bluuebunny/crossref_metadata_2025 huggingface dataset:
Adsorption of organic molecules on the TiO2(011) surface: STM study
Authors: Godlewski Szymon , Tekiel Antoni , Prauzner-Bechcicki Jakub S. , Budzioch Janusz , Gourdon Andre , Szymonski Marek
Published: June 2011

High resolution scanning tunneling microscopy has been applied to investigate adsorption and self-assembly of large organic molecules on the TiO2(011) surface. The (011) face of the rutile titania has been rarely examined in this context. With respect to possible industrial applications of rutile, quite often in a powder form, knowledge on behavior of organic molecules on that face is required. In the presented study we fill in the gap and report on experiments focused on the self-assembly of organic nanostructures on the TiO2(011) surface. We use three different kinds of organic molecules of potential interest in various applications, namely, PTCDA and CuPc representing flat, planar stacking species, and Violet Landers specially designed for new applications in molecular electronics. In order to reach a complete picture of molecular behavior, extended studies with different surface coverage ranging from single molecule up to 2 monolayer (ML) thick films are performed. Our results show that the adsorption behavior is significantly different from previously observed for widely used metallic templates. Creation of highly ordered molecular lines, quasi-ordered wetting layers, controlled geometrical reorientation upon thermal treatment, existence of specific adsorption geometries, and prospects for tip-induced molecule ordering and manipulation provide better understanding and add new phenomena to the knowledge on the (011) face of rutile titania.
Excess-conductivity of (Bi0.5Tl0.5)Ba2Ca2Cu3O10-δ superconductors
Authors: Khan Nawazish A. , Firdous Umber , Shahreyar
Published: June 2011

Excess conductivity analysis of electrical resistivity ρ(T) versus temperature data is carried out for as-prepared, Nitrogen (N2) and Oxygen (O2) annealed (Bi0.5Tl0.5)Ba2Ca2Cu3O10-δ samples. Such analyses have been done following the lawrence doniach model. Two cross-over temperatures have been observed, one for transformation from 0D to 2D at higher temperature and the other for 2D to 3D closer to the transition temperature. The widths of 3D AL regime remains unchanged after post-annealing in N2 and O2 atmospheres whereas that of 2D AL regimes in N2 and O2 post-annealed samples is significantly decreased. The width of 3D AL regimes remains unaltered after post-annealing in N2 and O2 atmosphere, however, the width of 2D AL regimes is significantly decreased after annealing experiments. The shrinkage of 2D AL region to lower temperature after annealing is most likely consequence of readjustment of carrier’s density in the conducting CuO2 planes. The coherence length along the c-axis (ξc) is determined at the cross-over To of 2D to 3D conductivity. In as prepared samples ξc is around 1.18 Å, which is marginally increased to 1.22 Å in the samples annealed in N2 atmosphere and to 1.27 Å in O2 annealed samples. The coherence length ξc and inter-plane coupling J are enhanced with post-annealing in nitrogen and oxygen atmosphere. The phase relaxation time and Fermi-velocity of the carrier are significantly enhanced after post-annealing in oxygen. The optimized density of the carriers suppresses overall coupling energy in oxygen post-annealed samples and the lower value of it suggests the dominance of electron-electron correlation effects in the conductivity mechanism of oxygen post-annealed Bi0.5Tl0.5Ba2Ca2Cu3O10-δ samples. Our FIC data suggests a significant suppression of spin and charged density gaps in oxygen post-annealed samples.
Experimental investigation of the night heat losses of hot water storage tanks in thermosyphon solar water heaters
Authors: Michaelides Ioannis , Eleftheriou Polyvios , Siamas George A. , Roditis George , Kyriacou Paraskevas
Published: June 2011

The effects of night heat losses on the performance of thermosyphon solar water heaters have been experimentally examined. Three typical thermosyphon solar water heating systems with different storage tank sizes were tested by utilising the method suggested by ISO 9459-2:95. The results were analysed to quantify the night heat losses and to investigate the effect that these may have on the system daily performance. Analysis of the results showed that a linear behavior of the heat losses with the night mean ambient temperature exists. The correlation coefficients of the linearity, for the three systems under consideration, range from 0.93 to 0.97, with the losses reaching almost 8000 kJ at a mean ambient air temperature of 10 °C. This value represents a significant percentage of the daily collected energy, making the night losses one of the most important sources of energy loss in thermosyphonic systems.
Single-wire photodetectors based on InGaN/GaN radial quantum wells in GaN wires grown by catalyst-free metal-organic vapor phase epitaxy
Authors: Bugallo A. De Luna , Rigutti L. , Jacopin G. , Julien F. H. , Durand C. , Chen X. J. , Salomon D. , Eymery J. , Tchernycheva M.
Published: June 2011

We present a letter on single-wire photodetectors based on radial n-i-n multiquantum well (QW) junctions. The devices are realized from GaN wires grown by catalyst-free metalorganic vapor phase epitaxy coated at their top by five nonpolar In0.16Ga0.84N/GaN undoped radial QWs, and are sensitive to light with energy E>2.6 eV. Their photoconductive gain is as high as 2×103. The scanning photocurrent microscopy maps evidence that the detector response is localized at the extremity containing the QWs for both below (at λ=488 nm) and above GaN band gap (at λ=244 nm) excitation. This confirms that the device operates as a radial n-i-n junction.
Construction of CASCI-type wave functions for very large active spaces
Authors: Boguslawski Katharina , Marti Konrad H. , Reiher Markus
Published: June 2011

We present a procedure to construct a configuration-interaction expansion containing arbitrary excitations from an underlying full-configuration-interaction-type wave function defined for a very large active space. Our procedure is based on the density-matrix renormalization group (DMRG) algorithm that provides the necessary information in terms of the eigenstates of the reduced density matrices to calculate the coefficient of any basis state in the many-particle Hilbert space. Since the dimension of the Hilbert space scales binomially with the size of the active space, a sophisticated Monte Carlo sampling routine is employed. This sampling algorithm can also construct such configuration-interaction-type wave functions from any other type of tensor network states. The configuration-interaction information obtained serves several purposes. It yields a qualitatively correct description of the molecule's electronic structure, it allows us to analyze DMRG wave functions converged for the same molecular system but with different parameter sets (e.g., different numbers of active-system (block) states), and it can be considered a balanced reference for the application of a subsequent standard multi-reference configuration-interaction method.
Resilience of gated avalanche photodiodes against bright illumination attacks in quantum cryptography
Authors: Yuan Z. L. , Dynes J. F. , Shields A. J.
Published: June 2011

Semiconductor avalanche photodiodes (APDs) are commonly used for single photon detection in quantum key distribution. Recently, many attacks using bright illumination have been proposed to manipulate gated InGaAs APDs. In order to devise effective countermeasures, careful analysis of these attacks must be carried out to distinguish between incorrect operation and genuine loopholes. Here, we show that correctly operated, gated APDs are immune to continuous-wave illumination attacks, while monitoring the photocurrent for anomalously high values is a straightforward countermeasure against attacks using temporally tailored light.
Tuneable polaritonics at room temperature with strongly coupled Tamm plasmon polaritons in metal/air-gap microcavities
Authors: Grossmann C. , Coulson C. , Christmann G. , Farrer I. , Beere H. E. , Ritchie D. A. , Baumberg J. J.
Published: June 2011

We report strong coupling between Tamm plasmons and excitons in III–V quantum wells at room temperature in ultracompact sample designs. A high refractive index contrast air-gap mirror together with optical Tamm states at a metal/semiconductor interface tightly confines the intracavity field leading to substantial local field enhancements. Angular-resolved reflectivity spectra give clear evidence for anticrossing in the dispersion relation. Room temperature Rabi splittings of 10 meV are found in excellent agreement with simulations. Electrical control of the polariton modes is realized without need for doped mirror layers. Such air-gap microcavities open innovative possibilites for electrically tunable microcavities and polaritonic microelectromechanics.
Disaggregating meteorites by automated freeze thaw
Authors: Charles Christopher R. J.
Published: June 2011

An automated freeze-thaw (AFT) instrument for disaggregating meteorites is described. Meteorite samples are immersed in 18.2 MΩ water and hermetically sealed in a clean 30 ml Teflon vial. This vial and its contents are dipped between baths of liquid nitrogen and hot water over a number of cycles by a dual-stepper motor system controlled by LabView. Uniform and periodic intervals of freezing and thawing induce multiple expansions and contractions, such that cracks propagate along natural flaws in the meteorite for a sufficient number of AFT cycles. For the CR2 chondrite NWA801, the boundaries between different phases (i.e., silicates, metal, matrix) became progressively weaker and allowed for an efficient recovery of 500 individual chondrules and chondrule fragments spanning 0.2–4.7 mm diameters after 243 AFT cycles over 103.3 h. Further FT experiments on a basalt analog showed that the time required for freezing and thawing the same number of cycles can be reduced by a factor of ∼4.
81 fJ/bit energy-to-data ratio of 850 nm vertical-cavity surface-emitting lasers for optical interconnects
Authors: Moser P. , Hofmann W. , Wolf P. , Lott J. A. , Larisch G. , Payusov A. , Ledentsov N. N. , Bimberg D.
Published: June 2011

Extremely energy-efficient oxide-confined high-speed 850 nm vertical-cavity surface-emitting lasers for optical interconnects are presented. Error-free performance at 17 and 25 Gb/s via a 100 m multimode fiber link is demonstrated at record high dissipation-power-efficiencies of up to 69 fJ/bit (<0.1 mW/Gbps) and 99 fJ/bit, respectively. These are the most power efficient high-speed directly modulated light sources reported to date. The total energy-to-data ratio is 83 fJ/bit at 25 °C and reduces to 81 fJ/bit at 55 °C. These results were obtained without adjustment of driving conditions. A high D-factor of 12.0 GHz/(mA)0.5 and a K-factor of 0.41 ns are measured.
In situ synchrotron based x-ray fluorescence and scattering measurements during atomic layer deposition: Initial growth of HfO2 on Si and Ge substrates
Authors: Devloo-Casier K. , Dendooven J. , Ludwig K. F. , Lekens G. , D’Haen J. , Detavernier C.
Published: June 2011

The initial growth of HfO2 was studied by means of synchrotron based in situ x-ray fluorescence (XRF) and grazing incidence small angle x-ray scattering (GISAXS). HfO2 was deposited by atomic layer deposition (ALD) using tetrakis(ethylmethylamino)hafnium and H2O on both oxidized and H-terminated Si and Ge surfaces. XRF quantifies the amount of deposited material during each ALD cycle and shows an inhibition period on H-terminated substrates. No inhibition period is observed on oxidized substrates. The evolution of film roughness was monitored using GISAXS. A correlation is found between the inhibition period and the onset of surface roughness.
Electrical injection, continuous wave operation of subwavelength-metallic-cavity lasers at 260 K
Authors: Ding Kang , Liu Zhicheng , Yin Leijun , Wang Hua , Liu Ruibin , Hill Martin T. , Marell Milan J. H. , van Veldhoven Peter J. , Nötzel Richard , Ning C. Z.
Published: June 2011

We report continuous wave lasing operation at T=260 K of subwavelength-metallic-cavities with semiconductor core encapsulated in silver under electric injection. The physical cavity volumes of the two lasers presented are 0.96λ3 (λ=1563.4 nm) and 0.78λ3 (λ=1488.7 nm), respectively. Longitudinal modes observed in one of lasers correspond to the Fabry–Perot cavity in the length direction. Such record high temperature operation of a subwavelength laser is of great importance for the development of small light sources in future integrated photonic circuits and other on-chip applications.
Band alignment between GeTe and SiO2/metals for characterization of junctions in nonvolatile resistance change elements
Authors: Chua E. K. , Shi L. P. , Li M. H. , Zhao R. , Chong T. C. , Schlesinger T. E. , Bain J. A.
Published: June 2011

GeTe materials were characterized using x-ray photoelectron spectroscopy in both the amorphous and crystalline states. Valence and conduction band alignments relative to a SiO2 reference were measured to allow the GeTe band diagram, work function, and electron affinity to be inferred. Hole barrier heights was also studied for several metal/GeTe systems (metal=Al,Ni,W) to extract the charge neutrality level of these interfaces for GeTe in both the crystalline and amorphous states. Near perfect Fermi-level pinning was observed for crystalline GeTe in contact with all of the metals with much less pinning observed for amorphous GeTe.
Paneth cell marker expression in intestinal villi and colon crypts characterizes dietary induced risk for mouse sporadic intestinal cancer
Authors: Wang Donghai , Peregrina Karina , Dhima Elena , Lin Elaine Y. , Mariadason John M. , Augenlicht Leonard H.
Published: June 2011

Nutritional and genetic risk factors for intestinal tumors are additive on mouse tumor phenotype, establishing that diet and genetic factors impact risk by distinct combinatorial mechanisms. In a mouse model of dietary-induced sporadic small and large intestinal cancer in WT mice in which tumor etiology, lag, incidence, and frequency reflect >90% of intestinal cancer in Western societies, dietary-induced risk altered gene expression profiles predominantly in villus cells of the histologically normal mucosa, in contrast to targeting of crypt cells by inheritance of an

Apc
1638N

allele or homozygous inactivation of

p21
Waf1/cip1

, and profiles induced by each risk factor were distinct at the gene or functional group level. The dietary-induced changes in villus cells encompassed ectopic expression of Paneth cell markers (a lineage normally confined to the bottom of small intestinal crypts), elevated expression of the Wnt receptor Fzd5 and of EphB2 (genes necessary for Paneth cell differentiation and localization to the crypt bottom), and increased Wnt signaling in villus cells. Ectopic elevation of these markers was also present in the colon crypts, which are also sites of sporadic tumors in the nutritional model. Elevating dietary vitamin D
3
and calcium, which prevents tumor development, abrogated these changes in the villus and colon cells. Thus, common intestinal cancer driven by diet involves mechanisms of tumor development distinct from those mechanisms that cause tumors induced by the rare inheritance of a mutant adenomatous polyposis coli (
Apc
) allele. This is fundamental for understanding how common sporadic tumors arise and in evaluating relative risk in the population.
Interaction of survival of motor neuron (SMN) and HuD proteins with mRNA cpg15 rescues motor neuron axonal deficits
Authors: Akten Bikem , Kye Min Jeong , Hao Le T. , Wertz Mary H. , Singh Sasha , Nie Duyu , Huang Jia , Merianda Tanuja T. , Twiss Jeffery L. , Beattie Christine E. , Steen Judith A. J. , Sahin Mustafa
Published: June 2011

Spinal muscular atrophy (SMA), caused by the deletion of the
SMN1
gene, is the leading genetic cause of infant mortality. SMN protein is present at high levels in both axons and growth cones, and loss of its function disrupts axonal extension and pathfinding. SMN is known to associate with the RNA-binding protein hnRNP-R, and together they are responsible for the transport and/or local translation of β-actin mRNA in the growth cones of motor neurons. However, the full complement of SMN-interacting proteins in neurons remains unknown. Here we used mass spectrometry to identify HuD as a novel neuronal SMN-interacting partner. HuD is a neuron-specific RNA-binding protein that interacts with mRNAs, including candidate plasticity-related gene 15 (cpg15). We show that SMN and HuD form a complex in spinal motor axons, and that both interact with cpg15 mRNA in neurons. CPG15 is highly expressed in the developing ventral spinal cord and can promote motor axon branching and neuromuscular synapse formation, suggesting a crucial role in the development of motor axons and neuromuscular junctions. Cpg15 mRNA previously has been shown to localize into axonal processes. Here we show that SMN deficiency reduces cpg15 mRNA levels in neurons, and, more importantly, cpg15 overexpression partially rescues the SMN-deficiency phenotype in zebrafish. Our results provide insight into the function of SMN protein in axons and also identify potential targets for the study of mechanisms that lead to the SMA pathology and related neuromuscular diseases.
Reduction-induced Fermi level pinning at the interfaces between Pb(Zr,Ti)O3 and Pt, Cu and Ag metal electrodes
Authors: Chen Feng , Schafranek Robert , Wu Wenbin , Klein Andreas
Published: June 2011

The interface formation between Pb(Zr,Ti)O3 and Pt, Cu and Ag was studied using in situ photoelectron spectroscopy. A strong interface reaction and a reduction of the substrate surface is observed for all three interfaces as evidenced by the appearance of metallic Pb species. Despite the different work function of the metals, nearly identical barrier heights are found with E
F − E
VB = 1.6 ± 0.1 eV, 1.8 ± 0.1 eV and 1.7 ± 0.1 eV of the as-prepared interfaces with Pt, Cu and Ag, respectively. The barrier heights are characterized by a strong Fermi level pinning, which is attributed to an oxygen deficient interface induced by the chemical reduction of Pb(Zr,Ti)O3 during metal deposition.
High dielectric permittivity and room temperature magneto-dielectric response of charge disproportionate La0.5Ba0.5FeO3 perovskite
Authors: Masud Md G , Chaudhuri B K , Yang H D
Published: June 2011

A charge disproportionate La0.5Ba0.5FeO3 (LBFO) ceramic sample with cubic structure has been synthesized by the conventional high-temperature solid-state reaction route. Dielectric behaviour of LBFO has been studied over a wide temperature (100–370 K) and frequency (100 Hz–5 MHz) ranges. LBFO exhibits relatively high dielectric permittivity (εr ∼ 5 × 103) around room temperature and very weak temperature- and frequency-dependent behaviour over the mentioned ranges. Another interesting feature of LBFO is the appearance of room temperature magneto-dielectric response (magneto-dielectric ∼7%) even at low magnetic field ∼0.5 T. The combined complex impedance and modulus spectroscopic studies exhibit two relaxation processes corresponding to grain and grain boundary contributions with activation energies ∼0.20 (for grain boundaries) and ∼0.14 eV (for grains), respectively. The high εr value of this electrically inhomogeneous sample with differently conducting grains and grain boundaries could be explained considering the Maxwell–Wagner-type interfacial polarization model. Magnetic field-dependent non-ferroelectric high dielectric behaviour of LBFO might be important for its applications in devices.
The microwave dielectric properties of dual-layer PZT/ZrO2 thin films deposited by chemical solution deposition
Authors: Min D , Hoivik N , Jensen G U , Tyholdt F , Hanke U
Published: June 2011

The dielectric properties of dual-layer PZT/ZrO2 thin films were measured at microwave frequencies in both a metal–insulator–metal (MIM) capacitor and a coplanar waveguide (CPW) up to 50 GHz. Both PZT and ZrO2 films were prepared by the chemical solution deposition method. The measured dielectric loss of the PZT/ZrO2 film was approximately 0.08 at 30 GHz, much lower than that of typical PZT thin films. The dielectric constants obtained using the MIM capacitor with 360 nm PZT/65 nm ZrO2 and using the CPW with 420 nm PZT/280 nm ZrO2 were 47 and 130, respectively, at 50 GHz. Capacitance tunability was ∼30% at +25 V and up to 50 GHz. The measured values obtained indicate that PZT/ZrO2 thin films may be suitable for the use of dielectric layers in tunable RF devices and RF MEMS capacitive switches operating at millimetre wave frequencies.
A theoretical study of pressure-induced phase transitions and electronic band structure of anti-A-sesquioxide type γ-Be3N2
Authors: Paliwal Uttam , Joshi Kunj Bihari
Published: June 2011

Structural parameters and electronic band structure of anti-A-sesquioxide (aAs) type γ-Be3N2 are presented following the first-principles linear combination of atomic orbitals method within the framework of a posteriori density-functional theory implemented in the CRYSTAL code. Pressure-induced phase transitions among the four polymorphs α, β, cubic-γ and aAs-γ of Be3N2 are examined. Enthalpy–pressure curves do not show the possibility of pressure-induced structural phase transition to the cubic-γ phase. However, α → aAs-γ and β → aAs-γ structural phase transitions are observed at 139 GPa and 93 GPa, respectively. Band structure calculations predict that aAs-γ Be3N2 is an indirect semiconductor with 4.73 eV bandgap at L point. Variation of bandgap with pressure and deformation potentials are studied for the α, β and aAs-γ polymorphs. Pressure-dependent band structure calculations reveal that, within the low-pressure limit, bandgaps of β and aAs-γ increase with pressure unlike α-Be3N2.
A high-speed on-chip pseudo-random binary sequence generator for multi-tone phase calibration
Authors: Gommé Liesbeth , Vandersteen Gerd , Rolain Yves
Published: June 2011

An on-chip reference generator is conceived by adopting the technique of decimating a pseudo-random binary sequence (PRBS) signal in parallel sequences. This is of great benefit when high-speed generation of PRBS and PRBS-derived signals is the objective. The design implemented standard CMOS logic is available in commercial libraries to provide the logic functions for the generator. The design allows the user to select the periodicity of the PRBS and the PRBS-derived signals. The characterization of the on-chip generator marks its performance and reveals promising specifications.
Small ball probability estimates for log-concave measures
Authors: Paouris Grigoris
Published: June 2011

We establish a small ball probability inequality for isotropic

log
\log

-concave probability measures: there exist absolute constants

c

1

,

c

2

>
0

c_{1}, c_{2}>0

such that if

X
X

is an isotropic

log
\log

-concave random vector in

R

n

{\mathbb R}^n

with

ψ

2

\psi _{2}

constant and bounded by

b
b

and if

A
A

is a non-zero

n
×
n

n\times n

matrix, then for every

ε
∈
(
0
,

c

1

)

\varepsilon \in (0,c_{1})

and

y
∈

R

n

y \in \mathbb R^n

,
\[
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="double-struck upper P left-parenthesis double-vertical-bar upper A x minus y double-vertical-bar Subscript 2 Baseline less-than-or-equal-to epsilon double-vertical-bar upper A double-vertical-bar Subscript HS Baseline right-parenthesis less-than-or-equal-to epsilon Superscript left-parenthesis StartFraction c 2 Over b EndFraction StartFraction double-vertical-bar upper A double-vertical-bar Super Subscript HS Superscript Over double-vertical-bar upper A double-vertical-bar Super Subscript op Superscript EndFraction right-parenthesis squared Baseline comma">

P

(
‖
A
x
−
y

‖

2

≤
ε
‖
A

‖

HS

)

≤

ε

(

c

2

b

‖
A

‖

HS

‖
A

‖

op

)

2

,

\mathbb P \left ( \|Ax-y\|_{2} \leq \varepsilon \|A\|_{\textrm {HS}} \right ) \leq \varepsilon ^{\big ( \frac {c_{2}}{b}\frac {\|A\|_{\textrm {HS}}}{\|A\|_{\textrm {op}}} \big )^{2} },

\]
where

c

1

,

c

2

>
0

c_{1}, c_{2}>0

are absolute constants.
Samuel Victor Perry. 16 July 1918 — 17 December 2009
Authors: Trentham David R.
Published: June 2011

Samuel Victor Perry (1918–2009) was a biochemist who was born in the Isle of Wight, moved shortly thereafter to King’s Lynn, Norfolk, and then spent the greater part of his youth in Southport, Lancashire. His undergraduate education and early research at Liverpool University were followed by army service for the duration of World War II. After his capture in North Africa he spent much of the war as a prisoner of war, during which time his several escapes became the stuff of legends. In 1946 he began research towards his PhD degree at Cambridge University on the protein chemistry of muscle, a central theme in which he was actively engaged for more than 60 years. These were his halcyon days—member of a leading research group in muscle, alongside distinguished achievements as an English rugby international. After a Cambridge University lectureship he was appointed Head of Biochemistry in Birmingham University in 1959—a post he occupied with distinction until retirement, elevating his department to one of international stature. Among his many contributions to the protein biochemistry of muscle contraction and its regulation were the discovery of skeletal muscle myosin phosphorylation, whose significance is still a field of active research, and the recognition that the presence of the cardiac protein troponin I in the bloodstream could be used as a diagnostic marker of myocardial infarction. Perry was an inveterate gardener, especially happy in his beloved Felin Werndew, a beautiful retreat in Dinas Cross, Pembrokeshire. In August 1948 he married Maureen Shaw. She and their son and two daughters survive him.
Transmission ofChlamydia trachomatisthrough sexual partnerships: a comparison between three individual-based models and empirical data
Authors: Althaus Christian L. , Turner Katherine M. E. , Schmid Boris V. , Heijne Janneke C. M. , Kretzschmar Mirjam , Low Nicola
Published: June 2011

Chlamydia trachomatisis the most common bacterial sexually transmitted infection (STI) in many developed countries. The highest prevalence rates are found among young adults who have frequent partner change rates. Three published individual-based models have incorporated a detailed description of age-specific sexual behaviour in order to quantify the transmission ofC. trachomatisin the population and to assess the impact of screening interventions. Owing to varying assumptions about sexual partnership formation and dissolution and the great uncertainty about critical parameters, such models show conflicting results about the impact of preventive interventions. Here, we perform a detailed evaluation of these models by comparing the partnership formation and dissolution dynamics with data from Natsal 2000, a population-based probability sample survey of sexual attitudes and lifestyles in Britain. The data also allow us to describe the dispersion ofC. trachomatisinfections as a function of sexual behaviour, using the Gini coefficient. We suggest that the Gini coefficient is a useful measure for calibrating infectious disease models that include risk structure and highlight the need to estimate this measure for other STIs.
Non-thermal dielectric barrier discharge plasma induces angiogenesis through reactive oxygen species
Authors: Arjunan Krishna Priya , Friedman Gary , Fridman Alexander , Clyne Alisa Morss
Published: June 2011

Vascularization plays a key role in processes such as wound healing and tissue engineering. Non-thermal plasma, which primarily produces reactive oxygen species (ROS), has recently emerged as an efficient tool in medical applications including blood coagulation, sterilization and malignant cell apoptosis. Liquids and porcine aortic endothelial cells were treated with a non-thermal dielectric barrier discharge plasmain vitro. Plasma treatment of phosphate-buffered saline (PBS) and serum-free medium increased ROS concentration in a dose-dependent manner, with a higher concentration observed in serum-free medium compared with PBS. Species concentration inside cells peaked 1 h after treatment, followed by a decrease 3 h post treatment. Endothelial cells treated with a plasma dose of 4.2 J cm–2had 1.7 times more cells than untreated samples 5 days after plasma treatment. The 4.2 J cm–2plasma dose increased two-dimensional migration distance by 40 per cent compared with untreated control, while the number of cells that migrated through a three-dimensional collagen gel increased by 15 per cent. Tube formation was also enhanced by plasma treatment, with tube lengths in plasma-treated samples measuring 2.6 times longer than control samples. A fibroblast growth factor-2 (FGF-2) neutralizing antibody and ROS scavengers abrogated these angiogenic effects. These data indicate that plasma enhanced proliferation, migration and tube formation is due to FGF-2 release induced by plasma-produced ROS. Non-thermal plasma may be used as a potential tool for applying ROS in precise doses to enhance vascularization.
Reconciling the influence of predictiveness and uncertainty on stimulus salience: a model of attention in associative learning
Authors: Esber Guillem R. , Haselgrove Mark
Published: June 2011

Theories of selective attention in associative learning posit that the salience of a cue will be high if the cue is the best available predictor of reinforcement (high predictiveness). In contrast, a different class of attentional theory stipulates that the salience of a cue will be high if the cue is an inaccurate predictor of reinforcement (high uncertainty). Evidence in support of these seemingly contradictory propositions has led to: (i) the development of hybrid attentional models that assume the coexistence of separate, predictiveness-driven and uncertainty-driven mechanisms of changes in cue salience; and (ii) a surge of interest in identifying the neural circuits underpinning these mechanisms. Here, we put forward a formal attentional model of learning that reconciles the roles of predictiveness and uncertainty in salience modification. The issues discussed are relevant to psychologists, behavioural neuroscientists and neuroeconomists investigating the roles of predictiveness and uncertainty in behaviour.
Trade-off between warning signal efficacy and mating success in the wood tiger moth
Authors: Nokelainen Ossi , Hegna Robert H. , Reudler Joanneke H. , Lindstedt Carita , Mappes Johanna
Published: June 2011

The coloration of species can have multiple functions, such as predator avoidance and sexual signalling, that directly affect fitness. As selection should favour traits that positively affect fitness, the genes underlying the trait should reach fixation, thereby preventing the evolution of polymorphisms. This is particularly true for aposematic species that rely on coloration as a warning signal to advertise their unprofitability to predators. Nonetheless, there are numerous examples of aposematic species showing remarkable colour polymorphisms. We examined whether colour polymorphism in the wood tiger moth is maintained by trade-offs between different functions of coloration. In Finland, males of this species have two distinct colour morphs: white and yellow. The efficacy of the warning signal of these morphs was tested by offering them to blue tits in the laboratory. Birds hesitated significantly longer to attack yellow than white males. In a field experiment, the survival of the yellow males was also higher than white males. However, mating experiments in the laboratory revealed that yellow males had lower mating success than white males. Our results offer an explanation for the maintenance of polymorphism via trade-off between survival selection and mating success.
Aerobic capacity influences the spatial position of individuals within fish schools
Authors: Killen Shaun S. , Marras Stefano , Steffensen John F. , McKenzie David J.
Published: June 2011

The schooling behaviour of fish is of great biological importance, playing a crucial role in the foraging and predator avoidance of numerous species. The extent to which physiological performance traits affect the spatial positioning of individual fish within schools is completely unknown. Schools of juvenile mulletLiza auratawere filmed at three swim speeds in a swim tunnel, with one focal fish from each school then also measured for standard metabolic rate (SMR), maximal metabolic rate (MMR), aerobic scope (AS) and maximum aerobic swim speed. At faster speeds, fish with lower MMR and AS swam near the rear of schools. These trailing fish required fewer tail beats to swim at the same speed as individuals at the front of schools, indicating that posterior positions provide hydrodynamic benefits that reduce swimming costs. Conversely, fish with high aerobic capacity can withstand increased drag at the leading edge of schools, where they could maximize food intake while possibly retaining sufficient AS for other physiological functions. SMR was never related to position, suggesting that high maintenance costs do not necessarily motivate individuals to occupy frontal positions. In the wild, shifting of individuals to optimal spatial positions during changing conditions could influence structure or movement of entire schools.
De novo discovery of mutated driver pathways in cancer
Authors: Vandin Fabio , Upfal Eli , Raphael Benjamin J.
Published: June 2011

Next-generation DNA sequencing technologies are enabling genome-wide measurements of somatic mutations in large numbers of cancer patients. A major challenge in the interpretation of these data is to distinguish functional “driver mutations” important for cancer development from random “passenger mutations.” A common approach for identifying driver mutations is to find genes that are mutated at significant frequency in a large cohort of cancer genomes. This approach is confounded by the observation that driver mutations target multiple cellular signaling and regulatory pathways. Thus, each cancer patient may exhibit a different combination of mutations that are sufficient to perturb these pathways. This mutational heterogeneity presents a problem for predicting driver mutations solely from their frequency of occurrence. We introduce two combinatorial properties, coverage and exclusivity, that distinguish driver pathways, or groups of genes containing driver mutations, from groups of genes with passenger mutations. We derive two algorithms, called Dendrix, to find driver pathways de novo from somatic mutation data. We apply Dendrix to analyze somatic mutation data from 623 genes in 188 lung adenocarcinoma patients, 601 genes in 84 glioblastoma patients, and 238 known mutations in 1000 patients with various cancers. In all data sets, we find groups of genes that are mutated in large subsets of patients and whose mutations are approximately exclusive. Our Dendrix algorithms scale to whole-genome analysis of thousands of patients and thus will prove useful for larger data sets to come from The Cancer Genome Atlas (TCGA) and other large-scale cancer genome sequencing projects.
Parameters Affecting Telomere-Mediated Chromosomal Truncation inArabidopsis
Authors: Nelson Andrew D. , Lamb Jonathan C. , Kobrossly Pierre S. , Shippen Dorothy E.
Published: June 2011

Conversion of a double-strand break into a telomere is a dangerous, potentially lethal event. However, little is known about the mechanism and control of de novo telomere formation (DNTF). DNTF can be instigated by the insertion of a telomere repeat array (TRA) into the host genome, which seeds the formation of a new telomere, resulting in chromosome truncation. Such events are rare and concentrated at chromosome ends. Here, we introduce tetraploid Arabidopsis thaliana as a robust genetic model for DNTF. Transformation of a 2.6-kb TRA into tetraploid plants resulted in a DNTF efficiency of 56%, fivefold higher than in diploid plants and 50-fold higher than in human cells. DNTF events were recovered across the entire genome, indicating that genetic redundancy facilitates recovery of DNTF events. Although TRAs as short as 100 bp seeded new telomeres, these tracts were unstable unless they were extended above a 1-kb size threshold. Unexpectedly, DNTF efficiency increased in plants lacking telomerase, and DNTF rates were lower in plants null for Ku70 or Lig4, components of the nonhomologous end-joining repair pathway. We conclude that multiple competing pathways modulate DNTF, and that tetraploid Arabidopsis will be a powerful model for elucidating the molecular details of these processes.
Transcriptional Programming and Functional Interactions within the Phytophthora sojae RXLR Effector Repertoire
Authors: Wang Qunqing , Han Changzhi , Ferreira Adriana O. , Yu Xiaoli , Ye Wenwu , Tripathy Sucheta , Kale Shiv D. , Gu Biao , Sheng Yuting , Sui Yangyang , Wang Xiaoli , Zhang Zhengguang , Cheng Baoping , Dong Suomeng , Shan Weixing , Zheng Xiaobo , Dou Daolong , Tyler Brett M. , Wang Yuanchao
Published: June 2011

The genome of the soybean pathogen Phytophthora sojae contains nearly 400 genes encoding candidate effector proteins carrying the host cell entry motif RXLR-dEER. Here, we report a broad survey of the transcription, variation, and functions of a large sample of the P. sojae candidate effectors. Forty-five (12%) effector genes showed high levels of polymorphism among P. sojae isolates and significant evidence for positive selection. Of 169 effectors tested, most could suppress programmed cell death triggered by BAX, effectors, and/or the PAMP INF1, while several triggered cell death themselves. Among the most strongly expressed effectors, one immediate-early class was highly expressed even prior to infection and was further induced 2- to 10-fold following infection. A second early class, including several that triggered cell death, was weakly expressed prior to infection but induced 20- to 120-fold during the first 12 h of infection. The most strongly expressed immediate-early effectors could suppress the cell death triggered by several early effectors, and most early effectors could suppress INF1-triggered cell death, suggesting the two classes of effectors may target different functional branches of the defense response. In support of this hypothesis, misexpression of key immediate-early and early effectors severely reduced the virulence of P. sojae transformants.
Conformational preference of chlorothioformate species: molecular structure of ethyl chlorothioformate, ClC(O)SCH2CH3, in the solid phase and NBO analysis
Authors: Rodríguez Pirani Lucas , Erben Mauricio F. , Boese Roland , Pozzi C. Gustavo , Fantoni Adolfo C. , Della Védova Carlos O.
Published: June 2011

The molecular structure of ethyl chlorothioformate, ClC(O)SCH2CH3, has been investigated in the solid phase by X-ray diffraction analysis at low temperature using a miniature zone-melting procedure and IR laser radiation. The crystalline solid consists exclusively of molecules with thesynperiplanarconformation with respect to the C=O double bond and the S—C single bond, andgaucheorientation of the ethyl group (syn-gauche). These results coincide with previous studies devoted to gas-phase conformational properties. The conformational preference for the ClC(O)SY(Y= Cl, CF3, CH3and CH2CH3) series of molecules was rationalized using the natural bond orbital (NBO) scheme. It was found that both resonance (mesomeric) and anomeric (hyperconjugation) intermolecular charge-transfer interactions are important for describing thesyn↔antiequilibrium, also illustrating the effect of electronegativity of the substituent in the conformation preference of the ClC(O)S— moiety. On the basis of the atoms in molecules (AIM) theory, intermolecular interactions have been characterized in the B3LYP/6-31G** periodic boundary electron density.
The effectiveness of an early parenting intervention for mothers with infants with sleep and settling concerns: a prospective non‐equivalent before‐after design
Authors: Hauck Yvonne L , Hall Wendy A , Dhaliwal Satvinder S , Bennett Elaine , Wells Gail
Published: June 2011

Aim.  The study aim was to compare changes in maternal confidence, competence, depression, anxiety and settling behaviours and children’s sleep and settling behaviours for mothers and infants (4–6 months of age) attending a Day Stay intervention at an early parenting centre in Western Australia and a community group.

Background.  Infant difficulties in getting to sleep and frequent night waking are concerns for parents. Techniques are available to assist parents with infants exhibiting behavioural sleep problems; however, parents often lack confidence to consistently initiate sleep interventions.

Design.  The study incorporated a prospective non‐equivalent before‐after design.

Method.  The conceptual framework guiding this intervention emphasised the development of parental confidence and competence through connection with practitioners to promote change. Both groups provided baseline data (time 1) and four weeks postbaseline (time 2). Recruitment occurred between July 2007–July 2009.

Results.  The Ngala group (n = 93) and community group (n = 85) were not equivalent for infant age and maternal parity; there were more multiparous mothers in the community group, with infants on average one week older. The Ngala group, the majority of which were primiparous women, had significantly higher levels of competence and confidence four weeks following their Day Stay visit. There were no significant differences between groups at time 2 for time to settle the infant at night, infant night waking and maternal depression and anxiety scores.

Conclusions.  Although both groups demonstrated an improvement in depression and anxiety scores, with decreased sleep and settling concerns, the results indicate parental inconsistency in settling approaches. Given links between inconsistent infant settling approaches and infants’ difficulty with sleep self‐initiation, further exploration is warranted.

Relevance to clinical practice.  The conceptual framework guiding the Ngala practitioners was effective in developing confidence and competence for the sample.
Clinical heterogeneity in Italian patients with amyotrophic lateral sclerosis
Authors: Piaceri I , Del Mastio M , Tedde A , Bagnoli S , Latorraca S , Massaro F , Paganini M , Corrado A , Sorbi S , Nacmias B
Published: June 2011

Piaceri I, Del Mastio M, Tedde A, Bagnoli S, Latorraca S, Massaro F, Paganini M, Corrado A, Sorbi S, Nacmias B. Clinical heterogeneity in Italian patients with amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a rare and devastating neurodegenerative disorder. The majority of cases are sporadic ALS (SALS), with 5–10% being familial ALS (FALS), and are inherited mostly as autosomal dominant. Mutations in Cu/Zn superoxide dismutase (SOD1) and the TAR DNA‐binding protein (TARDBP) gene are the most commonly known cause of ALS. We analyzed these genes in 61 Italian ALS patients using high‐resolution melting analysis to confirm the role of SOD1 and TARDBP in the physiopathology of ALS. The screenings showed a single mutation in SOD1 (Asp109Tyr) and three in TARBDP (Ala382Thr, Gly295Ser, Gly294Val) in five unrelated ALS patients. This report enlarges the spectrum of clinical phenotypes associated with genetic mutations in SOD1 and TARDBP genes confirming the variability of phenotypes associated with the same mutation and emphasizes the importance of genetic analysis. The different genotype–phenotype correlations suggest the implication of other factors possibly influencing clinical manifestation of the disease, such as an epigenetic or epistatic effect with other genes not yet identified.
ACVRL1 germinal mosaic with two mutant alleles in hereditary hemorrhagic telangiectasia associated with pulmonary arterial hypertension
Authors: Eyries M , Coulet F , Girerd B , Montani D , Humbert M , Lacombe P , Chinet T , Gouya L , Roume J , Axford MM , Pearson CE , Soubrier F
Published: June 2011

Eyries M, Coulet F, Girerd B, Montani D, Humbert M, Lacombe P, Chinet T, Gouya L, Roume J, Axford MM, Pearson CE, Soubrier F. ACVRL1 germinal mosaic with two mutant alleles in hereditary hemorrhagic telangiectasia associated with pulmonary arterial hypertension.

Germline mutations in genes encoding members of the transforming growth factor‐β (TGF‐β)/bone morphogenetic protein (BMP) superfamily are causal for two hereditary vascular disorders, hereditary hemorrhagic telangiectasia (HHT) and heritable pulmonary arterial hypertension (PAH). When the two diseases coexist, activin A receptor type II‐like kinase‐1 (ACVRL1) gene mutations are usually identified. We report a remarkable ACVRL1 germinal and somatic mosaicism characterized by the presence of two distinct mutant alleles and a non‐mutant ACVRL1 allele in a woman diagnosed with PAH at the age 40. She also met the Curaçao diagnostic criteria for HHT based on additional findings of telangiectases, epistaxis and arteriovenous malformations. Mutation analysis of ACVRL1 identified two adjacent heterozygous deleterious mutations within exon 10: c.1388del (p.Gly463fsX2) and c.1390del (p.Leu464X) in a region enriched by mutation‐associated DNA motifs. The mother transmitted the c.1388del to one child and the c.1390del to two children confirming germinal mosaicism. Allele‐specific polymerase chain reaction analysis showed that c.1388del is the predominant mutation in lymphocytes of the index case. Haplotype analysis revealed that both mutant alleles have a common chromosomal origin which is distinct from that of the mother's non‐mutant ACVRL1 allele. These distinct mutant alleles in tissues and germline could have arisen by DNA structure‐mediated events occurring in the early stages of the mother's embryogenesis, prior to the segregation of her germline, which ultimately led to the independent transmission of each allele. These highlight the complexity of genomic events occurring during early embryogenesis and the consequences of mutational mosaicism upon pathogenic variability.
Genetics of aluminium tolerance in chickpea (Cicer arietinum)
Authors: Singh Dharmendra , Raje Ranjeet S.
Published: June 2011

With 5 figures and 6 tables

An understanding of the inheritance of aluminium (Al) tolerance is important to breed for Al‐tolerant genotypes of chickpea (Cicer arietinum L.). Therefore, a study was undertaken to infer genes governing Al tolerance in chickpea. Tolerant lines ‘ICC14880’ and ‘IPC92‐39’ were crossed with sensitive lines ‘IPCK96‐3’ and ‘IPC99‐4’. Parental, F1, F2, F3 and backcross generations were evaluated in a nutrient solution containing 20 ppm Al for haematoxylin staining and root re‐growth and classified for tolerance by staining of root tips and root re‐growth. The F1 hybrids responded similarly to the tolerant parents indicating dominance of Al tolerance over sensitivity. Segregation for tolerance vs. sensitivity in F2 fitted well with the 3 : 1 ratio expected for a single gene. The backcross and F3 data confirmed the presence of single dominant gene common in tolerant parents. Experimental findings showed that Al tolerance is a monogenic dominant trait that can be easily transferred to high yielding lines through a backcross breeding.