bluuebunny/crossref_metadata_2025 huggingface dataset:
Aging process of unipolar resistive switching in microscale cylindrical Fe-base alloy/TiO2/Au-cells
Authors: Miranda M. A. , Gómez-Polo C. , Gil A.
Published: August 2012

Evidence of unipolar resistive switching is observed along the aging process of cylindrical microscale Fe-base alloy/TiO2/Au devices (MIM-cells). In the early stages of aging, under low electric fields, we show evidence of the effect of a blocking barrier (a Schottky-type depletion layer) at the active TiO2/Au interface which is measured in the OFF-state before the set process is triggered. Resistance transients after resets, ROFF(t), provide a relaxation time that is explained in terms of the drifting processes of oxygen vacancies. In the aged stages under high electric fields, a highly insulating behavior is observed in the OFF-state (before the set is produced) which yields fluctuating values of ROFF. Under these conditions, we show that a recovery of the blocking barrier is still feasible by inverting the polarity of the applied voltage. Further on, the resistance switching is studied at different voltage sweep rates which provide the maximum rate that is necessary to accomplish with the resistive switching dynamics, in order to allow the diffusion of the mobile species.
Energy level pinning of an n-type semiconducting polymer on conductive polymer electrodes: Effects of work function and annealing
Authors: Frisch J. , Vollmer A. , Koch N.
Published: August 2012

Using photoelectron spectroscopy, we investigated the energy level alignment at interfaces between the organic n-type semiconductor poly{[N,N′-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)} [P(NDI2OD-T2] and poly(ethylenedioxythiophene):poly(styrenesulfonate) (PEDT:PSS) electrodes with different work function (Φ). The P(NDI2OD-T2) film thickness was varied between monolayer and multilayer (up to 12 nm) coverage. Vacuum level alignment was found for polymer electrode Φ ≤ 5.30 eV, whereas the valence band of P(NDI2OD-T2) becomes Fermi level pinned for higher Φ values. In situ annealing of un-pinned P(NDI2OD-T2) films on electrodes with Φ below 5.3 eV resulted in a transition to the Fermi level pinning regime. This transition is due to an increase of the effective polymer electrode Φ below the semiconductor polymer due to annealing. Pinning the P(NDI2OD-2T) energy levels at the conduction band with a low Φ electrode allowed estimating the charge transport gap of this polymer to be ≥ 1.7 eV.
Thermal conductivity of self-assembled nano-structured ZnO bulk ceramics
Authors: Zhao Yu , Yan Yongke , Kumar Ashok , Wang Hsin , Porter Wallace D. , Priya Shashank
Published: August 2012

In this study, we describe the changes in thermal conductivity behavior of ZnO-Al micro- and nano-two-phase self-assembled composites with varying grain sizes. The reduction in thermal conductivity values of micro-composites was limited to ∼15% for ZnO-4% Al. However, nano-composites exhibited large reduction, by a factor of about three, due to uniform distribution of nano-precipitates (ZnAl2O4) and large grain boundary area. Interestingly, the micro-composites revealed continuous decrease in thermal conductivity with increase in Al substitution while the nano-composites exhibited the lowest magnitudes for 2% Al concentration. Raman spectra indicated that phonon confinement in ZnO-Al nano-composites causes drastic decrease in the value of thermal conductivity.
An analytical molecular mechanics model for the elastic properties of crystalline polyethylene
Authors: Zhao Junhua , Guo Wanlin , Rabczuk Timon
Published: August 2012

We present an analytical model to relate the elastic properties of crystalline polyethylene based on a molecular mechanics approach. Along the polymer chains direction, the united-atom (UA) CH2-CH2 bond stretching, angle bending potentials are replaced with equivalent Euler-Bernoulli beams. Between any two polymer chains, the explicit formulae are derived for the van der Waals interaction represented by the linear springs of different stiffness. Then, the nine independent elastic constants are evaluated systematically using the formulae. The analytical model is finally validated by present united-atom molecular dynamics (MD) simulations and against available all-atom molecular dynamics results in the literature. The established analytical model provides an efficient route for mechanical characterization of crystalline polymers and related materials.
Simulation of N-face InGaN-based p-i-n solar cells
Authors: Chang Jih-Yuan , Kuo Yen-Kuang
Published: August 2012

GaN/InGaN p-i-n solar cells with N-face are simulated. In contrast to the detrimental effect of normal polarization, the internal electric field induced by reversed polarization enhances the efficiency of carrier collection by enlarging the energy band tilting to the favorable direction in the InGaN absorption layer. This beneficial effect becomes more remarkable when the indium composition of the InGaN absorption layer is higher.
Effect of mycotoxin deactivator product supplementation on dairy cows
Authors: Kiyothong K. , Rowlinson P. , Wanapat M. , Khampa S.
Published: August 2012

A total mixed ration (TMR) containing a blend of feedstuffs naturally contaminated with harmful mycotoxins was fed for 84 days to 24 primiparous and multiparous Holstein–Friesian × local dairy cows in a randomised complete block design. The dietary treatments consisted of a contaminated TMR diet plus various levels of the mycotoxin deactivator product (MDP) (0, 15, 30 or 45 g/head.day). Deoxynivalenol (DON), fumonisin B1 (FB1), zearalenone (ZON) and ochratoxin A (OTA) were found in the TMR at levels up to 720, 701, 541 and 501 μg/kg, whereas aflatoxin B1 (AfB1) and T-2 toxin (T-2) were found in the TMR at levels of 38 and 270 μg/kg, respectively. Rumen microbial ecology, ruminal volatile fatty acid (VFA) concentrations, ruminal microorganism populations, feed intake, total tract digestibility, milk yield, milk composition and serum immunoglobulin (Ig) concentrations were measured. The results revealed that the ruminal pH, ruminal ammonia nitrogen (NH3-N) concentration, total ruminal VFA concentrations and ruminal bacterial counts were significantly (P < 0.05) higher in supplemented than in non-supplemented cows. Ruminal protozoal counts were significantly (P < 0.05) lower in supplemented than in non-supplemented cows. DM intake, and digestibility of crude protein (CP) and neutral detergent fibre (NDF) were significantly (P < 0.05) higher in supplemented than in non-supplemented cows. Serum IgA concentrations were significantly (P < 0.05) higher in supplemented than in non-supplemented cows. Milk yield and milk protein were significantly (P < 0.05) higher in supplemented than in non-supplemented cows. On the basis of this experiment, it can be concluded that milk production and feed intake can be increased with the addition of MDP to cow diet in the presence of mycotoxins. These increases were accompanied by decreases in the negative effects of mycotoxins on rumen and immune function.
Effects of the forage content of the winter diet on the growth performance and carcass quality of steers finished on mountain pasture with a barley supplement
Authors: Blanco M. , Joy M. , Panea B. , Albertí P. , Ripoll G. , Carrasco S. , Revilla R. , Casasús I.
Published: August 2012

Eighteen Parda de Montaña steers (366 kg liveweight, 10 months of age) received diets of either forage (F; lucerne hay + straw) or forage and concentrate (FC; lucerne hay + straw + barley) during the winter feeding period, which lasted 118 days. Thereafter, steers continuously grazed in meadows in a dry mountain area until the end of the grazing period in September (160–167 days) and received 4.1 kg DM barley per head for the final 103–110 days of the grazing season. The steers that received the FC winter diet were heavier (491 vs 457 kg, respectively; P < 0.05) and had deposited more fat (7.2 vs 5.8 mm, P < 0.05) and muscle (63 vs 54 mm, P < 0.05) at the end of the winter than the steers that received the F winter diet. During the grazing period, the steers from both groups had similar weight gains (0.728 and 0.756 kg/day for FC and F diet, respectively). At slaughter, the steers from both groups were of similar age (590 vs 599 days, for FC and F diet, respectively) and had similar liveweights (560 vs 539 kg), muscle depths (54 vs 63 mm) and subcutaneous fat thicknesses (7.3 vs 7.2 mm). The serum leptin concentration differed only at the end of the winter period, when steers on the FC diet had higher leptin concentrations than did steers on the F diet (P < 0.05), reflecting differences in fatness. The carotenoid concentration in the plasma during the winter feeding period was higher in steers on the F than on the FC winter diet, but this difference was not seen during the grazing period. Carcasses from steers on the FC winter diet were heavier (324 vs 300 kg; P < 0.05) and had a higher dressing percentage (57.3% vs 56.1%, P < 0.05) than those reared on the F winter diet, but the fatness and conformation scores were similar between the groups. The percentages of fat, muscle and bone in the commercial dissection and 10th rib dissection did not differ between the winter diet groups. In conclusion, the differences resulting from the winter feeding period disappeared after the grazing period, and the carcass quality did not differ between the diets. Therefore, both strategies are equally technically advisable.
Modelling genetic covariance structure across ages of mean fibre diameter in sheep using multivariate and random regression analysis
Authors: Fozi M. Asadi , Van der Werf J. H. J. , Swan A. A.
Published: August 2012

Mean fibre diameter measurements from yearling to 5-year-old Australian fine- and medium-wool Merino sheep were analysed using several multivariate models that varied in covariance structure. A pre-structured multivariate model was found to be the most parsimonious model in comparison with the other models fitted such as banded, autoregressive and random regression. In the preferred model, the ages of mean fibre diameter for fine-wool data were genetically partitioned into yearling, 2 years, 3 years and later ages and for medium-wool data into hogget, 2 years and later ages. The estimates of genetic correlations between mean fibre diameter measured at different ages for medium-wool sheep were higher (0.89–1.00) than those for fine-wool Merino (0.75–1.00).
Developmental exposure to Passiflora incarnata induces behavioural alterations in the male progeny
Authors: Bacchi André D. , Ponte Bianca , Vieira Milene L. , de Paula Jaqueline C. C. , Mesquita Suzana F. P. , Gerardin Daniela C. C. , Moreira Estefânia G.
Published: August 2012

Passiflora incarnata is marketed in many countries as a phytomedicine and is prescribed mainly as a sedative and anxiolytic. Even though the directions of most marketed phytomedicines recommend them to be used under medical supervision, reproductive and developmental studies are sparse and not mandatory for regulatory purposes. To evaluate the reproductive and developmental toxicity of P. incarnata, Wistar female rats were gavaged with 30 or 300 mg kg–1 of this herb from gestational Day (GD) 0 to postnatal Day (PND) 21. P. incarnata treatment did not influence dams’ bodyweight or food intake or their reproductive performance (post-implantation loss, litter size, litter weight). There was also no influence on the physical development of pups (bodyweight gain, day of vaginal opening or preputial separation) or their behaviour in the open-field at PND 22, 35 and 75. Sexual behaviour was disrupted in adult male pups exposed to 300 mg kg–1 of P. incarnata; in this group, only 3 out of 11 pups were sexually competent. This behavioural disruption was not accompanied by alterations in plasma testosterone levels, reproductive-related organs and glands weights or sperm count. It is hypothesised that aromatase inhibition may be involved in the observed effect.
Cryotolerance of in vitro-produced porcine blastocysts is improved when using glucose instead of pyruvate and lactate during the first 2 days of embryo culture
Authors: Castillo-Martín M. , Yeste M. , Morató R. , Mogas T. , Bonet S.
Published: August 2012

The objective of the present study was to determine the effects of replacing glucose with pyruvate and lactate during the first 48 h of in vitro culture (IVC) in NCSU-23 medium on embryo development, embryo quality and survival of porcine blastocysts after vitrification. To this end, in vitro-produced (IVP) porcine oocytes were cultured with either glucose for 6 days (IVC-Glu) or pyruvate–lactate from Day 0 to Day 2 and then with glucose until Day 6 (IVC-PyrLac). Blastocysts were vitrified on Day 6 using the Cryotop device and, after warming, survival rate and the apoptosis index were evaluated after 24 h incubation in NCSU-23 medium. No significant differences were observed between IVC-Glu and IVC-PyrLac in terms of cleavage rate, blastocyst yield, total number of cells per blastocyst or the apoptosis index (1.82 ± 0.75% vs 3.18 ± 0.88%, respectively) of non-vitrified embryos. However, a significant increase was seen in hatching/hatched blastocysts in the IVC-PyrLac compared with IVC-Glu treatment group (12.71 ± 1.20% vs 3.54 ± 0.47%, respectively). Regardless of treatment, vitrification impaired the survival rate and the apoptosis index. When comparing both treatments after warming, the percentage of apoptotic cells was significantly higher for blastocysts in the IVC-PyrLac compared with IVC-Glu group (18.55 ± 3.49% vs 9.12 ± 2.17%, respectively). In conclusion, under the conditions of the present study, replacement of glucose with pyruvate–lactate during the first 48 h of culture resulted in a lower cryotolerance of IVP porcine embryos.
Persistence of an immunoreactive MUC1 protein at the feto - maternal interface throughout pregnancy in the mare
Authors: Wilsher Sandra , Gower Sue , Allen W. R.
Published: August 2012

A polyclonal human mucin-1 (MUC1) antibody was used to stain immunohistochemically for the presence of MUC1 on the endometrium and fetal membranes in mares between 20 and 309 days of gestation. Western blot analysis demonstrated the presence of a protein equivalent in size to a human MUC1 isoform, MUC1/Y, in equine endometrium, allantochorion and amnion. At all stages of gestation examined immunoreactivity to the MUC1 antibody was detected on the apical surface of the lumenal epithelium of the endometrium and the epithelium lining the mouths and apical regions of the endometrial glands. Furthermore, it persisted unchanged on the surface of the lumenal epithelium lying beneath the highly-invasive chorionic girdle component of the trophoblast before, during and after development of the endometrial cups. The MUC1 immunoreactive protein was also present on the trophoblast and other components of the fetal membranes during the post-fixation, pre-attachment period of gestation (20–40 days) and it persisted on the apical surface of the non-invasive trophoblast of the allantochorion before, during and after attachment, microvillous interdigitation and development of the microcotyledonary epitheliochorial placenta. Hence, the delayed placentation response in mares appears to occur independently of the persistence of an immunoreactive MUC1 protein at the feto–maternal interface.
Keap1 degradation by autophagy for the maintenance of redox homeostasis
Authors: Taguchi Keiko , Fujikawa Nanako , Komatsu Masaaki , Ishii Tetsuro , Unno Michiaki , Akaike Takaaki , Motohashi Hozumi , Yamamoto Masayuki
Published: August 2012

The Kelch-like ECH-associated protein 1 (Keap1)-NF-E2-related factor 2 (Nrf2) system is essential for cytoprotection against oxidative and electrophilic insults. Under unstressed conditions, Keap1 serves as an adaptor for ubiquitin E3 ligase and promotes proteasomal degradation of Nrf2, but Nrf2 is stabilized when Keap1 is inactivated under oxidative/electrophilic stress conditions. Autophagy-deficient mice show aberrant accumulation of p62, a multifunctional scaffold protein, and develop severe liver damage. The p62 accumulation disrupts the Keap1-Nrf2 association and provokes Nrf2 stabilization and accumulation. However, individual contributions of p62 and Nrf2 to the autophagy-deficiency–driven liver pathogenesis have not been clarified. To examine whether Nrf2 caused the liver injury independent of p62, we crossed liver-specific
Atg7
::
Keap1-Alb
double-mutant mice into
p62
- and
Nrf2
-null backgrounds. Although
Atg7
::
Keap1-Alb
::
p62
−/−
triple-mutant mice displayed defective autophagy accompanied by the robust accumulation of Nrf2 and severe liver injury,
Atg7
::
Keap1-Alb
::
Nrf2
−/−
triple-mutant mice did not show any signs of such hepatocellular damage. Importantly, in this study we noticed that Keap1 accumulated in the
Atg7
- or
p62
-deficient mouse livers and the Keap1 level did not change by a proteasome inhibitor, indicating that the Keap1 protein is constitutively degraded through the autophagy pathway. This finding is in clear contrast to the Nrf2 degradation through the proteasome pathway. We also found that treatment of cells with
tert
-butylhydroquinone accelerated the Keap1 degradation. These results thus indicate that Nrf2 accumulation is the dominant cause to provoke the liver damage in the autophagy-deficient mice. The autophagy pathway maintains the integrity of the Keap1-Nrf2 system for the normal liver function by governing the Keap1 turnover.
Atp6v0a4
knockout mouse is a model of distal renal tubular acidosis with hearing loss, with additional extrarenal phenotype
Authors: Norgett Elizabeth E. , Golder Zoe J. , Lorente-Cánovas Beatriz , Ingham Neil , Steel Karen P. , Karet Frankl Fiona E.
Published: August 2012

Autosomal recessive distal renal tubular acidosis (dRTA) is a severe disorder of acid–base homeostasis, often accompanied by sensorineural deafness. We and others have previously shown that mutations in the tissue-restricted a4 and B1 subunits of the H
+
-ATPase underlie this syndrome. Here, we describe an
Atp6v0a4
knockout mouse, which lacks the a4 subunit. Using β-galactosidase as a reporter for the null gene, developmental a4 expression was detected in developing bone, nose, eye, and skin, in addition to that expected in kidney and inner ear. By the time of weaning,
Atp6v0a4
−/−
mice demonstrated severe metabolic acidosis, hypokalemia, and early nephrocalcinosis. Null mice were hypocitraturic, but hypercalciuria was absent. They were severely hearing-impaired, as shown by elevated auditory brainstem response thresholds and absent endocochlear potential. They died rapidly unless alkalinized. If they survived weaning with alkali supplementation, treatment could later be withdrawn, but −/− animals remained acidotic with alkaline urine. They also had an impaired sense of smell. Heterozygous animals were biochemically normal until acid-challenged, when they became more acidotic than +/+ animals. This mouse model recapitulates the loss of H
+
-ATPase function seen in human disease and can provide additional insights into dRTA and the physiology of the a4 subunit.
Structural basis for substrate recognition by a unique
Legionella
phosphoinositide phosphatase
Authors: Hsu FoSheng , Zhu Wenhan , Brennan Lucy , Tao Lili , Luo Zhao-Qing , Mao Yuxin
Published: August 2012

Legionella pneumophila
is an opportunistic intracellular pathogen that causes sporadic and epidemic cases of Legionnaires’ disease. Emerging data suggest that
Legionella
infection involves the subversion of host phosphoinositide (PI) metabolism. However, how this bacterium actively manipulates PI lipids to benefit its infection is still an enigma. Here, we report that the
L. pneumophila
virulence factor SidF is a phosphatidylinositol polyphosphate 3-phosphatase that specifically hydrolyzes the D3 phosphate of PI(3,4)P
2
and PI(3,4,5)P
3
. This activity is necessary for anchoring of PI(4)P-binding effectors to bacterial phagosomes. Crystal structures of SidF and its complex with its substrate PI(3,4)P
2
reveal striking conformational rearrangement of residues at the catalytic site to form a cationic pocket that specifically accommodates the D4 phosphate group of the substrate. Thus, our findings unveil a unique
Legionella
PI phosphatase essential for the establishment of lipid identity of bacterial phagosomes.
Athletes' expectations with regard to officiating competence
Authors: Dosseville Fabrice , Laborde Sylvain , Bernier Marjorie
Published: August 2012

This study aimed to identify the cues upon which athletes rely when developing their expectations with regard to the competence of sports officials and to examine the sources of information, which are given priority in different kinds of sport (i.e. team, racquet and fighting sports). A questionnaire – the Athlete Perception of Sports Officials Questionnaire (APSO‐Q) – was developed in which athletes (N=472) were asked to indicate the influence of 32 cues on their impressions of sports officials. Exploratory factor analysis (EFA) yielded a four‐factor model (i.e. static cues, psychological, communicational and performance cues). Athletes mostly rely on psychological and personal communication attributes when evaluating officiating competence. Moreover, team players perceived that static cues were more influential when forming their expectations of sports officials than racquet players and fighting contestants. Such findings may have implications for athlete–official relationships and training of sports officials.
Magneto-optical spectrum of Mn-doped CdS nanorods
Authors: Xiong Wen
Published: August 2012

The electronic structure of CdS nanorods doped with manganese ions in the magnetic field is calculated based on the effective-mass theory, the conduction and valence subbands are found to be non-degenerate in Mn-doped CdS nanorods, the split energies of the valence subbands increase as the increment of the concentration of manganese ions. The possible transitions between the six lowest conduction subbands and the eight highest valence subbands are presented, the optical circularly polarized properties of each transition are also labelled. Through the calculation, it is found that the optical transitions can be influenced by the concentration of manganese ions and the applied magnetic field, and the radiative intensity of the transition in Mn-doped CdS nanorods increases with the increase in the manganese ions.
Transmission resonances in a symmetry-broken square coaxial aperture in a metal film
Authors: He Meng-Dong , Liu Jian-Qiang , Wang Kai-Jun
Published: August 2012

We present a computational study of the transmission resonances in a symmetry-broken square coaxial aperture with an inserted particle offset (δ) from the centre. According to the distribution characteristics of oscillating charges on the exit surface, the TE11- and TE21-like mode resonances in the hole may be regarded as dipole and quadrupole plasmon resonances, respectively. It is found that symmetry breaking, due to the particle offset, makes the quadrupole plasmon resonance, which is dark in symmetric geometry, visible. Based on the charge oscillation induced light emission mechanism, we qualitatively explain the variation of the transmission peaks of dipole and quadrupole plasmon resonances with the geometrical parameter δ, and the refractive index of the dielectric filled in the hole. Using polarization-dependent surface charge plots, we illustrate two distinct mode configurations of quadrupole plasmon resonance. Our findings will be of value in tuning the electromagnetic wave in subwavelength optics and designing chemical and biomedical sensors.
On the stochastic heat equation with spatially-colored random forcing
Authors: Foondun Mohammud , Khoshnevisan Davar
Published: August 2012

We consider the stochastic heat equation of the following form:
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="StartFraction partial-differential Over partial-differential t EndFraction u Subscript t Baseline left-parenthesis x right-parenthesis equals left-parenthesis script upper L u Subscript t Baseline right-parenthesis left-parenthesis x right-parenthesis plus b left-parenthesis u Subscript t Baseline left-parenthesis x right-parenthesis right-parenthesis plus sigma left-parenthesis u Subscript t Baseline left-parenthesis x right-parenthesis right-parenthesis ModifyingAbove upper F With dot Subscript t Baseline left-parenthesis x right-parenthesis for t greater-than 0 comma x element-of bold upper R Superscript d Baseline comma">

∂

∂
t

u
t

(
x
)
=
(

L

u
t

)
(
x
)
+
b
(

u
t

(
x
)
)
+
σ
(

u
t

(
x
)
)

F
˙

t

(
x
)

for 
t
>
0
,
 
x
∈

R

d

,

\begin{equation*} \frac {\partial }{\partial t}u_t(x) = (\mathcal {L} u_t)(x) +b(u_t(x)) + \sigma (u_t(x))\dot {F}_t(x)\quad \text {for }t>0,\ x\in \mathbf {R}^d, \end{equation*}

where

L

\mathcal {L}

is the generator of a Lévy process and

F
˙

\dot {F}

is a spatially-colored, temporally white, Gaussian noise. We will be concerned mainly with the long-term behavior of the mild solution to this stochastic PDE.

For the most part, we work under the assumptions that the initial data

u
0

u_0

is a bounded and measurable function and

σ
\sigma

is nonconstant and Lipschitz continuous. In this case, we find conditions under which the preceding stochastic PDE admits a unique solution which is also weakly intermittent. In addition, we study the same equation in the case where

L

u

\mathcal {L}u

is replaced by its massive/dispersive analogue

L

u
−
λ
u

\mathcal {L}u-\lambda u

, where

λ
∈

R

\lambda \in \mathbf {R}

. We also accurately describe the effect of the parameter

λ
\lambda

on the intermittence of the solution in the case where

σ
(
u
)

\sigma (u)

is proportional to

u
u

[the “parabolic Anderson model”].

We also look at the linearized version of our stochastic PDE, that is, the case where

σ
\sigma

is identically equal to one [any other constant also works]. In this case, we study not only the existence and uniqueness of a solution, but also the regularity of the solution when it exists and is unique.
Daphnia magna
shows reduced infection upon secondary exposure to a pathogen
Authors: McTaggart Seanna J. , Wilson Philip J. , Little Tom J.
Published: August 2012

Previous pathogen exposure is an important predictor of the probability of becoming infected. This is deeply understood for vertebrate hosts, and increasingly so for invertebrate hosts. Here, we test if an initial pathogen exposure changes the infection outcome to a secondary pathogen exposure in the natural host–pathogen system
Daphnia magna
and
Pasteuria ramosa
. Hosts were initially exposed to an infective pathogen strain, a non-infective pathogen strain or a control. The same hosts underwent a second exposure, this time to an infective pathogen strain, either immediately after the initial encounter or 48 h later. We observed that an initial encounter with a pathogen always conferred protection against infection compared with controls.
Spatially balanced topological interaction grants optimal cohesion in flocking models
Authors: Camperi Marcelo , Cavagna Andrea , Giardina Irene , Parisi Giorgio , Silvestri Edmondo
Published: August 2012

Models of self-propelled particles (SPPs) are an indispensable tool to investigate collective animal behaviour. Originally, SPP models were proposed with metric interactions, where each individual coordinates with neighbours within a fixed metric radius. However, recent experiments on bird flocks indicate that interactions are topological: each individual interacts with a fixed number of neighbours, irrespective of their distance. It has been argued that topological interactions are more robust than metric ones against external perturbations, a significant evolutionary advantage for systems under constant predatory pressure. Here, we test this hypothesis by comparing the stability of metric versus topological SPP models in three dimensions. We show that topological models are more stable than metric ones. We also show that a significantly better stability is achieved when neighbours are selected according to a spatially balanced topological rule, namely when interacting neighbours are evenly distributed in angle around the focal individual. Finally, we find that the minimal number of interacting neighbours needed to achieve fully stable cohesion in a spatially balanced model is compatible with the value observed in field experiments on starling flocks.
Frequency-dependent fitness induces multistability in coevolutionary dynamics
Authors: Arnoldt Hinrich , Timme Marc , Grosskinsky Stefan
Published: August 2012

Evolution is simultaneously driven by a number of processes such as mutation, competition and random sampling. Understanding which of these processes is dominating the collective evolutionary dynamics in dependence on system properties is a fundamental aim of theoretical research. Recent works quantitatively studied coevolutionary dynamics of competing species with a focus on linearly frequency-dependent interactions, derived from a game-theoretic viewpoint. However, several aspects of evolutionary dynamics, e.g. limited resources, may induce effectively nonlinear frequency dependencies. Here we study the impact of nonlinear frequency dependence on evolutionary dynamics in a model class that covers linear frequency dependence as a special case. We focus on the simplest non-trivial setting of two genotypes and analyse the co-action of nonlinear frequency dependence with asymmetric mutation rates. We find that their co-action may induce novel metastable states as well as stochastic switching dynamics between them. Our results reveal how the different mechanisms of mutation, selection and genetic drift contribute to the dynamics and the emergence of metastable states, suggesting that multistability is a generic feature in systems with frequency-dependent fitness.
The effect of non-uniform damping on flutter in axial flow and energy-harvesting strategies
Authors: Singh Kiran , Michelin Sébastien , De Langre Emmanuel
Published: August 2012

The problem of energy harvesting from flutter instabilities in flexible slender structures in axial flows is considered. In a recent study, we used a reduced-order theoretical model of such a system to demonstrate the feasibility for harvesting energy from these structures. Following this preliminary study, we now consider a continuous fluid-structure system. Energy harvesting is modelled as strain-based damping, and the slender structure under investigation lies in a moderate fluid loading range, for which the flexible structure may be destabilized by damping. The key goal of this work is to analyse the effect of damping distribution and intensity on the amount of energy harvested by the system. The numerical results indeed suggest that non-uniform damping distributions may significantly improve the power-harvesting capacity of the system. For low-damping levels, clustered dampers at the position of peak curvature are shown to be optimal. Conversely for higher damping, harvesters distributed over the whole structure are more effective.
Food security and climate change: on the potential to adapt global crop production by active selection to rising atmospheric carbon dioxide
Authors: Ziska Lewis H. , Bunce James A. , Shimono Hiroyuki , Gealy David R. , Baker Jeffrey T. , Newton Paul C. D. , Reynolds Matthew P. , Jagadish Krishna S. V. , Zhu Chunwu , Howden Mark , Wilson Lloyd T.
Published: August 2012

Agricultural production is under increasing pressure by global anthropogenic changes, including rising population, diversion of cereals to biofuels, increased protein demands and climatic extremes. Because of the immediate and dynamic nature of these changes, adaptation measures are urgently needed to ensure both the stability and continued increase of the global food supply. Although potential adaption options often consider regional or sectoral variations of existing risk management (e.g. earlier planting dates, choice of crop), there may be a global-centric strategy for increasing productivity. In spite of the recognition that atmospheric carbon dioxide (CO
2
) is an essential plant resource that has increased globally by approximately 25 per cent since 1959, efforts to increase the biological conversion of atmospheric CO
2
to stimulate seed yield through crop selection is not generally recognized as an effective adaptation measure. In this review, we challenge that viewpoint through an assessment of existing studies on CO
2
and intraspecific variability to illustrate the potential biological basis for differential plant response among crop lines and demonstrate that while technical hurdles remain, active selection and breeding for CO
2
responsiveness among cereal varieties may provide one of the simplest and direct strategies for increasing global yields and maintaining food security with anthropogenic change.
Offspring fitness varies with parental extra-pair status in song sparrows,Melospiza melodia
Authors: Sardell Rebecca J. , Arcese Peter , Reid Jane M.
Published: August 2012

Numerous studies have tested for indirect selection on female extra-pair reproduction (EPR) by quantifying whether extra-pair young (EPY) are fitter than their within-pair young (WPY) maternal half-siblings. In contrast, the hypothesis that offspring of EPY and WPY (rather than the EPY and WPY themselves) differ in fitness has not been tested, even though inter-generational effects of parental extra-pair status on offspring fitness could alter the magnitude and direction of indirect selection on EPR. We tested whether offspring of EPY song sparrows,Melospiza melodia, were more likely to recruit or produce hatched or recruited offspring over their lifetimes than offspring of WPY. Hatchlings with one or two EPY parents were more likely to recruit and produce hatched offspring than hatchlings with two WPY parents. Furthermore, these relationships differed between maternal versus paternal extra-pair status. Hatchlings with EPY fathers were more likely to recruit and produce offspring than hatchlings with WPY fathers. In contrast, hatchlings with EPY mothers were as likely to recruit as hatchlings with WPY mothers and tended to be less likely to produce recruited offspring. Depending on the causal genetic and environmental mechanisms, such conflicting inter-generational relationships between parental extra-pair status and offspring fitness could substantially influence the evolutionary dynamics of EPR.
Stem Transcriptome Reveals Mechanisms to Reduce the Energetic Cost of Shade-Avoidance Responses in Tomato
Authors: Cagnola Juan Ignacio , Ploschuk Edmundo , Benech-Arnold Tomás , Finlayson Scott A. , Casal Jorge José
Published: August 2012

While the most conspicuous response to low red/far-red ratios (R:FR) of shade light perceived by phytochrome is the promotion of stem growth, additional, less obvious effects may be discovered by studying changes in the stem transcriptome. Here, we report rapid and reversible stem transcriptome responses to R:FR in tomato (Solanum lycopersicum). As expected, low R:FR promoted the expression of growth-related genes, including those involved in the metabolism of cell wall carbohydrates and in auxin responses. In addition, genes involved in flavonoid synthesis, isoprenoid metabolism, and photosynthesis (dark reactions) were overrepresented in clusters showing reduced expression in the stem of low R:FR-treated plants. Consistent with these responses, low R:FR decreased the levels of flavonoids (anthocyanin, quercetin, kaempferol) and selected isoprenoid derivatives (chlorophyll, carotenoids) in the stem and severely reduced the photosynthetic capacity of this organ. However, lignin contents were unaffected. Low R:FR reduced the stem levels of jasmonate, which is a known inducer of flavonoid synthesis. The rate of stem respiration was also reduced in low R:FR-treated plants, indicating that by downsizing the stem photosynthetic apparatus and the levels of photoprotective pigments under low R:FR, tomato plants reduce the energetic cost of shade-avoidance responses.
Performance of Cu-coated vanadium cans forin situneutron powder diffraction experiments on hydrogen storage materials
Authors: Flacau Roxana , Bolduc Jim , Bibienne Thomas , Huot Jacques , Fritzsche Helmut
Published: August 2012

In situneutron powder diffraction (NPD) measurements of hydrogenation processes taking place at high temperatures pose difficulties related to the choice of sample can material. This article describes a simple design for a copper-coated vanadium can and its connection to the gas-handling system, tested up to 523 K. High-quality NPD patterns of TiV1.2Mn0.8body-centred cubic alloy, as-cast and partially hydrogenated, were collected at 373 K and deuterium pressures up to 2 bar (200 kPa).
Coating thickness determination in highly absorbent core–shell systems
Authors: Palancher Herve , Bonnin Anne , Honkimäki Veijo , Suhonen Heikki , Cloetens Peter , Zweifel Tobias , Tucoulou Rémi , Rack Alexander , Voltolini Marco
Published: August 2012

This article describes a single-shot methodology to derive an average coating thickness in multi-particle core–shell systems exhibiting high X-ray absorption. Powder composed of U–Mo alloy particles surrounded by a micrometre-thick UO2protective layer has been used as a test sample. Combining high-energy X-ray diffraction and laser granulometry, the average shell thickness could be accurately characterized. These results have been validated by additional measurements on single particles by two techniques: X-ray nanotomography and high-energy X-ray diffraction. The presented single-shot approach gives rise to many potential applications on core–shell systems and in particular on as-fabricated heterogeneous nuclear fuels.
Unambiguous indexing of trigonal crystals from white-beam Laue diffraction patterns: application to Dauphiné twinning and lattice stress mapping in deformed quartz
Authors: Chen Kai , Dejoie Catherine , Wenk Hans-Rudolf
Published: August 2012

Synchrotron X-ray Laue microdiffraction is used to investigate the microstructure of deformed quartz, which has trigonal symmetry. The unambiguous indexing of a Laue diffraction pattern can only be achieved by taking the intensities of the diffraction peaks into account. The intensities are compared with theoretical structure factors after correction for the incident X-ray beam flux, X-ray beam polarization, air absorption, detector response and Lorentz factor. This allows mapping of not only the grain orientation but also the stress tensor. The method is applicable for correct orientation determination of all crystals with trigonal symmetry and is indispensable for structure refinements of such materials from Laue diffraction data.
Arginine vasopressin‐dependent and AVP‐independent mechanisms of renal fluid absorption during thirsting despite glucocorticoid‐mediated vasopressin suppression
Authors: Ufer Friederike , Diederich Sven , Pedersen Erling B. , Spranger Joachim , Pfeiffer Andreas F. H. , Bähr Volker , Mai Knut
Published: August 2012

Objective

Glucocorticoids seem to modify the release and effects of plasma arginine vasopressin (pAVP). However, underlying processes are not well understood. This study aimed to evaluate the mechanism of the modulating effects of glucocorticoids on pAVP and renal water reabsorption.

Design

Fluid deprivation tests were performed without (d0) and after one (d1) and five days (d5) of oral prednisolone (Pred) pretreatment in a dosage relevant to drug therapy (30 mg/day).

Patients

Twelve healthy male volunteers participated in this trial.

Measurements

Plasma and urinary osmolality, pAVP, renin, aldosterone, plasma atrial natriuretic peptide (ANP) as well as urinary secretion of aquaporin‐2 (AQP2) and prostaglandin E2 (PGE2) were analysed.

Results

An appropriate rise in pAVP was observable during thirsting (P < 0·001), which was absent after Pred pretreatment. However, the plasma and urinary osmolality after Pred treatment did not differ when compared with the basal thirsting test. Unchanged urinary AQP2 excretion suggests AVP‐independent mechanisms of renal fluid reabsorption. Plasma renin concentration as well as ANP was substantially increased after Pred intake at d1 and d5 (both P < 0·05), which may mediate such AVP‐independent mechanisms. Urinary PGE2 secretion was not influenced by Pred pretreatment, making a PGE2‐mediated effect on renal AQP2 translocation and water permeability unlikely. Increased efficacy of exogenous desmopressin at d1 and d5 indicates also a relative increase in AVP sensitivity of the tubular cells after Pred intake.

Conclusions

The here presented data are compatible with an increased AVP sensitivity and a partially AVP‐independent regulation of AQP2 translocation and renal fluid reabsorption during glucocorticoid treatment.
Comparative proteomic profiles indicating genetic factors may involve in hepatocellular carcinoma familial aggregation
Authors: Zhong Da‐Ni , Ning Qiu‐Yue , Wu Ji‐Zhou , Zang Ning , Wu Jian‐Lin , Hu Die‐Fei , Luo Shuang‐Yan , Huang Ai‐Chun , Li Lan‐Lan , Li Guo‐Jian
Published: August 2012

Familial aggregation of hepatocellular carcinoma (HCC), the third leading cause of cancer death worldwide, has shown to be a common phenomenon. We investigated the association between the genetic background and HCC familial aggregation. Serum samples were collected from HCC family members and normal control family members for screening the differentially expressed protein peaks with the approach of surface‐enhanced laser desorption ionization time‐of‐flight mass spectrometry. Potential genetically associated protein peaks were selected and further identified by matrix assisted laser desorption ionization‐time of flight mass spectrometry. A panel of six protein peaks (m/z 6432.94, 8478.35, 9381.91, 17284.67, 17418.34, and 18111.04) were speculated to reflect the genetic susceptibility of HCC familial aggregation. Three of them (m/z 6432.94, 8478.35, and 9381.91) were selected to identify as the candidate proteins. Nine identified proteins, including mostly apolipoprotein family (ApoA1, ApoA2, ApoC3, ApoE) and serum amyloid A protein (SAA), were found overexpressed in the multiple HCC cases family members. The comparative proteomic profiles have suggested that genetic factors ought to be taken into account for familial aggregation of HCC.
Differences in stability effects on the marine survival of hatchery pink salmon (Oncorhynchus gorbuscha) within the upwelling and downwelling domains of the northeast Pacific Ocean
Authors: MILLER SARA E. , ADKISON MILO D. , HALDORSON LEWIS J.
Published: August 2012

Regional coastal conditions have a strong influence on juvenile salmon survival during their critical first months in the marine environment. Salmon (genusOncorhynchus)survival has been thought to be favored within the high latitude downwelling domain if water column stabilities increase, whereas stability may have the opposite effect in upwelling‐dominated lower latitudes. In this study, the relationships between water column stabilities during early marine residence of pink salmon (Oncorhynchus gorbuscha) in both the upwelling and downwelling domains of the northeast Pacific Ocean and marine survival rates for hatchery stocks ranging from Vancouver Island, British Columbia, to Kodiak Island, Alaska, were explored. Contrary to expectation, there was no clear difference in the effect of stability on marine survival rates in the downwelling and upwelling domains. In both domains, marine survival rates increased for pink salmon stocks that experienced below‐average stability on the inner shelf during early marine residence. Stability effects from the outer shelf showed no consistent relationship to marine survival within the northeast Pacific.
Expression of aquaporin3 in human neoplastic tissues
Authors: Niu Dongfeng , Kondo Tetsuo , Nakazawa Tadao , Yamane Tetsu , Mochizuki Kunio , Kawasaki Tomonori , Matsuzaki Toshiyuki , Takata Kuniaki , Katoh Ryohei
Published: August 2012

Niu D, Kondo T, Nakazawa T, Yamane T, Mochizuki K, Kawasaki T, Matsuzaki T, Takata K & Katoh R  (2012) Histopathology 61, 543–551

Expression of aquaporin3 in human neoplastic tissues

Aims:  Aquaporin3 (AQP3) is distributed widely in mammalian tissues and plays an important role in fluid homeostasis. The aim of this study was to investigate the pattern of expression of AQP3 in a variety of human neoplastic tissues and to explore its diagnostic implications.

Methods and results:  We studied 798 neoplastic tissues using immunohistochemistry with anti‐AQP3 antibody. We demonstrated a high positive frequency of AQP3 immunoreactivity in pituitary adenomas, salivary gland tumours, thymic tumours, adenocarcinoma of the lung and prostate, squamous cell carcinomas of the skin, oesophagus and uterine cervix, apocrine carcinoma of the breast, germinal cell tumours of the ovary and testis and urothelial carcinoma of the bladder. None of the sarcomas or central nervous system tumours showed AQP3 immunoreactivity. Most tumours with a high frequency of AQP3 positivity had corresponding or surrounding normal cells that also expressed AQP3. AQP3 was not a specific marker for benign or malignant epithelial neoplasms.

Conclusion:  AQP3 protein is expressed in a variety of epithelial tumours limiting its use as a diagnostic marker. Furthermore, AQP3 expression in tumour cells reflected the expression status of AQP3 in the corresponding normal cells. Our data suggest that water metabolism through AQP3 is maintained during neoplastic transformation in most human tissues.
Process optimisation and physicochemical characterisation of enzymatic hydrolysates of proteins from co‐products of Atlantic Salmon (Salmo salar) and Yellowtail Kingfish (Seriola lalandi)
Authors: He Shan , Franco Chris , Zhang Wei
Published: August 2012

The aim of this study was to develop an enzymatic hydrolysis process of protein co‐products for two major commercial fish species in Australia: Atlantic salmon (AS) and Yellowtail kingfish (YTK). The outcomes are to produce high protein recovery of fish protein hydrolysates within controlled molecular weight ranges that display enhanced physicochemical properties of oil binding and emulsification. Three enzymes (Flavourzyme, Neutrase and Alcalase) were applied to processing co‐products. Protein recovery and physicochemical properties were evaluated with increasing hydrolysis time from 30 min to 180 min and ratio of enzyme to substrate (E/S) from 0.5% to 3.0%. In order to achieve a product with optimum emulsifying capacity (50 ± 0.6 m2 g−1), an E/S ratio of 0.6–1.3% Flavourzyme was applied for 30–111 min with a protein recovery of 55%; in order to achieve a product with optimum oil‐binding capacity (8.3 ± 0.3 g oil g hydrolysates−1), an E/S ratio of 2.3–3.0% Flavourzyme was applied for 25–64 min with a protein recovery of 70%. YTK protein hydrolysates were further membrane‐fractionated into five fractions (>100 kDa, 50–100 kDa, 30–50 kDa, 10–30 kDa and <10 kDa), and of these, the 10–30 kDa exhibited the best properties of oil binding (19 ± 0.3 g oil g hydrolysates−1) and emulsification (57 ± 0.7 m2 g−1). These results demonstrate the importance of enzymatic hydrolysis of seafood co‐products into high‐value ingredients for food products and processing.