bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of the SpaCBA Pilus Fibers in the Probiotic Lactobacillus rhamnosus GG
Authors: Reunanen Justus , von Ossowski Ingemar , Hendrickx Antoni P. A. , Palva Airi , de Vos Willem M.
Published: January 2012

Lactobacillus rhamnosus
GG is a human intestinal isolate that has been studied intensively because of its probiotic properties. We have previously shown that
L. rhamnosus
GG produces proteinaceous pili that earlier had been observed only in Gram-positive pathogens (M. Kankainen et al., Proc. Natl. Acad. Sci. U. S. A.
106:
17193–17198, 2009). These pili were found to be encoded by the
spaCBA
gene cluster, and the pilus-associated SpaC pilin was shown to confer on the cells a mucus-binding ability. In addition to the
spaCBA
cluster, another putative pilus cluster,
spaFED
, was predicted from the
L. rhamnosus
GG genome sequence. Herein, we show that only SpaCBA pili are produced by
L. rhamnosus
, and we describe a detailed analysis of cell wall-associated and affinity-purified SpaCBA pili by Western blotting and immunogold electron microscopy. Our results indicate that SpaCBA pili are heterotrimeric protrusions with a SpaA subunit as the shaft-forming major pilin. Only a few SpaB subunits could be observed in pilus fibers. Instead, SpaB pilins were found at pilus bases, as assessed by immunogold double labeling of thin sections of cells, suggesting that SpaB is involved in the termination of pilus assembly. The SpaC adhesin was present along the whole pilus length at numbers nearly equaling those of SpaA. The relative amount and uniform distribution of SpaC within pili not only makes it possible to exert both long-distance and intimate contact with host tissue but also provides mucus-binding strength, which explains the prolonged intestinal residency times observed for
L. rhamnosus
GG compared to that of nonpiliated lactobacilli.
Membrane Lipid Peroxidation in Copper Alloy-Mediated Contact Killing of Escherichia coli
Authors: Hong Robert , Kang Tae Y. , Michels Corinne A. , Gadura Nidhi
Published: January 2012

Copper alloy surfaces are passive antimicrobial sanitizing agents that kill bacteria, fungi, and some viruses. Studies of the mechanism of contact killing in
Escherichia coli
implicate the membrane as the target, yet the specific component and underlying biochemistry remain unknown. This study explores the hypothesis that nonenzymatic peroxidation of membrane phospholipids is responsible for copper alloy-mediated surface killing. Lipid peroxidation was monitored with the thiobarbituric acid-reactive substances (TBARS) assay. Survival, TBARS levels, and DNA degradation were followed in cells exposed to copper alloy surfaces containing 60 to 99.90% copper or in medium containing CuSO
4
. In all cases, TBARS levels increased with copper exposure levels. Cells exposed to the highest copper content alloys, C11000 and C24000, exhibited novel characteristics. TBARS increased immediately at a very rapid rate but peaked at about 30 min. This peak was associated with the period of most rapid killing, loss in membrane integrity, and DNA degradation. DNA degradation is not the primary cause of copper-mediated surface killing. Cells exposed to the 60% copper alloy for 60 min had fully intact genomic DNA but no viable cells. In a
fabR
mutant strain with increased levels of unsaturated fatty acids, sensitivity to copper alloy surface-mediated killing increased, TBARS levels peaked earlier, and genomic DNA degradation occurred sooner than in the isogenic parental strain. Taken together, these results suggest that copper alloy surface-mediated killing of
E. coli
is triggered by nonenzymatic oxidative damage of membrane phospholipids that ultimately results in the loss of membrane integrity and cell death.
Identification of the Haloarchaeal Phasin (PhaP) That Functions in Polyhydroxyalkanoate Accumulation and Granule Formation in Haloferax mediterranei
Authors: Cai Shuangfeng , Cai Lei , Liu Hailong , Liu Xiaoqing , Han Jing , Zhou Jian , Xiang Hua
Published: January 2012

The polyhydroxyalkanoate (PHA) granule-associated proteins (PGAPs) are important for PHA synthesis and granule formation, but currently little is known about the haloarchaeal PGAPs. This study focused on the identification and functional analysis of the PGAPs in the haloarchaeon
Haloferax mediterranei
. These PGAPs were visualized with two-dimensional gel electrophoresis (2-DE) and identified by matrix-assisted laser desorption ionization–tandem time of flight mass spectrometry (MALDI-TOF/TOF MS). The most abundant protein on the granules was identified as a hypothetical protein, designated PhaP. A genome-wide analysis revealed that the
phaP
gene is located upstream of the previously identified
phaEC
genes. Through an integrative approach of gene knockout/complementation and fermentation analyses, we demonstrated that this PhaP is involved in PHA accumulation. The Δ
phaP
mutant was defective in both PHA biosynthesis and cell growth compared to the wild-type strain. Additionally, transmission electron microscopy results indicated that the number of PHA granules in the Δ
phaP
mutant cells was significantly lower, and in most of the Δ
phaP
cells only a single large granule was observed. These results demonstrated that the
H. mediterranei
PhaP was the predominant structure protein (phasin) on the PHA granules involved in PHA accumulation and granule formation. In addition, BLASTp and phylogenetic results indicate that this type of PhaP is exclusively conserved in haloarchaea, implying that it is a representative of the haloarchaeal type PHA phasin.
Prevalence, Characterization, and Antimicrobial Resistance of Listeria monocytogenes Isolates from Bovine Hides and Carcasses
Authors: Wieczorek Kinga , Dmowska Katarzyna , Osek Jacek
Published: January 2012

Listeria monocytogenes
isolates from bovine hides and carcasses (
n
= 812) were mainly of serogroup 1/2a. All strains were positive for internalin genes. Several isolates were resistant to oxacillin (72.2%) or clindamycin (37.0%). These findings indicate that
L. monocytogenes
of beef origin can be considered a public health concern.
Culture-Independent Approaches for Studying Viruses from Hypersaline Environments
Authors: Santos Fernando , Yarza Pablo , Parro Víctor , Meseguer Inmaculada , Rosselló-Móra Ramon , Antón Josefa
Published: January 2012

Hypersaline close-to-saturation environments harbor an extremely high concentration of virus-like particles, but the number of haloviruses isolated so far is still very low. Haloviruses can be directly studied from natural samples by using different culture-independent techniques that include transmission electron microscopy, pulsed-field gel electrophoresis, and different metagenomic approaches. Here, we review the findings of these studies, with a main focus on the metagenomic approaches. The analysis of bulk viral nucleic acids directly retrieved from the environment allows estimations of viral diversity, activity, and dynamics and tentative host assignment. Results point to a diverse and active viral community in constant interplay with its hosts and to a “hypersalineness” quality common to viral assemblages present in hypersaline environments that are thousands of kilometers away from each other.
Characterization of Airborne Bacteria at an Underground Subway Station
Authors: Dybwad Marius , Granum Per Einar , Bruheim Per , Blatny Janet Martha
Published: January 2012

The reliable detection of airborne biological threat agents depends on several factors, including the performance criteria of the detector and its operational environment. One step in improving the detector's performance is to increase our knowledge of the biological aerosol background in potential operational environments. Subway stations are enclosed public environments, which may be regarded as potential targets for incidents involving biological threat agents. In this study, the airborne bacterial community at a subway station in Norway was characterized (concentration level, diversity, and virulence- and survival-associated properties). In addition, a SASS 3100 high-volume air sampler and a matrix-assisted laser desorption ionization–time of flight mass spectrometry-based isolate screening procedure was used for these studies. The daytime level of airborne bacteria at the station was higher than the nighttime and outdoor levels, and the relative bacterial spore number was higher in outdoor air than at the station. The bacterial content, particle concentration, and size distribution were stable within each environment throughout the study (May to September 2010). The majority of the airborne bacteria belonged to the genera
Bacillus
,
Micrococcus
, and
Staphylococcus
, but a total of 37 different genera were identified in the air. These results suggest that anthropogenic sources are major contributors to airborne bacteria at subway stations and that such airborne communities could harbor virulence- and survival-associated properties of potential relevance for biological detection and surveillance, as well as for public health. Our findings also contribute to the development of realistic testing and evaluation schemes for biological detection/surveillance systems by providing information that can be used to mimic real-life operational airborne environments in controlled aerosol test chambers.
Design of Chimeric Levansucrases with Improved Transglycosylation Activity
Authors: Olvera Clarita , Centeno-Leija Sara , Ruiz-Leyva Paulina , López-Munguía Agustín
Published: January 2012

Fructansucrases (FSs), including levansucrases and inulosucrases, are enzymes that synthesize fructose polymers from sucrose by the direct transfer of the fructosyl moiety to a growing polymer chain. These enzymes, particularly the single domain fructansucrases, also possess an important hydrolytic activity, which may account for as much as 70 to 80% of substrate conversion, depending on reaction conditions. Here, we report the construction of four chimeric levansucrases from SacB, a single domain levansucrase produced by
Bacillus subtilis
. Based on observations derived from the effect of domain deletion in both multidomain fructansucrases and glucansucrases, we attached different extensions to SacB. These extensions included the transitional domain and complete C-terminal domain of
Leuconostoc citreum
inulosucrase (IslA),
Leuconostoc mesenteroides
levansucrase (LevC), and a
L. mesenteroides
glucansucrase (DsrP). It was found that in some cases the hydrolytic activity was reduced to less than 10% of substrate conversion; however, all of the constructs were as stable as SacB. This shift in enzyme specificity was observed even when the SacB catalytic domain was extended only with the transitional region found in multidomain FSs. Specific kinetic analysis revealed that this change in specificity of the SacB chimeric constructs was derived from a 5-fold increase in the transfructosylation
k
cat
and not from a reduction of the hydrolytic
k
cat
, which remained constant.
Human-Associated Extended-Spectrum β-Lactamase in the Antarctic
Authors: Hernández Jorge , Stedt Johan , Bonnedahl Jonas , Molin Ylva , Drobni Mirva , Calisto-Ulloa Nancy , Gomez-Fuentes Claudio , Astorga-España M. Soledad , González-Acuña Daniel , Waldenström Jonas , Blomqvist Maria , Olsen Björn
Published: January 2012

Escherichia coli
bacteria with extended-spectrum β-lactamase (ESBL) type CTX-M resistance were isolated from water samples collected close to research stations in Antarctica. The isolates had
bla
CTX-M-1
and
bla
CTX-M-15
genotypes and sequence types (ST) indicative of a human-associated origin. This is the first record of ESBL-producing enterobacteria from Antarctica.
Thermal Inactivation of Infectious Pancreatic Necrosis Virus in a Peptone-Salt Medium Mimicking the Water-Soluble Phase of Hydrolyzed Fish By-Products
Authors: Nygaard Halvor , Modahl Ingebjørg , Myrmel Mette
Published: January 2012

Infectious pancreatic necrosis virus (IPNV) (serotype Sp) was exposed to temperatures between 60 and 90°C in a medium mimicking the water-soluble phase of hydrolyzed fish by-products.
D
values ranged from 290 to 0.5 min, and the
z
value was approximately 9.8°C. Addition of formic acid to create a pH 4 medium did not enhance heat inactivation. Predicted inactivation effects at different temperature-time combinations are provided.
Development of a Modified Gentamicin Resistance Cassette for Genetic Manipulation of the Oral Spirochete Treponema denticola
Authors: Bian Jiang , Fenno J. Christopher , Li Chunhao
Published: January 2012

Herein, we report that a modified gentamicin cassette and a PCR-based method can be used for targeted mutagenesis of the oral spirochete
Treponema denticola
. This approach minimizes polar effects and spontaneous antibiotic resistance. Therefore, it can serve as a reliable tool for genetic manipulation of
T. denticola
.
Floating Wire for Enhancing Ignition of Atmospheric Pressure Inductively Coupled Microplasma
Authors: Kumagai Shinya , Asano Hirotaka , Hori Masaru , Sasaki Minoru
Published: January 2012

Placing a floating metal wire inside an atmospheric-pressure inductively coupled microplasma source enhances ignition. Under a He gas flow, plasma ignition is realized without using additional equipment for plasma ignition. Ignition power varies from 100 to 4 W by changing the wire length and wire position relative to the antenna coil for plasma generation. Minimum ignition power is observed by setting the floating wire slightly shifted from the coil center. The electric potential at the floating wire that is induced by applying power to the antenna coil is measured to be 80 V. Electric potential generation is discussed using an equivalent electric circuit model. The model explains that high-electric-potential generation at the wire is derived from the inductance of the floating wire and the difference in capacitances that are induced between each floating wire end and the surroundings.
Multiple-Height Microstructure Fabricated by Deep Reactive Ion Etching and Selective Ashing of Resist Layer Combined with Ultraviolet Curing
Authors: Kumagai Shinya , Hikita Akiyoshi , Iwamoto Takuya , Tomikawa Takashi , Hori Masaru , Sasaki Minoru
Published: January 2012

UV-cured photoresist is applied to the delay masking process to realize a multiple-height microstructure for the first time. Although the UV-cured photoresist is a soft mask, its material property becomes stable against resist thinner and UV exposure. A layered resist pattern can be realized by stacking normal photoresist on the UV-cured photoresist. The UV curing increases the glass transition temperature from 120 to 160 °C. By controlling the temperature, the normal photoresist can be ashed twice as fast as the UV-cured photoresist. This selectivity can be combined with the deep reactive ion etching of Si, and a microstructure having three different etching depths is realized, thus forming a micromirror. The multiple-height structure is advantageous for reducing the inertia of the mirror plate. For the same rotational spring constant, the micromirror has a higher resonant frequency, which is required for realizing higher-resolution laser displays.
Low-Temperature Fabrication of Germanium Nanostructures by Ion Irradiation: Effect of Supplied Particle Species
Authors: Miyawaki Ako , Hayashi Toshiaki , Tokunaga Tomoharu , Hayashi Akari , Hayashi Yasuhiko , Tanemura Masaki
Published: January 2012

Germanium (Ge) surfaces were irradiated by argon (Ar+) ions at 600 eV with a simultaneous Ge, Al, or Au supply at room temperature. The surfaces thus ion-irradiated were characterized by densely distributed nanowalls, nanobelts (narrower than the nanowalls in width), and cones tipped with nanoribbons (narrower than the nanobelts in width), depending on the supplied particle species and the supply rate. The higher the melting points of the supplied materials, the narrower the width of the top of the nanostructures. Thus the melting point and the supply rate of the supplied material are the key parameters for controlling the shape and size in the fabrication of ion-induced Ge nanostructures. It was also demonstrated that for nanowalls and nanobelts, a higher particle supply rate yielded wider nanostructures. For many nanoribbon-tipped cones, the width of the nanoribbon increased with distance from the cone top, and hence resulted in a bottleneck structure.
Anisotropic Bond Orientation of Amorphous Carbon by Deposition
Authors: Saito Seiki , Ito Atsushi M. , Takayama Arimichi , Nakamura Hiroaki
Published: January 2012

In general, diamond-like carbon is classified on the basis of the sp2, sp3, and hydrogen contents, otherwise known as the ternary phase diagram of amorphous carbon. In this study, however, it has been found that there is still some structural difference even though amorphous carbons may be located at the same point on the ternary phase diagram. Bond orientations of two types of amorphous carbon, arising in the deposition and annealing processes, are investigated, and it is shown that the bond orientations are totally different from each other even though the sp2, sp3, and hydrogen contents are the same.
Growth of Less Bowed GaN Epitaxial Layers on Sapphire Substrates by Formation of Low-Temperature GaN Buffer Layer with Columnar Microstructure
Authors: Lee Keon-Hun , Shin In Su , Park Sung Hyun , Moon Dae Young , Kim Minhwa , Park Jinsub , Nanishi Yasushi , Yoon Euijoon
Published: January 2012

Low-temperature (LT) GaN layers with a columnar microstructure were grown on InN layers with various thicknesses. Subsequently, thick, high-temperature GaN layers were grown on the columnar LT GaN/InN/sapphire template. The microstructure of the InN interlayer and the LT GaN columnar structure were investigated by transmission electron microscopy. From the X-ray diffraction analysis, it was shown that the InN layer was decomposed at the initial stage of LT GaN growth. The depth profile of Ga and In atoms from the GaN/InN/sapphire structure obtained by secondary ion mass spectrometry showed that the distribution of In atoms was confined only within the columnar LT GaN and InN/GaN layer interface. Wafer bowing was measured by optical methods and a significant reduction in the extent of wafer bowing was observed for the samples with the columnar LT GaN layer compared with the GaN layer grown on conventional LT GaN buffer layers. It is suggested that the epitaxial growth of a columnar LT GaN layer induced by a polycrystalline InN interlayer helped relax the GaN layer strain energy associated with thermal expansion mismatch, resulting in a less bowed GaN epitaxial layer on the sapphire substrate.
Numerical Design of SiO2 Bridges in Stretchable Thin Film Transistors
Authors: Kim Byung-Jae , Park Kyung-Yea , Ahn Jong-Hyun , Kim Youn-Jea
Published: January 2012

An amorphous indium–gallium–zinc oxide based inverter (a-IGZO inverter) was fabricated. Subsequently, its mechanical characteristics were investigated. A numerical method was adopted to optimize the a-IGZO inverter design. This optimization secured mechanical stability. The curvature at the edge of the SiO2 pad and the thickness of the indium–tin-oxide (ITO) electrode were accounted for in the models. The new model improved the mechanical stability when it was stretched by a total of 5% of its length along the x-axis and did not exhibit fractures or cracks. In contrast, the referenced model fractured under the same condition. It has been verified by both experiments and simulations that newly designed models obtain mechanical stability.
Fabrication and Electrochemical Characterization of Carbon Nanosheets by Microwave Plasma-Enhanced Chemical Vapor Deposition
Authors: Wang Zhipeng , Shoji Mao , Ogata Hironori
Published: January 2012

We employed Ar–CH4 to synthesize carbon nanosheets (CNSs), which are two-dimensional carbon nanostructures, by microwave plasma-enhanced chemical vapor deposition at relatively low temperatures and working pressures. The CNSs consist of few-layer graphene nanosheets with 1–3 nm thick sharp edges and possess a large amount of defects, as characterized by scanning and transmission electron microscopies, energy-dispersive X-ray and Raman spectroscopy. Owing to their extraordinary characteristics, the synthesized CNSs can be used to modify the electrodes and exhibit fast electron transfer kinetics in the inner sphere redox system of Fe(CN)6
3-/4- and remarkably active electrocatalytic and biosensing properties.
Epitaxial Graphene on Si(111) Substrate Grown by Annealing 3C-SiC/Carbonized Silicon
Authors: Aryal Hare Ram , Fujita Kazuhisa , Banno Kazuya , Egawa Takashi
Published: January 2012

High-quality epitaxial graphene has been a continuous focus of research interest owing to its viable device applications. Epitaxial graphene growth on silicon (Si) substrates is of great interest for its application to electronics. Here, we report experimental findings of atmospheric-pressure-grown epitaxial graphene on 3C-SiC(111)/carbonized Si(111) substrates. X-ray photoelectron spectroscopy and Raman spectroscopy were used for surface structural analysis and graphitic composition analysis. A Raman mapping image of the Lorentzian width of the 2D peak of graphene grown at 1300 °C signals the coexistence of single layers and multilayers. Transmission electron microscopy also confirmed the existence of monolayer graphene.
Epoxy Resin Surface Functionalization Using Atmospheric Pressure Plasma Jet Treatment
Authors: Sangprasert Waleepan , Nimmanpipug Piyarat , Yavirach Piriya , Lee Vannajan Sanghiran , Boonyawan Dheerawan
Published: January 2012

Atmospheric pressure plasma jet (APPJ) of N2 has been applied to promote adhesion between the epoxy resin post and composite core material due to the chemical active functional groups created. The APPJ was proved to be able to improve adhesive ability of the epoxy resin through the polar groups such as carbonyl group on its surface revealed by decreasing contact angle. The jet was generated from N2/Ar and N2/He gas mixture with ratio as low as 0.40–0.44 vol %, respectively. The optical emission spectrometry showed that the active species which could react with the substrate surface are nitrogen molecules and nitrogen molecules ion. The radial distribution functions (RDFs) calculations indicated that the most probable position of nitrogen active species reacting on the epoxy surface is at hydroxyl group with hydrogen bonding distance less than 35 nm.
Resistance Switching in Ni/HfOx/Ni Nonvolatile Memory Device with CF4/O2 Plasma Post-treatment
Authors: Lai Chiung-Hui , Chang Te-Shun , Tzeng Wen-Hsien , Chang Kow-Ming
Published: January 2012

The resistance switching characteristics of Ni/HfO
x
/Ni capacitor structures with CF4/O2 plasma post-treatment of different gas flow rate ratios were investigated. The HfO
x
film was deposited by an electron-gun evaporator, followed by the CF4/O2 plasma post-treatment with different gas flow rate ratios. According to the filament model, conducting filaments (CFs) are formed by the percolation of various types of defects such as oxygen ions and oxygen vacancies. Moreover, the incorporation of oxygen/fluorine may terminate the oxygen vacancies to form Hf–F bonds and eliminate both fixed and interface traps, which can help to form fixed CFs in the film owing to local stronger Hf–F bonds. In this work, the improvement in the stability of resistance switching and current in the high-resistance state (HRS) was achieved by suitable plasma post-treatment. This may be attributed to the formation of Hf–F bonds as observed through electron spectroscopy for chemical analysis.
Experimental Study on Severe Plastic Deformation of Ti by Novel Equal-Channel Angular Pressing
Authors: Jamian Saifulnizan , Sato Hisashi , Miura-Fujiwara Eri , Watanabe Yoshimi
Published: January 2012

This study involves experimental investigation on severe plastic deformation (SPD) of Ti using novel equal-channel angular pressing (ECAP) at ambient temperature. Ti wire is tightly encapsulated in a hollow host material made of Al-based functionally graded material (FGM). The host material is prepared by embedding Al–Al3Ti alloy into Al. Three types of the Al–Al3Ti alloys with different Al3Ti volume fractions are used to prepare the host materials. ECAP for specimens is carried out for up to eight passes by route A. The microstructure and hardness of ECAPed specimens are investigated. The changes in microstructure and the increase in the hardness value of Ti with increased number of ECAP passes are evidences showing that Ti is successfully deformed by this technique.
In-situ Annular Bright-Field Imaging of Structural Transformation of Spinel LiV2O4 Crystals into Defective LixV2O4
Authors: Lee Soyeon , Oshima Yoshifumi , Niitaka Seiji , Takagi Hidenori , Tanishiro Yasumasa , Takayanagi Kunio
Published: January 2012

Thin LiV2O4 crystals with a spinel structure were observed by annular bright-field (ABF) imaging in which the contrast of lithium, vanadium, and oxygen columns varies depending on the number of ions in each column. On intense electron beam irradiation, lithium ions started to be displaced from the tetrahedral sites, which induced the redistribution of vanadium ions at octahedral sites. Consequently, the spinel structure was transformed into a defective NaCl structure. In-situ ABF imaging of thin specimens is a promising method for investigating local structural transformations accompanied by the displacement of lithium ions.
Unitary Transflective Liquid Crystal Display with an In-Cell Retarder on a Wire Grid Plate as a Reflector–Polarizer in a Single Driving Configuration
Authors: Hong Jong-Ho , Park Seung-Chul , Lee Sin-Doo , Lim Yong-Woon
Published: January 2012

A unitary type of a transflective liquid crystal display (LCD), having the same optical efficiency in both the transmissive (T) part and the reflective (R) part, is developed using an in-cell patterned (IP) retarder fabricated directly on a wire grid (WG) plate in a twisted-nematic geometry. The WG plate is used for a substrate and served as a polarizer in the T region and a reflector in the R region. In this unitary transflective LCD, it was found that the high optical efficiency and the fast response are easily achieved in a single driving scheme since the electro-optical disparity between the transmittance and the reflectance is intrinsically eliminated.
Preparation and Luminescence Properties of Organic Phosphorescent Nanoparticles
Authors: Miyashita Yousuke , Horino Shinichi , Kasai Hitoshi , Oikawa Hidetoshi , Nakanishi Hachiro
Published: January 2012

Organic phosphorescent nanoparticles, which have a host–guest-type structure and show photosensitized phosphorescence, were successfully prepared by a reprecipitation method. Concentration quenching, which is disadvantage for organic nanophosphors, was efficiently suppressed with a host–guest-type structure widely used in organic light-emitting diodes. The study of luminescence properties revealed that the host material acts as a photosensitizer leading to the phosphorescence of the guest materials. Depending on the guest material, organic phosphorescent nanoparticles showed emission spectra of blue, green, and red. By adjusting the mixing ratio of phosphorescent nanoparticle dispersion liquids, the emission spectrum was tunable and white luminescence was observed.
Magnetic Properties of Cobalt Plate Compared with Iron and Nickel Plates
Authors: Tsunawaki Yoshiaki , Ohigashi Nobuhisa , Asakawa Makoto R.
Published: January 2012

The magnetic behavior of Co plates has been compared with those of Fe and Ni plates studied in a previous work. It was found that the factor of magnetization ηb for Co plates does not show abrupt reduction with decreasing thickness, and magnetic flux density B
m and magnetization P
m are similar to those of Fe plates rather than Ni plates.
Stratigraphy and environmental conditions of the terminal Neoproterozoic–Cambrian Period in Oman: evidence from sulphur isotopes
Authors: SchrÖder Stefan , Schreiber B.Charlotte , Amthor Joachim E. , Matter Albert
Published: January 2012

Terminal Neoproterozoic and Cambrian evaporite rocks worldwide record a marked sulphur isotope excursion to very heavy δ
34
S isotopes that reflect a period of significant burial of reduced sulphur. New δ
34
S data from anhydrite and pyrite of the Ara Group in Oman extend this record to Arabia. Depositional history of the Ara Group spans
c
. 8 Ma across the terminal Neoproterozoic–Cambrian boundary. Therefore, these rocks provide a detailed record of sulphur isotopic evolution in this important time interval. Ara Group sulphur isotope values include a mean δ
34
S
anhydrite
of 39.4‰ ± 2.6‰ (1σ; range 32.4–46.4‰;
n
=61), and a mean δ
34
S
pyrite
of 1.4‰ ± 7.3‰ (1σ; range −10.8‰ to 11.4‰;
n
=12). The isotope signatures were not altered significantly during diagenesis and are representative of the isotopic composition of parent waters in the basin. Marine bromine concentrations in halite and marine fossils in associated carbonate rocks indicate that these waters had a marine origin. Bacterial sulphate reduction was the dominant process leading to the segregation between isotopically heavy sulphur incorporated in evaporite rocks and isotopically light sulphur buried in pyrite and organic matter. Strong sulphate reduction operated in a hypersaline and partly anoxic basin; these environmental conditions were also conducive to the preservation of organic material and make the Ara Group a prolific hydrocarbon province. Significant variation of the observed values is attributed to the inherent variability of bacterial sulphate reduction, including partially closed-system behaviour, disproportionation processes, limited diagenesis, and possibly secular variation of sulphur isotopes within the basin. Ara Group δ
34
S
anhydrite
values overlap with data from other terminal Neoproterozoic to Cambrian basins, but the mean δ
34
S
anhydrite
is highest in Oman. This observation cannot be attributed solely to the specific anoxic conditions and strong bacterial sulphate reduction in Oman, because such conditions were widespread in most evaporite basins of the terminal Neoproterozoic–Cambrian Periods. Instead, slight age differences between these basins can introduce a bias in the sulphur isotope curve. Excellent preservation of Ara Group deposits and in particular the precise age constraints make the Ara Group representative for the seawater sulphur isotopic composition at the terminal Neoproterozoic–Cambrian boundary. As a result of the inherent variability of bacterial sulphate reduction, δ
34
S values at the lower end of the spectrum should be most representative for the global signal. Based on results of this study, the global signal is estimated to be approximately 35–40‰.
The Bulawayan Supergroup: a late Archaean passive margin-related large igneous province in the Zimbabwe craton
Authors: Prendergast M.D.
Published: January 2012

The four principal lithostratigraphic units (Koodoovale, Manjeri, Reliance and Zeederbergs) of the widespread, late Archaean Bulawayan Supergroup in the Zimbabwe craton record the early to middle-stage development of a major (
c
. 250 000 km
2
) volcanosedimentary basin. The craton-wide
c
. 2.70 Ga Manjeri unit varies systematically from a tens of metres thick, dominantly chemogenic, basinal sediment in gradational, conformable contact with the underlying, several kilometres thick, diachronous, 2.83–2.71 Ga felsic Koodoovale unit in the north and west, to an up to hundreds of metres thick, dominantly siliciclastic, retrogradational, platformal sediment unconformably overlying protocratonic basement in the south and east. The intermittent,
c
. 2.70 Ga Reliance unit consists of the flow fields of several discrete komatiitic sill–flow complexes scattered throughout the craton and fed by an interlinked system of mid- to upper-crustal ‘flow-through’ feeder sills. The
c
. 2.70 Ga Zeederbergs unit comprises a submarine, flood basalt sequence of several kilometres thickness that erupted from ENE-trending, parallel mafic dykes preserved in the south and east. The basalts form a craton-wide blanket to the Reliance flow fields and intervening Manjeri sediments. Certain structural–stratigraphic features rule out primary construction of the Bulawayan Supergroup by early lateral accretion as proposed by several previous workers. Instead, evolution of the Bulawayan basin can best be explained by vertical accretion involving (1) abundant, episodic and bimodal, plume-related volcanism and (2) extension and rapid subsidence of continental lithosphere. Many aspects of the Bulawayan Supergroup provide important insights into Archaean tectonics, mantle plume activity, magma generation and lithospheric plumbing.
Dating fault reactivation by Ar/Ar laserprobe: an alternative view of apparently cogenetic mylonite–pseudotachylite assemblages
Authors: SHERLOCK S.C. , WATTS L.M. , HOLDSWORTH R.E. , ROBERTS D.
Published: January 2012

Apparently cogenetic mylonite–pseudotachylite assemblages are commonly reported in major fault zones. They represent two very incompatible modes of deformation, and complex formation mechanisms have been proposed to explain this paradox. We report here one such assemblage from Central Norway in which apparently synchronous mylonite and pseudotachylite formation is separated by 100 Ma-mean muscovite Ar/Ar laserprobe spot ages from mylonite, and pseudotachylite matrix, are 406 ± 11 Ma and 290 ± 10 Ma respectively. In preference to a complex cogenetic model we invoke fault reactivation as a viable alternative, and suggest that assumed contemporaneity in such assemblages may be invalid in many cases.
Cardiac-specific genetic inhibition of nuclear factor-κB prevents right ventricular hypertrophy induced by monocrotaline
Authors: Kumar Sandeep , Wei Chuanyu , Thomas Candice M. , Kim Il-Kwon , Seqqat Rachid , Kumar Rajesh , Baker Kenneth M. , Jones W. Keith , Gupta Sudhiranjan
Published: January 2012

Uncontrolled pulmonary arterial hypertension (PAH) results in right ventricular (RV) hypertrophy (RVH), progressive RV failure, and low cardiac output leading to increased morbidity and mortality (McLaughlin VV, Archer SL, Badesch DB, Barst RJ, Farber HW, Lindner JR, Mathier MA, McGoon MD, Park MH, Rosenson RS, Rubin LJ, Tapson VF, Varga J. J Am Coll Cardiol 53: 1573–1619, 2009). Although the exact figures of its prevalence are difficult to obtain because of the diversity of identifiable causes, it is estimated that the incidence of pulmonary hypertension is seven to nine cases per million persons in the general population and is most prevalent in the age group of 20–40, occurring more commonly in women than in men (ratio: 1.7 to 1; Rubin LJ. N Engl J Med 336: 111–117, 1997). PAH is characterized by dyspnea, chest pain, and syncope. Unfortunately, there is no cure for this disease and medical regimens are limited (Simon MA. Curr Opin Crit Care 16: 237–243, 2010). PAH leads to adverse remodeling that results in RVH, progressive right heart failure, low cardiac output, and ultimately death if left untreated (Humbert M, Morrell NW, Archer SL, Stenmark KR, MacLean MR, Lang IM, Christman BW, Weir EK, Eickelberg O, Voelkel NF, Rabinovitch M. J Am Coll Cardiol 43: 13S-24S, 2004; Humbert M, Sitbon O, Simonneau G. N Engl J Med 351: 1425–1436, 2004. LaRaia AV, Waxman AB. South Med J 100: 393–399, 2007). As there are no direct tools to assess the onset and progression of PAH and RVH, the disease is often detected in later stages marked by full-blown RVH, with the outcome predominantly determined by the level of increased afterload (D'Alonzo GE, Barst RJ, Ayres SM, Bergofsky EH, Brundage BH, Detre KM, Fishman AP, Goldring RM, Groves BM, Kernis JT, et al. Ann Intern Med 115: 343–349, 1991; Sandoval J, Bauerle O, Palomar A, Gomez A, Martinez-Guerra ML, Beltran M, Guerrero ML. Validation of a prognostic equation Circulation 89: 1733–1744, 1994). Various studies have been performed to assess the genetic, biochemical, and morphological components that contribute to PAH. Despite major advances in the understanding of the pathogenesis of PAH, the molecular mechanism(s) by which PAH promotes RVH and cardiac failure still remains elusive. Of all the mechanisms involved in the pathogenesis, inflammation and oxidative stress remain the core of the etiology of PAH that leads to development of RVH (Dorfmüller P, Perros F, Balabanian K, Humbert M. Eur Respir J 22: 358–363, 2003).
New mechanisms of pulmonary arterial hypertension: role of Ca2+signaling
Authors: Kuhr Frank K. , Smith Kimberly A. , Song Michael Y. , Levitan Irena , Yuan Jason X-J.
Published: January 2012

Pulmonary arterial hypertension (PAH) is a severe and progressive disease that usually culminates in right heart failure and death if left untreated. Although there have been substantial improvements in our understanding and significant advances in the management of this disease, there is a grim prognosis for patients in the advanced stages of PAH. A major cause of PAH is increased pulmonary vascular resistance, which results from sustained vasoconstriction, excessive pulmonary vascular remodeling, in situ thrombosis, and increased pulmonary vascular stiffness. In addition to other signal transduction pathways, Ca2+signaling in pulmonary artery smooth muscle cells (PASMCs) plays a central role in the development and progression of PAH because of its involvement in both vasoconstriction, through its pivotal effect of PASMC contraction, and vascular remodeling, through its stimulatory effect on PASMC proliferation. Altered expression, function, and regulation of ion channels and transporters in PASMCs contribute to an increased cytosolic Ca2+concentration and enhanced Ca2+signaling in patients with PAH. This review will focus on the potential pathogenic role of Ca2+mobilization, regulation, and signaling in the development and progression of PAH.
Effect of sex and ovarian hormones on carotid baroreflex resetting and function during dynamic exercise in humans
Authors: Kim Areum , Deo Shekhar H. , Fisher James P. , Fadel Paul J.
Published: January 2012

To date, no studies have examined whether there are either sex- or ovarian hormone-related alterations in arterial baroreflex resetting and function during dynamic exercise. Thus we studied 16 young men and 18 young women at rest and during leg cycling at 50% heart rate (HR) reserve. In addition, 10 women were studied at three different phases of the menstrual cycle. Five-second pulses of neck pressure (NP) and neck suction (NS) from +40 to −80 Torr were applied to determine full carotid baroreflex (CBR) stimulus response curves. An upward and rightward resetting of the CBR function curve was observed during exercise in all groups with a similar magnitude of CBR resetting for mean arterial pressure (MAP) and HR between sexes ( P > 0.05) and at different phases of the menstrual cycle ( P > 0.05). For CBR control of MAP, women exhibited augmented pressor responses to NP at rest and exercise during mid-luteal compared with early and late follicular phases. For CBR control of HR, there was a greater bradycardic response to NS in women across all menstrual cycle phases with the operating point (OP) located further away from centering point (CP) on the CBR-HR curve during rest (OP-CP; in mmHg: −13 ± 3 women vs. −3 ± 3 men; P < 0.05) and exercise (in mmHg: −31 ± 2 women vs. −15 ± 3 men; P < 0.05). Collectively, these findings suggest that sex and fluctuations in ovarian hormones do not influence exercise resetting of the baroreflex. However, women exhibited greater CBR control of HR during exercise, specifically against acute hypertension, an effect that was present throughout the menstrual cycle.
Cathepsin B Inhibition Limits Bone Metastasis in Breast Cancer
Authors: Withana Nimali P. , Blum Galia , Sameni Mansoureh , Slaney Clare , Anbalagan Arulselvi , Olive Mary B. , Bidwell Bradley N. , Edgington Laura , Wang Ling , Moin Kamiar , Sloane Bonnie F. , Anderson Robin L. , Bogyo Matthew S. , Parker Belinda S.
Published: January 2012

Metastasis to bone is a major cause of morbidity in breast cancer patients, emphasizing the importance of identifying molecular drivers of bone metastasis for new therapeutic targets. The endogenous cysteine cathepsin inhibitor stefin A is a suppressor of breast cancer metastasis to bone that is coexpressed with cathepsin B in bone metastases. In this study, we used the immunocompetent 4T1.2 model of breast cancer which exhibits spontaneous bone metastasis to evaluate the function and therapeutic targeting potential of cathepsin B in this setting of advanced disease. Cathepsin B abundancy in the model mimicked human disease, both at the level of primary tumors and matched spinal metastases. RNA interference–mediated knockdown of cathepsin B in tumor cells reduced collagen I degradation in vitro and bone metastasis in vivo. Similarly, intraperitoneal administration of the highly selective cathepsin B inhibitor CA-074 reduced metastasis in tumor-bearing animals, a reduction that was not reproduced by the broad spectrum cysteine cathepsin inhibitor JPM-OEt. Notably, metastasis suppression by CA-074 was maintained in a late treatment setting, pointing to a role in metastatic outgrowth. Together, our findings established a prometastatic role for cathepsin B in distant metastasis and illustrated the therapeutic benefits of its selective inhibition in vivo. Cancer Res; 72(5); 1199–209. ©2012 AACR.
Infiltration of Lynch Colorectal Cancers by Activated Immune Cells Associates with Early Staging of the Primary Tumor and Absence of Lymph Node Metastases
Authors: de Miranda Noel F.C.C. , Goudkade Danny , Jordanova Ekaterina S. , Tops Carli M.J. , Hes Frederik J. , Vasen Hans F.A. , van Wezel Tom , Morreau Hans
Published: January 2012

Purpose: Lynch syndrome colorectal cancers often lose human leukocyte antigen (HLA) class I expression. The outgrowth of clones with immune evasive phenotypes is thought to be positively selected by the action of cytotoxic T cells that target HLA class I–positive cancer cells. To investigate this hypothesis, we related the type and density of tumor lymphocytic infiltrate in Lynch colorectal cancers with their HLA class I phenotype and clinicopathologic stage.

Experimental Design: HLA class I expression was assessed by means of immunohistochemistry. Characterization of tumor-infiltrating lymphocytes was carried out by using a triple immunofluorescence procedure that allowed the simultaneous detection of CD3-, CD8-, and granzyme B (GZMB)-positive cells. Additional markers were also used for further characterization of an elusive CD3−/CD8−/GZMB+ cell population.

Results: We discovered that high tumor infiltration by activated CD8+ T cells correlated with aberrant HLA class I expression and associated with early tumor stages (P < 0.05). CD8+ T cells were most abundant in HLA class I heterogeneous tumors (P = 0.02) and frequent in HLA class I–negative cases (P = 0.04) when compared with HLA class I–positive carcinomas. An elusive immune cell population (CD45+/CD8−/CD56−/GZMB+) was characteristic for HLA class I–negative tumors lacking lymph node metastases (P < 0.01).

Conclusions: The immune system assumes an important role in counteracting the progression of Lynch colorectal cancers and in selecting abnormal HLA class I phenotypes. Our findings support the development of clinical strategies that explore the natural antitumor immune responses occurring in Lynch syndrome carriers. Clin Cancer Res; 18(5); 1237–45. ©2012 AACR.
Special Aspects of the Treatment of HIV-2-Infected Patients
Authors: Camacho Ricardo Jorge
Published: January 2012

HIV-2 is responsible for a limited epidemic in West Africa. Around 20% of all infected patients will progress to AIDS, and will need antiretroviral therapy. Unfortunately, antiretrovirals were developed to suppress HIV-1 replication; not all of them are active against HIV-2, e.g. all nonnucleoside reverse transcriptase inhibitors or fusion inhibitors. Moreover, only three protease inhibitors have the same activity in HIV-1 and HIV-2: lopinavir, saquinavir and darunavir. Even if all nucleoside and nucleotide reverse transcriptase inhibitors appear to be equally efficient against HIV-2, different resistance pathways and an increased facility of resistance selection make their use much more difficult than in HIV-1. Integrase inhibitors have a potent inhibitory effect on HIV-2 replication, but questions about the best timing for their use remain unanswered, as well as those regarding the use of entry inhibitors in this setting. The lack of reliable monitoring tools adds to the difficulty of treating HIV-2-infected patients, mostly because the viral load is not as useful as it is in HIV-1, and the incomplete knowledge about resistance pathways limits the clinical usefulness of resistance testing. With all these limitations, HIV-2 treatment remains a challenge. Further research is urgently needed, since antiretroviral therapy is now becoming available in countries where the HIV-2 prevalence is significant. The need for appropriate guidelines for HIV-2 treatment has become an emergency.
Late Embryonic and Postnatal Development of Interstitial Cells of Cajal in Mouse Esophagus: Distribution, Proliferation and Kit Dependence
Authors: He Xiao , Yang Wen-cui , Wen Xiang-yin , Tang Di , Xiao Lan , Han Juan , Yu Bin , Zhang Wei , Mei Feng
Published: January 2012

This paper investigates alterations in interstitial cells of Cajal (ICC) in the esophagus of mice from embryonic day 13.5 (E13.5) to 36 days postpartum (P0–P36) using immunohistochemistry. At E13.5, Kit+ cells presented in clusters and differentiated into spindle-like cells with biopolar processes within the outer (longitudinal) and inner (circular) muscle layers at E17.5. These Kit+ ICC with long processes were also Ano1+ and prominent at birth. The density of ICC gradually decreased, and at P36 it became about one twentieth of that at birth. Kit ligand (stem cell factor) expression is lower in striated muscle cells than that in smooth muscle cells. The ICC number was higher in the distal (close to the cardia) than in the proximal esophagus (close to the pharynx). Some Kit+/Ki67+ and Kit+/bromodeoxyuridine+ cells were observed within the muscle layers, and proliferation persisted from birth through adulthood (P28) with a gradually decreasing cell number. At 24 h, Kit+ ICC were dramatically decreased and almost missing 48 h after administration of imatinib (a Kit inhibitor). Our results indicate that ICC proliferation is age dependent and persists throughout the postnatal period. There is a dramatic decrease in the ICC number from P0 to adult life. The Kit signal is essential for the postnatal development of ICC in the esophagus.
Enrollment in Clinical Trials Correlates with Improved Survival in Metastatic Melanoma
Authors: Seetharamu Nagashree , Tu Ting J. , Christos Paul , Ott Patrick A. , Berman Russell S. , Shapiro Richard L. , Osman Iman , Pavlick Anna C.
Published: January 2012

Background: Although the current median survival time of stage-IV melanoma patients is less than 12 months, there is a subset of patients who experience long-term survival. Due to poor response rates to standard cytotoxic agents in metastatic melanoma, patients are encouraged to participate in clinical trials, the overall impact of which has not been studied, however. The aim of our study was to identify the factors associated with long-term survival and to determine the impact of clinical trial enrollment on patient outcome. Methods: We studied stage-IV melanoma patients prospectively enrolled at New York University Medical Center from 2002–2008. Associations between clinicopathologic variables and overall post-stage-IV survival were examined. Kaplan-Meier survival analysis was used to identify univariate predictors of post-stage-IV survival and the independent effect of these variables was assessed in a multivariate Cox proportional hazards regression model. The associations between clinicopathologic variables and long-term survival status (≧2 vs. <2 years) were examined by χ2 analysis and the independent effect of these variables on the latter was assessed in a multivariate logistic regression model. Results: Site of metastasis, treatment (systemic vs. localized) and pretreatment lactate dehydrogenase (LDH) level independently correlated with post-stage-IV survival. Participation in clinical trials and normal LDH levels were associated with a long-term survival of ≧2 years. Conclusion: Our data suggest that enrollment in clinical trials independently correlates with prolonged survival after a diagnosis of stage IV melanoma.