bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hypercholesterolemia Impairs Immunity to Tuberculosis
Authors: Martens Gregory W. , Arikan Meltem Cevik , Lee Jinhee , Ren Fucheng , Vallerskog Therese , Kornfeld Hardy 
Published: May 2008

ABSTRACT

We demonstrate that apolipoprotein E -deficient (
ApoE
−/
−
) mice are highly susceptible to tuberculosis and that their susceptibility depends on the severity of hypercholesterolemia. Wild-type (WT) mice and
ApoE
−/
−
mice fed a low-cholesterol (LC) or high-cholesterol (HC) diet were infected with ∼50 CFU
Mycobacterium tuberculosis
Erdman by aerosol.
ApoE
−/
−
LC mice were modestly more susceptible to tuberculosis than WT LC mice. In contrast,
ApoE
−/
−
HC mice were extremely susceptible, as evidenced by 100% mortality after 4 weeks with tuberculosis. The lung pathology of
ApoE
−/
−
HC mice was remarkable for giant abscess-like lesions, massive infiltration by granulocytes, elevated inflammatory cytokine production, and a mean bacterial load ∼2 log units higher than that of WT HC mice. Compared to WT HC mice, the gamma interferon response of splenocytes restimulated ex vivo with
M. tuberculosis
culture filtrate protein was delayed in
ApoE
−/
−
HC mice, and they failed to control
M. tuberculosis
growth in the lung. OT-II cells adoptively transferred into uninfected
ApoE
−/
−
HC mice had a weak proliferative response to their antigen, indicating impaired priming of the adaptive immune response. Our studies show that
ApoE
−/
−
deficiency is associated with delayed expression of adaptive immunity to tuberculosis caused by defective priming of the adaptive immune response and that elevated serum cholesterol is responsible for this effect.
The Terminal Sialic Acid of Glycoconjugates on the Surface of Intestinal Epithelial Cells Activates Excystation of
Cryptosporidium parvum
Authors: Choudhry Naheed , Bajaj-Elliott Mona , McDonald Vincent 
Published: May 2008

ABSTRACT

The apicomplexan
Cryptosporidium parvum
reproduces in the intestinal epithelial cells of many mammalian species and is an agent of the important diarrheal disease cryptosporidiosis. Infection is transmitted fecal-orally by oocysts that pass through the stomach and excystation occurs in the intestine, releasing four invasive sporozoites. Some factors involved in inducing excystation have been identified, but the role of the enterocyte is not known. The present study showed that excystation was accelerated in the presence of the three enterocyte cell lines Caco2, HCT8, and CMT93. Epithelial cell lines derived from other organs, including the stomach, had no effect on excystation. No evidence was obtained that factors secreted from enterocytes induced excystation, but an enterocyte membrane preparation promoted sporozoite release. In addition, modification of the enterocyte surface by trypsin digestion or paraformaldehyde fixation abrogated the ability to enhance excystation. Importantly, the level of excystation in the presence of enterocytes decreased after treatment with either sialidase/neuraminidase to deplete surface terminal sialic acid or with lectins that specifically bind to sialic acid. Furthermore, the addition of sialic acid to oocysts in the absence of cells increased the level of excystation. These results suggest that sialic acid on the surface of enterocytes may provide an important local signal for the excystation of
C. parvum
sporozoites.
Chloroplast DNA phylogeography in long-lived Huon pine, a Tasmanian rain forest conifer
Authors: Clark Catherine M. , Carbone Ignazio 
Published: June 2008

Genealogy based methods were used to estimate phylogeographic history for a Tasmanian endemic conifer, Huon pine ( Lagarostrobos franklinii (Hook. f.) Quinn). DNA from trees in eight populations was sequenced using three chloroplast primers (trnS–trnT, trnD–trnT, and psbC–trnS). Mean nucleotide diversity was low (π = 0.000 93 ± 0.000 06) from 892 base pairs of sequence, but varied in stands from 0.0 to 0.001 15. Two of the five haplotypes were widely distributed, but the most frequently occurring haplotype was found only in the western portion of the range. Population structure was highly significant among populations overall (GST= 0.261, where GSTis the coefficient of gene differentiation, and p ≤ 0.0001), and there were indications of significant isolation by distance (p ≤ 0.022). Populations exhibited the highest levels of differentiation between the southeastern and northwestern watersheds. Estimates of migration between populations obtained using both parametric and nonparametric methods indicated levels of gene flow consistent with an isolation by distance model. Nested clade analysis demonstrated a pattern of genetic diversity in Huon pine that is consistent with a history of range expansion. The exceptionally low level of nucleotide diversity, haplotype distribution, and paleoecological data are congruent with a history of long-term range reduction, population bottlenecks, and subsequent colonization events from refugial areas.
Variation in soil microbial communities across a boreal spruce forest landscape
Authors: Bach Lisbet Holm , Frostegård Åsa , Ohlson Mikael 
Published: June 2008

We investigated soil microbial community structure by phospholipid fatty acid (PLFA) analysis in a mature boreal spruce forest landscape in southern Norway, with low diversity of vascular plants. We investigated the spatial variation in PLFAs and the importance of environmental variables in 10 plots (each 13 samples) in a study area of 1 km × 1 km. The scales investigated were 15 cm to 10 m within study plots and 100 m to 1 km between study plots. Soil microbial biomass varied 10-fold and we found a large variation in microbial community structure, even at distances of 15 cm. Samples aggregated into plots when PLFAs were subjected to a principal components analysis. Plot identity explained 36.3% of the variation in the PLFAs and geostatistical analysis showed that the microbial community structure displayed spatial dependence at within-plot distances. Environmental variables differed significantly between all plots but explained only minor parts of the variation in the overall PLFA pattern. The vegetation variables were, however, the best at explaining the PLFA pattern, and up to 60% of within-plot variation in individual plots, respectively, could be explained by vegetation variables, pH, and soil depth.
Latitudinal variation in tree-ring and wood cell characteristics of Picea mariana across the continuous boreal forest in Quebec
Authors: St-Germain Jean-Luc , Krause Cornelia 
Published: June 2008

Wood anatomical features measured in tree-rings are useful indicators of environmental change and wood quality. The effect of latitude on the wood anatomy of mature black spruce ( Picea mariana (Mill.) BSP) was investigated along a 500 km transect from 47°N to 52°N across the continuous boreal forest in Quebec, Canada. Total tree-ring width, earlywood width, latewood width, latewood proportion, cell numbers, tracheid length, radial diameter, lumen diameter, and cell wall thickness were measured using image analysis on samples from 15 mature stands. Our results suggest that tree-ring, earlywood, and latewood widths, cell numbers, latewood radial cell diameter, and cell wall thickness decrease with latitude. No significant trend was observed for latewood proportion, despite a slight increase with latitude (p = 0.0856). However, the high variability in radial growth seen along the gradient might explain the absence of a significant relationship. Latitude and the associated growth rate reduction had no effect on tracheid length. The existence of a latitudinal pattern of variation in black spruce wood anatomy may be the result of tree adaptation to differing environmental conditions along the gradient.
THE OBLIQUE PENETRATION AND PERFORATION OF A RIGID PROJECTILE INTO A THICK METALLIC TARGET: ANALYTICAL MODEL
Authors: MOHAMMADI AMIR HOSSEIN MOUSAVI , LIAGHAT GHOLAM HOSSEIN , KHODARAHMI HOSSEIN 
Published: June 2008

In this paper, the oblique penetration and perforation process has been analyzed in three stages. In the first and second stages, the entering of projectile nose into the target and the tunneling process have been considered, respectively. The calculation of force in these stages is based on spherical cavity expansion method. In both of these stages, the friction coefficient has been considered to vary with velocity changes during the process. At the end of each time step, the velocity components are readily determined by solving the equations of motion. The plug formation is modeled in the third stage, where the residual velocity is calculated by the application of energy balance. In summary, a new approach has been developed to determine the residual velocity, the exit angle, and the depth of penetration of projectiles with spherical nose into the targets, for both cases of oblique and normal striking. The predicted results from this analytical model are in good agreement with experimental and analytical results from other researchers.
New occurrence of
Mawsonia
(Sarcopterygii: Actinistia) from the Early Cretaceous of the Sanfranciscana Basin, Minas Gerais, southeastern Brazil
Authors: de Carvalho Marise S. S. , Maisey John G. 
Published: June 2008

Abstract

The Cretaceous actinistian
Mawsonia
is represented by more than 360 dissociated, but well-preserved, bones obtained from the Areado Group in the Sanfranciscana Basin of Minas Gerais, Brazil. These are among the oldest records of
Mawsonia
(Berriasian, Lower Neocomian) and include previously undescribed or poorly known skeletal elements (e.g. splenial, dentary, autopalatine, zygals). The new material is referred to the type species,
M. gigas
. Morphological variation in the sample blurs some of the distinctions formerly drawn between nominal species of
Mawsonia
, and species level diversity in the genus is difficult to establish.
Mawsonia ubangiensis
,
M. libyca
, and
M. brasiliensis
are considered to be junior subjective synonyms of
M. gigas. Mawsonia gigas
probably appeared prior to the separation of S America and Africa and became widespread throughout much of western Gondwana (including parts of Africa), even surviving briefly on both continents following their separation.
Mawsonia tegamensis
is a morphologically distinctive Late Cretaceous African species with no evident fossil record in Brazil and which probably arose by vicariant speciation following isolation of a local
Mawsonia
population during the later stages of rifting between Northern Africa and the rest of Western Gondwana. Similarities between
Axelrodichthys
,
Lualabaea
(here regarded as Early Cretaceous in age) and recently described fossils from Morocco, Niger, and Madagascar suggest the presence of a second endemic Cretaceous mawsoniid lineage in northeastern Brazil and Africa.
Predictive data grouping
Authors: Essary David , Amer Ahmed 
Published: May 2008

We demonstrate that predictive grouping is an effective mechanism for reducing disk arm movement, thereby simultaneously reducing energy consumption and data access latency. We further demonstrate that predictive grouping has untapped dramatic potential to further improve access performance and limit energy consumption. Data retrieval latencies are considered a major bottleneck, and with growing volumes of data and increased storage needs it is only growing in significance. Data storage infrastructure is therefore a growing consumer of energy at data-center scales, while the individual disk is already a significant concern for mobile computing (accounting for almost a third of a mobile system's energy demands). While improving responsiveness of storage subsystems and hence reducing latencies in data retrieval is often considered contradictory with efforts to reduce disk energy consumption, we demonstrate that predictive data grouping has the potential to simultaneously work towards both these goals. Predictive data grouping has advantages in its applicability compared to both prior approaches to reducing latencies and to reducing energy usage. For latencies, grouping can be performed opportunistically, thereby avoiding the serious performance penalties that can be incurred with prior applications of access prediction (such as predictive prefetching of data). For energy, we show how predictive grouping can even save energy use for an individual disk that is never idle.
Predictive data grouping with effective replication results in a reduction of the overall mechanical movement required to retrieve data. We have built upon our detailed measurements of disk power consumption, and have estimated both the energy expended by a hard disk for its mechanical components, and that needed to move the disk arm. We have further compared, via simulation, three models of predictive grouping of on-disk data, including an optimal arrangement of data that is guaranteed to minimize disk arm movement. These experiments have allowed us to measure the limits of performance improvement achievable with optimal data grouping and replication strategies on a single device, and have further allowed us to demonstrate the potential of such schemes to reduce energy consumption of mechanical components by up to 70%.
A new approach to dynamic self-tuning of database buffers
Authors: Tran Dinh Nguyen , Huynh Phung Chinh , Tay Y. C. , Tung Anthony K. H. 
Published: May 2008

Current businesses rely heavily on efficient access to their databases. Manual tuning of these database systems by performance experts is increasingly infeasible: For small companies, hiring an expert may be too expensive; for large enterprises, even an expert may not fully understand the interaction between a large system and its multiple changing workloads. This trend has led major vendors to offer tools that automatically and dynamically tune a database system.
Many database tuning knobs concern the buffer pool for caching data and disk pages. Specifically, these knobs control the buffer allocation and thus the cache miss probability, which has direct impact on performance.
Previous methods for automatic buffer tuning are based on simulation, black-box control, gradient descent, and empirical equations. This article presents a new approach, using calculations with an analytically-derived equation that relates miss probability to buffer allocation; this equation fits four buffer replacement policies, as well as twelve datasets from mainframes running commercial databases in large corporations.
The equation identifies a buffer-size limit that is useful for buffer tuning and powering down idle buffers. It can also replace simulation in predicting I/O costs. Experiments with PostgreSQL illustrate how the equation can help optimize online buffer partitioning, ensure fairness in buffer reclamation, and dynamically retune the allocation when workloads change. It is also used, in conjunction with DB2's interface for retrieving miss data, for tuning DB2 buffer allocation to achieve targets for differentiated service.
Cathodic Electrodeposition of Mixed Rhenium-Molybdenum Oxides
Authors: Hahn Benjamin P. , Stevenson Keith J. 
Published: May 2008

The electrochemical deposition of molybdenum-rhenium oxides, MoxRe1-xO3, from acidic peroxo-polymolybdo-perrhenate solutions is described. The presence of perrhenate in the deposition solution is observed to accelerate the electrodeposition rate of MoxRe1-xO3 in comparison to that seen for MoO3. Cyclic voltammetry, spectroelectrochemistry, and electrochemical quartz crystal microbalance (EQCM) experiments are used to	understand the electrodeposition mechanism.
Electrochemical Behaviour of Platinum Nanoparticles Supported on Polypyrrole (PPy)/C Composite
Authors: Mokrane Souad , Makhloufi Laid , Alonso-Vante Nicolas 
Published: May 2008

We report on the synthesis of composites Polypyrrole/Carbon (PPy/C) to be used as matrix-support of platinum nanoparticles prepared by carbonyl chemical route. The composite materials with different PPy loading were characterized by physical chemical methods, such as elemental analysis, infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM). The catalysts: 20 wt. % Pt/composites were used as substrates for the oxygen reduction reaction in acid medium. For the same catalyst loading (50 µg	cm-2), it was observed that the nature of the composite strongly influences the electrochemical activity of nanoparticulated platinum.
Proton Transfer and Storage Behavior in Nanoparticles of Hydrous Ruthenium Oxide
Authors: Zheng Jim P. 
Published: May 2008

A model of proton transfer and storage in amorphous RuO2.xH2O was proposed to explain the relationship between the specific capacitance and the structure and water content in RuO2.xH2O materials. The morphologies and crystalline structures of	RuO2.xH2O annealed at different temperatures were investigated	using electrochemical (EC) methods, transmission electron microscope (TEM) and selected area electron diffraction (SAED) techniques, respectively. From EC measurements, it was found that the specific capacitance increased with increasing annealing temperature, and reached the maximum value at a critical temperature, at which the crystalline RuO2.xH2O started to be formed. It was also found from EC measurement that proton conductivity is low for RuO2.xH2O at steady-state. From the SAED patterns, the structure disorder brought about by proton insertion was obtained from a sample annealed at the critical temperature. From 1H nuclear magnetic reso nance (NMR) spectroscopy, it was demonstrated that the activation energy of	proton in RuO2.xH2O samples is directly associated with the proton transport and storage ability of these materials.
Self-Limiting Electropolymerization of o-Aminophenol on Ultraporous Carbon Nanoarchitectures for Electrochemical Capacitor Applications
Authors: Fischer Anne E. , Saunders Matthew P. , Lytle Justin C. , Rolison Debra R. , Long Jeffrey 
Published: May 2008

Electropolymerization of o-aminophenol at planar glassy carbon and ultraporous carbon nanofoam electrodes in buffered aqueous electrolytes produces an ultrathin coating of poly(o- aminophenol), POAP. Poly(o-aminophenol) is not electroactive at the deposition pH of 4.7, and thus the electrodeposited POAP	film rapidly passivates the electrode surface against further	monomer oxidation. The self-limiting nature of the deposition	process allows ultrathin coatings to be deposited onto and within ultraporous electrode structures without occluding the through-connected pore network of the nanofoam. When transferred to acidic aqueous electrolytes, POAP protonates and	becomes electroactive.	The charge-storage capacity for the resulting composite POAP-coated carbon is higher than that for bare carbon because of the added faradaic electrochemical reactions from the polymer coating.
Oxidation of Metallic Mn Thin Films Prepared in Butylmethylpyrrolidinium Bis(trifluoromethylsulfony)imide Ionic Liquid and the Pseudo-Capacitive Performance of the Anodized Oxides
Authors: Chang Jeng-Kuei , Huang Chiung-Hui , Tsai Wen-Ta , Sun I-Wen , Chen Po-Yu 
Published: May 2008

Metallic Manganese (Mn) thin films were successfully prepared by electrodeposition in butylmethylpyrrolidinium bis (trifluoromethylsulfony)imide (BMP-NTf2) ionic liquid, which has a very wide potential window extending over the reduction potential of Mn. Potentiostatic, galvanostatic, and cyclic voltammetric methods were performed to anodize the Mn films in	Na2SO4 solution. The surface morphology and crystal structure	of the obtained oxides were examined by a scanning electron microscope and X-ray diffractometer, respectively. Moreover, their chemical states were also analyzed with an X-ray photoelectron spectroscopy. It was clearly confirmed that the anodization methods could affect the material characteristics of the Mn oxides and therefore their pseudo-capacitive performance. The Mn oxide anodized by the cyclic voltammetric method showed a promising specific capacitance of 355 F/g (measured in 0.1 M Na2SO4 solution at a potential scan rate o f 25 mV/s). Its capacitance retained ratio after 500 charge-	discharge cycles was as high as 94 %.
Ethanol Electrooxidation on Pt-Sn Catalysts Deposited by Pulsed Laser Ablation
Authors: Bommersbach Pascale , Mohamedi Mohamed , Guay Daniel 
Published: May 2008

Pt3Sn catalysts were prepared from pure Pt and Sn targets by crossed beam pulsed laser deposition. The deposition was performed either under vacuum or in the presence of a He background pressure (1, 2, 3, 4 and 5 Torr). The pressure in the deposition chamber influences the surface structure and the morphology of the catalytic nanoparticles, as determined from scanning electron microscopy. Cyclic voltammogram curves reveal that Pt3Sn catalysts deposited under He lower the onset oxidation potential of ethanol compared to Pt3Sn electrodes synthesized under vacuum. This effect is particularly evident for Pt3Sn elaborated at 2 Torr He which provides a high current density value close to 20 mA.cm-2 at 0.7 V vs. RHE. Chronoamperometric measurements conducted at + 0.5 V vs. RHE also demonstrated that Pt3Sn deposited at 2 Torr He is the most	active electrocatalyst after 1 hour of electrolysis.
Electrochemical Characterization of the n = 2 Ruddlesden-Popper Sr3FeMO6+δ (M = Fe, Co, Ni) Phases by Electrochemical Impedance Spectroscopy
Authors: Mogni Liliana , Prado Fernando , Caneiro Alberto 
Published: May 2008

The electrochemical characterization of the porous Sr3FeMO6+d (M = Fe, Co, Ni) electrode materials has been performed by	EIS under pure O2 atmosphere and temperatures between 500 and	800 ºC. Thick films of porous Sr3FeMO6+d were deposited on a dense Ce0.9Gd0.1O2-x electrolyte disc by spray deposition and heat treated at 1000 ºC during 1 h. XRD and SEM were used to evaluate the structure and microstructure of the cells before and after the EIS measurements. Data of the Area Specific Resistance (ASR), defined by ASR = Z'(ω→0)-Z'(ωHF), associated with the overall oxygen reduction reaction, were obtained for the three compositions (Sr3Fe2O6+d, Sr3FeCoO6+d, Sr3FeNiO6+dγ). The ASR values are quite similar for the Sr3FeNiO6+d and Sr3FeCoO6+d compositions, and they are higher than those of Sr3Fe2O6+d. The activation energy (Ea) corresponding to the ASR for the Sr3FeNiO6+dγ material (1.3 eV) is high er than those of Sr3FeCoO6+d and Sr3Fe2O6+d, (0.9-1.0 eV).
Electrochemical Charging of Ultra-Thin Films of Conducting Polymer Supported Carbon Nanotubes and Particles: Application to Supercapacitors
Authors: Kulesza Pawel J. , Skunik Magdalena , Baranowska Beata , Chojak Malgorzata , Miecznikowski Krzysztof 
Published: May 2008

Modification of multi-walled carbon nanotubes with ultra-thin films of oxocyanoruthenium structures resulted in their improved capacitive characteristics, as evident from increased	specific capacitances and energy densities determined using diagnostic charging-discharging electrochemical experiments (involving cyclic voltammetry, galvanostatic and AC impedance methods). The largest specific capacitance (123 F g-1) was	found when the oxocyanoruthenium modified carbon nanotubes were further covered or linked with conducting polymer, namely poly (3,4-ethylenedioxythiophene) or PEDOT, structures. Among important issues are high stability of both inorganic and organic components, attractive electrostatic interactions between negatively charged oxocyanoruthenate and positively charged PEDOT, fast redox transitions of oxocyanoruthenium and high dynamics of charge propagation in PEDOT species, as well as ability to improve distribution of charge by mul ti-walled carbon nanotubes.