bluuebunny/crossref_metadata_2025 huggingface dataset:
Androgen stimulates glycolysis for de novo lipid synthesis by increasing the activities of hexokinase 2 and 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 2 in prostate cancer cells
Authors: Moon Jong-Seok , Jin Won-Ji , Kwak Jin-Hye , Kim Hyo-Jeong , Yun Mi-Jin , KIM Jae-Woo , Park Sahng Wook , Kim Kyung-Sup
Published: October 2010

Up-regulation of lipogenesis by androgen is one of the most characteristic metabolic features of LNCaP prostate cancer cells. The present study revealed that androgen increases glucose utilization for de novo lipogenesis in LNCaP cells through the activation of HK2 (hexokinase 2) and activation of the cardiac isoform of PFKFB2 (6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase). Activation of PKA (cAMP-dependent protein kinase) by androgen increased phosphorylation of CREB [CRE (cAMP-response element)-binding protein], which in turn bound to CRE on the promoter of the HK2 gene resulting in transcriptional activation of the HK2 gene. Up-regulation of PFKFB2 expression was mediated by the direct binding of ligand-activated androgen receptor to the PFKFB2 promoter. The activated PI3K (phosphoinositide 3-kinase)/Akt signalling pathway in LNCaP cells contributes to the phosphorylation of PFKFB2 at Ser466 and Ser483, resulting in the constitutive activation of PFK-2 (6-phosphofructo-2-kinase) activity. Glucose uptake and lipogenesis were severely blocked by knocking-down of PFKFB2 using siRNA (small interfering RNA) or by inhibition of PFK-2 activity with LY294002 treatment. Taken together, our results suggest that the induction of de novo lipid synthesis by androgen requires the transcriptional up-regulation of HK2 and PFKFB2, and phosphorylation of PFKFB2 generated by the PI3K/Akt signalling pathway to supply the source for lipogenesis from glucose in prostate cancer cells.
Relationship of late Quaternary tectonics and volcanism in the Khanarassar active fault zone, the Armenian Upland
Authors: Karakhanian Arkadiy S. , Trifonov Vladimir G. , Azizbekian Ovanes G. , Hondkarian David G.
Published: October 2010

The Syunik rhombus‐like structure in the Khanarassar active dextral fault zone of Armenia is a typical pull‐apart basin, formed between terminal parts of two adjacent en echelon fault segments. Some component of subsidence associated with the faults of the structure is found between the en echelon segments; nevertheless, the dextral component continues to be predominant even on the boundaries of the pull‐apart basin. The late Pleistocene and Holocene lava volcanoes of the basin are also associated with those faults that have a component of extension. The relative ages of fault displacements and volcanic eruptions have been identified by the mutual correlation of lavas, moraines and topographic features and by archaeological and radiocarbon dating. According to the interpretation of rupturing and volcanism, major earthquakes and volcanic eruptions appear inter‐related and three pulses of such activity during the earlier and middle Holocene have been identified.
Styles of back‐arc extension in the Central Mediterranean
Authors: Faccenna Claudio , Mattei Massimo , Funiciello Renato , Jolivet Laurent
Published: October 2010

In the Central Mediterranean two back‐arc basins, the Liguro‐Provençal (LPb) and the Tyrrhenian basin (Tb), opened progressively and consecutively from the late Eocene–Oligocene to the present. Evolution in space and time of rifting and drifting processes, along three different transects across these basins, shows differences in the style of extension: LPb opened with the formation of a narrow, single rift, while in the Tb deformation and magmatism is spread over a wide area. Moreover at the Northern end of the Tb the locus of extension progressively migrated towards the east whereas in the Southern Tb the locus of extension and magmatism migrated inside the basin, inducing continental break‐up and drifting of the previously formed older conjugate basins. We propose that these different styles of back‐arc extension depend upon internal conditions, such as prerift rheology linked with its geological heritage, and external conditions, e.g. the style of subduction.
Internal deformation and compaction of the Makran accretionary wedge
Authors: Fruehn J. , White R. S. , Minshull T. A.
Published: October 2010

The Makran accretionary wedge is one of the largest on Earth. A 7‐km‐thick column of sands and quartzolithic turbidites are incorporated into this wedge in a series of deformed thrust sheets. We present the results of prestack depth migration and focusing‐error analysis (migration velocity analysis) performed on a profile across the Makran wedge. The depth section shows the deformation style of the accreted sediments, and the migration velocities allow us to estimate porosity variations in the sediments. The thrust sheets show evidence of fault‐propagation folding, with a long wavelength of deformation (≈ 12 km) and secondary thrusting in the kink bands of the folds, such that the central part of each thrust sheet is elevated to form an additional ridge. This deformation style and the 15° steep surface slope of the first ridge suggest a high degree of consolidation. Porosities were calculated from the seismic migration velocities and the ratio of fluid pressure to lithostatic pressure λ was estimated for 5 locations along the profile. Rather than being undercompacted and overpressured as in most accretionary wedges, the sedimentary input is normally compacted (exponential porosity decay) throughout almost the whole wedge. However, a slight increase in porosity and λ at depth, with respect to the normal compaction curve indicates, that the turbiditic sequence might be overpressured landward of the deformation front.
Rates of magma ascent and depths of magma reservoirs beneath La Palma (Canary Islands)
Authors: Klügel Andreas , Hansteen Thor H. , Schmincke Hans‐Ulrich
Published: October 2010

Peridotitic mantle xenoliths from historic and prehistoric eruptions on La Palma show many similarities. Prolonged reactions of the xenoliths with their host magmas have been used to place constraints on the magma transport system beneath the island. All xenoliths show crystalline selvages and 0.9–2.6 mm wide diffusion zones in olivine along most of their surface. Diffusion kinetics in olivine, combined with fluid inclusion barometry, document that selvages and diffusion zones formed at crustal levels within 8 to about 100 years. Some xenolith fractures lack selvages and were in contact with the host magma for less than 4 days. A multistage magma ascent is proposed: (i) peridotite wall rock was fragmented and became incorporated into the ascending magma years to decades prior to the eruption; (ii) the xenoliths were rapidly transported to, and deposited in, crustal magma reservoirs, forming selvages and diffusion zones at the xenolith rims; (iii) renewed fragmentation of the xenoliths occurred days to hours prior to eruption, possibly by decompressive strain fracturing during rapid ascent.
The Western Mediterranean extensional basins and the Alpine orogen
Authors: Doglioni Carlo , Gueguen Erwan , Sàbat Francesc , Fernandez Manuel
Published: October 2010

The western Mediterranean late Oligocene–Miocene basins (Alboran, Valencia and Provençal basins) are a coherent system of interrelated troughs. In all basins normal faults and thermal subsidence migrated toward the east progressively moving to the Miocene‐to‐Pleistocene Algerian and Tyrrhenian basins. All those troughs appear elements of the back‐arc opening related to the eastward roll‐back of the W‐directed Apennines–Maghrebides subduction zone, similarly to western Pacific back‐arc settings.

These late Oligocene–early Miocene basins nucleated both within the Betic cordillera (e.g. Alboran sea) and in its foreland (Valencia and Provençal troughs). The N40–70° direction of grabens is oblique to the coexisting N60–80°‐trending orogen and shows its structural independence from the orogenic roots. Thus, as the extension cross‐cuts the orogen and developed also well outside the thrust belt front, the westernmost basins of the Mediterranean had to develop independently from the Alps‐Betics orogen. Therefore, the Alboran extension, considered a classic example of a basin generated by the collapse of an orogen, cannot be ascribed to the detachment or annihilation of the lithospheric root. In contrast with the eastward migrating extensional basins, the Betic‐Balearic thrust front was migrating westward producing interference or inversion structures.
Temperate carbonate platform drowning linked to Miocene oceanographic events: Maiella platform margin, Italy
Authors: Mutti Maria , Bernoulli Daniel , Stille Peter
Published: October 2010

Carbonate platform drownings are frequent, often synchronous global occurrences, yet explanations for these world‐wide events remain unsatisfactory. In the Central Apennines, Lower and Middle Miocene carbonate rocks deposited on a ‘temperate’ ramp in the Maiella platform margin record two episodes of platform drowning followed by hemipelagic sedimentation, dated as latest Oligocene–Aquitanian (26–23 Ma) and as Burdigalian–Langhian (20–16 Ma). A high‐resolution stratigraphy, based on strontium‐ isotopes, allows us to correlate key phases of platform evolution with events recorded in deep water ocean sediments. This paper suggests that high weathering rates and nutrient input in the Mediterranean during the early and middle Miocene –possibly linked to the uplift of the Tibetan region – set the preconditions for platform drowning, which were ultimately caused by rapid eustatic sea‐level rises.
Glacier outburst floods and outwash plain development: Skeiäarársandur, Iceland
Authors: Gomez B. , Smith L.C. , Magilligan F.J. , Mertes L.A.K. , Smith N.D.
Published: October 2010

Outwash plains, such as Skeiäarársandur, serve as prototypes for braided river facies and analogs for the Mars Pathfinder and Viking 1 landing sites on the margins of the Chryse Basin. Glacier outburst floods (jökulhlaups) have generated some of the largest known terrestrial freshwater flows and recent studies suggest that the stratigraphy of outwash plains (sandur) is dominated by sedimentary sequences laid down during jökulhlaups, rather than by braided river facies produced by an ablation‐related flow regime. The modern point‐source drainage configuration on Skeiäarársandur evolved from a diffuse, multipoint distributary system during glacier retreat, when meltwater began to be routed parallel to the ice front. The contemporary pattern of water and sediment dispersal across Skeiäarársandur differs from the conditions that prevailed when the ice front was coupled to the sandur, and the November 5–6 1996 outburst flood from Skeiäarárjökull had little impact on the proximal surface of Skeiäarársandur beyond the confines of the entrenched channels that traverse it. Thus, the point‐source dispersal system on Skeiäarársandur may not provide an exact analogue for the pattern of meltwater dispersal responsible for the sediment assemblage laid down during past jökulhlaups, and caution may be required when comparing conditions on Skeiäarársandur to those presumed to have been experienced during massive outburst floods elsewhere.
Thermal history vs. fabric anisotropy in granitoids emplaced at different crustal levels: an example from Calabria, southern Italy
Authors: Caggianelli A. , Prosser G. , Rottura A.
Published: October 2010

The Sila and Serre granitoids of Calabria were emplaced in the late Carboniferous at depths ranging from 6 to 23 km in a postcollisional extensional regime. Their fabric, which developed during and after final crystallization up to the solid state, strongly increases in intensity with emplacement depth. This relationship is attributed to the thermal history of the Calabrian basement. Cooling histories of granitoids, constrained by geological data and Rb–Sr cooling ages on micas, demonstrate that residence times of rocks at temperatures greater than those of the brittle–ductile transition vary greatly as a function of initial emplacement depth. This explains why shallow‐level granitoids, that remained for about 10 Myr at temperatures above those of the brittle domain, retain their original magmatic fabric. By contrast, the strong fabrics of the deep‐seated granitoids are explained by solid‐state strain overprint that lasted more than 100 Myr at temperatures above those of the brittle domain.
Genetic and molecular characterization of murine GATA‐1 in Aspergillus defines a critical role for the N‐terminal finger
Authors: Caddick Mark , Peters David , Hooley Paul , Nayler Andrew
Published: October 2010

We have utilized Aspergillus nidulans as a model system for the characterization of the major vertebrate transcription factor GATA‐1. This has been achieved both by analysing the function of murine GATA‐1 directly and by using direct gene replacement to introduce chimaeric areA::GATA‐1 derivatives at the areA locus, which encodes a GATA factor involved in regulating nitrogen metabolism in A. nidulans. Although GATA‐1 shows only limited function when expressed in A. nidulans, the C‐terminal GATA DNA‐binding domain can replace the native GATA domain of AREA and retain near wild‐type function. Surprisingly, inclusion of the N‐terminal DNA‐binding domain of GATA‐1 has a major role in determining the function of areA::GATA constructs in vivo, leading to a general loss of activation. This negative function is partially dominant and is dependent on both the fidelity of the zinc‐chelating structure and a second factor encoded by A. nidulans. The presence of two GATA domains also disrupts modulation of AREA activity. The ability of duplicate GATA domains to disrupt normal signal transduction is not dependent on the relative position of the domains or on the fidelity of the zinc‐chelating structure. This demonstrates the utility of nitrogen metabolism’s regulation in A. nidulans as a model system for the molecular and genetic characterization of heterologous GATA factors while also providing insights into native Aspergillus regulatory components.
one‐eyed pinhead is required for development of the ventral midline of the zebrafish (Danio rerio) neural tube
Authors: Strähle Uwe , Jesuthasan Suresh , Blader Patrick , Garcia‐Villalba Pilar , Hatta Kohei , Ingham Philip W.
Published: October 2010

Axial midline structures play a central role as signalling centres during the development of the vertebrate embryo. We have isolated mutant alleles of a new locus, one‐eyed pinhead (oep), in the zebrafish that are characterized by cyclopia and impaired development of the floor plate. oep mutants fail to establish expression of axial (zebrafish HNF3β) and sonic hedgehog in the midline of the neural plate but form a notochord that expresses both genes. In the spinal cord of the 1‐day‐old embryo, mutation of oep impairs floor‐plate but not motor‐neuron development. Floor‐plate development is absolutely dependent on oep only at early stages, since partial recovery of the floor plate can be detected at 48 h in the spinal cord, suggesting compensatory pathways. Ectopic expression of sonic hedgehog and a dominant‐negative protein kinase A regulatory subunit induces expression of floor‐plate marker genes in the oep mutant neural tube in a manner indistinguishable from wild‐type embryos. Our data suggest that the oep mutation does not impair Sonic hedgehog signalling and thus implicate a second process that acts synergistically with Sonic hedgehog signalling in the specification of the midline of the neuroectoderm and that can partially be compensated for during later development.
Physical mapping of a collection of MaeI‐generating amber mutations in the β gene of Escherichia coli RNA polymerase and the functional effect of internal deletions constructed through their manipulation
Authors: Buyukuslu Nihal , Trigwell Susan M. , Lim Ping‐Ping , Fujita Nobuyuki , Ishihama Akira , Ralphs Nikki T. , Glass Robert E.
Published: October 2010

We report the fine mapping of 55 of our 95 amber mutations in the β gene of Escherichia coli RNA polymerase by virtue of the unique MaeI restriction sites created by this subset of nonsense mutations (i.e. CTAG, where the amber codon is underlined). [The full data are reported in Supplementary Publication SUP 50181 (12 pages), which has been deposited at the British Library Document Supply Centre, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1997) 321, 8–10.] The CTAG mutations, which have been positioned to within approx. 9–60 bp, are distributed almost along the entire length of the rpoB gene, the one exception being the interval 400–499. The lack of amber fragments for mutations within the 5′ approx. 265 codons suggests lability of the extreme N‐terminal region; further potential destabilizing ‘signals’ may be present in the non‐conserved ‘spacer’ regions. The locations of four of the eleven rpoB amber mutations that are strongly polar on expression of the downstream rpoC gene have been determined through a combination of MaeI mapping, PCR amplification and DNA sequencing. Surprisingly, one such mutant carries two tandem CTAG sites but is viable with three of the nonsense suppressors tested. These polar amber sites define three different amino acids (Gln‐31, Gln‐83 and Trp‐183) that fall within three sequence‐conservation blocks in the N‐terminal region. Six of the MaeI/Am (where MaeI/Am is an amber mutation generating a MaeI restriction site) rpoB alleles (Gln‐83, Gln‐276, Gln‐327, Gln‐618, Gln‐649 and Trp‐183) have been used to generate small in‐frame deletions (31–100 codons) within conserved and non‐conserved regions of the β gene, and the properties of these deletion variants were assessed in vivo. The smallest deletion reported in this study removes 31 amino acids from the middle of a region common to the eubacterial/chloroplast subgroup of β homologues, and our results strongly suggest βΔQ618–Q649 is assembled into a holoenzyme form capable of transcriptional initiation in vivo.
Recombination and joining: different means to the same ends
Authors: Kanaar Roland , Hoeijmakers Jan
Published: October 2010

DNA double‐strand breaks are very genotoxic lesions that can result in chromosome aberrations. The current view is that DNA double‐strand breaks are repaired most efficiently through homologous recombination in yeast and simple end‐joining in mammalian cells. However, recent experiments reveal that both repair pathways are conserved from yeast to mammals, including humans. The challenge ahead is to put the different pieces of the jigsaw together into coherent mechanisms for both pathways and to determine their relative contributions to ionizing‐radiation resistance and to the prevention of genetic instability and carcinogenesis.
Evaluation of the renin–angiotensin system in a congenic renin Dahl salt‐sensitive rat
Authors: DiPaola Nicholas , Rapp John , Brand Paul , Beierwaltes William , Metting Patricia , Britton Steven
Published: October 2010

When an ∼30 centiMorgan (cM) region of chromosome 13 containing the renin gene from the Dahl salt‐resistant rat (R) was introgressed into the Dahl salt‐sensitive rat (S), the resulting congenic rat (designated S.R‐Ren) had a systolic blood pressure on a 2% (w/w) salt diet that was 24 mmHg lower than that of its S counterpart. Due to the large size of the transferred segment (over 30 million bp), the question remained as to whether or not the renin gene was the cause of the blood‐pressure difference between the strains. We evaluated the role of the renin–angiotensin system in S.R‐Ren and S rats fed a 0.05% salt diet by examining differences between strains in (1) expression of renin in three tissue types, (2) the blood‐pressure response to blockade of both angiotensin‐converting enzyme and angiotensin II receptors, and (3) pressure natriuresis. No differences were found in renin levels in plasma, kidney or adrenal gland between strains. The blood‐pressure responses to the angiotensin‐converting‐enzyme inhibitor captopril and to the angiotensin II‐receptor blocker saralasin in conscious S and S.R‐Ren rats were similar. Furthermore, renal function, evaluated by a pressure‐natriuresis index that took into account both the time and the arterial pressure needed to excrete an acute salt load, did not differ between strains. Our findings therefore fail to demonstrate a role for the renin gene in conferring lower blood pressure in the congenic rat and suggest that there is an unknown arterial‐pressure‐regulating locus in this 30 cM region of chromosome 13.
Mutation analysis of the mouse myosin VIIA deafness gene
Authors: Mburu Philomena , Liu Xue Zhong , Walsh James , Saw Dennis , Cope M. , Gibson Fernando , Kendrick‐Jones John , Steel Karen , Brown Steve
Published: October 2010

The shaker‐1 (Myo7a) mouse deafness locus is encoded by an unconventional myosin gene: myosin VIIA [Gibson, Walsh, Mburu, Varela, Brown, Antonio, Biesel, Steel and Brown (1995) Nature (London) 374, 62–64]. The myosin VIIA gene is expressed in hair cells in the cochlea, where it is thought to function in the development of the critical neuroepithelium where auditory transduction takes place. In order to understand better the function of myosin VIIA, we have determined the complete sequence of the mouse myosin VIIA cDNA and employed the wild‐type sequence for mutational analysis of a number of shaker‐1 alleles. Analysis of the mouse myosin VIIA tail sequence demonstrates a large internal repeat with regions of similarity to myosins IV, X and XII as well as members of the band 4.1 family. In addition, the myosin VIIA repeats are similar along their entire length to a tail domain from a plant kinesin. The mouse myosin VIIA tail also contains a putative Src homology 3 (SH3) domain. Along with three previously reported shaker‐1 mutations, mutations for seven shaker‐1 alleles in total have now been identified. The mutational changes have been analysed in terms of their predicted effect on both myosin motor head and tail domain function and the predictions related to the known phenotypes of the shaker‐1 alleles. Five of the mutations lie in the motor head, and analysis of their likely effect on myosin head structure correlates well with the known severity of the shaker‐1 alleles. Of the two mutations in the tail, one is a missense mutation within the kinesin and myosin IV, X and XII homology domains that substitutes a conserved amino acid and leads to a severe deafness phenotype. This and other data suggest that myosin VIIA may have properties of a myosin‐motor–kinesin‐tail hybrid and be involved in membrane turnover within the actin‐rich environment of the apical hair cell surface.
Influence of Nitrogen Supply on the Susceptibility of Wheat to Septoria tritici
Authors: Simón M. R. , Cordo C. A. , Perelló A. E. , Struik P. C.
Published: October 2010

Nitrogen (N) fertilization is required for achieving high yields in wheat (Triticum aestivum L.) but may enhance the development of Septoria tritici Rob. ex Desm. A study was undertaken to investigate how N supply influences the area under disease progress curve (AUDPC). Two field experiments were carried out in a typical argiudol in 1996 and 1997. Six cultivars were grown at two N treatments (0 and 100–150 kg N/ha) in a split plot design. Percentage of necrosis (severity) of the two upper leaves of each treatment was evaluated three times during the growing season. Height and heading date were also scored and related to the resistance level. In 1996, with weather conditions conducive to the disease, AUDPC values were higher in the fertilized treatment. In 1997, with insufficient rain immediately after inoculation, the disease only progressed faster under N fertilization in the flag leaf, which was exposed to conducive environmental conditions from its appearance. The effect of N fertilization was influenced by the cultivar characteristics, climatic and agronomic conditions. Knowledge that N fertilization promotes the development of S. tritici in conducive conditions will be useful for deciding management strategies of the cultivars and for optimizing conditions for the selection in breeding programmes.
Validation of grading scales for contact lens complications
Authors: Efron Nathan , Morgan Philip B. , Katsara Smaragda S.
Published: October 2010

The validity of use of two artist‐rendered and two photographic sets of grading scales (grading ‘systems’) designed for gauging the severity of contact lens‐related ocular pathology was assessed in terms of precision and reliability. Thirteen observers each graded 30 images — by interpolation or extrapolation to the nearest 0.1 increment — of each of the three contact lens complications (corneal staining, conjunctival redness and papillary conjunctivitis) that were common to all four grading systems. This entire procedure was repeated approximately two weeks later, yielding a total data base comprising of 9360 individual grading estimates. Analysis of variance revealed statistically significant differences in both precision and reliability between systems, observers and conditions (p<0.03 for system reliability; p=0.0001 for all other combinations). The artist‐rendered systems generally afforded lower grading estimates and better grading reliability than the photographic systems. Corneal staining could be graded less reliably than conjunctival redness and papillary conjunctivitis. Grading reliability was generally unaffected by the severity of the condition being assessed. Notwithstanding the above differences, all four grading systems are validated for clinical use and practitioners can initially expect to use these systems with average 95% confidence limits of ±1.2 grading scale units (observer range ±0.7 to ±2.5 grading scale units). In view of the significant between‐system differences revealed in this study, it is advisable to consistently use the same grading system. It may be possible to reduce between‐observer differences by applying personalised correction factors to normalise grading estimates.
Wall reflection issues for optical diagnostics in fusion devices
Authors: Lotte Ph. , Aumeunier M. H. , Devynck P. , Fenzi C. , Martin V. , Travère J. M.
Published: October 2010

The problem of light reflection has been raised as a high priority issue for optical diagnostics in next step fusion devices where metallic wall environment will generate significant perturbations in the diagnostics measurements. Tore Supra is a large size tokamak equipped with water-cooled stainless-steel panels used to sustain the plasma long shot radiations. These panels are highly reflective and affect significantly optical systems. In particular, we show that the infrared imaging diagnostic, which surveys the plasma facing component surface temperature for safety purposes, can give incorrect information due to reflected light coming from the bottom limiter. In the visible range, motional Stark effect and Zeff measurements experience important drifts during the plasma heating phases due to parasitic light coming from the limiter, but also from the plasma itself when the viewing lines are facing the reflecting walls. In the next step fusion devices such as ITER, the possibility to use optical measurements needs to be accessed by a modeling of the diagnostic light in its machine environment and the development of new techniques of online correction.
A molecular dynamics study on heat conduction characteristics in DPPC lipid bilayer
Authors: Nakano Takeo , Kikugawa Gota , Ohara Taku
Published: October 2010

In this paper, nonequilibrium molecular dynamics simulations were performed on a single component 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine lipid bilayer in order to investigate the thermal conductivity and its anisotropy. To evaluate the thermal conductivity, we applied a constant heat flux to the lipid bilayer along and across the membrane with ambient water. The contribution of molecular interaction to the heat conduction was also evaluated. Along the bilayer plane, there is little transfer of thermal energy by the interaction between lipid molecules as compared with the interaction between water molecules. Across the bilayer plane, the local thermal conductivity depends on the constituents (i.e., water, head group, and tail group of lipid molecule) that occupy the domain. Although the intramolecular transfer of thermal energy in the tail groups of lipid molecules works efficiently to promote high local thermal conductivity in this region, the highest thermal resistance appears at the center of lipid bilayer where acyl chains of lipid molecules face each other due to a loss of covalent-bond and low number density. The overall thermal conductivities of the lipid bilayer in the directions parallel and perpendicular to the lipid membrane have been compared, and it was found that the thermal conductivity normal to the membrane is higher than that along the membrane, but it is still smaller than that of bulk water.
A compact and continuously driven supersonic plasma and neutral source
Authors: Asai T. , Itagaki H. , Numasawa H. , Terashima Y. , Hirano Y. , Hirose A.
Published: October 2010

A compact and repetitively driven plasma source has been developed by utilizing a magnetized coaxial plasma gun (MCPG) for diagnostics requiring deep penetration of a large amount of neutral flux. The system consists of a MCPG 95mm in length with a DN16 ConFlat connection port and an insulated gate bipolar transistor (IGBT) inverter power unit. The power supply consists of an array of eight IGBT units and is able to switch the discharge on and off at up to 10 kV and 600 A with a maximum repetitive frequency of 10 kHz. Multiple short duration discharge pulses maximize acceleration efficiency of the plasmoid. In the case of a 10 kHz operating frequency, helium-plasmoids in the velocity range of 20 km/s can be achieved.
Photoelectron imaging of tetrahydrofuran cluster anions (THF)n− (1≤n≤100)
Authors: Young Ryan M. , Yandell Margaret A. , Niemeyer Markus , Neumark Daniel M.
Published: October 2010

Anionic tetrahydrofuran clusters (THF)n− (1≤n≤100) are studied with photoelectron imaging as gas-phase precursors for electrons solvated in THF. Photoelectron spectra of clusters up to n=5 show two peaks, one of which is attributed to a solvated open chain radical anion and the other to the closed THF ring. At n=6, the spectra change shape abruptly, which become more characteristic of (THF)n− clusters containing solvated electrons. From n=6–100, the vertical detachment energies (VDEs) of these solvated electron clusters increase from 1.96 to 2.71 eV, scaling linearly with n−1/3. For fully deuterated (THF-d8)n− clusters, the apparent transition to a solvated electron cluster is delayed to n=11. Extrapolation of the VDEs to infinite cluster size yields a value of 3.10 eV for the bulk photoelectric threshold. The relatively large VDEs at onset and small stabilization with increasing cluster size compared to other solvated electron clusters may reflect the tendency of the bulk solvent to form preexisting voids that can readily solvate a free electron.
Bragg diffraction using a 100 ps 17.5 keV x-ray backlighter and the Bragg diffraction imager
Authors: Maddox B. R. , Park H.-S. , Hawreliak J. , Elsholz A. , Van Maren R. , Remington B. A. , Comley A. , Wark J. S.
Published: October 2010

A new diagnostic for measuring Bragg diffraction of petawatt-generated high-energy x rays off a laser-compressed crystal was designed and tested successfully at the Omega EP laser facility on static Mo and Ta (111) oriented single crystal samples using a 17.5 keV Mo Kα backlighter. The Bragg diffraction imager consists of a heavily shielded enclosure and a precisely positioned beam block attached to the enclosure by an aluminum arm. Fuji image plates are used as the x-ray detectors. The diffraction from Mo and Ta (222) crystal planes was clearly detected with a high signal-to-noise. This technique will be applied to shock- and quasi-isentropically loaded single crystals on the Omega EP laser.
Calibration of electron cyclotron emission radiometer for KSTAR
Authors: Kogi Y. , Jeong S. H. , Lee K. D. , Akaki K. , Mase A. , Kuwahara D. , Yoshinaga T. , Nagayama Y. , Kwon M. , Kawahata K.
Published: October 2010

We developed and installed an electron cyclotron emission radiometer for taking measurements of Korea Superconducting Tokamak Advanced Research (KSTAR) plasma. In order to precisely measure the absolute value of electron temperatures, a calibration measurement of the whole radiometer system was performed, which confirmed that the radiometer has an acceptably linear output signal for changes in input temperature. It was also found that the output power level predicted by a theoretical calculation agrees with that obtained by the calibration measurement. We also showed that the system displays acceptable noise-temperature performance around 0.23 eV.
High-performance soft x-ray spectromicroscopy beamline at SSRF
Authors: Xue Chaofan , Wang Yong , Guo Zhi , Wu Yanqing , Zhen Xiangjun , Chen Min , Chen Jiahua , Xue Song , Peng Zhongqi , Lu Qipeng , Tai Renzhong
Published: October 2010

The Shanghai Synchrotron Radiation Facility (SSRF) is the first third-generation synchrotron facility in China and operated at an electron energy of 3.5 GeV. One of the seven beamlines in the first construction phase is devoted to soft x-ray spectromicroscopy and is equipped with an elliptically polarized undulator light source, a plane grating monochromator, and a scanning transmission x-ray microscope end station. Initial results reveal the high performance of this beamline, with an energy resolving power estimated to be over 10 000 at the argon L-edge and a spatial resolution better than 30 nm.
Curvature effects upon interactions of polymer-grafted nanoparticles in chemically identical polymer matrices
Authors: Trombly David M. , Ganesan Venkat
Published: October 2010

We study the interactions between polymer-grafted nanoparticles immersed in a chemically identical polymer melt using a numerical implementation of polymer mean-field theory. We focus on the interpenetration width between the grafted and free chains and its relationship to the polymer-mediated interparticle interactions. To this end, we quantify the interpenetration width as a function of particle curvature, grafting density, and the relative molecular weights of the grafted and free chains. We show the onset of wetting and dewetting as a function of these quantities and explain our results through simple scaling arguments to include the effects of curvature. Subsequently, we show that the interparticle potentials correlate quantitatively with the trends displayed by the interpenetration widths.
Note: Controllable positioning of a single particle in between nanogap electrodes
Authors: Govor L. V. , Bauer G. H. , Parisi J.
Published: October 2010

We have developed a relatively simple procedure capable to position a single nanoparticle in between nanogap electrodes for nanoelectronic applications. The well-defined particle positioning was achieved via pinning the edge of a dispersion droplet over the nanogap. Pinning time, substrate temperature, and its displacement velocity are excellent control parameters.
Communication: Bond length alternation of conjugated oligomers: Another step on the fifth rung of Perdew’s ladder of functional
Authors: Chabbal Sylvain , Jacquemin Denis , Adamo Carlo , Stoll Hermann , Leininger Thierry
Published: October 2010

In this work, we present the application of the hybrid short-range density functional theory/long-range MP2 energy gradients to the bond length alternation in polymethineimine and polyacetylene conjugated oligomers. Compared to other density functional calculations, our results are quite superior, even to fourth rung functionals, usually better than MP2 and very close to the available CCSD(T) values.
High pressure stability of bismuth sillenite: A Raman spectroscopic and x-ray diffraction study
Authors: Rao Rekha , Garg Alka B. , Sakuntala T.
Published: October 2010

High pressure behavior of the compound Bi12SiO20 is investigated using in situ Raman spectroscopic and synchrotron-based angle dispersive x-ray diffraction techniques. Results indicate that the compound remains stable in the ambient pressure cubic structure up to 26 GPa. From the structural studies, bulk modulus B0, and its pressure derivative B′ of Bi12SiO20 are evaluated to be 36 GPa and 16.7 GPa, respectively. Mode Grüneissen parameters of various Raman active modes of Bi12SiO20 are also reported. The stability of Bi12SiO20 at high pressure is discussed in the light of the pressure-induced amorphization reported in bismuth-orthosilicate (Bi4Si3O12) and -orthogermanate. Comparison of the observed phonon behavior with that reported for Bi4Si3O12 reveals that two of the Raman modes in Bi4Si3O12 have negative pressure dependencies clearly indicating dynamic instability while Bi12SiO20 does not show any signatures of zone-center instabilities.
The absorption coefficient of PbSe/CdSe core/shell colloidal quantum dots
Authors: De Geyter Bram , Hens Zeger
Published: October 2010

PbSe/CdSe core/shell colloidal quantum dots (QDs) are used as a model system to study the absorption coefficient of colloidal QD heterostructures, consisting of at least two semiconductor materials. We show that at energies far above the band gap (3.1 and 3.5 eV) the experimental intrinsic absorption coefficient is in excellent agreement with the Maxwell–Garnett effective medium theory for core/shell heterostructures and bulk values for the dielectric function. This allows for a straightforward measurement of the QD concentration from the absorbance spectrum. It also implies that basic optical measurements on core/shell heterostructures, such as measurements of the oscillator strength and photoluminescence lifetime, can be corrected for the local field reduction in QD heterostructures.
Mechanism analysis of photoleakage current in ZnO thin-film transistors using device simulation
Authors: Kimura Mutsumi , Kamada Yudai , Fujita Shizuo , Hiramatsu Takahiro , Matsuda Tokiyoshi , Furuta Mamoru , Hirao Takashi
Published: October 2010

We analyzed the photoleakage current (Ileak) in ZnO thin-film transistors using device simulation. The dependences of Ileak on the location of light irradiation and drain voltage are reproduced by considering a Schottky barrier at the source contact using a two-dimensional device simulation. First, carrier generation is induced by light irradiation, the generated holes accumulate near the source contact, and some of these are captured in the donor traps. Next, the Schottky barrier becomes narrow, and electron injection increases via a tunneling effect. This discussion also suggests that the off-current is exceedingly low because the Schottky barrier prevents electron injection.
Low energy (0–4 eV) electron impact to N2O clusters: Dissociative electron attachment, ion-molecule reactions, and vibrational Feshbach resonances
Authors: Vizcaino Violaine , Denifl Stephan , Märk Tilmann D. , Illenberger Eugen , Scheier Paul
Published: October 2010

Electron attachment to clusters of N2O in the energy range of 0–4 eV yields the ionic complexes [(N2O)nO]−, [(N2O)nNO]−, and (N2O)n− . The shape of the ion yields of the three homologous series differs substantially reflecting the different formation mechanisms. While the generation of [(N2O)nO]− can be assigned to dissociative electron attachment (DEA) of an individual N2O molecule in the target cluster, the formation of [(N2O)nNO]− is interpreted via a sequence of ion molecule reactions involving the formation of O− via DEA in the first step. The nondecomposed complexes (N2O)n− are preferentially formed at very low energies (below 0.5 eV) as a result of intramolecular stabilization of a diffuse molecular anion at low energy. The ion yields of [(N2O)nO]− and (N2O)n− versus electron energy show sharp peaks at the threshold region, which can be assigned to vibrational Feshbach resonances mediated by the diffuse anion state as already observed in an ultrahigh resolution electron attachment study of N2O clusters [E. Leber, S. Barsotti, J. Bömmels, J. M. Weber, I. I. Fabrikant, M.-W. Ruf, and H. Hotop, Chem. Phys. Lett. 325, 345 (2000)].
Gate voltage dependence of weak localization in bilayer graphene
Authors: Liao Zhi-Min , Han Bing-Hong , Wu Han-Chun , Yu Da-Peng
Published: October 2010

Weak localization modulated by gate voltage in bilayer graphene was studied experimentally. A transition from weak localization [near the carrier charge neutrality point (CNP)] to weak antilocalization (away from the CNP) was found. The suppressed intervalley scattering due to screening of atomically sharp defects and spin-orbit coupling regulated by gate voltage can explain the experimental results well. Our experimental results confirm the theoretical prediction that the weak localization in bilayer graphene is strongly suppressed by the trigonal warping and it is only present in systems with pronounced intervalley scattering.
Very low surface recombination velocities on p- and n-type c-Si by ultrafast spatial atomic layer deposition of aluminum oxide
Authors: Werner Florian , Veith Boris , Tiba Veronica , Poodt Paul , Roozeboom Fred , Brendel Rolf , Schmidt Jan
Published: October 2010

Using aluminum oxide (Al2O3) films deposited by high-rate spatial atomic layer deposition (ALD), we achieve very low surface recombination velocities of 6.5 cm/s on p-type and 8.1 cm/s on n-type crystalline silicon wafers. Using spatially separated reaction zones instead of the conventional time-sequenced precursor dosing enables growth rates up to 70 nm/min, whereas conventional ALD limits the growth rate to <2 nm/min. The excellent passivation level is predominantly assigned to a high negative fixed charge density of Qf=−(4±1)×1012 cm−2 in the Al2O3 films. We demonstrate an excellent thermal stability of the passivation quality.
Gold on graphene as a substrate for surface enhanced Raman scattering study
Authors: Wang Yingying , Ni Zhenhua , Hu Hailong , Hao Yufeng , Wong Choun Pei , Yu Ting , Thong John T. L. , Shen Ze Xiang
Published: October 2010

In this paper, we report our study on gold (Au) films with different thicknesses deposited on single layer graphene (SLG) as surface enhanced Raman scattering (SERS) substrates for the characterization of rhodamine (R6G) molecules. We find that an Au film with a thickness of ∼7 nm deposited on SLG is an ideal substrate for SERS, giving the strongest Raman signals for the molecules and the weakest photoluminescence (PL) background. While Au films effectively enhance both the Raman and PL signals of molecules, SLG effectively quenches the PL signals from the Au film and molecules. The former is due to the electromagnetic mechanism involved while the latter is due to the strong resonance energy transfer from Au to SLG. Hence, the combination of Au films and SLG can be widely used in the characterization of low concentration molecules with relatively weak Raman signals.
Spin transport in germanium at room temperature
Authors: Shen C. , Trypiniotis T. , Lee K. Y. , Holmes S. N. , Mansell R. , Husain M. , Shah V. , Li X. V. , Kurebayashi H. , Farrer I. , de Groot C. H. , Leadley D. R. , Bell G. , Parker E. H. C. , Whall T. , Ritchie D. A. , Barnes C. H. W.
Published: October 2010

Spin-dependent transport is investigated in a Ni/Ge/AlGaAs junction with an electrodeposited Ni contact. Spin-polarized electrons are excited by optical spin orientation and are subsequently used to measure the spin dependent conductance at the Ni/Ge Schottky interface. We demonstrate electron spin transport and electrical extraction from the Ge layer at room temperature.
Behavioural responses of 6-month-old beef calves prevented from suckling: influence of dam's milk yield
Authors: Hötzel M. J. , Ungerfeld R. , Quintans G.
Published: October 2010

The objective of the present experiment was to compare the behavioural response of calves reared by cows of different milk yields to the prevention of suckling with the aid of nose-flaps that allowed the maintenance of social contact with the dam. Twenty Hereford or Hereford × Angus crossbred primiparous cows from a single herd remained with their calves suckling until the beginning of the experiment, in late summer–early autumn. Milk production was determined monthly during the lactation period and the pairs were selected according to the cows’ milk production, for higher or lower milk yield (HMY and LMY, respectively). On Day 0, suckling was prevented by placing a nose-flap anti-suckling device on each calf for 11 days. Calf behaviour was recorded from Day –3 to Day 5, using instantaneous sampling of individual animals in each group, and the calves were weighed monthly since birth, and on Days –8 and 11. Bodyweight profiles for HMY and LMY calves were similar until Day –8; from then on, up to Day 11, HMY calves lost weigh, whereas LMY calves gained weight. Suckling frequency before nose-flaps were fitted was similar for HMY and LMY calves. There was no relationship between the cow’s milk yield and the changes observed in behaviour. Apart from playing, all behaviours were affected by prevention of suckling. The distance between the calves and the dam, and the frequency of grazing and rumination, decreased after nose-flaps were placed, whereas vocalisations, suckling attempts, walking and standing increased. In conclusion, the behavioural responses to prevention of suckling did not differ between the 6-month-old calves reared by cows with high yields and those with low milk yields. The behavioural response of calves that were prevented from suckling but were kept with the dams indicates that the cessation of suckling contributes to the weaning distress of 6-month-old beef calves.
Predicting the quality of browse-containing diets fed to sheep using faecal near-infrared reflectance spectroscopy
Authors: Mahipala M. B. P. Kumara , Krebs G. L. , McCafferty P. , Naumovski T. , Dods K. , Stephens R.
Published: October 2010

The potential of data collected from past feeding trials to derive faecal near-infrared reflectance spectroscopy (fNIRS) calibrations for predicting the attributes of browse-containing sheep diets was examined. Reference data and faecal near-infrared spectrum pairs (n = 240) originated from five feeding trials involving 40 diets consisting of varying levels of fresh browse and oaten chaff. The fNIRS calibrations were developed to predict crude protein (CP), total phenolics (TP), total tannin (TT) and phosphorus (P) contents, protein precipitation capacity of tannin (PPC), in vivo digestibility of dry matter (DMD), organic matter (OMD) and crude protein (CPD) and in vitro OMD (IVOMD), metabolisable energy (ME) and short chain fatty acid production (eSCFA) in the diet. The precision of calibrations was evaluated by the coefficient of determination (R2c) and standard error (SEC) of calibration. The predictive ability of calibrations was evaluated by standard error of cross-validation (SECV), standard error of prediction (SEP), slope of the validation regression and the ratio of the standard deviation of the reference data to the SECV (RPD). For all fNIRS calibrations, R2c was >0.80 and SEC was close to the respective SECV. Slope of the validation regressions did not deviate from 1 for chemical attributes but deviated from 1 for functional attributes (except eSCFA). The RPD of DMD and OMD was <3, whereas the ratio was >3 for CP, TP, TT, PPC, P, CPD, IVOMD, ME and eSCFA calibrations. Data derived from the past feeding trials could be used to derive robust fNIRS calibrations to predict chemical attributes (CP, TP, TT, PPC, P) of browse-containing sheep diets. Although, fNIRS calibrations predicting dietary in vitro functional properties (digestibility and ME) were superior to those predicting in vivo functional properties, both were not so robust. Statistics of fNIRS calibrations derived using reference data originating from in vitro methods needs to be carefully interpreted.