bluuebunny/crossref_metadata_2025 huggingface dataset:
Nanobubble clusters of dissolved gas in aqueous solutions of electrolyte. I. Experimental proof
Authors: Bunkin N. F. , Shkirin A. V. , Ignatiev P. S. , Chaikov L. L. , Burkhanov I. S. , Starosvetskij A. V.
Published: August 2012

Results of experiments with dynamic light scattering, phase microscopy, and polarimetric scatterometry allow us to claim that long-living gas nanobubbles and the clusters composed of such nanobubbles are generated spontaneously in an aqueous solution of salt, saturated with dissolved gas (say, atmospheric air). The characteristic sizes of both nanobubbles and their clusters are found by solving the inverse problem of optical wave scattering in ionic solutions. These experimental results develop our earlier study reported by Bunkin et al. [J. Chem. Phys. 130, 134308 (2009)]10.1063/1.3095476 and can be treated as evidence for the special role of ions in the generation and stabilization of gas nanobubbles.
Nanobubble clusters of dissolved gas in aqueous solutions of electrolyte. II. Theoretical interpretation
Authors: Bunkin N. F. , Shkirin A. V.
Published: August 2012

A quantitative model of ion-stabilized gas bubbles is suggested. Charging the bubbles by the ions, which are capable of adsorption, and the screening by a cloud of counter-ions, which are less absorptable, is modeled. It is shown that, subject to the charge of bubble, two regimes of such screening can be realized. For low-charged bubbles, the screening is described in the framework of the known linearized Debye–Huckel approach, when the sign of the counter-ion cloud is preserved everywhere in the liquid, whereas at large charge this sign is changed at some distance from the bubble surface. This effect provides the mechanism for the emergence of two types of compound particles having the opposite polarity, which leads to the aggregation of such compound particles into fractal clusters. Based on experimental data, arguments in favor of the existence of the clusters composed of the ion-stabilized bubbles in aqueous electrolyte solutions are advanced. This paper provides theoretical grounds for the experimental results presented in the previous paper (part I) published in this journal.
De-aging of Fe-doped lead-zirconate-titanate ceramics by electric field cycling: 180°- vs. non-180° domain wall processes
Authors: Glaum Julia , Genenko Yuri A. , Kungl Hans , Ana Schmitt Ljubomira , Granzow Torsten
Published: August 2012

Acceptor-doped ferroelectrics tend to show pronounced aging behavior. The microscopic effects of aging are commonly related to oxygen vacancies, however, there are still open questions with respect to their impact on domain wall movements. To elucidate the latter, the reverse process of de-aging by electric field cycling is investigated here on Pb(Zr0.54Ti0.46)O3 doped with iron in different concentrations. Measurements of the hysteretic behavior of large-signal parameters, i.e., polarization and strain, as well as small-signal parameters, i.e., electrical permittivity and piezoelectric coefficient, are used to distinguish between reversible and irreversible movement of 180°- and non-180° domain walls. The results indicate that for low doping concentrations, the de-aging behavior of 180° domain wall motion is governed by irreversible domain wall motion and a coarsening of the domain structure, while for non-180° domain walls the change in reversible domain wall mobility is the dominant de-aging mechanism. For high doping concentrations, an additional clamping effect related to the smaller grain size occurs.
Study of exciton-polariton modes in nanocrystalline thin films of CuCl using reflectance spectroscopy
Authors: Foy Barry , McGlynn Enda , Cowley Aidan , McNally Patrick J. , Henry Martin O.
Published: August 2012

CuCl thin films grown on (100) Si by thermal evaporation are studied using reflectance spectroscopy. The reflectance spectra in the near UV spectral range close to the CuCl bandgap are modeled using a dielectric response function based on an exciton-polariton response with various models involving dead layers and reflected waves in the thin film. The exciton-polariton structure obtained is compared to other studies of bulk CuCl crystals. These different models are analyzed using a matrix-based approach and they yield theoretical spectra of reflected intensity. The fits provide parameter values which can be compared to bulk data known for CuCl and provide a non-destructive means of quantitative analysis of CuCl thin films. The best models are shown to match the experimental data quite well, with the closest fits produced when thin film front and rear interfaces are included. This model also accurately simulates the Fabry-Perot fringes present at energies lower than the Z3 free exciton position in CuCl (at 3.272 eV).
N-fold Darboux transformations and soliton solutions of three nonlinear equations
Authors: Wang Fan-Fan , Chen Ai-Hua
Published: August 2012

In this paper, by constructing N-fold Darboux transformations, we obtain new solutions of the generalized coupled modified Korteweg-de Vries (GC-mKdV) equation, the mKdV equation and the coupled integrable dispersionless equation. Particularly, we get single and two-kink solutions, single and two-hyperbolic soliton solutions, single and two-parabola soliton solutions, respectively.
Critical behavior and magnetocaloric effect of Gd65Mn35−xGex (x = 0, 5, and 10) melt-spun ribbons
Authors: Zhong X. C. , Min J. X. , Zheng Z. G. , Liu Z. W. , Zeng D. C.
Published: August 2012

Gd65Mn35−xGex (x = 0, 5, 10) alloy ribbons were prepared by melt-spinning. A fully amorphous structure was obtained for the alloys with x = 5 and 10, whereas, in melt-spun Gd65Mn35 ribbons, crystalline phases (α-Gd and GdMn2) precipitate in the amorphous matrix. The magnetic phase transition from ferromagnetic to paramagnetic is second order. The critical exponents are deduced from the Kouvel-Fisher method and scaling behavior. The obtained critical exponents are in agreement with the theoretical values of 3D Ising model. The Ising-like behavior suggests the presence of large anisotropy and short-range magnetic-coupling behavior. The maximum magnetic-entropy changes of the melt-spun alloys with x = 0, 5, and 10 for a magnetic field change from 0 to 5 T are 4.2, 4.1, and 4.5 Jkg−1 K−1, respectively. All three alloys have a broad temperature range of the magnetic-entropy peak, resulting in large refrigerant capacities.
Tuning the interfacial hole injection barrier between p-type organic materials and Co using a MoO3 buffer layer
Authors: Wang Yu-Zhan , Cao Liang , Qi Dong-Chen , Chen Wei , Wee Andrew T. S. , Gao Xing-Yu
Published: August 2012

We demonstrate that the interfacial hole injection barrier Δh between p-type organic materials (i.e., CuPc and pentacene) and Co substrate can be tuned by the insertion of a MoO3 buffer layer. Using ultraviolet photoemission spectroscopy, it was found that the introduction of MoO3 buffer layer effectively reduces the hole injection barrier from 0.8 eV to 0.4 eV for the CuPc/Co interface, and from 1.0 eV to 0.4 eV for the pentacene/Co interface, respectively. In addition, by varying the thickness of the buffer, the tuning effect of Δh is shown to be independent of the thickness of MoO3 interlayer at both CuPc/Co and pentacene/Co interfaces. This Fermi level pinning effect can be explained by the integer charge-transfer model. Therefore, the MoO3 buffer layer has the potential to be applied in p-type organic spin valve devices to improve the device performance via reducing the interfacial hole injection barrier.
Kink modes and surface currents associated with vertical displacement events
Authors: Manickam Janardhan , Boozer Allen , Gerhardt Stefan
Published: August 2012

The fast termination phase of a vertical displacement event (VDE) in a tokamak is modeled as a sequence of shrinking equilibria, where the core current profile remains constant so that the safety-factor at the axis, qaxis, remains fixed and the qedge systematically decreases. At some point, the n = 1 kink mode is destabilized. Kink modes distort the magnetic field lines outside the plasma, and surface currents are required to nullify the normal component of the B-field at the plasma boundary and maintain equilibrium at finite pressure. If the plasma touches a conductor, the current can be transferred to the conductor, and may be measurable by the halo current monitors. This report describes a practical method to model the plasma as it evolves during a VDE, and determine the surface currents, needed to maintain equilibrium. The main results are that the onset conditions for the disruption are that the growth-rate of the n = 1 kink exceeds half the Alfven time and the associated surface current needed to maintain equilibrium exceeds one half of the core plasma current. This occurs when qedge drops below a low integer, usually 2. Application to NSTX provides favorable comparison with non-axisymmetric halo-current measurements. The model is also applied to ITER and shows that the 2/1 mode is projected to be the most likely cause of the final disruption.
Pressure effect on the ferroelectric phase transition in nanosized NH4HSO4
Authors: Ciżman Agnieszka , Marciniszyn Tomasz , Poprawski Ryszard
Published: August 2012

The dielectric permittivity and the specific heat results of the ammonium hydrogen sulphate NH4HSO4 embedded into porous glasses with different average pore sizes in a wide temperature and frequency ranges are presented. The influence of the pore size on the ferroelectric phase transition temperature is considered. The results suggest a possibility of the size-effect influence on the phase transition type. The results show a good agreement with a theory [W. L. Zhong et al., Phys. Rev. B 50, 698 (1994)] indicating a non-monotonic behavior of the low-temperature phase transition with a confined particle.
Design and 3D simulation of a two-cavity wide-gap relativistic klystron amplifier with high power injection
Authors: Bai Xianchen , Yang Jianhua , Zhang Jiande
Published: August 2012

By using an electromagnetic particle-in-cell (PIC) code, an S-band two-cavity wide-gap klystron amplifier (WKA) loaded with washers/rods structure is designed and investigated for high power injection application. Influences of the washers/rods structure on the high frequency characteristics and the basic operation of the amplifier are presented. Generally, the rod structure has great impacts on the space-charge potential depression and the resonant frequency of the cavities. Nevertheless, if only the resonant frequency is tuned to the desired operation frequency, effects of the rod size on the basic operation of the amplifier are expected to be very weak. The 3-dimension (3-D) PIC simulation results show an output power of 0.98 GW corresponding to an efficiency of 33% for the WKA, with a 594 keV, 5 kA electron beam guided by an external magnetic field of 1.5 Tesla. Moreover, if a conductive plane is placed near the output gap, such as the electron collector, the beam potential energy can be further released, and the RF power can be increased to about 1.07 GW with the conversion efficiency of about 36%.
Derivation of nonlinear Schrödinger equation for electrostatic and electromagnetic waves in fully relativistic two-fluid plasmas by the reductive perturbation method
Authors: Lee Nam C.
Published: August 2012

The reductive perturbation method is used to derive a generic form of nonlinear Schrödinger equation (NLSE) that describes the nonlinear evolution of electrostatic (ES)/electromagnetic (EM) waves in fully relativistic two-fluid plasmas. The matrix eigenvector analysis shows that there are two mutually exclusive modes of waves, each mode involving only either one of two electric potentials, A and ϕ. The general result is applied to the electromagnetic mode in electron-ion plasmas with relativistically high electron temperature (Te≫mec2). In the limit of high frequency (ck≫ωe), the NLSE predicts bump type electromagnetic soliton structures having width scaling as ∼kTe5/2. It is shown that, in electron-positron pair plasmas with high temperature, dip type electromagnetic solitons can exist. The NLSE is also applied to electrostatic (Langmuir) wave and it is shown that dip type solitons can exist if kλD≪1, where λD is the electron’s Debye length. For the kλD≫1, however, the solution is of bump type soliton with width scaling as ∼1/(k5Te). It is also shown that dip type solitons can exist in cold plasmas having relativistically high streaming speed.
Communication: Effect of the orbital-overlap dependence in the meta generalized gradient approximation
Authors: Sun Jianwei , Xiao Bing , Ruzsinszky Adrienn
Published: August 2012

We study for the first time the effect of the dependence of meta generalized gradient approximation (MGGA) for the exchange-correlation energy on its input, the kinetic energy density, through the dimensionless inhomogeneity parameter, α, that characterizes the extent of orbital overlap. This leads to a simple MGGA exchange functional, which interpolates between the single-orbital regime, where α = 0, and the slowly varying density regime, where α ≈ 1, and then extrapolates to α → ∞. When combined with a variant of the Perdew-Burke-Ernzerhof GGA correlation, the resulting MGGA performs equally well for atoms, molecules, surfaces, and solids.
Parametric decays in relativistic magnetized electron-positron plasmas with relativistic temperatures
Authors: López Rodrigo A. , Asenjo Felipe A. , Muñoz Víctor , Alejandro Valdivia J.
Published: August 2012

The nonlinear evolution of a circularly polarized electromagnetic wave in an electron-positron plasma propagating along a constant background magnetic field is considered, by studying its parametric decays. Relativistic effects, of the particle motion in the wave field and of the plasma temperature, are included to obtain the dispersion relation of the decays. The exact dispersion relation of the pump wave has been previously calculated within the context of a relativistic fluid theory and presents two branches: an electromagnetic and an Alfvén one. We investigate the parametric decays for the pump wave in these two branches, including the anomalous dispersion zone of the Alfvén branch where the group velocity is negative. We solve the nonlinear dispersion relation for different pump wave amplitudes and plasma temperatures, finding various resonant and nonresonant wave couplings. We are able to identify these couplings and study their behavior as we modify the plasma parameters. Some of these couplings are suppressed for larger amplitudes or temperatures. We also find two kinds of modulational instabilities, one involving two sideband daughter waves and another involving a forward-propagating electroacoustic mode and a sideband daughter wave.
Modular microfluidic system as a model of cystic fibrosis airways
Authors: Skolimowski M. , Weiss Nielsen M. , Abeille F. , Skafte-Pedersen P. , Sabourin D. , Fercher A. , Papkovsky D. , Molin S. , Taboryski R. , Sternberg C. , Dufva M. , Geschke O. , Emnéus J.
Published: August 2012

A modular microfluidic airways model system that can simulate the changes in oxygen tension in different compartments of the cystic fibrosis (CF) airways was designed, developed, and tested. The fully reconfigurable system composed of modules with different functionalities: multichannel peristaltic pumps, bubble traps, gas exchange chip, and cell culture chambers. We have successfully applied this system for studying the antibiotic therapy of Pseudomonas aeruginosa, the bacteria mainly responsible for morbidity and mortality in cystic fibrosis, in different oxygen environments. Furthermore, we have mimicked the bacterial reinoculation of the aerobic compartments (lower respiratory tract) from the anaerobic compartments (cystic fibrosis sinuses) following an antibiotic treatment. This effect is hypothesised as the one on the main reasons for recurrent lung infections in cystic fibrosis patients.
Secondary dust density waves excited by nonlinear dust acoustic waves
Authors: Heinrich J. R. , Kim S.-H. , Meyer J. K. , Merlino R. L. , Rosenberg M.
Published: August 2012

Secondary dust density waves were observed in conjunction with high amplitude (nd/nd0>2) dust acoustic waves (DAW) that were spontaneously excited in a dc glow discharge dusty plasma in the moderately coupled, Γ∼1, state. The high amplitude dust acoustic waves produced large dust particle oscillations, displacements, and trapping. Secondary dust density waves were excited in the wave troughs of the high amplitude DAWs. The waveforms, amplitudes, wavelengths, and wave speeds of the primary DAWs and the secondary waves were measured. A dust-dust streaming instability is discussed as a possible mechanism for the production of the secondary waves.
Dynamic nonlinear thermal optical effects in coupled ring resonators
Authors: Huang Chenguang , Fan Jiahua , Zhu Lin
Published: August 2012

We investigate the dynamic nonlinear thermal optical effects in a photonic system of two coupled ring resonators. A bus waveguide is used to couple light in and out of one of the coupled resonators. Based on the coupling from the bus to the resonator, the coupling between the resonators and the intrinsic loss of each individual resonator, the system transmission spectrum can be classified by three different categories: coupled-resonator-induced absorption, coupled-resonator-induced transparency and over coupled resonance splitting. Dynamic thermal optical effects due to linear absorption have been analyzed for each category as a function of the input power. The heat power in each resonator determines the thermal dynamics in this coupled resonator system. Multiple “shark fins” and power competition between resonators can be foreseen. Also, the nonlinear absorption induced thermal effects have been discussed.
Reactions of 7,7,8,8-Tetracyanoquinodimethane (TCNQ) with Alkynyl-Iron- and -Ruthenium Complexes: Synthesis of Ru{C=CC(CN)=C6H4=C(CN)2}(PPh3)2Cp, a New Donor - Acceptor Molecular Array
Authors: Bruce Michael I. , Burgun Alexandre , Grelaud Guillaume , Lapinte Claude , Skelton Brian W. , Zaitseva Natasha N.
Published: August 2012

Reactions of 7,7,8,8-tetracyanoquinodimethane (TCNQ) with the alkynyl-iron and ruthenium complexes [M](C≡CR) {[M] = Fe(dppe)Cp*, Ru(PPh3)2Cp; R = H, Ph} are described. The iron complex Fe(C≡CPh)(dppe)Cp* (2a) is oxidized by TCNQ to give the kinetically stable salt [2a•+][TCNQ]•– . Displacement of [TCNQ]•– is achieved by ionic metathesis upon addition of KPF6 to produce [2a•+]PF6. In contrast, Fe(C≡CH)(dppe)Cp* (2b) reacted with TCNQ to give a mixture of compounds containing Fe(=C=CH2)(dppe)Cp* (3a), {Fe(dppe)Cp*}2(μ-C=CHCH=C) (3b), and the zwitterionic complex Fe+{=C=CHC(CN)2C6H4C–(CN)2}(dppe)Cp* (3c). In contrast, the reaction of TCNQ with Ru(C≡CR)(PPh3)2Cp (4a, R = Ph; 4b, R = H) gave selectively the zwitterionic vinylidenes Ru+{=C=CRC(CN)2C6H4C–(CN)2}(PPh3)2Cp (5a, R = Ph; 5b, R = H), in which the Ru centres are positively charged and the counter-anion is located on the further C(CN)2 group. On heating 5b, elimination of HCN affords Ru{C≡CC(CN)=C6H4=C(CN)2}(PPh3)2Cp (1), while similar treatment of 5a gives Ru{η3-C(CN)2CPh=C6H4=C(CN)2}(PPh3)Cp (6) with loss of PPh3. X-ray structures of 1, 5a, and 6, cyclic voltammetry, and UV-vis spectroscopy of 1 provided evidence for the electronic structures of the new complexes.
Legume receptors perceive the rhizobial lipochitin oligosaccharide signal molecules by direct binding
Authors: Broghammer Angelique , Krusell Lene , Blaise Mickaël , Sauer Jørgen , Sullivan John T. , Maolanon Nicolai , Vinther Maria , Lorentzen Andrea , Madsen Esben B. , Jensen Knud J. , Roepstorff Peter , Thirup Søren , Ronson Clive W. , Thygesen Mikkel B. , Stougaard Jens
Published: August 2012

Lipochitin oligosaccharides called Nod factors function as primary rhizobial signal molecules triggering legumes to develop new plant organs: root nodules that host the bacteria as nitrogen-fixing bacteroids. Here, we show that the
Lotus japonicus
Nod factor receptor 5 (NFR5) and Nod factor receptor 1 (NFR1) bind Nod factor directly at high-affinity binding sites. Both receptor proteins were posttranslationally processed when expressed as fusion proteins and extracted from purified membrane fractions of
Nicotiana benthamiana
or
Arabidopsis thaliana
. The N-terminal signal peptides were cleaved, and NFR1 protein retained its in vitro kinase activity. Processing of NFR5 protein was characterized by determining the
N
-glycosylation patterns of the ectodomain. Two different glycan structures with identical composition, Man
3
XylFucGlcNAc
4
, were identified by mass spectrometry and located at amino acid positions N68 and N198. Receptor–ligand interaction was measured by using ligands that were labeled or immobilized by application of chemoselective chemistry at the anomeric center. High-affinity ligand binding was demonstrated with both solid-phase and free solution techniques. The
K
d
values obtained for Nod factor binding were in the nanomolar range and comparable to the concentration range sufficient for biological activity. Structure-dependent ligand specificity was shown by using chitin oligosaccharides. Taken together, our results suggest that ligand recognition through direct ligand binding is a key step in the receptor-mediated activation mechanism leading to root nodule development in legumes.
Health performance of individuals within the Campbell paradigm
Authors: Byrka Katarzyna , Kaiser Florian G.
Published: August 2012

In this paper, we developed a comprehensive health performance measure that formally links individual health attitudes with the likelihood of engaging in a wide variety of health‐related behaviours from various domains such as sustenance, hygiene, and physical exercise. Within what Kaiser, Byrka, and Hartig (2010) call the Campbell paradigm, we equated general health attitude with what a person does to retain or promote his or her health. Thus, health behaviours, on one hand, were expected to form a homogeneous, transitively ordered class of behaviours. On the other hand, the very behavioural class was in turn thought to be the basis from which an individual's health attitude could be directly assessed. A sample of 391 adults provided us with survey data containing different sets of health behaviours as well as variables and personality measures that had been corroborated as health‐behaviour relevant in previous research. We found that self‐reports of 50 behaviours and expressions of appreciation for 20 of these behaviours from various domains formed a transitively ordered class of activities. In contrast to the conventional view in health psychology, in which attitudes are regarded as a psychological cause behind individual behaviour, and in contrast to conventional findings in health psychology, where behaviours appear to fall into numerous sets of more or less distinct domains of health‐enhancing activities (e.g., exercising or avoiding risks), our findings speak of the psychological and formal unity of health behaviour. Inevitably, attitude measures grounded in the Campbell paradigm gauge individual attitudes, and just as much, they measure the health performance of individuals.
Contributions of mRNA abundance, ribosome loading, and post- or peri-translational effects to temporal repression of C. elegans heterochronic miRNA targets
Authors: Stadler Michael , Artiles Karen , Pak Julia , Fire Andrew
Published: August 2012

miRNAs are post-transcriptional regulators of gene activity that reduce protein accumulation from target mRNAs. Elucidating precise molecular effects that animal miRNAs have on target transcripts has proven complex, with varied evidence indicating that miRNA regulation may produce different molecular outcomes in different species, systems, and/or physiological conditions. Here we use high-throughput ribosome profiling to analyze detailed translational parameters for five well-studied targets of miRNAs that regulate C. elegans developmental timing. For two targets of the miRNA lin-4 (lin-14 and lin-28), functional down-regulation was associated with decreases in both overall mRNA abundance and ribosome loading; however, these changes were of substantially smaller magnitude than corresponding changes observed in protein abundance. For three functional targets of the let-7 miRNA family for which down-regulation is critical in temporal progression of the animal (daf-12, hbl-1, and lin-41), we observed only modest changes in mRNA abundance and ribosome loading. lin-41 provides a striking example in that populations of ribosome-protected fragments from this gene remained essentially unchanged during the L3–L4 time interval when lin-41 activity is substantially down-regulated by let-7. Spectra of ribosomal positions were also examined for the five lin-4 and let-7 target mRNAs as a function of developmental time, with no indication of miRNA-induced ribosomal drop-off or significant pauses in translation. These data are consistent with models in which physiological regulation by this set of C. elegans miRNAs derives from combinatorial effects including suppressed recruitment/activation of translational machinery, compromised stability of target messages, and post- or peri-translational effects on lifetimes of polypeptide products.
Positive Regulation of psbA Gene Expression by cis-Encoded Antisense RNAs in Synechocystis sp. PCC 6803
Authors: Sakurai Isamu , Stazic Damir , Eisenhut Marion , Vuorio Eerika , Steglich Claudia , Hess Wolfgang R. , Aro Eva-Mari
Published: August 2012

The D1 protein of photosystem II in the thylakoid membrane of photosynthetic organisms is encoded by psbA genes, which in cyanobacteria occur in the form of a small gene family. Light-dependent up-regulation of psbA gene expression is crucial to ensure the proper replacement of the D1 protein. To gain a high level of gene expression, psbA transcription can be enhanced by several orders of magnitude. Recent transcriptome analyses demonstrated a high number of cis-encoded antisense RNAs (asRNAs) in bacteria, but very little is known about their possible functions. Here, we show the presence of two cis-encoded asRNAs (PsbA2R and PsbA3R) of psbA2 and psbA3 from Synechocystis sp. PCC 6803. These asRNAs are located in the 5′ untranslated region of psbA2 and psbA3 genes. Their expression becomes up-regulated by light and down-regulated by darkness, similar to their target mRNAs. In the PsbA2R-suppressing strain [PsbA2R(−)], the amount of psbA2 mRNA was only about 50% compared with the control strain. Likewise, we identified a 15% lowered activity of photosystem II and a reduced amount of the D1 protein in PsbA2R(−) compared with the control strain. The function of PsbA2R in the stabilization of psbA2 mRNA was shown from in vitro RNase E assay when the AU box and the ribosome-binding site in the 5′ untranslated region of psbA2 mRNA were both covered by PsbA2R. These results add another layer of complexity to the mechanisms that contribute to psbA gene expression and show PsbA2R as a positively acting factor to achieve a maximum level of D1 synthesis.
A Chimeric Arabinogalactan Protein Promotes Somatic Embryogenesis in Cotton Cell Culture
Authors: Poon Simon , Heath Robyn Louise , Clarke Adrienne Elizabeth
Published: August 2012

Arabinogalactan proteins (AGPs) are a family of extracellular plant proteoglycans implicated in many aspects of plant growth and development, including in vitro somatic embryogenesis (SE). We found that specific AGPs were produced by cotton (Gossypium hirsutum) calli undergoing SE and that when these AGPs were isolated and incorporated into tissue culture medium, cotton SE was promoted. When the AGPs were partly or fully deglycosylated, SE-promoting activity was not diminished. Testing of AGPs separated by reverse-phase high-performance liquid chromatography revealed that the SE-promoting activity resided in a hydrophobic fraction. We cloned a full-length complementary DNA (cotton PHYTOCYANIN-LIKE ARABINOGALACTAN-PROTEIN1 [GhPLA1]) that encoded the protein backbone of an AGP in the active fraction. It has a chimeric structure comprising an amino-terminal signal sequence, a phytocyanin-like domain, an AGP-like domain, and a hydrophobic carboxyl-terminal domain. Recombinant production of GhPLA1 in tobacco (Nicotiana tabacum) cells enabled us to purify and analyze a single glycosylated AGP and to demonstrate that this chimeric AGP promotes cotton SE. Furthermore, the nonglycosylated phytocyanin-like domain from GhPLA1, which was bacterially produced, also promoted SE, indicating that the glycosylated AGP domain was unnecessary for in vitro activity.
The supramolecular architecture of tris(naphthalene-1,5-diaminium) bis(5-aminonaphthalen-1-aminium) octakis[hydrogen (5-carboxypyridin-3-yl)phosphonate]
Authors: Wilk Magdalena , Janczak Jan , Videnova-Adrabinska Veneta
Published: August 2012

The asymmetric unit of the title compound, 3C10H12N22+·2C10H11N2+·8C6H5NO5P−, contains one and a half naphthalene-1,5-diaminium cations, in which the half-molecule has inversion symmetry, one 5-aminonaphthalen-1-aminium cation and four hydrogen (5-carboxypyridin-3-yl)phosphonate anions. The crystal structure is layered and consists of hydrogen-bonded anionic monolayers between which the cations are arranged. The acid monoanions are organized into one-dimensional chains along the [101] directionviahydrogen bonds established between the phosphonate sites. (C)O—H...Npyhydrogen bonds (py is pyridine) crosslink the chains to form an undulating (010) monolayer. The cations serve both to balance the charge of the anionic network and to connect neighbouring layersviamultiple hydrogen bonds to form a three-dimensional supramolecular architecture.
Is the subjective perception of lactose intolerance influenced by the psychological profile?
Authors: Tomba C. , Baldassarri A. , Coletta M. , Cesana B. M. , Basilisco G.
Published: August 2012

Background

Symptoms of lactose intolerance are often attributed to lactose malabsorption but, as this relationship has not been demonstrated when a small dose of lactose similar to that contained in one cup of milk is ingested by intolerant patients, psychological factors may play a role in altered symptom perception.

Aim

To assess the hypothesis that the psychological profile influences the symptoms of lactose intolerance.

Methods

One hundred and two consecutive patients underwent a 15 g lactose hydrogen breath test to assess lactose malabsorption. The patients recorded the presence and severity of symptoms of lactose intolerance during the breath test using visual analogue scales. The psychological profile was assessed using a psychological symptom checklist, and health‐related quality of life by means of the short‐form health survey.

Results

Lactose malabsorption and intolerance were diagnosed in, respectively, 18% and 29% of the patients. The two conditions were not associated, and the severity of intolerance was even less in the patients with malabsorption. Multivariate logistic analysis showed that a high somatisation t‐score was significantly associated with lactose intolerance (odds ratio 4.184; 1.704–10.309); the effects of the other psychological variables and of lactose malabsorption were not statistically significant. Health‐related quality of life was significantly reduced in the patients with somatisation, but not in those with lactose malabsorption.

Conclusions

The symptoms of lactose intolerance during hydrogen breath testing at a low physiological lactose load, are unrelated to lactose malabsorption, but may reveal a tendency towards somatisation that could impair the quality of life.
Molecular Scaffold Analysis of Natural Products Databases in the Public Domain
Authors: Yongye Austin B. , Waddell Jacob , Medina‐Franco José L.
Published: August 2012

Natural products represent important sources of bioactive compounds in drug discovery efforts. In this work, we compiled five natural products databases available in the public domain and performed a comprehensive chemoinformatic analysis focused on the content and diversity of the scaffolds with an overview of the diversity based on molecular fingerprints. The natural products databases were compared with each other and with a set of molecules obtained from in‐house combinatorial libraries, and with a general screening commercial library. It was found that publicly available natural products databases have different scaffold diversity. In contrast to the common concept that larger libraries have the largest scaffold diversity, the largest natural products collection analyzed in this work was not the most diverse. The general screening library showed, overall, the highest scaffold diversity. However, considering the most frequent scaffolds, the general reference library was the least diverse. In general, natural products databases in the public domain showed low molecule overlap. In addition to benzene and acyclic compounds, flavones, coumarins, and flavanones were identified as the most frequent molecular scaffolds across the different natural products collections. The results of this work have direct implications in the computational and experimental screening of natural product databases for drug discovery.
The Transformative Power of Youth Grants: Sparks and Ripples of Change Affecting Marginalised Youth and their Communities
Authors: Blanchet‐Cohen Natasha , Cook Philip
Published: August 2012

This study, based on research into a youth empowerment initiative inCanada, examines the transformational power of youth grants for marginalised youth and their communities. The positive changes on individual youth included increased confidence and skills, as well as strengthened social interactions between youth, and involved adults and organisations. To leverage grant impact, we identify the critical role of creating accountability at multiple levels, promoting sharing among grantees, and fostering allies and system thinkers. The evaluation points to the potential of grants for changing community's perception that youth are incapable of fostering community youth development.
The acute effects of physical activity on cigarette cravings: systematic review and meta‐analysis with individual participant data
Authors: Haasova Marcela , Warren Fiona C. , Ussher Michael , Janse Van Rensburg Kate , Faulkner Guy , Cropley Mark , Byron‐Daniel James , Everson‐Hock Emma S. , Oh Hwajung , Taylor Adrian H.
Published: August 2012

Aims

To conduct an updated systematic review and the first meta‐analysis of experimental trials investigating the acute effects of short bouts of physical activity (PA) on strength of desire (SoD) and desire to smoke (DtS) using individual participant data (IPD).

Methods

A systematic review of literature and IPD meta‐analyses included trials assessing the acute effects of shorts bouts of PA on SoD and DtS among temporarily abstaining smokers not using pharmaceutical aids for smoking cessation. Authors of eligible studies were contacted and raw IPD were obtained. Two‐stage and one‐stage IPD random‐effects meta‐analyses were conducted. Participants engaging in PA were compared against control participants, using post‐intervention SoD and DtS with baseline adjustments.

Results

A two‐stage IPD meta‐analysis assessing effects of PA on SoD yielded an average standardized mean difference (SMD) between PA and control conditions (across 15 primary studies) of −1.91 [95% confidence interval (CI): −2.59 to −1.22]. A two‐stage IPD meta‐analysis assessing effects of PA on DtS yielded an average SMD between PA and control conditions (across 17 primary studies) of −2.03 (95% CI: −2.60 to −1.46). Additional meta‐analyses, including those using a one‐stage model, those including only parallel arm studies and meta‐analyses comparing only moderate exercise against a control condition, showed significant craving reduction following PA. Despite a high degree of between‐study heterogeneity, effects sizes of all primary studies were in the same direction, with PA showing a greater reduction in cravings compared with controls.

Conclusions

There is strong evidence that physical activity acutely reduces cigarette craving.
Interaction of barley powdery mildew effector candidate CSEP0055 with the defence protein PR17c
Authors: Zhang Wen‐Jing , Pedersen Carsten , Kwaaitaal Mark , Gregersen Per L. , Mørch Sara M. , Hanisch Susanne , Kristensen Astrid , Fuglsang Anja T. , Collinge David B. , Thordal‐Christensen Hans
Published: August 2012

A large number of effector candidates have been identified recently in powdery mildew fungi. However, their roles and how they perform their functions remain unresolved. In this study, we made use of host‐induced gene silencing and confirmed that the secreted barley powdery mildew effector candidate, CSEP0055, contributes to the aggressiveness of the fungus. This result suggests that CSEP0055 is involved in the suppression of plant defence. A yeast two‐hybrid screen indicated that CSEP0055 interacts with members of the barley pathogenesis‐related protein families, PR1 and PR17. Interaction with PR17c was confirmed by bimolecular fluorescence complementation analyses. Down‐regulation and over‐expression of PR17c in epidermal cells of barley confirmed that this protein is important for penetration resistance against the powdery mildew fungus. In line with this, PR17c was found to be apoplastic, localizing to the papillae formed in response to this fungus. The CSEP0055 transcript did not start to accumulate until 24 h after inoculation. This suggests that this gene is expressed too late to influence primary penetration events, but rather sustains the fungus at sites of secondary penetration, where PR17c appears to be able to accumulate.
Regulation of TCR signalling by tyrosine phosphatases: from immune homeostasis to autoimmunity
Authors: Stanford Stephanie M. , Rapini Novella , Bottini Nunzio
Published: August 2012

More than half of the known protein tyrosine phosphatases (PTPs) in the human genome are expressed in T cells, and significant progress has been made in elucidating the biology of these enzymes in T‐cell development and function. Here we provide a systematic review of the current understanding of the roles of PTPs in T‐cell activation, providing insight into their mechanisms of action and regulation in T‐cell receptor signalling, the phenotypes of their genetically modified mice, and their possible involvement in T‐cell‐mediated autoimmune disease. Our projection is that the interest in PTPs as mediators of T‐cell homeostasis will continue to rise with further functional analysis of these proteins, and PTPs will be increasingly considered as targets of immunomodulatory therapies.
The intensity of immune activation is linked to the level of  CCR5 expression in human immunodeficiency virus type  1‐infected persons
Authors: Portales Pierre , Psomas Katerina Christina , Tuaillon Edouard , Mura Thibault , Vendrell Jean‐Pierre , Eliaou Jean‐François , Reynes Jacques , Corbeau Pierre
Published: August 2012

Immune activation is a main driver of AIDS‐ and non‐AIDS‐linked morbidities in the course of HIV‐1 infection. As CCR5, the main HIV‐1 co‐receptor, is not only a chemokine receptor but also a co‐activation molecule expressed at the surface of T cells, it could be directly involved in this immune activation. To test this hypothesis, we measured by flow cytometry the mean number of CCR5 molecules at the surface of non‐activated CD4+ T cells (CCR5 density), which determines the intensity of CCR5 signalling, and the percentage of CD8+ T cells over‐expressing CD38 (CD38 expression), a major marker of immune activation, in the blood of 67 HIV‐1‐infected, non‐treated individuals. CCR5 density was correlated with CD38 expression independently of viral load (P = 0·016). CCR5 density remained unchanged after highly active anti‐retroviral therapy (HAART) introduction or cessation, whereas CD38 expression decreased and increased, respectively. Moreover, pre‐therapeutic CCR5 density was highly predictive (r = 0·736, P < 10−4) of residual CD38 over‐expression after 9 months of HAART. Hence, CCR5 might play an immunological role in HIV‐1 infection as a driver of immune activation. This could explain why CCR5 antagonists may have an inhibitory effect on immune activation.
Effect of edible coating and gamma irradiation on inhibition of mould growth and quality retention of strawberry during refrigerated storage
Authors: Hussain Peerzada R. , Dar Mohd A. , Wani Ali M.
Published: August 2012

The aim of this study was to investigate the effect of edible coating and gamma irradiation treatment on mould growth and storage quality of strawberry. Strawberry fruit after harvest were treated with 0.5–1.0% (w/v) carboxymethyl cellulose (CMC) coating followed by irradiation at 2.0 kGy and subsequent storage under refrigerated conditions for 21 days. The investigations revealed that CMC coating alone at levels 0.5% and 0.75% w/v was not effective in delaying the decay and inhibiting the appearance of mould growth in strawberry fruit. Treatment of irradiation in combination with 1.0% w/v CMC coating was found significantly (P ≤ 0.05) effective compared with other treatments in maintaining the quality and delaying the decay and appearance of the mould growth in strawberry up to 18 days of refrigerated storage. Combinatory treatment of irradiation and coating can help to a greater extent in facilitating the marketing of the strawberry fruit to distant markets other than the local market, thereby benefiting growers and consumers.
Development of regression model to differentiate quality of black tea (Dianhong): correlate aroma properties with instrumental data using multiple linear regression analysis
Authors: Pang Xueli , Qin Zihan , Zhao Lei , Cheng Huan , Hu Xiaosong , Song Huanlu , Wu Jihong
Published: August 2012

To develop a flexible and objective method to discriminate Dianhong tea quality level, the instrumental analysis of odour‐active compounds of three commercial grades of Dianhong tea and quantitative descriptive analysis of their overall aromas were conducted. Eight aroma properties were then statistically correlated with odorants using stepwise multiple linear regression analysis. Thirty‐nine odour‐active components were screened in Dianhong tea infusion, among which dimethyl disulphide and 1‐(1H‐pyrrol‐2yl)‐ethanone were identified for the first time. Adjusted R2 of multiple regression models for eight sensory properties were all >0.95, except ‘resinous’ attribute (R2 = 0.834), and RMSE were <0.18 for all. Regression models showed that 2‐methylbutanal, 3‐methylbutanal, linalool, geraniol, linalool oxides, phenyl acetaldehyde, methyl salicylate, ethyl 2‐methylbutyrate, 3,7‐dimethyl‐3‐octanol, benzaldehyde and 6,10‐dimethyl‐5,9‐undecadien‐2‐one positively contributed to the Dianhong tea aroma profile, while 1‐penten‐3‐ol, (Z)‐3‐hexen‐1‐ol and (E,E)‐2,4‐heptadienal were negative aroma contributors. Regression model development for Dianhong tea aroma quality would provide a uniform standard for objectively assessing tea quality among different laboratories and cultures.
Study on enhanced absorption of phenolic compounds of Lactobacillus‐fermented turmeric (Curcuma longa Linn.) beverages in rats
Authors: Pianpumepong Plangpin , Anal Anil Kumar , Doungchawee Galayanee , Noomhorm Athapol
Published: August 2012

Lactobacillus plantarum, used as starter culture to produce turmeric beverages, was isolated and screened from the turmeric rhizomes. Fermented turmeric beverages were evaluated for its antioxidant activity using 2‐2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical‐scavenging activity and ferric‐reducing antioxidant power (FRAP) assay. The fermentative process resulted in an increase in antioxidant activity. The absorption of turmeric powder, turmeric powder‐mixed encapsulated probiotic (TP) and encapsulated fermented turmeric beverage (TB) in rats was measured in terms of antioxidant activity in the plasma. Plasma antioxidant concentration was higher in rats administrated fermented turmeric beverage than other turmeric products, at all the time points. The maximum concentration (Cmax) value and area under the plasma concentration versus time curve (AUC) were higher in the rat administered with TB. The value was lower in the plasma of rats administered with turmeric powder and TP. The results indicated that the fermentative turmeric possesses better bioavailability and in accordance with the concentrations of polyphenolic compounds in the rat plasma.
Effect of native and germinated finger millet flour on rheological and sensory characteristics of biscuits
Authors: Shimray Crassina A. , Gupta Sheetal , Venkateswara Rao G.
Published: August 2012

Wheat flour was replaced with native finger millet flour (NFMF) and germinated finger millet flour (GFMF) at 30–50% levels to make soft dough biscuits. Dough rheological properties and baking characteristics of the blends were evaluated. Farinograph data of wheat flour replaced with NFMF and GFMF showed a decrease in water absorption, dough stability and an increase in mixing tolerance index as the level of replacement increased. Extensibility of dough decreased for both NFMF and GFMF as the levels increased. The hardness of biscuit dough measured by texture profile analysis increased from 125 to 234 N for NFMF and 118 to 126 N for GFMF. Scanning electron microscopic studies on the biscuit dough showed polygonal finger millet starch granules adhering to wheat starch granules and protein matrix. The results of the study indicated that the replacement level of 40% with either NFMF or GFMF produced biscuits with acceptable sensory attributes. Addition of sodium stearoyl‐2‐lactylate (SSL) showed further improvement in terms of spread ratio, surface characteristics and texture.
Solvent retention capacity values in relation to the Czech commercial wheat quality
Authors: Hrušková Marie , Švec Ivan , Karas Jan
Published: August 2012

Technological quality in the sets of eighty commercial wheat samples was evaluated by grain milling traits (test weight, thousand kernel weight, grain hardness as Particle Size Index, one‐stream flour yield) and common analytical parameters (wet gluten and protein contents, Zeleny test value, falling number) together with the solvent retention capacity (SRC) method (AACC 56‐11). For the commercial wheat, the latter analytical procedure (originally designed for flour quality analysis) was verified also for grain wholemeal. Within the mentioned sample group, anova revealed the strongest effect of the harvest year, both for milling and for technological parameters. For the SRC profiles, the effect of the sample form used dominated the crop year influence. The grain SRCs were correlated with the milling traits foursome, while an agreement between the flour SRC profiles and technological quality data was not so tight. However, the flour lactic acid SRC was associated with the wet gluten and protein contents (r = 0.24, P < 0.05), and the protein quality as Zeleny value with the flour water SRC (r = 0.24, P < 0.05). Relationship between Zeleny's value and flour lactic acid SCR was confirmed by nonlinear Spearman correlation (R = −0.26, P < 0.05).
Quality changes of farmed cobia steaks held in cold stores (−18 °C)
Authors: Robinson Jeyashakila , Barnabas Edwin R. , Nathan Felix
Published: August 2012

Cobia (Rachycentron canadum) steaks held in cold store (−18 °C) were analysed aseptically in triplicates for the sensory, total aerobic bacterial count, proximate composition, pH, thiobarbituric acid‐reactive substance (TBA‐RS), formaldehyde, total volatile base nitrogen (TVB‐N), trimethyl amine‐nitrogen (TMA‐N), salt soluble nitrogen (SSN), nonprotein nitrogen (NPN), sodium dodecyl sulphate‐poly acrylamide gel electrophoresis (SDS‐PAGE) pattern. Steaks were sensorially acceptable up to 5 months of storage and the total bacterial counts did not exceed 6 log CFU counts. There were no significant changes in the pH values. TBA‐RS values increased significantly (P < 0.05) and reached 7.34 mg of malonaldehyde kg−1 fat at the end. Formaldehyde content remained constant upto 4th month and later increased to 2.06 μg g−1 (P < 0.05). TVB‐N and TMA‐N values did not exceed the acceptable limits. NPN contents showed no change, while SSN contents increased to 1.24% after 5 months. SDS‐PAGE pattern indicated no protein denaturation in the fish tissue. Results indicated that TBA‐RS value can only be considered as the valuable indicator in determining the quality of fish steaks held in cold stores.