiles of the stack module were analyzed to study their effects on stack impedance.
A Novel Lightweight Polymer Electrolyte Fuel Cell Stack for Robot Systems
Authors: Hwang Sun-Wook , Choi Gyeungho , Bates Alex , Ench Robert Michael , Lee Sang Cheol , Kwon O Sung , Lee Dong Ha , Mukherjee Santanu , Park Sam
Published: March 2013

Proton exchange membrane fuel cells (PEMFCs) are the most appropriate for energy sources of small robot applications. PEMFCs have superior power density and thermodynamic efficiency compared with direct methanol fuel cells (DMFCs). Furthermore, PEMFCs are lighter and smaller than DMFCs, which are very important factors in small robot power systems. Operating conditions and fabricating methods are of key importance to fuel cell performance and efficiency. In this study, analysis of pressure drop, concentration variation, deformation of GDL and electrolytes, and stack clamping pressure were completed by 500-watt polymer electrolyte membrane fuel cell stacks. Several novel designs were discussed and will be continuously studied.
Spatially Resolved Characterization of DMFCs Aged under Critical Conditions
Authors: Löhmer Andreas , Wippermann Klaus , Müller Martin , Korte Carsten , Stolten Detlef
Published: March 2013

Methanol depletion in direct methanol fuel cells was investigated by either substituting methanol by water or interrupting the methanol flow. Two time phases, I and II, were identified by analyzing the anode exhaust gas and controlling the cell voltage. Phase I is characterized by oxygen evolution reaction, while phase II is dominated by carbon corrosion. Degradation during phase I is caused by ruthenium dissolution. The degradation appeared to be homogeneous in the cell, as no significant local degradation was found. Partial methanol depletion on one side of a stack cell (315cm²) over a period of 100h caused a 10% performance loss, which was nearly completely recovered after cycling under normal operation conditions. The methanol concentration and flow rate were varied to evaluate critical operation conditions. The current distribution is nearly unaffected by methanol stoichiometry values higher than 5. If the stoichiometry drops below 2.5, the current distribution becomes more uneven.
Copolymeric Short-Long Side Chain PFSA/PTFE Membranes with High Ion Exchange Capacities for Fuel Cell Applications
Authors: Zhu Yan , Tang Junke , Zhang Yongming
Published: March 2013

Copolymeric perfluorosulfonic acid ionomers consisting of both short and long side chain segments (SLSC PFSA) were designed and successfully synthesized. To further enhance the performance of such new ionomers based membranes, SLSC PFSA/PTFE composite membranes were fabricated. On one hand, the membranes kept such advantages of short side chain (SSC) PFSA membranes as high IEC, high crystallinity, and moreover excellent thermal and chemical stability. On the other hand, the long-side chain will affect the membrane microstructures, such as ion cluster size, density, and distribution, thus endowing the new membranes unique and excellent performances.
Numerical Validation of Water Transport in a Polymer Electrolyte Membrane
Authors: Fu Richard S , Khajeh-Hosseini-Dalasm Navvab , Pasaogullari Ugur
Published: March 2013

Water transport phenomena under non-isothermal conditions was numerically investigated by modeling the through-plane water transport across a polymer electrolyte membrane (PEM), sandwiched between two gas diffusion layers (GDLs). The model predictions of water thickness distribution under various thermal gradient and relative humidity were compared with our latest high resolution neutron radiography (NR) experimental data. The numerical model was able to predict water flux direction and the general trend in water content gradient in the PEM. Improvement in the prediction accuracy was sought through investigation into material and transport properties.
Poly(Arylene Ether Sulfone) Ionomers with Different Acidity Strengths and Fuel Cell Membrane Properties
Authors: Chang Ying , Brunello Giuseppe F. , Disabb-Miller Melanie , Hawley Marilyn , Kim Yu Seung , Hickner Michael A. , Jang Seung Soon , Bae Chulsung
Published: March 2013

Poly(arylene ether sulfone) (PSU) ionomers functionalized with different sulfonic acid groups were synthesized and their fuel cell membrane properties were investigated. Under low relative humidity, PSU ionomers with strong acidity and comparable ionic exchange capacity exhibited significantly higher conductivity than those with lower acidity.
In Situ Anomalous Small-Angle X-ray Scattering Study of Fuel Cell Catalyst Degradation in Aqueous and Membrane Electrode Assembly Environments
Authors: Gilbert James A. , Kariuki Nancy N. , Kropf A. Jeremy , Morgan Dane , Myers Debbie J , Ball Sarah , Sharman Jonathan , Theobald Brian , Hards Graham
Published: March 2013

Anomalous small-angle X-ray scattering (ASAXS) is a powerful technique for probing catalyst particle sizes on the nanometer scale making it ideal for monitoring particle size distributions (PSDs) of Pt-based cathode electrocatalysts for polymer electrolyte fuel cells. Potential cycling experiments were performed on Pt nano-particles in both aqueous and membrane-electrode assembly (MEA) environments. PSDs were resolved through in-situ ASAXS and used to calculate geometric surface areas (GSA) and mass losses. A comparison of the losses in the GSA and mass of Pt along with changes in the evolutions of the PSDs over 900 potential cycles elucidated differences between degradation mechanisms in the two different environments. The MEA environment induced greater GSA and mass losses while maintaining similar growth in the mean particle size as compared to the aqueous environment. Results show changes in PSDs consistent with dominant mechanisms of Pt dissolution/coarsening in the aqueous environment and dissolution in the MEA environment.
Platinum Dissolution in Nitrogen Oxides-Containing HClO4 Solution Studied by Electrochemical Quartz Crystal Microbalance
Authors: Kuroe Hironori , Morita Takafumi , Uchiyama Yuki , Abe Tomohiro , Imabayashi Shin-ichiro
Published: March 2013

Platinum (Pt) dissolution has been elucidated by measuring a mass loss of Pt black-deposited Au quartz resonators in 0.1 mol dm-3 HClO4 containing NaNO2. A continuous weight loss of ca. 50 ng cm-2 cycle-1 was detected at [NaNO2] = 0.01 mol dm-3 under the potential cycling between 0.6 and 1.4 V vs. RHE. The magnitude of Pt dissolution depends on the concentration of NaNO2 and the range of potential cycling. The average mass loss decreases to 5~10 ng cm-2 cycle-1 at [NaNO2] = 1 mmol dm-3. The Pt dissolution occurs when the higher potential limit is more than 1.0 V vs. RHE and the lower potential limit is less than 0.9 V vs. RHE, suggesting that the reduction of Pt oxide in the presence of NaNO2 in the bulk solution contributes to the dissolution.
Dietary oils modify the host immune response and colonic tissue damage followingCitrobacter rodentiuminfection in mice
Authors: Hekmatdoost Azita , Wu Xiujuan , Morampudi Vijay , Innis Sheila M. , Jacobson Kevan
Published: March 2013

Inflammatory bowel disease is an intestinal inflammatory disorder of multifactorial origin, in which diets that favor high n-6 and low n-3 fatty acids have been implicated. The present study addressed whether dietary n-6 and n-3 fatty acids alter colonic mucosal response to Citrobacter rodentium ( C. rodentium) infection. Mice were fed diets identical except for fatty acids, with an energy percentage of 15% 18:2n-6 and <0.06% 18:3n-3, 4.2% 18:2n-6 and 1.9% 18:3n-3, or 1.44% 20:5n-3, 4.9% 22:6n-3, 0.32% 18:2n-6, and 0.12% 18:3n-3 from safflower, canola, or fish oil, respectively for 3 wk before infection. Dietary oils had no effect on colonic C. rodentium growth but altered colon 20:4n-6/(20:5n-3+22:6n-3) with 9.40 ± 0.06, 1.94 ± 0.08, and 0.32 ± 0.03% in colon phosphatidylcholine and 3.82 ± 0.18, 1.14 ± 0.02, and 0.30 ± 0.02% in phosphatidylethanolamine of mice fed safflower, canola, or fish oil, respectively. At 10 days postinfection, histological damage, F4/80-positive macrophages, and myeloperoxidase-positive neutrophils in colonic mucosa were higher in infected mice fed safflower than fish oil. Colon gene transcripts for macrophage inflammatory protein 2, keratinocyte cytokine, and monocyte chemoattractant protein 1 expression were significantly higher in infected mice fed safflower than canola or fish oil; IFN-γ, IL-6, and IL-17A expression were significantly elevated in mice fed safflower rather than fish oil; and IL-10 was significantly higher in mice fed fish oil rather than canola or safflower oil. This study demonstrates that oils high in 18:2n-6 with minimal n-3 fatty acids exacerbate mucosal immune response, whereas oils high in n-3 fatty acids attenuate mucosal immune response to C. rodentium. These studies implicate dietary oils as environmental modifiers of intestinal inflammation in response to infection.
ANGPTL4 expression induced by butyrate and rosiglitazone in human intestinal epithelial cells utilizes independent pathways
Authors: Korecka Agata , de Wouters Tomas , Cultrone Antonietta , Lapaque Nicolas , Pettersson Sven , Doré Joël , Blottière Hervé M. , Arulampalam Velmurugesan
Published: March 2013

Short-chain fatty acids (SCFAs), such as butyrate and propionate, are metabolic products of carbohydrate fermentation by the microbiota and constitute the main source of energy for host colonocytes. SCFAs are also important for gastrointestinal health, immunity, and host metabolism. Intestinally produced angiopoietin-like protein 4 (ANGPTL4) is a secreted protein with metabolism-altering properties and may offer a route by which microbiota can regulate host metabolism. Peroxisome proliferator-activated receptor (PPAR)-γ has previously been shown to be involved in microbiota-induced expression of intestinal ANGPTL4, but the role of bacterial metabolites in this process has remained elusive. Here, we show that the SCFA butyrate regulates intestinal ANGPTL4 expression in a PPAR-γ-independent manner. Although PPAR-γ is not required for butyrate-driven intestinal ANGPTL4 expression, costimulating with PPAR-γ ligands and SCFAs leads to additive increases in ANGPTL4 levels. We suggest that PPAR-γ and butyrate rely on two separate regulatory sites, a PPAR-responsive element downstream the transcription start site and a butyrate-responsive element(s) within the promoter region, 0.5 kb upstream of the transcription start site. Furthermore, butyrate gavage and colonization with Clostridium tyrobutyricum, a SCFA producer, can independently induce expression of intestinal ANGPTL4 in germ-free mice. Thus, oral administration of SCFA or use of SCFA-producing bacteria may be additional routes to maintain intestinal ANGPTL4 levels for preventive nutrition or therapeutic purposes.
Potent stimulation of fibroblast growth factor 19 expression in the human ileum by bile acids
Authors: Zhang Justine H. , Nolan Jonathan D. , Kennie Sarah L. , Johnston Ian M. , Dew Tracy , Dixon Peter H. , Williamson Catherine , Walters Julian R. F.
Published: March 2013

Fibroblast growth factor 19 (FGF19) is proposed to be a negative feedback regulator of hepatic bile acid (BA) synthesis. We aimed to clarify the distribution of FGF19 expression in human intestine and to investigate induction in a novel explant system. Ileal and colonic mucosal biopsies were obtained at endoscopy and analyzed for FGF19 transcript expression. Primary explants were incubated with physiological concentrations of various BA for up to 6 h, and expression of FGF19 and other genes was determined. FGF19 transcripts were detected in ileum but were unquantifiable in colon. No loss of FGF19 mRNA occurred as a consequence of the explant system. Ileal FGF19 transcript expression was induced 350-fold by 50 μM chenodeoxycholate (CDCA, n = 24, P < 0.0001) and 161-fold by 50 μM glycochenodeoxycholate (GCDCA, n = 12, P = 0.0005). The responses of other genes to CDCA or GCDCA (50 μM) were smaller: median increases of ileal bile acid binding protein, organic solute transporter-α and -β, and short heterodimer partner were 2.4- to 4.0-fold; apical membrane sodium bile acid transporter and farnesoid X receptor (FXR) showed little change. The EC50 for FGF19 transcript induction by CDCA was 20 μM. FGF19 protein concentrations were significantly higher in the culture fluid from BA-stimulated explants. FGF19 induction with cholate was 81% of that found with CDCA, but deoxycholate (40%) and lithocholate (4%) were significantly less potent. The synthetic FXR agonist obeticholic acid was much more potent than CDCA with a 70-fold FGF19 stimulation at 1 μM. We concluded that FGF19 expression in human ileum is very highly responsive to BA. Changes in FGF19 induction are a potential mechanism involved in disorders of BA homeostasis.
Dose-dependent effects of angiotensin-(1–7) on the NHE3 exchanger and [Ca2+]iin in vivo proximal tubules
Authors: Castelo-Branco Regiane C. , Leite-Delova Deise C. A. , de Mello-Aires Margarida
Published: March 2013

The acute direct action of angiotensin-(1–7) [ANG-(1–7)] on bicarbonate reabsorption ( JHCO3−) was evaluated by stationary microperfusions on in vivo middle proximal tubules in rats using H ion-sensitive microelectrodes. The control JHCO3−is 2.82 ± 0.078 nmol·cm−2·s−1(50). ANG-(1–7) (10−12or 10−9M) in luminally perfused tubules decreases JHCO3−(36 or 60%, respectively), but ANG-(1–7) (10−6M) increases it (80%). A779 increases JHCO3−(30%) and prevents both the inhibitory and the stimulatory effects of ANG-(1–7) on it. S3226 decreases JHCO3−(45%) and changes the stimulatory effect of ANG-(1–7) to an inhibitory effect (30%) but does not affect the inhibitory effect of ANG-(1–7). Our results indicate that in the basal condition endogenous ANG-(1–7) inhibits JHCO3−and that the biphasic dose-dependent effect of ANG-(1–7) on JHCO3−is mediated by the Mas receptors via the Na+/H+exchanger 3 (NHE3). The control value of intracellular Ca2+concentration ([Ca2+]i), as monitored using fura-2 AM, is 101 ± 2 nM ( 6 ), and ANG-(1–7) (10−12, 10−9, or 10−6M) transiently (3 min) increases it (by 151, 102, or 52%, respectively). A779 increases the [Ca2+]i(25%) but impairs the stimulatory effect of all doses of ANG-(1–7) on it. The use of BAPTA or thapsigargin suggests a correlation between the ANG-(1–7) dose-dependent effects on [Ca2+]iand JHCO3−. Therefore, the interaction of the opposing dose-dependent effects of ANG II and ANG-(1–7) on [Ca2+]iand JHCO3−may represent an physiological regulatory mechanism of extracellular volume and/or pH changes. However, whether [Ca2+]imodification is an important direct mechanism for NHE3 activation by these peptides or is a side effect of other signaling pathways will require additional studies.
Pathophysiology of muscle dysfunction in COPD
Authors: Gea Joaquim , Agustí Alvar , Roca Josep
Published: March 2013

Muscle dysfunction often occurs in patients with chronic obstructive pulmonary disease (COPD) and may involve both respiratory and locomotor (peripheral) muscles. The loss of strength and/or endurance in the former can lead to ventilatory insufficiency, whereas in the latter it limits exercise capacity and activities of daily life. Muscle dysfunction is the consequence of complex interactions between local and systemic factors, frequently coexisting in COPD patients. Pulmonary hyperinflation along with the increase in work of breathing that occur in COPD appear as the main contributing factors to respiratory muscle dysfunction. By contrast, deconditioning seems to play a key role in peripheral muscle dysfunction. However, additional systemic factors, including tobacco smoking, systemic inflammation, exercise, exacerbations, nutritional and gas exchange abnormalities, anabolic insufficiency, comorbidities and drugs, can also influence the function of both respiratory and peripheral muscles, by inducing modifications in their local microenvironment. Under all these circumstances, protein metabolism imbalance, oxidative stress, inflammatory events, as well as muscle injury may occur, determining the final structure and modulating the function of different muscle groups. Respiratory muscles show signs of injury as well as an increase in several elements involved in aerobic metabolism (proportion of type I fibers, capillary density, and aerobic enzyme activity) whereas limb muscles exhibit a loss of the same elements, injury, and a reduction in fiber size. In the present review we examine the current state of the art of the pathophysiology of muscle dysfunction in COPD.
Primary gene response to mechanical loading in healing rat Achilles tendons
Authors: Eliasson Pernilla , Andersson Therese , Hammerman Malin , Aspenberg Per
Published: March 2013

Loading can stimulate tendon healing. In healing rat Achilles tendons, we have found more than 150 genes upregulated or downregulated 3 h after one loading episode. We hypothesized that these changes were preceded by a smaller number of regulatory genes and thus performed a microarray 15 min after a short loading episode, to capture the primary response to loading. We transected the Achilles tendon of 54 rats and allowed them to heal. The hind limbs were unloaded by tail-suspension during the entire experiment, except during the loading episode. The healing tendon tissue was analyzed by mechanical testing, microarray, and quantitative real-time polymerase chain reaction (qRT-PCR). Mechanical testing showed that 5 min of loading each day for 4 days created stronger tissue. The microarray analysis after one loading episode identified 15 regulated genes. Ten genes were analyzed in a repeat experiment with new rats using qRT-PCR. This confirmed the increased expression of four genes: early growth response 2 (Egr2), c-Fos, FosB, and regulation of G protein signaling 1 (Rgs1). The other genes were unaltered. We also analyzed the expression of early growth response 1 (Egr1), which is often co-regulated with c-Fos or Egr2, and found that this was also increased after loading. Egr1, Egr2, c-Fos, and FosB are transcription factors that can be triggered by numerous stimuli. However, Egr1 and Egr2 are necessary for normal tendon development, and can induce ectopic expression of tendon markers. The five regulated genes appear to constitute a general activation machinery. The further development of gene regulation might depend on the tissue context.
Binocular integration and disparity selectivity in mouse primary visual cortex
Authors: Scholl Benjamin , Burge Johannes , Priebe Nicholas J.
Published: March 2013

Signals from the two eyes are first integrated in primary visual cortex (V1). In many mammals, this binocular integration is an important first step in the development of stereopsis, the perception of depth from disparity. Neurons in the binocular zone of mouse V1 receive inputs from both eyes, but it is unclear how that binocular information is integrated and whether this integration has a function similar to that found in other mammals. Using extracellular recordings, we demonstrate that mouse V1 neurons are tuned for binocular disparities, or spatial differences, between the inputs from each eye, thus extracting signals potentially useful for estimating depth. The disparities encoded by mouse V1 are significantly larger than those encoded by cat and primate. Interestingly, these larger disparities correspond to distances that are likely to be ecologically relevant in natural viewing, given the stereo-geometry of the mouse visual system. Across mammalian species, it appears that binocular integration is a common cortical computation used to extract information relevant for estimating depth. As such, it is a prime example of how the integration of multiple sensory signals is used to generate accurate estimates of properties in our environment.
Generation of a Reconfigurable Logical Cell Using Evolutionary Computation
Authors: Campos-Cantón I. , Torres-Treviño L. M. , Campos-Cantón E. , Femat R.
Published: March 2013

In nature, an interesting topic is about how a cell can be reconfigured in order to achieve a different task. Another interesting topic is about the learning process that seems to be a trial and error process. In this work, we present mechanisms about how to produce a reconfigurable logical cell based on the tent map. The reconfiguration is realized by modifying its internal parameters generating several logical functions in the same structure. The logical cell is built with three blocks: the initial condition generating function, the tent map, and the output function. Furthermore, we propose a reconfigurable structure based on a chaotic system and an evolutionary algorithm is used in order to tune the parameters of the cell via trial and error process.
Perturbation Theory for Abstract Volterra Equations
Authors: Kostić Marko
Published: March 2013

We consider additive perturbation theorems for subgenerators of (a, k)-regularizedC-resolvent families. A major part of our research is devoted to the study of perturbation properties of abstract time-fractional equations, primarily from their importance in modeling of various physical phenomena. We illustrate the results with several examples.
An Improved Harmony Search Based on Teaching-Learning Strategy for Unconstrained Optimization Problems
Authors: Tuo Shouheng , Yong Longquan , Zhou Tao
Published: March 2013

Harmony search (HS) algorithm is an emerging population-based metaheuristic algorithm, which is inspired by the music improvisation process. The HS method has been developed rapidly and applied widely during the past decade. In this paper, an improved global harmony search algorithm, named harmony search based on teaching-learning (HSTL), is presented for high dimension complex optimization problems. In HSTL algorithm, four strategies (harmony memory consideration, teaching-learning strategy, local pitch adjusting, and random mutation) are employed to maintain the proper balance between convergence and population diversity, and dynamic strategy is adopted to change the parameters. The proposed HSTL algorithm is investigated and compared with three other state-of-the-art HS optimization algorithms. Furthermore, to demonstrate the robustness and convergence, the success rate and convergence analysis is also studied. The experimental results of 31 complex benchmark functions demonstrate that the HSTL method has strong convergence and robustness and has better balance capacity of space exploration and local exploitation on high dimension complex optimization problems.
Epidemiology of Acute Kidney Injury in the Intensive Care Unit
Authors: Case James , Khan Supriya , Khalid Raeesa , Khan Akram
Published: March 2013

The incidence of acute kidney injury (AKI) in the intensive care unit (ICU) has increased during the past decade due to increased acuity as well as increased recognition. Early epidemiology studies were confounded by erratic definitions of AKI until recent consensus guidelines (RIFLE and AKIN) standardized its definition. This paper discusses the incidence of AKI in the ICU with focuses on specific patient populations. The overall incidence of AKI in ICU patients ranges from 20% to 50% with lower incidence seen in elective surgical patients and higher incidence in sepsis patients. The incidence of contrast-induced AKI is less (11.5%–19% of all admissions) than seen in the ICU population at large. AKI represents a significant risk factor for mortality and can be associated with mortality greater than 50%.
Lemierre’s Syndrome: A Rare Case of Pulmonic Valve Vegetation
Authors: Kwan Clara , Mastrine Lou , Moskovits Manfred
Published: March 2013

Lemierre’s syndrome is an uncommon complication of pharyngitis commonly associated with an anaerobic gram negative bacterium,Fusobacterium necrophorum. The syndrome usually affects young healthy adults with the mean age of 20 and is characterized by recent pharyngitis followed by ipsilateral internal jugular vein thrombosis and septic thromboembolism. The treatment is at least 6 weeks of antibiotics; the role of anticoagulation is unclear. The following presentation is a case of Lemierre’s syndrome in a 23-year-old healthy individual who is infected by a rare species:Fusobacterium nucleatum. The case is complicated by septic emboli to the lungs and impressive seeding vegetation to the right ventricular outflow tract (RVOT) at the pulmonic valve of the heart.
The Stimulation Effect of Auricular Magnetic Press Pellets on Older Female Adults with Sleep Disturbance Undergoing Polysomnographic Evaluation
Authors: Lo Chyi , Liao Wen-Chun , Liaw Jen-Jiuan , Hang Liang-Wen , Lin Jaung-Geng
Published: March 2013

Study Objectives. To examine the stimulation effect of auricular magnetic press pellet therapy on older female adults with sleep disturbance as determined by polysomnography (PSG).Design. Randomized, single-blind, experimental-controlled, parallel-group.Setting. Community.Participants. Twenty-seven older female adults with sleep disturbance according to the Pittsburgh Sleep Quality Index (PSQI) >5 for at least 3 months were recruited. Participants were screened by both the Hospital Anxiety and Depression Scale (HADS) and the Mini-Mental State Examination (MMSE), as well as polysomnography prior to randomization.Interventions. All eligible participants were randomly allocated into the experimental or control group. Both groups were taped with magnetic press pellet on auricular points for 3 weeks. The experimental group was treated by applying pressure on the magnetic press pellets 3 times per day while no stimulation was applied on the control group.Measurements and Results. Both groups were measured by PSG and PSQI at the beginning of the study and 3 weeks after the study. Both groups showed improvements on PSQI scores compared to the baseline. One-way analysis of covariance adjusted for baseline scores showed that significant improvements of PSG-derived sleep parameters, such as sleep efficiency, were found in the experimental group. However, no significant differences between groups were observed in the proportion of sleep stages with the exception of Stage 2.Conclusions. Auricular therapy using magnetic pellets and stimulation by pressing was more effective in improving the sleep quality compared to auricular therapy without any stimulation.
Small-World Properties in Mild Cognitive Impairment and Early Alzheimer’s Disease: A Cortical Thickness MRI Study
Authors: Zhou Yongxia , Lui Yvonne W.
Published: March 2013

Background. Small-world network consists of networks with local specialization and global integration. Our objective is to detect small-world properties alteration based on cortical thickness in mild cognitive impairment (MCI) including stables and converters, and early Alzheimer's disease (AD) compared to controls. Methods. MRI scans of 13 controls, 10 MCI, and 10 with early AD were retrospectively analyzed; 11 MCI converters, 11 MCI stables, and 10 controls from the ADNI website were also included. Results. There were significantly decreased local efficiencies in patients with MCI and AD compared to controls; and MCI patients showed increased global efficiency compared to AD and controls. The MCI converters experience the worst local efficiency during the converting period to AD; the stables, however, have highest local and global efficiency. Conclusions. The abnormal cortical thickness-based small-world properties in MCI and AD as well as the distinct patterns between two MCI subtypes suggest that small-world network analysis has the potential to better differentiate different stages of early dementia.
A Rare Mullerian Duct Anomaly Not Included in the Classification System by the American Society for Reproductive Medicine
Authors: Brown Shereene J. , Badawy Shawky Z. A.
Published: March 2013

This is a case report of a 37-year-old female with a uterine septum (two cavities), a normal single fundal contour, two cervices, and a longitudinal vaginal septum. This is a rare finding that is not described in the current classification system by the American Society for Reproductive Medicine.
Sensitivity Analysis of the Artificial Neural Network Outputs in Friction Stir Lap Joining of Aluminum to Brass
Authors: Shojaeefard Mohammad Hasan , Akbari Mostafa , Tahani Mojtaba , Farhani Foad
Published: March 2013

Al-Mg and CuZn34 alloys were lap joined using friction stir welding while the aluminum alloy sheet was placed on the CuZn34. In addition, the mechanical properties of each sample were characterized using shear tests. Scanning electron microscopy (SEM) and X-ray diffraction analysis were used to probe chemical compositions. An artificial neural network model was developed to simulate the correlation between the Friction Stir Lap Welding (FSLW) parameters and mechanical properties. Subsequently, a sensitivity analysis was performed to investigate the effect of each input parameter on the output in terms of magnitude and direction. Four methods, namely, the “PaD” method, the “Weights” method, the “Profile” method, and the “backward stepwise” method, which can give the relative contribution and/or the contribution profile of the input factors, were compared. The PaD method, giving the most complete results, was found to be the most useful, followed by the Profile method that gave the contribution profile of the input variables.