bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of lateral target size on hot electron production and electromagnetic pulse emission from laser-irradiated metallic targets
Authors: Chen Zi-Yu , Li Jian-Feng , Yu Yong , Wang Jia-Xiang , Li Xiao-Ya , Peng Qi-Xian , Zhu Wen-Jun
Published: November 2012

The influences of lateral target size on hot electron production and electromagnetic pulse emission from laser interaction with metallic targets have been investigated. Particle-in-cell simulations at high laser intensities show that the yield of hot electrons tends to increase with lateral target size, because the larger surface area reduces the electrostatic field on the target, owing to its expansion along the target surface. At lower laser intensities and longer time scales, experimental data characterizing electromagnetic pulse emission as a function of lateral target size also show target-size effects. Charge separation and a larger target tending to have a lower target potential have both been observed. The increase in radiation strength and downshift in radiation frequency with increasing lateral target size can be interpreted using a simple model of the electrical capacity of the target.
Complete integrability versus symmetry
Authors: Tudoran Răzvan M.
Published: November 2012

The purpose of this article is to show that on an open and dense set, complete integrability implies the existence of symmetry.
The fragility of liquids and colloids and its relation to the softness of the potential
Authors: Casalini R.
Published: November 2012

A parameter that is often used to characterize the dynamics of supercooled liquids is the dynamic fragility, however it is still debated how the fragility is related to other physical properties. Recent experimental data on colloidal systems have found that fragility decreases with increasing softness of the intermolecular potential. This result is in apparent disagreement with recent molecular dynamics simulations reporting the opposite behavior. Herein, using the thermodynamical scaling exponent γ as a measure of the steepness of the potential we show how these different results can be reconciled and also agree with previous results obtained for the dynamics of supercooled liquids at high pressures.
One-dimensional hybrid-direct kinetic simulation of the discharge plasma in a Hall thruster
Authors: Hara Kentaro , Boyd Iain D. , Kolobov Vladimir I.
Published: November 2012

In order to model the non-equilibrium plasma within the discharge region of a Hall thruster, the velocity distribution functions (VDFs) must be obtained accurately. A direct kinetic (DK) simulation method that directly solves the plasma Boltzmann equation can achieve better resolution of VDFs in comparison to particle simulations, such as the particle-in-cell (PIC) method that inherently include statistical noise. In this paper, a one-dimensional hybrid-DK simulation, which uses a DK simulation for heavy species and a fluid model for electrons, is developed and compared to a hybrid-PIC simulation. Time-averaged results obtained from the hybrid-DK simulation are in good agreement with hybrid-PIC results and experimental data. It is shown from a comparison of using a kinetic simulation and solving the continuity equation that modeling of the neutral atoms plays an important role for simulations of the Hall thruster discharge plasma. In addition, low and high frequency plasma oscillations are observed. Although the kinetic nature of electrons is not resolved due to the use of a fluid model, the hybrid-DK model provides spatially and temporally well-resolved plasma properties and an improved resolution of VDFs for heavy species with less statistical noise in comparison to the hybrid-PIC method.
Studies of space-charge-dominated multispecies beam in a solenoid based beam transport line
Authors: Sing Babu P. , Goswami A. , Pandit V. S.
Published: November 2012

A self-consistent particle-in-cell (PIC) simulation is used to study the transport properties of a space-charge-dominated multispecies beam propagating through a solenoid-based low energy beam transport line. The evolution of the beam radius and emittance growth of each species arising due to the nonlinear space-charge forces has been investigated. The self-consistent PIC simulation shows the formation of hollow density profiles of subdominant unwanted species around the primary beam, downstream of the transport line. We have utilized this effect for efficient removal of unwanted species by making use of a slit at a suitable location in the beam line.
Exact solutions for generalized variable-coefficients Ginzburg-Landau equation: Application to Bose-Einstein condensates with multi-body interatomic interactions
Authors: Kengne E. , Lakhssassi A. , Vaillancourt R. , Liu Wu-Ming
Published: November 2012

We present a double-mapping method (D-MM), a natural combination of a similarity with F-expansion methods, for obtaining general solvable nonlinear evolution equations. We focus on variable-coefficients complex Ginzburg-Landau equations (VCCGLE) with multi-body interactions. We show that it is easy by this method to find a large class of exact solutions of Gross-Pitaevskii and Gross-Pitaevskii-Ginzburg equations. We apply the D-MM to investigate the dynamics of Bose-Einstein condensation with two- and three-body interactions. As a surprising result, we obtained that it is very easy to use the built D-MM to obtain a large class of exact solutions of VCCGLE with two-body interactions via a generalized VCCGLE with two- and three-body interactions containing cubic-derivative terms. The results show that the proposed method is direct, concise, elementary, and effective, and can be a very effective and powerful mathematical tool for solving many other nonlinear evolution equations in physics.
Absorption saturation in optically excited graphene
Authors: Winzer Torben , Knorr Andreas , Mittendorff Martin , Winnerl Stephan , Lien Miao-Bin , Sun Dong , Norris Theodore B. , Helm Manfred , Malic Ermin
Published: November 2012

We investigate the saturation of the optical absorption in graphene induced by ultrafast optical pulses. Within a microscopic theory, we study the momentum-, angle-, and time-resolved interplay of anisotropic excitation, carrier-carrier, and carrier-phonon scattering, and its influence on the saturation of absorption and transmission. In agreement with performed experiments, we observe a linear regime for the intensity-dependence of the transmission at low pump fluences and a nonlinear saturation in the high excitation regime. Applying 10 fs-pulses, we obtain a saturation fluence of approximately 0.65 mJ/cm2. We demonstrate how the interplay of Pauli-blocking and intensity-dependent relaxation determines the saturation behavior.
Oscillating magnetocaloric effect on graphenes
Authors: Reis M. S.
Published: November 2012

The magnetocaloric effect of non-relativistic diamagnetic materials presents an oscillatory character due to the crossing of the Landau levels with the Fermi energy. This effect occurs at low temperature (ca 1 K) and high magnetic field (ca 10 T). Considering the relativistic properties of graphenes, a 2D massless diamagnetic material, these oscillations could be preserved and the effect occurs in a much higher temperature (ca 100 K), due to the huge Fermi velocity (106 m/s). In addition, the magnetocaloric effect can be tuned as either inverse or normal, by changing the magnetic field change in ca 3.4 T.
Flow manipulation and cell immobilization for biochemical applications using thermally responsive fluids
Authors: Haraksingh Thilsted Anil , Bazargan Vahid , Piggott Nina , Measday Vivien , Stoeber Boris
Published: November 2012

A flow redirection and single cell immobilization method in a microfluidic chip is presented. Microheaters generated localized heating and induced poly(N-isopropylacrylamide) phase transition, creating a hydrogel that blocked a channel or immobilized a single cell. The heaters were activated in sets to redirect flow and exchange the fluid in which an immobilized cell was immersed. A yeast cell was immobilized in hydrogel and a 4′,6-diamidino-2-phenylindole (DAPI) fluorescent stain was introduced using flow redirection. DAPI diffused through the hydrogel and fluorescently labelled the yeast DNA, demonstrating in situ single cell biochemistry by means of immobilization and fluid exchange.
Formation of a laminar electron flow for 300 GHz high-power pulsed gyrotron
Authors: Yamaguchi Yuusuke , Tatematsu Yoshinori , Saito Teruo , Ikeda Ryosuke , Mudiganti Jagadish C. , Ogawa Isamu , Idehara Toshitaka
Published: November 2012

This paper describes the design of a triode magnetron injection gun for use in a 200 kW, 300 GHz gyrotron. As power and frequency increase, the performance of the gyrotron becomes quite sensitive to the quality of the electron beam. Formation of a laminar electron flow is essential for the realization of a high quality beam with a small velocity spread. In this study, a new method is developed for a quantitative evaluation of the laminarity and is applied to optimize the electrode design. The laminarity depends not only on conventional design parameters such as the cathode slant angle but also on the spatial distribution of the electric field along the beam trajectory. In the optimized design, the velocity pitch factors, α, larger than 1.2 are obtained at 65 kV, 10 A with spreads, Δα, less than 5%.
Electron cyclotron maser emission mode coupling to the z-mode on a longitudinal density gradient in the context of solar type III bursts
Authors: Pechhacker R. , Tsiklauri D.
Published: November 2012

A beam of super-thermal, hot electrons was injected into maxwellian plasma with a density gradient along a magnetic field line. 1.5D particle-in-cell simulations were carried out which established that the EM emission is produced by the perpendicular component of the beam injection momentum. The beam has a positive slope in the distribution function in perpendicular momentum phase space, which is the characteristic feature of a cyclotron maser. The cyclotron maser in the overdense plasma generates emission at the electron cyclotron frequency. The frequencies of generated waves were too low to propagate away from the injection region, hence the wavelet transform shows a pulsating wave generation and decay process. The intensity pulsation frequency is twice the relativistic cyclotron frequency. Eventually, a stable wave packet formed and could mode couple on the density gradient to reach frequencies of the order of the plasma frequency that allowed for propagation. The emitted wave is likely to be a z-mode wave. The total electromagnetic energy generated is of the order of 0.1% of the initial beam kinetic energy. The proposed mechanism is of relevance to solar type III radio bursts, as well as other situations, when the injected electron beam has a non-zero perpendicular momentum, e.g., magnetron.
Local electric conductive property of Si nanowire models
Authors: Ikeda Yuji , Senami Masato , Tachibana Akitomo
Published: November 2012

Local electric conductive properties of Si nanowire models are investigated by using two local electric conductivity tensors, \documentclass[12pt]{minimal}\begin{document}${\mathop{\sigma }\limits^{\leftrightarrow }}_{\mathrm{ext}}(\vec{r})$\end{document}σ↔ ext (r⃗) and \documentclass[12pt]{minimal}\begin{document}${\mathop{\sigma }\limits^{\leftrightarrow }}_{\mathrm{int}}(\vec{r})$\end{document}σ↔ int (r⃗), defined in Rigged QED. It is emphasized that \documentclass[12pt]{minimal}\begin{document}${\mathop{\sigma }\limits^{\leftrightarrow }}_{\mathrm{int}}(\vec{r})$\end{document}σ↔ int (r⃗) is defined as the response of electric current to the actual electric field at a specific point and does not have corresponding macroscopic physical quantity. For the Si nanowire models, there are regions which show complicated response of electric current density to electric field, in particular, opposite and rotational ones. Local conductivities are considered to be available for the study of a negative differential resistance (NDR), which may be related to this opposite response. It is found that \documentclass[12pt]{minimal}\begin{document}${\mathop{\sigma }\limits^{\leftrightarrow }}_{\mathrm{int}}(\vec{r})$\end{document}σ↔ int (r⃗) shows quite different pattern from \documentclass[12pt]{minimal}\begin{document}${\mathop{\sigma }\limits^{\leftrightarrow }}_{\mathrm{ext}}(\vec{r})$\end{document}σ↔ ext (r⃗), local electric conductivity defined for the external electric field. The effects of impurities are also studied by using the model including a Ge atom, in terms of the local response to electric field. It is found that the difference from the pristine model is found mainly around the Ge atom.
Fluorescence enhancing under UV-NIR simultaneous-excitation in ZnS:Cu,Mn phosphors
Authors: Xie L. J. , Zou S. Y. , Zhang R. , Cai J. L. , Zou Y. , Cao L. W. , Meng J. X.
Published: November 2012

The fluorescence properties of a long-lasting phosphor, ZnS:Cu,Mn was studied for the first time under simultaneously excitation of both UV and NIR light. Up to 20% fluorescence enhancement of the phosphor was observed. In the present simultaneously-excitation process, broad-band NIR light was absorbed and converted to visible photons via a single-photon upconversion path. We propose that a novel kind of spectral-conversion material with the unique ability to simultaneously convert both UV and NIR photons can be developed and is promising in the application of enhancing the EQE of solar cells.
Using fuzzy clustering to reveal recurring spatial patterns in corpora of dialect maps
Authors: Meschenmoser Daniel , Pröll Simon
Published: November 2012

In this article, a new method to identify groups of spatially similar dialect maps is presented. This is done by comparing statistical properties of the maps: the empirical covariance is measured for every map in a corpus of dialect maps. Then, the Fuzzy C-Means clustering method is applied to these covariance data. Thereby, one is able to detect and measure gradual similarities between maps. By employing the method on lexical data from the dialect atlas Sprachatlas von Bayerisch-Schwaben, it can be shown that clusters of spatially similar maps also share semantic similarities. This method can thus be used for grouping maps based on spatial similarities while at the same time indicating patterns of semantic relationships between spatially related variables.
On ways of being on the way
Authors: Petré Peter , Davidse Kristin , Van Rompaey Tinne
Published: November 2012

This article presents a case study of a set of constructions containing the related way-nouns road, way, track and route, exemplified by (i) the farm road to the house, (ii) A senior Soviet official is on his way to the Iraqi capital, (iii) spies Burgess and Maclean escaped from Britain en route to Moscow, (iv) Queensland is on track to become the top bowling state in Australia. These distinct constructions are a case of layering (Hopper 1991). Constructions featuring lexical uses of way-nouns, illustrated by (i), coexist with strings containing way-nouns that have been reanalysed into units with new lexical or grammatical meanings, i.e. respectively composite predicates (ii), complex prepositions (iii) and aspectual markers (iv). We argue that these three constructions challenge the view of decategorialization as mere loss of the original categorial features. We also show on the basis of qualitative and quantitative corpus analysis that the structural variants display specialization in relation to the four way-nouns.
The discursive protection of national interests
Authors: Duncan Philip T.
Published: November 2012

This article combines methodology from the discourse-historical approach with critique from Indigenous feminism and postcolonial theory to examine the “update” feature of Internet news and its potential impact on knowledge. The notion of text becomes abstract as authors produce neo-texts labeled “updated,” leading to opacity in editorial processing. From a case study analyzing an Associated Press article discussing Pakistani responses to U.S. drone attacks, we observe negative (re)presentation of Indigenous peoples in Pakistan as authors use rhetorical strategies to achieve erasure in subsequent revisions. I interpret the authors as employing such strategies to legitimize United States’ power under the axiological guise of protecting “democracy.” The revisions silence tribal leaders’ and women’s voices, substituting elements that interdiscursively appeal to “terrorism” in a post-9/11 context. The authors dissolve the distinction between tribal peoples in Pakistan and “terrorists.” U.S. military aggression is linguistically realized as defensive, and Pakistani disapprobation framed as offensive attack.
Discourses of counter-Islamic-threat mobilization in post 9/11 documentaries
Authors: Mylonas Yiannis
Published: November 2012

This article critically studies documentaries focusing on the “Islamic terrorist threat”, produced in the US and in Western Europe. The particular films relate to the discourses of the growing far right political movements in liberal democracies. The article analyzes the communicational tactics deployed by the filmmakers for counter-terrorist mobilization of “Westerners”. The films’ producers objectify the terrorist threat as exceptional and ontological, in order to reconfigure the identity of the “West”. The analysis focuses on representations of the West’s threatening Other through the reflexive use of critical discourse analysis and post structuralist, discourse theory. Counter-threat strategies, varying from warfare to biopolitical control, are articulated as social demands and as individualized tasks of inclusion to the ideological space of the West and the sovereign space of western nation states. The critical study of the particular documentaries aims at highlighting the regressive and character of the passionate discourses of far right media, in relation to the political crisis that liberal democracies across the world are facing.
From “There are no Palestinian people” to “Sorry for their suffering”
Authors: Kampf Zohar
Published: November 2012

The aim of this paper is to examine the evolving Israeli discourse of recognition of the Palestinian people and their suffering as a case study for theorizing the role of recognition statements in peace processes. Three stages of recognition are characterized and applied in order to understand the changing attitudes of Israeli officials toward the Palestinians: (1) acknowledgment of a political entity; (2) acknowledgment of their suffering; (3) acknowledgment of responsibility for their suffering. An analysis of Israeli officials’ statements allows one to track the evolving recognition of one side in a conflict vis-à-vis the suffering of the other. Further, analysis of the response in Israel, in Palestinian territories and in the Arab world to what is considered the most far-reaching recognition statement made by an Israeli official enables us better to understand the role of such statements in promoting reconciliation.
The “National Left” in Israeli public discourse
Authors: Mandelbaum Moran M.
Published: November 2012

In 2000 the leftist camp in Israel experienced a crisis of meaning and identity. This was the result of the failure of the 2000 Camp David Talks between Israel and the Palestinian Authority. The atmosphere that emerged amongst the Israeli left was one of despair and disillusion, a void of meaning. Recently, however, a new Zionist “national left” discourse emerged, which refutes the idea of peace and reconstructs the ideology of the Israeli left. This paper engages critically with this discourse by deploying a discourse analytical approach, as it draws on Ernesto Laclau and Chantal Mouffe’s theory of hegemony as well as semantic analysis, specifically the use of “semantic fields” and “semantic networks”. This paper looks at a variety of public texts, which are exemplary of the “national left” discourse in Israel.
Epistemic capacity in research environments: a framework for process evaluation
Authors: Hellström Tomas
Published: November 2012

This paper is based on a study of 40 centers of excellence evaluations performed by the Swedish Research Council in 2008 and 2010. Building on an analysis of these evaluations, a new quality concept, epistemic capacity, is proposed, and it is shown how this may be utilized in the evaluation of research programs and centers. Epistemic capacity refers to a scientific research center’s capacity, as embodied in activities and processes, to generate first class research outcomes. In this sense, the concept is best applied in intermediary and process evaluation to ascertain how a research milieu is progressing towards future, but yet unrealized, research contributions. The framework is elaborated in the light of previous evaluation research, and conditions for its application are discussed.
Vocational education and training: the terra incognita of innovation policy
Authors: Toner Phillip , Dalitz Robert
Published: November 2012

Is what is known from research on systemic innovation reflected in innovation policy, both as guiding principles and as actions? This paper highlights a major paradox in the translation of research on innovation into innovation policy in Australia. The innovation studies literature has established the central role of the vocational education and training (VET) system and VET-trained workers in technology generation, diffusion and incremental innovation. Research has also established that the pattern of innovation in Australia, compared with that in many other OECD countries, makes firms more reliant on VET skills to implement innovation. Despite this recognition in the innovation literature, this paper argues that the VET system is largely excluded from government innovation policy and programmes in Australia. Evidence for this exclusion is derived from a textual analysis of the principal Australian government policy statements and government-sponsored studies of the Australian innovation system, and from an analysis of the interest groups represented on government innovation advisory and policy structures. Tentative explanations are advanced for this exclusion and a number of important benefits are identified for the VET system and the wider innovation system arising from closer integration of VET into innovation policy
Substance Misuse Subtypes among Women Convicted of Homicide
Authors: de Melo Nunes Adriana , Baltieri Danilo Antonio
Published: November 2012

Background: The proportion of women incarcerated is growing at a faster pace than that for men. The reasons for this important increase have been mainly attributed to drug-using lifestyle and drug-related offenses. About half of female inmates have history of substance misuse and one third demonstrate high impulsiveness levels. The objectives of this study were to (a) identify subtypes of alcohol and drug problems and impulsiveness among women convicted of homicide, and (b) examine the association between psychosocial and criminological features and the resulting clusters. Methods: Data come from 158 female inmates serving a sentence for homicide in the Penitentiary of Sant'Ana in São Paulo State, Brazil. Latent class analysis was used to group participants into substance misuse and impulsiveness classes. Results: Two classes were identified: nonproblematic (cluster 1: 54.53%, n = 86) and problematic (cluster 2: 45.57%, n = 72) ones. After controlling for several psychosocial and criminological variables, cluster 2 inmates showed an earlier beginning of criminal activities and a lower educational level than their counterparts. Conclusions: To recognize the necessities of specific groups of female offenders is crucial for the development of an adequate system of health politics and for the decrease of criminal recidivism among those offenders who have shown higher risk.
Visual memory for feature bindings: The disruptive effect of responding to new perceptual input
Authors: Fiacconi Chris M. , Milliken Bruce
Published: November 2012

In the current study, we examined how short-term memory for location–identity feature bindings is influenced by subsequent cognitive and perceptual processing demands. Previous work has shown that memory performance for feature bindings can be disrupted by the presentation of subsequent visual information, particularly when this information is similar to that held in memory. The present study demonstrates that memory performance for feature bindings can be profoundly disrupted by also requiring a response to visual information presented subsequent to the visual memory array. Across five experiments, memory for a location–identity binding was substantially impaired following a localization response to a following item that matched the location but mismatched the identity of the memory target. The results point to an important role for action in the episodic integration processes that control short-term visual memory performance.
Influence of stoichiometry and structure on the optical properties of AlNxOy films
Authors: Borges J , Barradas N P , Alves E , Beaufort M F , Eyidi D , Vaz F , Marques L
Published: November 2012

The AlN
x
O
y
system offers the possibility to obtain a wide range of responses, by tailoring the properties between Al, AlN and Al2O3, opening a significant number of possible applications. The aim of this work is to correlate the optical properties of AlN
x
O
y
thin films with their composition and structural features, taking as reference the binary systems AlN
x
and AlO
y
. In the AlN
x
system, the increase in the nitrogen content induced a wide variation in the optical properties, ranging from the typical profile of a polycrystalline Al-type film towards nearly constant reflectance values as low as 5%, as well as a smooth increase in samples transparency as the ratio N/Al approached unit. In the case of the AlO
y
system, the reflectance also decreased as the oxygen content increased; however, the transition to transparent films (Al2O3-like) was more abrupt. The ternary system AlN
x
O
y
, revealed optical responses that ranged from a typical profile of a polycrystalline Al-type film towards low and constant reflectance values in a wide range of x and y coefficients, ending up as semi-transparent when Al2O3-like films were formed. The unusual low optical reflectance of some films reveals some potential applications in solar power systems and sensors.
Homeomorphism groups of commutator width one
Authors: Tsuboi Takashi
Published: November 2012

We show that any element of the identity component

H
o
m
e
o

(

S
n

)
0

\mathrm {Homeo}(S^n)_0

of the group of homeomorphisms of the

n
n

-dimensional sphere

S
n

S^n

can be written as one commutator. We also show that any element of the group

H
o
m
e
o

(

μ
n

)

\mathrm {Homeo}(\mu ^n)

of homeomorphisms of the

n
n

-dimensional Menger compact space

μ
n

\mu ^n

can be written as one commutator.
Current aspects of the spectrum of acute heart failure syndromes in a real‐life setting: the OFICA study
Authors: Logeart Damien , Isnard Richard , Resche‐Rigon Matthieu , Seronde Marie‐France , de Groote Pascal , Jondeau Guillaume , Galinier Michel , Mulak Geneviève , Donal Erwan , Delahaye François , Juilliere Yves , Damy Thibaud , Jourdain Patrick , Bauer Fabrice , Eicher Jean‐Christophe , Neuder Yannick , Trochu Jean‐Noël ,   on behalf of the working group on Heart Failure of the French Society of Cardiology
Published: November 2012

Aims

To improve knowledge of epidemiological data, management, and clinical outcome of acute heart failure (AHF) in a real‐life setting in France.

Methods and results

We conducted an observational survey constituting a single‐day snapshot of all unplanned hospitalizations because of AHF in 170 hospitals throughout France (the OFICA survey). A total of 1658 patients (median age 79 years, 55% male) were included. Family doctors were the first medical contact in 43% of cases, and patients were admitted through emergency departments in 64% of cases. Clinical scenarios were mainly acutely decompensated HF (48%) and acute pulmonary oedema (38%) with similar clinical and biological characteristics as well as outcome. Characteristics were different and severity higher in both shock and right HF. Infection and arrhythmia were the most frequent precipitating factors (27% and 24% of cases); diabetes and chronic pulmonary disease were the most frequent co‐morbidities (31% and 21%). Over 80% of patients underwent both natriuretic peptide testing and echocardiography. LVEF was preserved (>50%) in 36% of patients and associated with specific characteristics and lower severity. Median hospital stay was 13 days; in‐hospital mortality was 8.2%, and independent predictors were age, blood pressure, and creatinine. Treatment at discharge in patients with reduced LVEF included ACE inhibitors/ARBs, beta‐blockers, and aldosterone inhibitors in 78, 67, and 27% cases. Non‐surgical devices were reported in <20% of potential candidates.

Conclusion

This comprehensive survey analysing AHF in real life emphasizes the heterogeneous nature and overall high severity of AHF. It could be a useful tool to identify unsolved medical issues and improve outcome.

Trial registration: NCT01080937
Photocatalysis: Effect of Light-Activated Nanoscale Formulations of TiO2 on Xanthomonas perforans and Control of Bacterial Spot of Tomato
Authors: Paret Mathews L. , Vallad Gary E. , Averett Devron R. , Jones Jeffrey B. , Olson Stephen M.
Published: November 2012

Protection of crops from bacterial diseases presents a continuing challenge, mandating the development of novel agents and approaches. Photocatalysis is a process where chemically reactive oxygen species are catalytically generated by certain minerals in the presence of light. These reactive oxygen species have the capacity to destroy organic molecular structures critical to pathogen viability. In this study, the antibacterial potential of photocatalytic nanoscale titanium dioxide (TiO2), nanoscale TiO2 doped (incorporation of other materials into the structure of TiO2) with silver (TiO2/Ag), and nanoscale TiO2 doped with zinc (TiO2/Zn; AgriTitan) was evaluated against Xanthomonas perforans, the causal agent for bacterial spot disease of tomato. In vitro experiments on photocatalytic activity and dose dependency were conducted on glass cover slips coated with the nanoscale formulations by adding a known population of X. perforans strain Xp-F7 and illuminating the cover slips under a visible light source. TiO2/Ag and TiO2/Zn had high photocatalytic activity against X. perforans within 10 min of exposure to 3 × 104 lux. Greenhouse studies on naturally and artificially infected transplants treated with TiO2/Zn at ≈500 to 800 ppm significantly reduced bacterial spot severity compared with untreated and copper control. Protection was similar to the grower standard, copper + mancozeb. The use of TiO2/Zn at ≈500 to 800 ppm significantly reduced disease incidence in three of the four trials compared with untreated and copper control, and was comparable to or better than the grower standard. The treatments did not cause any adverse effects on tomato yield in any of the field trials.
Complications of Flat Bed Rest After Incidental Durotomy
Authors: Radcliff Kristen E. , Sidhu Gursukhman D.S. , Kepler Christopher K. , Gruskay Jordan , Anderson David Greg , Hilibrand Alan , Albert Todd J. , Vaccaro Alexander R.
Published: November 2012

Study Design:

Retrospective case series.

Objective:

To determine whether bed rest is a risk factor for specific medical complications.

Summary of Background Data:

Flat bed rest after incidental durotomy is commonly used to reduce the risk of CSF leakage and associated complications.

Methods:

Retrospective case series of consecutive patients after lumbar laminectomy were identified. Medical records were reviewed for duration of bed rest and complications (pulmonary, wound, neurological, gastrointestinal, and urinary) in the chart notes, repair methods, subfascial drain placement, consultant notes, imaging reports, and discharge summaries. Patients were compared with duration of bed rest >24 hours versus duration of bed rest ≤24 hours. The incidence of complications was compared between groups using the Fisher exact test.

Results:

There were a total of 42 patients with incidental durotomy. There were 18 patients in the bed rest ≤24 hours group and 24 patients in the bed rest >24 hours group. Comparing the bed rest ≤24 hours to bed rest >24 hours patients, there was no statistically significant difference in the incidence of postdurotomy-related neurological complications, wound complications, and need for revision surgery. There was a statistically significant decrease in the incidence of total medical complications in the ≤24-hour group (0% vs. 50%, P=0.0003).

Conclusion:

There was an increased incidence of medical complications in the bed rest group >24 hours. Flat bed rest after modern dural repair method may not be a necessity in all cases and may be associated with a higher incidence of medical complications.
Metabolomic Phenotyping Validates the Infant Rhesus Monkey as a Model of Human Infant Metabolism
Authors: O'Sullivan Aifric , He Xuan , McNiven Elizabeth M.S. , Hinde Katie , Haggarty Neill W. , Lönnerdal Bo , Slupsky Carolyn M.
Published: November 2012

Objectives:

Rhesus macaque monkeys are widely used as models for human physiology and behavior. They are particularly suited for studies on infant nutrition and metabolism; however, few studies have directly compared their metabolic or microbiological phenotypes. The aim of the present study was to compare the metabolomic profiles and microbiome of milk from human and rhesus mothers, and the metabolomic profiles of urine and serum from human and rhesus infants to establish the value of this model for human nutrition research.

Methods:

Milk samples were collected from rhesus and human mothers at similar stages of lactation. Urine and serum samples were collected from breast‐fed rhesus and human infants. 1H nuclear magnetic resonance spectra were acquired for all samples and metabolites were identified and quantified using targeted profiling techniques. The microbial community structure of milk was examined using 16S rRNA gene sequencing.

Results:

An identical set of metabolites was identified in the urine and serum profiles from human and rhesus infants. In urine, 65% of the metabolites were present at similar concentrations, whereas ∼40% were similar in serum. The gross composition of human and rhesus milk was comparable, including the overall microbial community at both the phylum and order level; however, some oligosaccharides found in human milk were not present in monkey milk.

Conclusions:

Comparison of the milk microbiome and urine, serum, and milk metabolome of rhesus macaques and humans has revealed substantial similarities that provide unique biological information highlighting the significance of rhesus macaques as a model for infant nutrition and developmental research.
You Look All Right to Me
Authors: Hill Rebecca J. , Davies Peter S.W.
Published: November 2012

Objectives:

It is reported that malnutrition is not a feature of ulcerative colitis (UC). Body mass index (BMI) is frequently used clinically to indicate nutritional status; however, it is a proxy measure at best, and body cell mass (BCM) is a much more accurate representation. The present study aims to investigate BMI in patients with UC in relation to their BCM.

Methods:

A total of 18 patients (7M; 11F) had their nutritional status (BCM) measured using total body potassium40 counting every 6 months to yield a total of 77 measurements. BCM measurements were adjusted for height and sex, and BMI was calculated as weight/height2, with z scores determined for both parameters. Disease activity was determined using the Pediatric Ulcerative Colitis Activity Index.

Results:

Mean (±SD) height, weight, BMI, and BCM z scores were 0.39 (0.96), 0.20 (1.08), −0.05 (1.18), and −0.74 (1.41), respectively. No correlation was found between BMI and BCM z scores, and these z scores were significantly different (P = 0.02), particularly in the moderate/severe disease activity group (P = 0.01). Mean BCM z scores were −0.69 (1.65) of a z score below BMI z scores. Furthermore, where BMI z scores showed no relation to disease activity and no differences between disease activity categories, BCM z scores were significantly negatively correlated (r = −0.32, P = 0.01), with significantly lower scores found in the moderate/severe group (P = 0.01).

Conclusions:

Simply calculating BMI in patients with UC does not give adequate information regarding nutritional status, and more accurate, yet easily accessible “bedside” techniques need to be determined to improve patient care.
Ultrasonographic Assessment of Liquid Gastric Emptying and Antral Motility According to the Subtypes of Irritable Bowel Syndrome in Children
Authors: Devanarayana Niranga M. , Rajindrajith Shaman , Bandara Chandrika , Shashiprabha Gayani , Benninga Marc A.
Published: November 2012

Objectives:

Gastric motor abnormalities have been reported in adults with irritable bowel syndrome (IBS), commonly in constipation‐predominant IBS (IBS‐C); however, such studies are uncommon in children. Furthermore, differences of gastric motility have not been studied in children with different IBS subtypes.

Methods:

Seventy‐six children (33 [43%] boys, age 4–14 years, mean 7.9 years, SD 3.0 years) fulfilling Rome III criteria for IBS and 20 healthy controls (8 [40%] boys, age 4–14 years, mean 8.4 years, SD 3.0 years) were recruited (diarrhea‐predominant IBS = 21, IBS‐C = 31, mixed IBS = 19, and unsubtyped IBS = 5). Liquid gastric emptying rate (GER) and antral motility were assessed using an ultrasound method.

Results:

Average GER (43.8% vs 66.2% in controls), amplitude of antral contractions (56.4% vs 89%), and antral motility index (5.1 vs 8.3) were lower and fasting antral area (1.6 vs 0.6) was higher in patients with IBS (P < 0.0001). Frequency of antral contractions F (8.9 vs 9.3) did not show a significant difference. Patients exposed to stressful events had a significantly lower GER, compared to those not exposed to such events (P = 0.03). Gastric motility parameters had no correlation with severity of symptoms. GER (42.6%, 46.3%, 39.6%), fasting antral area (1.4 cm2, 1.8 cm2, 1.8 cm2), amplitude of antral contractions (53%, 58.9%, 51.8%), frequency of antral contractions (8.7, 8.9, 9.2), and antral motility index (4.7, 5.3, 4.8) were not different among diarrhea‐predominant IBS, IBS‐C, and mixed IBS (P > 0.05).

Conclusions:

GER and antral motility parameters were significantly impaired in children with IBS compared with controls. GER and antral motility parameters were not different between IBS subtypes.
Saccharide-mediated antagonistic effects of bark beetle fungal associates on larvae
Authors: Wang Bo , Lu Min , Cheng Chihang , Salcedo Christian , Sun Jianghua
Published: November 2012

Bark beetles are among the most destructive of pine forest pests and they form close symbiotic relationships with ophiostomatoid fungi. Although some fungi are considered to be mutualistic symbionts of bark beetles with respect to the supply of nutrients, detrimental effects of fungal symbionts on larval growth have also been frequently reported. The mechanisms of such antagonistic effects are hypothesized to be a decrease in nutritional resources caused by competition for saccharides by the fungi. Here, we provide experimental evidence that three beetle-associated fungi modify the nutritional content of an artificial phloem diet, leading to a detrimental effect on the growth of
Dendroctonus valens
larvae. When larvae were fed a diet of pine phloem in agar medium colonized with any of these fungi, feeding activity was not affected but weight significantly decreased. Additional analysis showed that fungi depleted the fructose and glucose concentrations in the phloem media. Furthermore, these detrimental effects were neutralized by supplementing the media with fructose or glucose, suggesting that fungi may affect larval growth by modifying diet saccharide contents. These data indicate that fungus-induced nutritional changes in bark beetle diet can affect larval growth, and that the mechanism involves fungus-induced saccharide depletion from the larval diet.
Ectoparasites increase swimming costs in a coral reef fish
Authors: Binning Sandra A. , Roche Dominique G. , Layton Cayne
Published: November 2012

Ectoparasites can reduce individual fitness by negatively affecting behavioural, morphological and physiological traits. In fishes, there are potential costs if ectoparasites decrease streamlining, thereby directly compromising swimming performance. Few studies have examined the effects of ectoparasites on fish swimming performance and none distinguish between energetic costs imposed by changes in streamlining and effects on host physiology. The bridled monocle bream (Scolopsis bilineatus) is parasitized by an isopod (Anilocra nemipteri),which attaches above the eye. We show that parasitized fish have higher standard metabolic rates (SMRs), poorer aerobic capacities and lower maximum swimming speeds than non-parasitized fish. Adding a model parasite did not affect SMR, but reduced maximum swimming speed and elevated oxygen consumption rates at high speeds to levels observed in naturally parasitized fish. This demonstrates that ectoparasites create drag effects that are important at high speeds. The higher SMR of naturally parasitized fish does, however, reveal an effect of parasitism on host physiology. This effect was easily reversed: fish whose parasite was removed 24 h earlier did not differ from unparasitized fish in any performance metrics. In sum, the main cost of this ectoparasite is probably its direct effect on streamlining, reducing swimming performance at high speeds.
Forest refugia in Western and Central Africa as ‘museums’ of Mesozoic biodiversity
Authors: Murienne Jérôme , Benavides Ligia R. , Prendini Lorenzo , Hormiga Gustavo , Giribet Gonzalo
Published: November 2012

The refugial speciation model, or ‘species pump’, is widely accepted in the context of tropical biogeography and has been advocated as an explanation for present species distributions in tropical Western and Central Africa. In order to test this hypothesis, a phylogeny of the cryptic arachnid order Ricinulei, based on four nuclear and mitochondrial DNA markers, was inferred. This ancient clade of litter-dwelling arthropods, endemic to the primary forests of Western and Central Africa and the Neotropics, might provide insights into the mode and tempo of evolution in Africa. Twenty-six African ricinuleid specimens were sampled from eight countries spanning the distribution of Ricinulei on the continent, and analysed together with Neotropical samples plus other arachnid outgroups. The phylogenetic and molecular dating results suggest that Ricinulei diversified in association with the fragmentation of Gondwana. The early diversification of
Ricinoides
in Western and Central Africa around 88 (±33) Ma fits old palaeogeographical events better than recent climatic fluctuations. Unlike most recent molecular studies, these results agree with fossil evidence, suggesting that refugia may have acted as ‘museums’ conserving ancient diversity rather than as engines generating diversity during successive episodes of climatic fluctuation in Africa.
Spider silk reduces insect herbivory
Authors: Rypstra Ann L. , Buddle Christopher M.
Published: November 2012

The role of predators in food webs extends beyond their ability to kill and consume prey. Such trait-mediated effects occur when signals of the predator influence the behaviour of other animals. Because all spiders are silk-producing carnivores, we hypothesized that silk alone would signal other arthropods and enhance non-lethal effects of spiders. We quantified the herbivory inflicted by two beetle species on green bean plants (Phaseolus vulgaris) in the presence of silkworm silk and spider silk along with no silk controls. Single leaflets were treated and enclosed with herbivores in the laboratory and field. Another set of leaflets were treated and left to experience natural herbivory in the field. Entire plants in the field were treated with silk and enclosed with herbivores or left exposed to herbivory. In all cases, the lowest levels of herbivory occurred with spider silk treatments and, in general, silkworm silk produced intermediate levels of leaf damage. These results suggest that silk may be a mechanism for the trait-mediated impacts of spiders and that it might contribute to integrated pest management programmes.
Immuno-localization of type-IV collagen in the blood-gas barrier and the epithelial–epithelial cell connections of the avian lung
Authors: Jimoh S. A. , Maina J. N.
Published: November 2012

The terminal respiratory units of the gas exchange tissue of the avian lung, the air capillaries (ACs) and the blood capillaries (BCs), are small and rigid: the basis of this mechanical feature has been highly contentious. Because the strength of the blood-gas barrier (BGB) of the mammalian lung has been attributed to the presence of type-IV collagen (T-IVc), localization of T-IVc in the basement membranes (BM) of the BGB and the epithelial–epithelial cell connections (E-ECCs) of the exchange tissue of the lung of the avian (chicken) lung was performed in order to determine whether it may likewise contribute to the strength of the BGB. T-IVc was localized in both the BM and the E-ECCs. As part of an integrated fibroskeletal scaffold on the lung, T-IVc may directly contribute to the strengths of the ACs and the BCs.
Osteoconductive phosphoserine-modified poly(ε-lysine) dendrons: synthesis, titanium oxide surface functionalization and response of osteoblast-like cell lines
Authors: Meikle S. T. , Bianchi G. , Olivier G. , Santin M.
Published: November 2012

The lack of direct bonding between the surface of an implant and the mineralized bony tissue is among the main causes of aseptic loosening in titanium-based implants. Surface etching and ceramic coatings have led to improved osteointegration, but their clinical performance is still limited either by partial bonding or by coating delamination. In this work, a solid-phase synthesis method has been optimized to produce poly(ε-lysine) dendrons, the outermost branching generation of which is functionalized by phosphoserine (PS), a known catalyst of the biomineralization process. The dendrons were deposited onto etched titanium oxide surfaces as a near-to-monolayer film able to induce the formation of a homogeneous calcium phosphate phase in a simulated body fluid over 3 days. The dendron films also stimulated MG63 and SAOS-2 osteoblast-like cells to proliferate at a rate significantly higher than etched titanium, with SAOS-2 also showing a higher degree of differentiation over 14 days. PS-tethered dendron films were not affected by various sterilization methods and UV treatment appeared to improve the cell substrate potential of these films, thus suggesting their potential as a surface functionalization method for bone implants.
On the role of lateral stabilization during early patterning in the pancreas
Authors: de Back Walter , Zhou Joseph Xu , Brusch Lutz
Published: November 2012

The cell fate decision of multi-potent pancreatic progenitor cells between the exocrine and endocrine lineages is regulated by Notch signalling, mediated by cell–cell interactions. However, canonical models of Notch-mediated lateral inhibition cannot explain the scattered spatial distribution of endocrine cells and the cell-type ratio in the developing pancreas. Based on evidence from acinar-to-islet cell transdifferentiationin vitro, we propose that lateral stabilization, i.e. positive feedback between adjacent progenitor cells, acts in parallel with lateral inhibition to regulate pattern formation in the pancreas. A simple mathematical model of transcriptional regulation and cell–cell interaction reveals the existence of multi-stability of spatial patterns whose simultaneous occurrence causes scattering of endocrine cells in the presence of noise. The scattering pattern allows for control of the endocrine-to-exocrine cell-type ratio by modulation of lateral stabilization strength. These theoretical results suggest a previously unrecognized role for lateral stabilization in lineage specification, spatial patterning and cell-type ratio control in organ development.