bluuebunny/crossref_metadata_2025 huggingface dataset:
Frequency-dependent complex permittivity and permeability of iron-based powders in 2–18 GHz
Authors: Yang R. B. , Hsu S. D. , Lin C. K.
Published: April 2009

A novel approach is presented to investigate the complex permittivity (ε′−jε″) and permeability (μ′−jμ″) of iron-based powders in the frequency range of 2-18 GHz. The effective permeability and permittivity of carbonyl iron-epoxy composites for various volume fractions are measured by using the transmission/reflection method. A genetic algorithm is implemented with four nonempirical effective medium theories to obtain the complex permittivity and permeability of the carbonyl iron powders in the corresponding frequency range. The use of the extracted permittivity and permeability of the carbonyl powders with Looyenga’s formula fit the experimental data well not only over a wide range of frequencies but also various concentrations of carbonyl iron.
Magnetic field influence on the structural transformation in ferromagnetic shape memory alloy Mn50Ni40In10 melt spun ribbons
Authors: Sánchez Llamazares J. L. , Hernando B. , Prida V. M. , García C. , González J. , Varga R. , Ross C. A.
Published: April 2009

Direct and reverse martensitic transformations have been studied in Mn50Ni40In10 ribbons by means of magnetization and electrical resistivity measurements. The alloy is L21-type single-phase austenite, which transforms into a 14M monoclinic martensite. The martensitic transformation is accompanied by a large change in the electrical resistivity. The field dependence of characteristic transformation temperatures is reported. A field-induced reverse martensitic transformation with large hysteretic losses was observed. The reversibility of magnetization isotherms in the temperature interval where direct martensitic transformation occurs is also reported.
High-temperature conductance loss dominated defect level in h-BN: Experiments and first principles calculations
Authors: Hou Zhi-Ling , Cao Mao-Sheng , Yuan Jie , Fang Xiao-Yong , Shi Xiao-Ling
Published: April 2009

The dielectric properties of hexagonal boron nitride are investigated in detail. The permittivities hold extremely low values ranging from room temperature to 1500 °C, however, the dielectric loss tangents increase rapidly above 1000 °C. At 1500 °C, the dielectric loss tangent is 20 times more than that at room temperature. The first principles calculations show that the boron vacancy (VB) that gives an acceptor energy level near the valence band presents the lowest ionization energy in the investigated defects, and the calculated VB ionization energy agrees with the experimental value. It indicates that the rapid increase in dielectric loss tangents at high temperature is contributed by electrical conductivity produced by VB ionization under thermal excitation.
Amorphization and dynamic annealing of hexagonal SiC upon heavy-ion irradiation: Effects on swelling and mechanical properties
Authors: Kerbiriou Xavier , Costantini Jean-Marc , Sauzay Maxime , Sorieul Stéphanie , Thomé Lionel , Jagielski Jacek , Grob Jean-Jacques
Published: April 2009

Structural, mechanical, and dimensional evolutions of silicon carbide (SiC) induced by heavy-ion irradiations are studied by means of Rutherford backscattering spectrometry and channeling (RBS/C), nanoindentation, and surface profilometry measurements. 4H- and 6H-SiC single crystals were irradiated with 4 MeV Au2+ and 4 MeV Xe+ ions at room temperature (RT) or 400 °C. Using a Monte Carlo program to simulate the RBS/C spectra (MCCHASY code), we find that Au ion irradiation at RT induces a total silicon sublattice disorder related to full amorphization at a dose of about 0.4 displacement per atom (dpa). A two-step damage process is found on the basis of the disordered fractions deduced from RBS/C data. Complete amorphization cannot be reached upon both Au and Xe ion irradiations at 400 °C up to about 26 dpa because of the dynamic annealing of defects. When complete amorphization is reached at RT, the Young’s modulus and Berkovich hardness of irradiated 6H-SiC samples are lower by, respectively, 40% and 45% than those of the virgin crystals. The out-of-plane expansion measured by surface profilometry increases versus irradiation dose and the saturation value measured in the completely amorphous layer (normalized to the ion projected range) is close to 25%. We show that the modifications of the macroscopic properties are mainly due to the amorphization of the material. The macroscopic elasticity constants and dimensional properties are predicted for a composite material made of crystalline matrix containing dispersed amorphous inclusions using simple analytical homogenization models. Voigt’s model seems to give the best approximation for disordered fractions larger than 20% in the second step of the damage process.
Changing the exchange bias of spin valves by means of current pulses: Role of the Joule heating
Authors: Tang X. L. , Zhang H. W. , Su H. , Jing Y. L. , Zhong Z. Y.
Published: April 2009

In-plane alternating pulses of current applied with an external magnetic field that changes the strength and direction of the exchange bias are observed in NiFe/Cu/NiFe/FeMn spin valves. To provide clear evidence of this spin-polarized current for antiferromagnets incorporated in spin valves, a series of measurements was carried out to rule out the influence of Joule heating caused by the pulse. The measurements revealed that Joule heating plays a minor role in the impact of exchange bias, thus providing more convincing evidence of the spin torque exerted on the interfacial antiferromagnetic moments.
Realization schemes for quantum instruments in finite dimensions
Authors: Chiribella Giulio , D’Ariano Giacomo Mauro , Perinotti Paolo
Published: April 2009

We present a general dilation scheme for quantum instruments with continuous outcome space in finite dimensions, in terms of a measurement on a finite-dimensional ancilla, described by a positive operator valued measure (POVM). The general result is then applied to a large class of instruments generated by operator frames, which contains group-covariant instruments as a particular case and allows one to construct dilation schemes based on a measurement on the ancilla followed by a conditional feed-forward operation on the output. In the case of tight operator frames, our construction generalizes quantum teleportation and telecloning, producing a whole family of generalized teleportation schemes in which the instrument is realized via a joint POVM at the sender combined with a conditional feed-forward operation at the receiver.
Structure of highly confined fluids: Mixture of polar and nonpolar macroparticles in an external field
Authors: Brunet C. , Malherbe J. G. , Amokrane S.
Published: April 2009

In this paper we study the structure of highly confined mixtures of polar and nonpolar macroparticles in an external field by Monte Carlo simulation in the canonical ensemble. Without attempting a systematic investigation of the model, several effects including confinement, polarization, and solvation forces are considered. In particular, we show that layering at different length scales can be obtained in mixtures of differently sized particles subject to an external electric field.
Bridging fluctuating hydrodynamics and molecular dynamics simulations of fluids
Authors: Voulgarakis Nikolaos K. , Chu Jhih-Wei
Published: April 2009

A new multiscale coarse-graining (CG) methodology is developed to bridge molecular and hydrodynamic models of a fluid. The hydrodynamic representation considered in this work is based on the equations of fluctuating hydrodynamics (FH). The essence of this method is a mapping from the position and velocity vectors of a snapshot of a molecular dynamics (MD) simulation to the field variables on Eulerian cells of a hydrodynamic representation. By explicit consideration of the effective lengthscale dmol that characterizes the volume of a molecule, the computed density fluctuations from MD via our mapping procedure have volume dependence that corresponds to a grand canonical ensemble of a cold liquid even when a small cell length (5–10 Å) is used in a hydrodynamic representation. For TIP3P water at 300 K and 1 atm, dmol is found to be 2.4 Å, corresponding to the excluded radius of a water molecule as revealed by its center-of-mass radial distribution function. By matching the density fluctuations and autocorrelation functions of momentum fields computed from solving the FH equations with those computed from MD simulation, the sound velocity and shear and bulk viscosities of a CG hydrodynamic model can be determined directly from MD. Furthermore, a novel staggered discretization scheme is developed for solving the FH equations of an isothermal compressive fluid in a three dimensional space with a central difference method. This scheme demonstrates high accuracy in satisfying the fluctuation-dissipation theorem. Since the causative relationship between field variables and fluxes is captured, we demonstrate that the staggered discretization scheme also predicts correct physical behaviors in simulating transient fluid flows. The techniques presented in this work may also be employed to design multiscale strategies for modeling complex fluids and macromolecules in solution.
Direct observation of ion exchange in mechanically activated LiH+MgB2 system using ultrahigh field nuclear magnetic resonance spectroscopy
Authors: Hu Jian Zhi , Kwak Ja Hun , Yang Zhenguo , Wan Xuefei , Shaw Leon L.
Published: April 2009

The LiBH4+MgH2 system has great potential for hydrogen vehicle applications. In this study, the reported solid-state hydrogenation system made of LiH+1/2MgB2 has been investigated using ultrahigh field nuclear magnetic resonance spectroscopy. It is found that Mg–Li ion exchange occurs within MgB2 during ball milling to form a compound of (Mg1−xLi2x)B2, which facilitates the formation of LiBH4 in the subsequent hydriding reaction. This discovery offers a scientific foundation for investigating the detailed mechanisms of solid-state hydrogenation and dehydrogenation of the LiBH4+MgH2 system in the future.
Flowing grains in an inclined duct
Authors: Zamankhan Piroz
Published: April 2009

Large scale, three-dimensional computer simulations were performed to investigate flow dynamics of monosized, viscoelastic, spherical solid particles past a stationary wedge located in the middle of an inclined duct. At low flow rates of solid particles, a continuous flow was observed similar to that excited by steadily and rapidly adding particles to the top of a heap. However, at high flow rates, a totally different situation arises, where a flow with a different nature was established in the duct. In this case, the granular flow within the upper part of the duct accelerates adjacent to the pointed tip of the wedge, and develops into vast masses of solid particles thrust and folded over each other. This is similar to the supercritical nappes in an open-channel flow of a liquid. In addition, some experimental evidences have been presented that suggest the existence of supercritical nappes in flowing grains over a stationary wedge within an inclined duct at high flow rates.
Nanostructured zinc oxide platform for cholesterol sensor
Authors: Solanki Pratima R. , Kaushik Ajeet , Ansari Anees A. , Malhotra B. D.
Published: April 2009

Nanostructured zinc oxide (nano-ZnO) film has been fabricated onto indium tin oxide (ITO) containing preferred (002) plane and 10 nm crystallite size using sol-gel technique for immobilization of cholesterol oxidase (ChOx). Electrochemical response of ChOx/nano-ZnO/ITO bioelectrode determined as a function of cholesterol concentration using cyclic voltammetry technique reveals improved detection range (5–400 mg/dl), low detection limit (0.5 mg/dl), fast response time (10 s), sensitivity (0.059 μA/mg dl−1 cm−2), and low value (0.98 mg/dl) of Michaelis–Menten constant (Km). It is shown that nano-ZnO film provides better environment and enhanced electron transfer between ChOx and electrode.
Liquid metal stretchable unbalanced loop antenna
Authors: Cheng Shi , Rydberg Anders , Hjort Klas , Wu Zhigang
Published: April 2009

We present a 2.4 GHz unbalanced loop antenna that can be stretched along multiple dimensions simultaneously. It was realized by incorporating room temperature liquid metal alloy into microstructured channels in an elastic material. The demonstrated prototype exhibits a stretchability of up to 40% along two orthogonal orientations as well as foldability and twistability. Port impedance and radiation characteristics of the nonstretched and stretched antenna were studied numerically and experimentally. Measured results indicate a radiation efficiency of more than 80%.
Metal-ferroelectric (BiFeO3)-insulator (Y2O3)-semiconductor capacitors and field effect transistors for nonvolatile memory applications
Authors: Lin Chih-Ming , Shih Wen-chieh , Chang Ingram Yin-ku , Juan Pi-Chun , Lee Joseph Ya-min
Published: April 2009

Metal-ferroelectric-insulator-semiconductor capacitors and field effect transistors with Al/BiFeO3/Y2O3/Si structure were fabricated and characterized for nonvolatile memory applications. The capacitance-voltage curves exhibit a maximum clockwise memory window of 0.92 V. The minimum leakage current density is 2×10−7 A/cm2 at an applied voltage of 5 V. The capacitance-voltage memory window as a function of the sweep voltage range was investigated. The IDS-VGS curves of metal-ferroelectric-insulator-semiconductor transistors show a maximum memory window of 0.84 V. The drain current on/off ratio maintained more than three orders of magnitude after an elapsed time of 104 s.
Paths of Local Development: Two Technological Districts Face-to-Face
Authors: Azzolina Laura , De Luca Deborah
Published: April 2009

In this paper we compare the two hi-tech districts of Catania and Genoa, which are within the same national context and economic sector, with the aim of explaining their different choices (the promotion of external investments, in the first case, and fostering of the development of small businesses, in the second case) in the light of the local economic structure and the role played by political, economic, and educational institutions. Local actors have differently influenced the development of a professional community through the interpersonal networks of entrepreneurs and the performance obtained by local small businesses. While Catania has experienced a higher and more rapid growth, development in Genoa seems to be better established.
Environmental and climatic variables as potential drivers of post-fire cover of cheatgrass (Bromus tectorum) in seeded and unseeded semiarid ecosystems
Authors: Shinneman Douglas J. , Baker William L.
Published: April 2009

Cheatgrass, a non-native annual grass, dominates millions of hectares in semiarid ecosystems of the Intermountain West (USA). Post-fire invasions can reduce native species diversity and alter ecological processes. To curb cheatgrass invasion, land managers often seed recently burned areas with perennial competitor species. We sampled vegetation within burned (1–9 years post-fire) and nearby unburned (representing pre-fire) piñon–juniper (Pinus edulis–Juniperus osteosperma) woodland and sagebrush (Artemisia sp.) in western Colorado to analyze variables that might explain cheatgrass cover after fire. A multiple regression model suggests higher cheatgrass cover after fire with: (1) sagebrush v. piñon–juniper; (2) higher pre-fire cover of annual forbs; (3) increased time since fire; (4) lower pre-fire cover of biological soil crust; and (5) lower precipitation the year before fire. Time since fire, which coincided with higher precipitation, accounts for most of the variability in cheatgrass cover. No significant difference was found in mean cheatgrass cover between seeded and unseeded plots over time. However, negative relationships with pre-fire biological soil crust cover and native species richness suggest livestock-degraded areas are more susceptible to post-fire invasion. Proactive strategies for combating cheatgrass should include finding effective native competitors and restoring livestock-degraded areas.
A point mutation in TRPC3 causes abnormal Purkinje cell development and cerebellar ataxia in moonwalker mice
Authors: Becker Esther B. E. , Oliver Peter L. , Glitsch Maike D. , Banks Gareth T. , Achilli Francesca , Hardy Andrea , Nolan Patrick M. , Fisher Elizabeth M. C. , Davies Kay E.
Published: April 2009

The hereditary ataxias are a complex group of neurological disorders characterized by the degeneration of the cerebellum and its associated connections. The molecular mechanisms that trigger the loss of Purkinje cells in this group of diseases remain incompletely understood. Here, we report a previously undescribed dominant mouse model of cerebellar ataxia, moonwalker (
Mwk
), that displays motor and coordination defects and loss of cerebellar Purkinje cells.
Mwk
mice harbor a gain-of-function mutation (T635A) in the
Trpc3
gene encoding the nonselective transient receptor potential cation channel, type C3 (TRPC3), resulting in altered TRPC3 channel gating. TRPC3 is highly expressed in Purkinje cells during the phase of dendritogenesis. Interestingly, growth and differentiation of Purkinje cell dendritic arbors are profoundly impaired in
Mwk
mice. Our findings define a previously unknown role for TRPC3 in both dendritic development and survival of Purkinje cells, and provide a unique mechanism underlying cerebellar ataxia.
The stability of AID and its function in class-switching are critically sensitive to the identity of its nuclear-export sequence
Authors: Geisberger Roland , Rada Cristina , Neuberger Michael S.
Published: April 2009

The carboxyterminal region of activation-induced deaminase (AID) is required for its function in Ig class switch recombination (CSR) and also contains a nuclear-export sequence (NES). Here, based on an extensive fine-structure mutation analysis of the AID NES, as well as from AID chimeras bearing heterologous NESs, we show that while a functional NES is indeed essential for CSR, it is not sufficient. The precise nature of the NES is critical both for AID stabilization and CSR function: minor changes in the NES can perturb stabilization and CSR without jeopardizing nuclear export. The results indicate that the AID NES fulfills a function beyond simply providing a signal for nuclear export and suggest the possibility that the quality of exportin-binding may be critical to the stabilization of AID and its activity in CSR.
Dynamical networks in tRNA:protein complexes
Authors: Sethi Anurag , Eargle John , Black Alexis A. , Luthey-Schulten Zaida
Published: April 2009

Community network analysis derived from molecular dynamics simulations is used to identify and compare the signaling pathways in a bacterial glutamyl-tRNA synthetase (GluRS):tRNA
Glu
and an archaeal leucyl-tRNA synthetase (LeuRS):tRNA
Leu
complex. Although the 2 class I synthetases have remarkably different interactions with their cognate tRNAs, the allosteric networks for charging tRNA with the correct amino acid display considerable similarities. A dynamic contact map defines the edges connecting nodes (amino acids and nucleotides) in the physical network whose overall topology is presented as a network of communities, local substructures that are highly intraconnected, but loosely interconnected. Whereas nodes within a single community can communicate through many alternate pathways, the communication between monomers in different communities has to take place through a smaller number of critical edges or interactions. Consistent with this analysis, there are a large number of suboptimal paths that can be used for communication between the identity elements on the tRNAs and the catalytic site in the aaRS:tRNA complexes. Residues and nucleotides in the majority of pathways for intercommunity signal transmission are evolutionarily conserved and are predicted to be important for allosteric signaling. The same monomers are also found in a majority of the suboptimal paths. Modifying these residues or nucleotides has a large effect on the communication pathways in the protein:RNA complex consistent with kinetic data.
Evidence on the emergence of the brain's default network from 2-week-old to 2-year-old healthy pediatric subjects
Authors: Gao Wei , Zhu Hongtu , Giovanello Kelly S. , Smith J. Keith , Shen Dinggang , Gilmore John H. , Lin Weili
Published: April 2009

Several lines of evidence have implicated the existence of the brain's default network during passive or undirected mental states. Nevertheless, results on the emergence of the default network in very young pediatric subjects are lacking. Using resting functional magnetic resonance imaging in healthy pediatric subjects between 2 weeks and 2 years of age, we describe the temporal evolution of the default network in a critical, previously unstudied, period of early human brain development. Our results demonstrate that a primitive and incomplete default network is present in 2-week-olds, followed by a marked increase in the number of brain regions exhibiting connectivity, and the percent of connection at 1 year of age. By 2 years of age, the default network becomes similar to that observed in adults, including medial prefrontal cortex (MPFC), posterior cingulate cortex/retrosplenial (PCC/Rsp), inferior parietal lobule, lateral temporal cortex, and hippocampus regions. While the anatomical representations of the default network highly depend on age, the PCC/Rsp is consistently observed at in both age groups and is central to the most and strongest connections of the default network, suggesting that PCC/Rsp may serve as the main “hub” of the default network as this region does in adults. In addition, although not as remarkable as the PCC/Rsp, the MPFC also emerges as a potential secondary hub starting from 1 year of age. These findings reveal the temporal development of the default network in the critical period of early brain development and offer new insights into the emergence of brain default network.
Tumor detection and elimination by a targeted gallium corrole
Authors: Agadjanian Hasmik , Ma Jun , Rentsendorj Altan , Valluripalli Vinod , Hwang Jae Youn , Mahammed Atif , Farkas Daniel L. , Gray Harry B. , Gross Zeev , Medina-Kauwe Lali K.
Published: April 2009

Sulfonated gallium(III) corroles are intensely fluorescent macrocyclic compounds that spontaneously assemble with carrier proteins to undergo cell entry. We report in vivo imaging and therapeutic efficacy of a tumor-targeted corrole noncovalently assembled with a heregulin-modified protein directed at the human epidermal growth factor receptor (HER). Systemic delivery of this protein-corrole complex results in tumor accumulation, which can be visualized in vivo owing to intensely red corrole fluorescence. Targeted delivery in vivo leads to tumor cell death while normal tissue is spared. These findings contrast with the effects of doxorubicin, which can elicit cardiac damage during therapy and required direct intratumoral injection to yield similar levels of tumor shrinkage compared with the systemically delivered corrole. The targeted complex ablated tumors at >5 times a lower dose than untargeted systemic doxorubicin, and the corrole did not damage heart tissue. Complexes remained intact in serum and the carrier protein elicited no detectable immunogenicity. The sulfonated gallium(III) corrole functions both for tumor detection and intervention with safety and targeting advantages over standard chemotherapeutic agents.
Public clonotype usage identifies protective Gag-specific CD8+ T cell responses in SIV infection
Authors: Price David A. , Asher Tedi E. , Wilson Nancy A. , Nason Martha C. , Brenchley Jason M. , Metzler Ian S. , Venturi Vanessa , Gostick Emma , Chattopadhyay Pratip K. , Roederer Mario , Davenport Miles P. , Watkins David I. , Douek Daniel C.
Published: April 2009

Despite the pressing need for an AIDS vaccine, the determinants of protective immunity to HIV remain concealed within the complexity of adaptive immune responses. We dissected immunodominant virus-specific CD8+ T cell populations in Mamu-A*01+ rhesus macaques with primary SIV infection to elucidate the hallmarks of effective immunity at the level of individual constituent clonotypes, which were identified according to the expression of distinct T cell receptors (TCRs). The number of public clonotypes, defined as those that expressed identical TCR β-chain amino acid sequences and recurred in multiple individuals, contained within the acute phase CD8+ T cell population specific for the biologically constrained Gag CM9 (CTPYDINQM; residues 181–189) epitope correlated negatively with the virus load set point. This independent molecular signature of protection was confirmed in a prospective vaccine trial, in which clonotype engagement was governed by the nature of the antigen rather than the context of exposure and public clonotype usage was associated with enhanced recognition of epitope variants. Thus, the pattern of antigen-specific clonotype recruitment within a protective CD8+ T cell population is a prognostic indicator of vaccine efficacy and biological outcome in an AIDS virus infection.
Plasma apelin concentration is depressed following acute myocardial infarction in man
Authors: Weir Robin A.P. , Chong Kwok Shiong , Dalzell Jonathan R. , Petrie Colin J. , Murphy Charles A. , Steedman Tracey , Mark Patrick B. , McDonagh Theresa A. , Dargie Henry J. , McMurray John J.V.
Published: April 2009

Aims

Apelin, a novel peptide with a putative role in cardiovascular homeostasis, has gained interest as an endogenous inotrope, but has yet to be described following acute myocardial infarction (AMI) in man. We aimed to characterize plasma apelin concentrations following AMI and to examine its relationship with clinical and prognostic biomarkers.

Methods and results

Plasma concentrations of apelin, N‐terminal probrain natriuretic peptide (NT‐proBNP), norepinephrine, and arginine vasopressin were measured in 100 patients [mean age 58.9 ± 12 (SD) years, 77% male] admitted with AMI, with echocardiographic left ventricular (LV) ejection fraction <40%, at mean 46 h after admission and at 24 weeks. Cardiac magnetic resonance imaging was performed pre‐discharge and at 24 weeks. Thirty‐eight subjects with no cardiac history acted as controls. Apelin concentration was reduced early after AMI (0.54 ± 0.25 vs. 3.22 ± 3.01 ng/mL, P <0.001) and remained low at 24 weeks, although it did increase significantly from baseline to 0.62 ± 0.36 ng/mL, P = 0.030. Apelin had no relationship with any parameter of LV function over time. A relationship was found between baseline apelin and norepinephrine (r = 0.26, P = 0.008). Both NT‐proBNP and norepinephrine correlated with adverse ventricular function after AMI.

Conclusion

Plasma apelin concentration is reduced early after AMI, increases significantly over time, but remains depressed at 24 weeks.
Estimates of batch fecundity and spawning fraction for the southern stock of horse mackerel (Trachurus trachurus) in ICES Division IXa
Authors: Gonçalves Patrícia , Costa Ana Maria , Murta Alberto G.
Published: April 2009

Gonçalves, P., Costa, A. M., and Murta, A. G. 2009. Estimates of batch fecundity, and spawning fraction for the southern stock of horse mackerel (Trachurus trachurus) in ICES Division IXa. – ICES Journal of Marine Science, 66: 617–622. Since 1995 the annual egg production method has been applied triennially to the southern stock of horse mackerel (Trachurus trachurus) in the Northeast Atlantic (ICES Division IXa). This method assumes that fecundity is determinate, but increasing evidence indicates that horse mackerel are indeterminate spawners. The daily egg production method (DEPM) does not rely on the assumption of determinate fecundity, making it the appropriate method for this species. Therefore, we reanalysed samples collected from previous surveys (2002, 2004, 2005, and 2007) to obtain estimates for batch fecundity and spawning fraction, which are important DEPM parameters. The estimates of batch fecundity are around 200 oocytes g−1 of female (total ovary-free weight). Several criteria were used to estimate spawning fraction (migratory nucleus stage, hydrated oocytes, and post-ovulatory follicles) and all showed the same trend among years, varying between 0.10 and 0.30 d−1. The estimates were significantly different among methods, but those differences were similar across surveys, indicating that a consistent bias would be reflected in the final spawning-stock biomass (SSB) estimates obtained from the DEPM. Until further information is available regarding the accuracy of the criteria used to estimate spawning fraction, the southern horse mackerel SSB estimates from the DEPM should only be taken as indicative of trends rather than measures of absolute abundance.
Early identification of haemodynamic response to pharmacotherapy is essential for primary prophylaxis of variceal bleeding in patients with ‘high‐risk’ varices
Authors: SHARMA P. , KUMAR A. , SHARMA B. C. , SARIN S. K.
Published: April 2009

Background  A beta‐blocker is recommended for primary prophylaxis of variceal bleeding; however, only one‐third have hepatic venous pressure gradient (HVPG) response. The role of addition of isosorbide‐5‐mononitrate (ISMN) to beta‐blocker and benefits of HVPG‐guided ‘a la carte’ approach remain unclear.

Aim  To determine the benefits of HVPG‐guided pharmacotherapy in primary prophylaxis of variceal bleeding using beta‐blocker and ISMN.

Patients and methods  Consecutive patients of cirrhosis, with high‐risk varices, with no previous variceal bleeding were included. After baseline HVPG, patients received incremental propranolol to achieve HR of 55/min. After one‐month, HVPG was repeated to determine response (<12 mmHg or ≥20% reduction). ISMN was added in nonresponders and HVPG repeated. Patients were followed up for 24 months.

Results  Of 56 patients (age 47 ± 13, males 79%) from 89 eligible patients, 21 (38%) responded to beta‐blocker alone. Six additional patients responded to combination. Thus, overall 48% (27/56) patients responded. Variceal bleeding occurred in seven of 56 (13%) patients [one of 27 (4%) responder, five of 23 (22%) nonresponders and one of six (17%) with unknown response; P = N.S.]. The actuarial probability of variceal bleeding at median 24 months was 4% in responders and 22% in nonresponders (P < 0.05). Ten (18%) patients developed adverse effects to propranolol and six of 35 (17%) to nitrates requiring dose reduction. Risk factors of variceal bleed were grade IV varices and haemodynamic nonresponse.

Conclusions  For primary prophylaxis, a beta‐blocker is effective in 38% and addition of ISMN raises the response rate to about half of patients. The HVPG‐guided ‘a la carte’ approach may be considered for these patients.
Short treatment with the tumour necrosis factor-α blocker infliximab diminishes chronic chagasic myocarditis in rats without evidence of Trypanosoma cruzi reactivation
Authors: Pérez A R , Fontanella G H , Nocito A L , Revelli S , Bottasso O A
Published: April 2009

Tumour necrosis factor (TNF)-α is crucial for resistance to Trypanosoma cruzi acute infection, but there is scant information on its role during the chronic phase. To address this issue, we analysed whether a short treatment with a TNF-α blocker affected the course and characteristics of chronic disease in a rat experimental model of T. cruzi infection. An anti-TNF-α agent (infliximab) was administered during the chronic phase for a period of 4 weeks (3 mg/kg/week), while control infected rats were inoculated with saline physiological solution. Search for parasites yielded non-successful results in all infected groups, irrespective of treatment. Nevertheless, the presence of T. cruzi kDNA in heart tissue was detected in infected and infected plus treated animals. Because infliximab might induce changes in the anti-parasite cytokine response, circulating levels of interleukin (IL)-10, interferon-gamma and nitric oxide were evaluated. An increase in IL-10 levels was observed only in the infected group treated with the anti-TNF-α blocker compared to the remaining groups (P < 0·05). A clear attenuation of histological damage associated with a diminution of cardiac TNF-α mRNA expression was observed in the infected and treated animals compared to the infected and non-treated group. Blocking of TNF-α during a relatively short period in chronically infected rats did not lead to evident parasite reactivation but reduced myocarditis severity significantly, indicating a role of this cytokine in the pathogenesis of chronic myocardial damage.
Development of troponin autoantibodies in experimental coxsackievirus B3 myocarditis
Authors: Latva‐Hirvelä J. , Kytö V. , Saraste A. , Eriksson S. , Vuorinen T. , Pettersson K. , Saukko P.
Published: April 2009

Background  Autoantibodies against various endogenous proteins are found in myocarditis. Troponin autoantibodies are detected in patients with chronic dilated cardiomyopathy, but their presence in myocarditis remains unknown. We set out to study the presence of troponin autoantibodies in experimental viral myocarditis.

Materials and methods  BALB/c mice infected with coxsackievirus B3 Nancy strain were followed‐up at days 1–7 and 2, 4, 8 and 12 weeks after infection. Levels of circulating cardiac troponin I and circulating troponin autoantibodies were measured. Transthoracic echocardiography was performed. Myocarditis was histopathologically graded and cardiomyocyte apoptosis was quantified (TUNEL).

Results  Histopathologically relatively mild acute myocarditis followed by persistent cardiomyocyte damage was observed. Rate of cardiomyocyte apoptosis was the highest on day 5 (0·16 ± 0·01% vs. 0·03 ± 0·01% in controls, P < 0·001). Circulating troponin I levels were increased to day 5 (45·2 ± 6·5 ng mL−1, P < 0·005 vs. controls). Troponin autoantibodies were detected from 2 weeks after infection (20% of animals had autoantibodies at 2 weeks, 60% at 4 and 8 weeks and 20% at 12 weeks, P < 0·05 vs. controls). Fractional shortening remained decreased after acute myocarditis (0·36 ± 0·02 at 4 weeks, 0·30 ± 0·02 at 8 and 12 weeks vs. 0·41 ± 0·01 before infection, P < 0·01) parallel to development of troponin autoantibodies.

Conclusion  Troponin autoantibodies are formed in experimental virus induced myocarditis following troponin I release and cardiomyocyte apoptosis. The definite role of these autoantibodies remains to be further characterized.
Dissipation rates of fenitrothion in greenhouse grown lettuce and under cold storage conditions
Authors: Fenoll José , Hellín Pilar , López Josefa , González Alberto , Lacasa Alfredo , Flores Pilar
Published: April 2009

The dissipation of fenitrothion (O,O‐dimethyl O‐p‐nitro‐m‐tolyl phosphothioate) was evaluated by gas chromatography (GC) with nitrogen‐phosphorus detection (NPD) in lettuce samples grown in an experimental greenhouse and harvested over a 4 weeks period following treatment with this insecticide. Dissipation followed a pseudo‐first‐order kinetics (r was 0.996). The recommended preharvest time (PT) of application is 15 days, and when the residual value of fenitrothion was evaluated at harvest, it was found to be above the maximum residue limit (MRL) established by Spanish law in the field experiment for this compound. During the experiment, the evolution of the two main fenitrothion metabolites (3‐methyl‐4‐nitrophenol and fenitrothion‐oxon) was also evaluated. When the dissipation of fenitrothion was evaluated in cold‐stored lettuce the half‐life was 9–10 times greater than in greenhouse conditions.
Biochemical changes in cut vs. intact lamb’s lettuce (Valerianella olitoria) leaves during storage
Authors: Ferrante Antonio , Martinetti Livia , Maggiore Tommaso
Published: April 2009

Consumers are oriented towards fresh‐cut vegetables that provide phytonutrients useful for preventing stress‐related diseases. The aim of this work was to evaluate the cut operations on the quality changes of lamb’s lettuce (Valerianella olitoria L.) cv. Trofy during storage at 4 °C for 8 days. Results showed that chlorophyll and carotenoids reduction was observed after 8 days of storage. In both treatments, total carotenoids after 8 days decreased from 20 to 16 mg g−1 FW. Free and total phenols increased with storage in both treatments. Total phenols were 23% higher in control (32 μmol g−1 FW) compared to cut leaves (25 μmol g−1 FW) after 8 days of storage. Anthocyanins increased after 8 days and reached 30 mg 100 g−1 FW without significant difference between treatments. Ascorbic acid (AsA) and dehydroascorbic (DHA) acid increased in cut leaves compared to control. After 1 day AsA concentration was 3 300 nmol g−1 FW in cut leaves, while in control leaves was 1 500 nmol g−1 FW. Analogously AsA + DHA was higher in cut leaves, 4 100 nmol g−1 FW, while in control leaves the mean was 3 000 nmol g−1 FW. After 5 days of storage the values of AsA returned to initial values, while AsA + DHA were lower.
The use of packaging techniques to maintain freshness in fresh‐cut fruits and vegetables: a review
Authors: Rojas‐Graü Mª Alejandra , Oms‐Oliu Gemma , Soliva‐Fortuny Robert , Martín‐Belloso Olga
Published: April 2009

Browning and other discolourations, softening, surface dehydration, water loss, translucency, off‐flavour and off‐odour development, as well as microbial spoilage are some of the most frequent causes of quality loss in fresh‐cut products. Nowadays, the use of innovative modified atmospheres and edible coatings stands out among other techniques in the struggle for maintaining freshness and safety of fresh‐cut fruits and vegetables. A few studies have demonstrated the effectiveness of these techniques when applied to different fresh‐cut commodities. However, treatment and storage conditions for fresh‐cut fruits are still being largely explored to better keep their fresh‐like quality attributes. This review discusses the recent advances in the use of innovative modified atmosphere packaging (MAP) systems to maintain freshness of fresh‐cut fruits and vegetables. Furthermore, special attention is devoted to the development of coatings that can be used as a complement or alternative to MAP.
A UK wide survey of insulin initiation in children with type 1 diabetes and nurses’ perceptions of associated decision‐making
Authors: Lowes Lesley , Davis Ruth ,   on behalf of the UK Insulin Initiation Study (UKIIS) Group
Published: April 2009

Aim and objectives.  The aim of this study was to examine insulin initiation practice across the UK in relation to children with newly diagnosed type 1 diabetes. Objectives of this study were to explore practices surrounding insulin initiation in children and nurses’ perceptions of associated decision‐making.

Background.  There are comparative studies of insulin treatments and regimens for children but few that describe the insulin initiation process or associated decision‐making. The literature suggests a heavy workload for nurses working in practice and insufficient resources for home initiation of insulin.

Design.  A survey design.

Method.  A questionnaire regarding insulin initiation was distributed to 247 diabetes specialist nurses working with children from all four UK countries.

Results.  One hundred and twelve responses (45%). Only 37 (33%) started clinically well, newly diagnosed children on insulin at home, but most would do so with adequate resources. The most common insulin regimen at diagnosis was twice daily injections, with 86% (n = 96) using re‐usable pens to deliver the insulin. As expected, no one commenced children on pump therapy at diagnosis. Analogue insulin was seen as the drug of choice by over a quarter of the nurses (29%, n = 32). Doctors appeared to be the main decision‐makers, supplemented by other members of the paediatric diabetes multi‐disciplinary team and decision‐making aids.

Conclusion.  Approaches to treatment at onset of type 1 diabetes in children remain relatively traditional. Nurses expressed a desire to stabilise clinically well children at home but were restricted by lack of resources. Decision‐making in most domains was largely medically dominated.

Relevance to clinical practice.  The study provides an insight into current insulin initiation practice in childhood diabetes and offers a useful comparator as practices change in the light of advances in treatment (medication and equipment), changes in professional roles (e.g. independent prescribing) and policy shifts (the move away from hospitals and resource constraints).
Validation of CARE‐Q in residential aged‐care: rating of importance of caring behaviours from an e‐cohort sub‐study
Authors: Tuckett Anthony G , Hughes Karen , Schluter Philip J , Turner Cathy
Published: April 2009

Aim and objective.  To validate the Caring Assessment Report Evaluation Q‐sort questionnaire in the residential aged‐care setting. Based on this determination, to conclude with what degree of confidence the questionnaire can be used to determine the ranking of the importance of caring behaviours amongst aged‐care nurses and residents in residential aged‐care.

Background.  Perceptions of caring may be context specific. Caring in residential aged‐care may stand in contrast to the sense of caring understood and practiced in other settings.

Design.  Self‐administered survey.

Methods.  Residents from three not‐for‐profit aged‐care facilities, across both high‐care (nursing‐home) and low‐care (hostel care) were surveyed relying on the Caring Assessment Report Evaluation Q‐sort questionnaire. A sub‐sample of registered and enrolled nurses working in residential aged‐care and registered with the Nurses & Midwives e‐cohort study completed the same survey.

Results.  Although the Caring Assessment Report Evaluation Q‐sort questionnaire showed good internal consistency for the sample of nurses, the results for the residents were more erratic. Both groups displayed large ranges for the inter‐item correlations. The results of the Mann–Whitney U‐test indicated that the nurses rated the Comforts, Anticipates and Trusting relationship as significantly more important than the residents. Both groups rated the Explains and facilitates subscale as least important. All subscales, however, received median scores greater than, or equal to, six (seven‐point, Likert scale) indicating that all were considered important overall.

Conclusion.  Based on poor Cronbach's alpha coefficients, negative inter‐item correlations and qualitative observations, without further development within the residential aged‐care facility the free response format version of the Caring Assessment Report Evaluation Q‐sort may not be an appropriate measure to use with residential aged‐care residents. More research needs to be conducted into how residents and nurses are interpreting the items in the Caring Assessment Report Evaluation Q‐sort.

Relevance to clinical practice.  There will always remain a need for nurses to enact behaviours that are meaningful to residents (and patients generally).
Biological Flora of the British Isles: Primula veris L.
Authors: Brys Rein , Jacquemyn Hans
Published: April 2009

This account presents information on all aspects of the biology of Primula veris that are relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the standard framework of the Biological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and diseases, history and conservation.

Primula veris is a distylous, perennial rosette hemicryptophyte, mostly found in well‐drained, herb‐rich meadows and grasslands, in scrub or woodland rides and edges, and on calcareous cliffs. It occurs on base‐rich loams or clays, on limestone, and sometimes in dunes.

Native to the British Isles, it is characteristic of many mesotrophic and calcicolous lowland grassland communities, but it also extends into upland valleys in northern England and Scotland. In Ireland it is also native and most abundant in the central plain. Primula veris occurs throughout the temperate areas of Europe as far east as the Russian border.

Primula veris is a shade‐intolerant species that shows reduced performance and flowering under shade or increased competition. The species is not able to penetrate anoxic soil layers and is therefore mostly absent from locations that are characterized by a high water table. It has a well‐developed drought tolerance.

Primula veris is an obligate outbreeder which entirely depends on foraging insects for successful pollination. Although the species shows heterostyly, with two reciprocal morphs (pin and thrum), only relatively low levels of intermorph pollination have been reported. Seed dispersal is restricted to a few centimetres from maternal plants, whereas pollen flow is wider, but still limited to a few metres from parental plants. Both are factors that contribute to a significantly fine‐scale spatial genetic structure and small neighbourhood size.

At several locations throughout the British Isles, P. veris occurs together with P. elatior and especially P. vulgaris. The hybrid P. veris × P. vulgaris = P. × polyantha occurs frequently in mixed populations, whereas the hybrid P. veris × P. elatior = P. × media has been rarely reported in Britain.

Although P. veris is still a widespread grassland herb, it is less abundant in the British Isles and continental Europe than before. This decline can be attributed to changes in land‐use practices, such as the loss of traditional hay–meadow management, the loss of grazing and an increase of ploughing, in combination with ongoing destruction and nutrient enrichment of permanent grasslands. However, from 1980 onwards the species has increased substantially in many areas of the UK, largely because its seeds are included in wildflower seed‐mixtures that are sown on new or upgraded road and motorway verges, embankments and urban conservation areas.
Physical intervention trainers: the case for greater accountability
Authors: HOLLINS L. P. , PATERSON B.
Published: April 2009

Physical intervention training courses are commonplace events in psychiatric and mental healthcare settings across the UK. While there is still debate as to what techniques should be taught on such courses, there is good evidence as to the mechanisms whereby pain, injury and even death can be inflicted. There is also a wealth of literature identifying how organizational culture can influence the quality of service delivery and standards of client care. It is well documented that the dignity, well‐being and physical integrity of service users can be compromised by staff acts and omissions stemming from corrupted cultures. What has not been explored in detail to date is the role of physical intervention trainer, specifically the values they model and how these may influence the readiness with which staff resort to physical restraint strategies. It is possible that even approved physical techniques can become compromised through poor training technique and expose end recipients to needless humiliation and potential harm. This paper discusses this area of practice, offers insight on how the learning process is compromised by trainers and suggests areas for future research.