bluuebunny/crossref_metadata_2025 huggingface dataset:
Review of field-reversed configurations
Authors: Steinhauer Loren C.
Published: July 2011

This review addresses field-reversed configurations (FRCs), which are compact-toroidal magnetic systems with little or no toroidal field and very high β (ratio of plasma pressure to magnetic pressure). Although enthusiasm for the FRC has primarily been driven by its potential for an attractive fusion reactor, this review focuses on the physics rather than on technological or engineering aspects. Major advances in both theory and experiment have taken place since the previous comprehensive FRC review in 1988. Even so many questions remain. In particular, even though FRC experiments have exhibited remarkable stability, how well this extrapolates to larger systems remains unresolved. The review considers FRCs under familiar topical categories: equilibrium, global stability, self-organization, transport, formation, and sustainment.
Opposite photo-induced deformations in azobenzene-containing polymers with different molecular architecture: Molecular dynamics study
Authors: Ilnytskyi Jaroslav M. , Neher Dieter , Saphiannikova Marina
Published: July 2011

Photo-induced deformations in azobenzene-containing polymers (azo-polymers) are central to a number of applications, such as optical storage and fabrication of diffractive elements. The microscopic nature of the underlying opto-mechanical coupling is yet not clear. In this study, we address the experimental finding that the scenario of the effects depends on molecular architecture of the used azo-polymer. Typically, opposite deformations in respect to the direction of light polarization are observed for liquid crystalline and amorphous azo-polymers. In this study, we undertake molecular dynamics simulations of two different models that mimic these two types of azo-polymers. We employ hybrid force field modeling and consider only trans-isomers of azobenzene, represented as Gay-Berne sites. The effect of illumination on the orientation of the chromophores is considered on the level of orientational hole burning and emphasis is given to the resulting deformation of the polymer matrix. We reproduce deformations of opposite sign for the two models being considered here and discuss the relevant microscopic mechanisms in both cases.
Electrohydrodynamic quenching in polymer melt electrospinning
Authors: Zhmayev Eduard , Cho Daehwan , Lak Joo Yong
Published: July 2011

Infrared thermal measurements on polymer melt jets in electrospinning have revealed rapid quenching by ambient air, an order of magnitude faster than predicted by the classical Kase and Matsuo correlation. This drastic heat transfer enhancement can be linked to electrohydrodynamic (EHD) effects. Analysis of EHD-driven air flow was performed and included into a comprehensive model for polymer melt electrospinning. The analysis was validated by excellent agreement of both predicted jet radius and temperature profiles with experimental results for electrospinning of Nylon-6 (N6), polypropylene (PP), and polylactic acid (PLA) melts. Based on this analysis, several methods that can be used to inhibit or enhance the quenching are described.
Highly textured laser annealed Pb(Zr0.52Ti0.48)O3 thin films
Authors: Bharadwaja S. S. N. , Griggio F. , Kulik J. , Trolier-McKinstry S.
Published: July 2011

RF sputtered amorphous Pb(Zr0.52Ti0.48)O3 (PZT) films (∼300–350 nm in thickness) on {111}Pt/Ti/SiO2/Si or {001}PbTiO3/Pt/Ti/SiO2/Si substrates were laser crystallized to obtain highly textured {111} and {001} PZT thin films. The measured remanent polarizations and coercive fields were 31 µC/cm2 and 86 kV/cm for {001} films and 24 µC/cm2 and 64 kV/cm for {111} oriented PZT films, respectively. The maximum e31,f piezoelectric charge coefficients are ∼ −11 C/m2 for {001} and ∼ −9 C/m2 for {111} PZT thin films respectively.
Weak antilocalization effect in high-mobility two-dimensional electron gas in an inversion layer on p-type HgCdTe
Authors: Yang Rui , Gao Kuanghong , Wei Laiming , Liu Xinzhi , Hu Gujin , Yu Guolin , Lin Tie , Guo Shaoling , Wei Yanfeng , Yang Jianrong , He Li , Dai Ning , Chu Junhao , Austing D. G.
Published: July 2011

Magnetoconductance of a gated two-dimensional electron gas (2DEG) in an inversion layer on a p-type HgCdTe film is investigated. At strong magnetic fields, characteristic features such as the quantum Hall effect of a 2DEG with single subband occupation are observed. At weak magnetic fields, the weak antilocalization effect in the ballistic regime is observed. Phase coherence time and zero-field spin-splitting are extracted following Golub’s model [L. E. Golub, Phys. Rev. B 71, 235310 (2005)]. The temperature dependence of the dephasing rate is consistent with the Nyquist mechanism.
Evolution of magnetic bubble domains in manganite films
Authors: Bakaul S. R. , Lin W. , Wu T.
Published: July 2011

We report a thickness-dependent evolution of magnetic domains from long stripe-like to bubble-like entities in La1−xSrxMnO3 (x ∼ 0.3) (LSMO) films grown on LaAlO3 substrates. By using 2-D fast Fourier transformation of magnetic force microscopy images and power spectral density function, we accurately determine the domain width in LSMO films with a wide range of thickness (50–325 nm). We find that the domain size scales with the Kittel’s square root law [C. Kittel, Phys. Rev. 70, 965 (1946).] only when reduced film thicknesses are used, which suggests the critical role of substrate-film interaction in domain formation.
Photoelectron emission control with polarized light in plasmonic metal random structures
Authors: Word R. C. , Fitzgerald J. , Könenkamp R.
Published: July 2011

We report on the possibility of switching the emission rate of photoelectrons by polarization changes in the plasmon excitation light. Photoelectron emission is strongly enhanced in the near-field of localized surface plasmons and occurs from areas with typical diameters of 20-70 nm. The underlying physical process involves excitation of a localized surface plasmon polariton with a femtosecond laser pulse, and a subsequent multi-photon photoemission process. The non-linearity of this process leads to a sharp polarization dependence that allows efficient switching of the emission. We demonstrate that a 90° polarization change can result in on/off ratios of ∼100 for electron emission.
Surface plasmon-enhanced light-emitting diodes with silver nanoparticles and SiO2 nano-disks embedded in p-GaN
Authors: Cho Chu-Young , Kim Ki Seok , Lee Sang-Jun , Kwon Min-Ki , Ko Hyungduk , Kim Sung-Tae , Jung Gun-Young , Park Seong-Ju
Published: July 2011

We report the fabrication and characterization of surface plasmon (SP)-enhanced blue light-emitting diodes (LEDs) with Ag nanoparticles and SiO2 nano-disks embedded in the p-GaN layer. Compared with LEDs without Ag nanoparticles, the optical output power increases for the SP-enhanced LEDs with and without SiO2 nano-disks are 72% and 49%, respectively. The greater increase in optical output power for the SP-enhanced LEDs with SiO2 nano-disks compared with SP-enhanced LEDs without SiO2 nano-disks can be attributed to the SiO2 nano-disks in the p-GaN layer, which reduce the Ag nanoparticle-induced defects and enhance the light extraction efficiency of the LEDs.
Low temperature solution-processed graphene oxide/Pr0.7Ca0.3MnO3 based resistive-memory device
Authors: Kim Insung , Siddik Manzar , Shin Jungho , Biju Kuyyadi P , Jung Seungjae , Hwang Hyunsang
Published: July 2011

We propose a graphene oxide (GO)/Pr0.7Ca0.3MnO3 (PCMO) based resistance random access memory (RRAM) device. Both active layers were prepared by a sol-gel spin-coating method at low temperature (<300 °C).The fabricated Pt/GO/PCMO/Pt RRAM device shows good switching performance with an on/off ratio of about 100 and a retention property of more than 104 at 85 °C and reliable endurance characteristics. Moreover, the observed bipolar switching phenomena could be explained by the movement of oxygen ions across the GO–PCMO interface. These results suggest that the GO/PCMO device is a good candidate for use in resistive memory applications.
Junction size effect on switching current and thermal stability in CoFeB/MgO perpendicular magnetic tunnel junctions
Authors: Sato H. , Yamanouchi M. , Miura K. , Ikeda S. , Gan H. D. , Mizunuma K. , Koizumi R. , Matsukura F. , Ohno H.
Published: July 2011

Junction size dependence of critical current (IC0) for spin transfer torque switching and thermal stability factor (E/kBT) was examined in CoFeB/MgO perpendicular magnetic tunnel junctions (p-MTJs). The IC0 increased with increasing recording layer area (Srec). On the other hand, the E/kBT showed almost constant values even though the Srec was increased from ∼1500 nm2 (44 nmφ) to ∼5000 nm2 (76 nmφ). Both IC0 and E/kBT behavior can be explained with assuming that the nucleation type magnetization reversal takes place in CoFeB/MgO p-MTJs.
Stoichiometric requirements for trapping and gating of Ca
2+
release-activated Ca
2+
(CRAC) channels by stromal interaction molecule 1 (STIM1)
Authors: Hoover Paul J. , Lewis Richard S.
Published: July 2011

Store-operated Ca
2+
entry depends critically on physical interactions of the endoplasmic reticulum (ER) Ca
2+
sensor stromal interaction molecule 1 (STIM1) and the Ca
2+
release-activated Ca
2+
(CRAC) channel protein Orai1. Recent studies support a diffusion-trap mechanism in which ER Ca
2+
depletion causes STIM1 to accumulate at ER-plasma membrane (PM) junctions, where it binds to Orai1, trapping and activating mobile CRAC channels in the overlying PM. To determine the stoichiometric requirements for CRAC channel trapping and activation, we expressed mCherry-STIM1 and Orai1-GFP at varying ratios in HEK cells and quantified CRAC current (I
CRAC
) activation and the STIM1:Orai1 ratio at ER-PM junctions after store depletion. By competing for a limited amount of STIM1, high levels of Orai1 reduced the junctional STIM1:Orai1 ratio to a lower limit of 0.3–0.6, indicating that binding of one to two STIM1s is sufficient to immobilize the tetrameric CRAC channel at ER-PM junctions. In cells expressing a constant amount of STIM1, CRAC current was a highly nonlinear bell-shaped function of Orai1 expression and the minimum stoichiometry for channel trapping failed to evoke significant activation. Peak current occurred at a ratio of ∼2 STIM1:Orai1, suggesting that maximal CRAC channel activity requires binding of eight STIM1s to each channel. Further increases in Orai1 caused channel activity and fast Ca
2+
-dependent inactivation to decline in parallel. The data are well described by a model in which STIM1 binds to Orai1 with negative cooperativity and channels open with positive cooperativity as a result of stabilization of the open state by STIM1.
Structural basis for the function of a small GTPase RsgA on the 30S ribosomal subunit maturation revealed by cryoelectron microscopy
Authors: Guo Qiang , Yuan Yi , Xu Yanji , Feng Boya , Liu Liang , Chen Kai , Sun Ming , Yang Zhixiu , Lei Jianlin , Gao Ning
Published: July 2011

The bacterial RsgA, a circularly permutated GTPase, whose GTPase activity is dependent on the 30S ribosomal subunit, is a late-stage ribosome biogenesis factor involved in the 30S subunit maturation. The role of RsgA is to release another 30S biogenesis factor, RbfA, from the mature 30S subunit in a GTP-dependent manner. Using cryoelectron microscopy, we have determined the structure of the 30S subunit bound with RsgA in the presence of GMPPNP at subnanometer resolution. In the structure, RsgA binds to the central part of the 30S subunit, close to the decoding center, in a position that is incompatible with multiple biogenesis factors, all three translation initiation factors, as well as A-, P-site tRNAs and the 50S subunit. Further structural analysis not only provides a structural model for the RsgA-dependent release of RbfA from the nascent 30S subunit, but also indicates RsgA’s role in the ribosomal protein assembly, to promote some tertiary binding protein incorporation. Moreover, together with available biochemical and genetic data, our results suggest that RsgA might be a general checkpoint protein in the late stage of the 30S subunit biogenesis, whose function is not only to release biogenesis factors (e.g., RbfA) from the nascent 30S subunit, but also to block the association of initiation factors to the premature 30S subunit.
Control of excitatory CNS synaptogenesis by astrocyte-secreted proteins Hevin and SPARC
Authors: Kucukdereli Hakan , Allen Nicola J. , Lee Anthony T. , Feng Ava , Ozlu M. Ilcim , Conatser Laura M. , Chakraborty Chandrani , Workman Gail , Weaver Matthew , Sage E. Helene , Barres Ben A. , Eroglu Cagla
Published: July 2011

Astrocytes regulate synaptic connectivity in the CNS through secreted signals. Here we identified two astrocyte-secreted proteins, hevin and SPARC, as regulators of excitatory synaptogenesis in vitro and in vivo. Hevin induces the formation of synapses between cultured rat retinal ganglion cells. SPARC is not synaptogenic, but specifically antagonizes synaptogenic function of hevin. Hevin and SPARC are expressed by astrocytes in the superior colliculus, the synaptic target of retinal ganglion cells, concurrent with the excitatory synaptogenesis. Hevin-null mice had fewer excitatory synapses; conversely, SPARC-null mice had increased synaptic connections in the superior colliculus. Furthermore, we found that hevin is required for the structural maturation of the retinocollicular synapses. These results identify hevin as a positive and SPARC as a negative regulator of synapse formation and signify that, through regulation of relative levels of hevin and SPARC, astrocytes might control the formation, maturation, and plasticity of synapses in vivo.
Male germ cells express abundant endogenous siRNAs
Authors: Song Rui , Hennig Grant W. , Wu Qiuxia , Jose Charlie , Zheng Huili , Yan Wei
Published: July 2011

In mammals, endogenous siRNAs (endo-siRNAs) have only been reported in murine oocytes and embryonic stem cells. Here, we show that murine spermatogenic cells express numerous endo-siRNAs, which are likely to be derived from naturally occurring double-stranded RNA (dsRNA) precursors. The biogenesis of these testicular endo-siRNAs is DROSHA independent, but DICER dependent. These male germ cell endo-siRNAs can potentially target hundreds of transcripts or thousands of DNA regions in the genome. Overall, our work has unveiled another hidden layer of regulation imposed by small noncoding RNAs during male germ cell development.
Eco-evolutionary spatial dynamics in the Glanville fritillary butterfly
Authors: Hanski Ilkka A.
Published: July 2011

Demographic population dynamics, gene flow, and local adaptation may influence each other and lead to coupling of ecological and evolutionary dynamics, especially in species inhabiting fragmented heterogeneous environments. Here, I review long-term research on eco-evolutionary spatial dynamics in the Glanville fritillary butterfly inhabiting a large network of approximately 4,000 meadows in Finland. The metapopulation persists in a balance between frequent local extinctions and recolonizations. The genetic spatial structure as defined by neutral markers is much more coarse-grained than the demographic spatial structure determined by the fragmented habitat, yet small-scale spatial structure has important consequences for the dynamics. I discuss three examples of eco-evolutionary spatial dynamics. (i) Extinction-colonization metapopulation dynamics influence allele frequency changes in the phosphoglucose isomerase (Pgi) gene, which leads to strong associations between genetic variation inPgiand dispersal, recolonization, and local population dynamics. (ii) Inbreeding in local populations increases their risk for extinction, whereas reciprocal effects between inbreeding, population size, and emigration represent likely eco-evolutionary feedbacks. (iii) Genetically determined female oviposition preference for two host plant species exhibits a cline paralleling a gradient in host plant relative abundances, and host plant preference of dispersing females in relation to the host plant composition of habitat patches influences immigration (gene flow) and recolonization (founder events). Eco-evolutionary spatial dynamics in heterogeneous environments may not lead to directional evolutionary changes unless the environment itself changes, but eco-evolutionary dynamics may contribute to the maintenance of genetic variation attributable to fluctuating selection in space and time.
Continued warming could transform Greater Yellowstone fire regimes by mid-21st century
Authors: Westerling Anthony L. , Turner Monica G. , Smithwick Erica A. H. , Romme William H. , Ryan Michael G.
Published: July 2011

Climate change is likely to alter wildfire regimes, but the magnitude and timing of potential climate-driven changes in regional fire regimes are not well understood. We considered how the occurrence, size, and spatial location of large fires might respond to climate projections in the Greater Yellowstone ecosystem (GYE) (Wyoming), a large wildland ecosystem dominated by conifer forests and characterized by infrequent, high-severity fire. We developed a suite of statistical models that related monthly climate data (1972–1999) to the occurrence and size of fires >200 ha in the northern Rocky Mountains; these models were cross-validated and then used with downscaled (∼12 km × 12 km) climate projections from three global climate models to predict fire occurrence and area burned in the GYE through 2099. All models predicted substantial increases in fire by midcentury, with fire rotation (the time to burn an area equal to the landscape area) reduced to <30 y from the historical 100–300 y for most of the GYE. Years without large fires were common historically but are expected to become rare as annual area burned and the frequency of regionally synchronous fires increase. Our findings suggest a shift to novel fire–climate–vegetation relationships in Greater Yellowstone by midcentury because fire frequency and extent would be inconsistent with persistence of the current suite of conifer species. The predicted new fire regime would transform the flora, fauna, and ecosystem processes in this landscape and may indicate similar changes for other subalpine forests.
The effect of achievement goals on enjoyment, effort, satisfaction and performance
Authors: Puente‐Díaz Rogelio
Published: July 2011

This study examined the effect of achievement goals and achievement emotions on sport satisfaction, performance and effort among competitive athletes. Participants were 200 athletes. Structural equation modeling was used to test the indirect effect of mastery‐approach goals on satisfaction with sport experience and performance, the direct effect of mastery‐approach goals on enjoyment and effort, the direct effect of performance‐approach and performance‐avoidance goals on performance, and the direct effect of mastery‐avoidance goals on effort. Results showed a positive direct effect of mastery‐approach goals on enjoyment and an indirect effect, through enjoyment, on satisfaction, performance, and effort. We did not find support for the hypothesized effect of performance‐approach or performance‐avoidance goals on performance. The applied implications of endorsing mastery‐approach goals are discussed.
Effect of Fe substitution on the magnetic properties of BiMn2O5
Authors: Kumar K Saravana , Venkateswaran C
Published: July 2011

Powders of BiFeMnO5, by the substitution of Fe ions at Mn3+ sites of parent BiMn2O5 system, were synthesized by a two-step process: initial high-energy ball milling of oxides in zirconia vials and then sintering of the as-milled powders. BiFeMnO5 has orthorhombic structure (Pbam) as that of the parent system, determined from x-ray diffraction. Above 850 °C it melts and transforms to a multi-phase system. Smaller particle size is observed from scanning electron microscopy in comparison with parent BiMn2O5. Thermo-magnetization studies indicate a Neel transition around 40 K. Isothermal magnetization measurements reveal paramagnetic nature at room temperature and a weak ferromagnetic property below the transition temperature. As an effect of Fe substitution in BiMn2O5, a significant increase in coercivity (H
c) and decrease in remanent magnetization (M
r) are observed below transition temperature which is discussed based on the dynamics of exchange interaction.
Swift heavy ion interaction with silver–silica nanocomposites: an experimental surface plasmon resonance study
Authors: Singh Fouran , Pivin J C , Dimova-Malisnovska Doriana , Stoquert J P
Published: July 2011

In situ and ex situ surface plasmon resonance (SPR) studies on swift heavy ion (SHI) irradiated silver–silica nanocomposite (NC) films are reported. The size of the ion tracks under dense electronic excitation density induced by mega-electronvolt (MeV) and giga-electronvolt (GeV) ions irradiation is determined. The red shifting in the SPR peak position upon irradiation at incremented ion fluences is observed. The detailed analysis shows that SHI can be used to control the size and interactions among the nanoparticles. The origin of the change in the SPR peak shape is attributed to the strong fluctuations in sizes, rearrangement and partial deformation of nanoparticles by the process of melting, sputtering and reprecipitation in the tracks by invoking the thermal spike model.
Impurity intrusion in radio-frequency micro-plasma jets operated in ambient air
Authors: Niermann B , Kanitz A , Böke M , Winter J
Published: July 2011

Space and time resolved concentrations of helium He (3S1) metastable atoms in an atmospheric pressure radio-frequency micro-plasma jet were measured using tunable diode laser absorption spectroscopy. Spatial profiles and lifetime measurements show significant influences of air entering the discharge from the front nozzle and of impurities originating from the gas supply system. Quenching of metastables was used to deduce quantitative concentrations of intruding impurities. The impurity profile along the jet axis was determined from optical emission spectroscopy as well as their dependence on the feed gas flow through the jet.
Mobility of Xe+ in Xe–Ne and Xe–He mixtures
Authors: de Urquijo J , Basurto E , Bekstein A
Published: July 2011

We report on the measurement of the mobility of Xe+ in Xe–Ne and Xe–He mixtures over the density-reduced electric field strength E/N, from 6.5 to 300 Td (1 Td = 10−17 V cm2), and Xe concentrations in the range 2–50%. The measurements are carried out with a pulsed Townsend apparatus (PT). Even though the PT apparatus lacks mass analysis, the measurements are thoroughly justified in terms of mass identification by ensuring that the majority ion species is Xe+ over carefully selected ranges of E/N where this ion is overwhelmingly predominant over either Ne+ or He+, the presence of which is limited to a maximum of 1% in this study. Ample evidence is given that the contribution of additional Xe+ to that provided by electron impact ionization via the charge transfer reaction Ne+(He+) + Xe+ → Ne(He) + Xe+ exerts a negligible effect on the evaluation of the drift velocity. Likewise, the finite bandwidth of the amplifier is shown not to influence the drift velocity (mobility) measurements at all. For all the mixtures under study the equilibration times are substantially smaller than the associated ion transit times so that full assurance is given to having the ion swarms in equilibrium with the neutral gas mixtures. No previously measured mobilities of Xe+ in these mixtures are found; however, there is good agreement between our measurements and those previously calculated.
Agricultural Land Elasticities in the United States and Brazil
Authors: Barr Kanlaya J. , Babcock Bruce A. , Carriquiry Miguel A. , Nassar Andre M. , Harfuch Leila
Published: July 2011

The elasticity of aggregate supply of cropland is one key to understanding the degree to which policy‐induced increases in demand for biofuel feedstocks or agricultural CO2 offsets will result in higher prices or expanded crop production. We report land supply elasticities for the United States and Brazil estimated directly from recent changes in planted crop acreage and estimated changes in expected returns. The resulting aggregate implied land‐use elasticities with respect to price are quite inelastic in the United States and Brazil elasticities have declined sharply in recent years. The estimated elasticities imply that current estimates of land‐based CO2 emissions from biofuels expansion may be overstated
Reducing Noninfectious Risks of Blood Transfusion
Authors: Gilliss Brian M. , Looney Mark R. , Gropper Michael A. , Warner David S.
Published: July 2011

As screening for transfusion-associated infections has improved, noninfectious complications of transfusion now cause the majority of morbidity and mortality associated with transfusion in the United States. For example, transfusion-related acute lung injury, transfusion-associated circulatory overload, and hemolytic transfusion-reactions are the first, second, and third leading causes of death from transfusion, respectively. These complications and others are reviewed, and several controversial methods for prevention of noninfectious complications of transfusion are discussed, including universal leukoreduction of erythrocyte units, use of male-only plasma, and restriction of erythrocyte storage age.
MyD88 and Trif Signaling Play Distinct Roles in Cardiac Dysfunction and Mortality during Endotoxin Shock and Polymicrobial Sepsis
Authors: Feng Yan , Zou Lin , Zhang Ming , Li Yan , Chen Chan , Chao Wei
Published: July 2011

Background

Toll-like receptors (TLRs) such as TLR2, TLR4, and TLR9 contribute to the pathogenesis of polymicrobial sepsis. These TLRs signal via the common myeloid differentiation factor 88 (MyD88)-dependent pathways. TLR4 also signals through MyD88-independent but TIR domain-containing adaptor inducing interferon-β-mediated transcription factor (Trif)-dependent pathway. The role of the two signaling pathways in cardiac dysfunction during polymicrobial sepsis and endotoxin shock is unknown.

Methods

Sepsis was generated by cecum ligation and puncture. Mice were divided into sham and cecum ligation and puncture groups or subjected to saline or endotoxin. Left ventricular function was assessed in a Langendorff apparatus or by echocardiography. Cytokines were examined using a multiplex immunoassay. Neutrophil migratory and phagocytic functions were assessed using flow cytometry.

Results

In comparison with wild-type mice, MyD88(-/-) but not Trif(-/-) mice had markedly improved cardiac function and survival after cecum ligation and puncture. In comparison, both MyD88(-/-) and Trif(-/-) mice were protected from cardiac depression and mortality during endotoxin shock. Septic MyD88(-/-) but not Trif(-/-) mice had diminished cytokine production in serum and in peritoneal space in comparison with wild-type mice after cecum ligation and puncture. In contrast, both MyD88(-/-) and Trif(-/-) mice had attenuated serum cytokines in comparison with wild-type mice after endotoxin challenge. Neither MyD88(-/-) nor Trif(-/-) signaling had any effect on neutrophil phagocytic function or bacterial clearance at 24 h of polymicrobial sepsis.

Conclusions

These studies establish that MyD88 but not Trif signaling plays a critical role in mediating cardiac dysfunction, systemic inflammation, and mortality during polymicrobial sepsis. Both MyD88 and Trif are essential for cardiac depression and mortality during endotoxin shock.
Free Cortisol and Accuracy of Total Cortisol Measurements in the Diagnosis of Adrenal Insufficiency in Brain-dead Patients
Authors: Nicolas-Robin Armelle , Barouk Jérome D. , Darnal Elsa , Riou Bruno , Langeron Olivier
Published: July 2011

Background

After brain death, adrenal insufficiency (AI) is very common and may be one of the mechanisms that contributes to hemodynamic instability and loss of potential organ donors. However, when diagnosed by total cortisol measurement, critically ill patients may be overdiagnosed as having AI. The aims of this study were to assess the prevalence of AI when diagnosed using free cortisol measurement and the accuracy of total cortisol measurement to diagnose AI in brain-dead patients.

Methods

All consecutive brain-dead patients were included in this single-center noninterventional clinical observation study. Assessment of adrenocorticotropin, corticosteroid-binding globulin, baseline and tetracosactin-stimulated serum free and total cortisol concentrations were performed. AI was defined as a baseline free cortisol concentration ≤ 55 nM(-1) and/or Δ free cortisol ≤ 55 nM(-1). Patients were considered to have a low albumin concentration if less than 25 g · L(-1) and a low corticosteroid-binding globulin concentration if less than 27 mg · L(-1) in men or 31 mg · L(-1) in women.

Results

Among the 42 included patients, the incidence of AI was 83% (95% CI, 69-93%). Baseline total cortisol was correlated with baseline free cortisol, whatever the albumin or corticosteroid-binding globulin concentration. The area under the receiver operating characteristic curve of baseline total cortisol measurement to diagnose AI was 0.94 (95% CI, 0.81-0.98). The optimal cutoff was 485 nM(-1), providing a sensitivity and a specificity of 89% and 100%, respectively.

Conclusion

Total baseline cortisol measurement is accurate and sufficient to diagnose AI in brain-dead patients, even if albumin or corticosteroid-binding globulin concentrations are low.
Acetylation of H2A.Z is a key epigenetic modification associated with gene deregulation and epigenetic remodeling in cancer
Authors: Valdés-Mora Fátima , Song Jenny Z. , Statham Aaron L. , Strbenac Dario , Robinson Mark D. , Nair Shalima S. , Patterson Kate I. , Tremethick David J. , Stirzaker Clare , Clark Susan J.
Published: July 2011

Histone H2A.Z (H2A.Z) is an evolutionarily conserved H2A variant implicated in the regulation of gene expression; however, its role in transcriptional deregulation in cancer remains poorly understood. Using genome-wide studies, we investigated the role of promoter-associated H2A.Z and acetylated H2A.Z (acH2A.Z) in gene deregulation and its relationship with DNA methylation and H3K27me3 in prostate cancer. Our results reconcile the conflicting reports of positive and negative roles for histone H2A.Z and gene expression states. We find that H2A.Z is enriched in a bimodal distribution at nucleosomes, surrounding the transcription start sites (TSSs) of both active and poised gene promoters. In addition, H2A.Z spreads across the entire promoter of inactive genes in a deacetylated state. In contrast, acH2A.Z is only localized at the TSSs of active genes. Gene deregulation in cancer is also associated with a reorganization of acH2A.Z and H2A.Z nucleosome occupancy across the promoter region and TSS of genes. Notably, in cancer cells we find that a gain of acH2A.Z at the TSS occurs with an overall decrease of H2A.Z levels, in concert with oncogene activation. Furthermore, deacetylation of H2A.Z at TSSs is increased with silencing of tumor suppressor genes. We also demonstrate that acH2A.Z anti-correlates with promoter H3K27me3 and DNA methylation. We show for the first time, that acetylation of H2A.Z is a key modification associated with gene activity in normal cells and epigenetic gene deregulation in tumorigenesis.
Purification and Biochemical Characterization of a Novel Ecto-Apyrase, MP67, from Mimosa pudica
Authors: Okuhata Riku , Takishima Takeshi , Nishimura Naoaki , Ueda Shogo , Tsuchiya Takahide , Kanzawa Nobuyuki
Published: July 2011

We have previously reported the presence of an apyrase in Mimosa pudica. However, only limited information is available for this enzyme. Thus, in this study, the apyrase was purified to homogeneity. The purified enzyme had a molecular mass of around 67 kD and was able to hydrolyze both nucleotide triphosphate and nucleotide diphosphate as substrates. The ratio of ATP to ADP hydrolysis velocity of the purified protein was 0.01 in the presence of calcium ion, showing extremely high substrate specificity toward ADP. Thus, we designated this novel apyrase as MP67. A cDNA clone of MP67 was obtained using primers designed from the amino acid sequence of trypsin-digested fragments of the protein. In addition, rapid amplification of cDNA ends-polymerase chain reaction was performed to clone a conventional apyrase (MpAPY2). Comparison of the deduced amino acid sequences showed that MP67 is similar to ecto-apyrases; however, it was distinct from conventional apyrase based on phylogenetic classification. MP67 and MpAPY2 were expressed in Escherichia coli, and the recombinant proteins were purified. The recombinant MP67 showed high substrate specificity toward ADP rather than ATP. A polyclonal antibody raised against the recombinant MP67 was used to examine the tissue distribution and localization of native MP67 in the plant. The results showed that MP67 was ubiquitously distributed in various tissues, most abundantly in leaves, and was localized to plasma membranes. Thus, MP67 is a novel ecto-apyrase with extremely high substrate specificity for ADP.
A comparison of pudendal block vs dorsal penile nerve block for circumcision in children: a randomised controlled trial
Authors: Naja Z. , Al‐Tannir M. A. , Faysal W. , Daoud N. , Ziade F. , El‐Rajab M.
Published: July 2011

We compared the analgesic and anaesthetic efficacy of pudendal nerve block with that of dorsal penile nerve block in male patients aged 3–5 years of age, undergoing elective circumcision. Thirty patients had a nerve stimulator‐guided pudendal nerve block with two separate injection points 1.5–2 cm from the centre of the anus, and thirty patients received a dorsal penile nerve block. The same total anaesthetic volume of 0.3 ml.kg−1 was used in both groups. The pudendal nerve group showed significantly lower postoperative pain scores than the dorsal group (SD) (p < 0.05), and significantly fewer patients consumed analgesics in the pudendal group than the dorsal group: 0 vs 5 (17%) at 0 and 6 h, respectively. This study demonstrates the effectiveness of pudendal nerve block in comparison to the dorsal nerve block, with improved postoperative outcomes in children undergoing circumcision.
The prevalence and association with transfusion, intensive care unit stay and mortality of pre‐operative anaemia in a cohort of cardiac surgery patients*
Authors: Hung M. , Besser M. , Sharples L. D. , Nair S. K. , Klein A. A.
Published: July 2011

Anaemia is increasingly prevalent in the United Kingdom. Despite recommendations to the contrary, many patients undergo cardiac surgery with undiagnosed and untreated anaemia. According to the World Health Organization definition, 1463/2688 (54.4%) patients undergoing cardiac surgery between 2008 and 2009 in our institution were anaemic. Compared with non‐anaemic patients, anaemia was significantly associated with transfusion (791 (54.1%) vs 275 (22.4%), p < 0.001, OR (95% CI) 3.4 (2.8–4.1)), death (45 (3.1%) vs 13 (1.1%), p = 0.0005, OR 2.4 (1.2–4.5)), and prolonged ICU stay (287 (19.6%) vs 168 (13.7%) p < 0.001, OR 1.3 (1.0–1.6)). The prevalence of anaemia in this cohort is much greater than that previously reported. The cause of this excess is not clear. Pre‐operative anaemia is a strong predictor of increased transfusion requirement, risk of ICU stay and death during cardiac surgery. The effect of increasing haemoglobin concentration therapeutically is not yet clear.
Con A‐binding protein Zn‐α2‐glycoprotein on human sperm membrane is related to acrosome reaction and sperm fertility
Authors: Liu Y. , Qu F. , Cao X. , Chen G. , Guo Q. , Ying X. , Guo W. , Lu L. , Ding Z.
Published: July 2011

Fertilization, the recognition and fusion between spermatozoa and oocyte, involves various molecules on the spermatozoa and oocyte membranes. Concanavalin A (ConA)‐binding proteins may be one of the molecules involved in mammal spermatozoa fertilization; however, their structure and function remain largely unknown. Here, we initially identified a ConA‐binding protein, Zn‐α2‐glycoprotein (ZAG), involved in regulating the acrosome reaction (AR) of human spermatozoa. ZAG is localized on the pre‐equatorial region covering the acrosome, neck and tail (some parts of middle piece and principal piece respectively) regions of the acrosome intact human spermatozoa, and disappears in the acrosomal region of the acrosome‐reacted spermatozoa. Polyclonal antibodies against human recombinant ZAG significantly reduced the AR and sperm capability binding to human zona pellucida or penetration into zona‐free hamster oocytes. Furthermore, assessment of the signaling pathways regulated by ZAG revealed that ZAG affects sperm AR through both the cAMP/PKA and PKC pathways. These results indicate that ZAG, which is present on the human sperm membrane, plays a critical role in the AR and subsequently, may be involved in sperm fertility.
Physicochemical properties, resistant starch content and enzymatic digestibility of unripe banana, edible canna, taro flours and their rice noodle products
Authors: Srikaeo Khongsak , Mingyai Sukanya , Sopade Peter A.
Published: July 2011

Unripe banana, edible canna and taro flours, which have been reported to contain significant amounts of fibre, were investigated for their physicochemical properties, resistant starch (RS) content and in vitro starch digestibility, and compared with commercial high‐fibre‐modified starches from corn and tapioca. Differential scanning calorimetry showed a single endothermic peak located around 70–83 °C for the samples except the modified starches, which exhibited no transition enthalpy. The samples showed different pasting behaviours in the Rapid Visco‐Analyser (RVA) ranging from full to restricted swelling. The RS content varied from 1–26 g per 100 g dry sample, and the estimated glycaemic indices (GIs) of the samples were from 67% to 99%. Generally, samples with high RS were low in GI values. The starches produced acceptable rice noodles but with reduced rate of starch digestion and GI. The effects of the unripe banana, edible canna and taro flours on starch digestibility were either comparable or better than the commercial modified starches. These flours can substitute commercial modified starches to lower GIs of noodles and identical foods.
The shifting nature of women’s experiences and perceptions of ductal carcinoma in situ
Authors: Kennedy Fiona , Harcourt Diana , Rumsey Nichola
Published: July 2011

kennedy f., harcourt d. & rumsey n. (2011) The shifting nature of women’s experiences and perceptions of ductal carcinoma in situ. Journal of Advanced Nursing 68(4), 856–867.

Aim.  This paper is a report of a descriptive qualitative study of the evolution of women’s perceptions and experiences of ductal carcinoma in situ from the period near to diagnosis to 1 year later.

Background.  Ductal carcinoma in situ is a non‐invasive breast condition where cancer cells are detected but confined to the ducts of the breast. With treatment, the condition has a positive prognosis but ironically patients undergo treatment similar to that for invasive breast cancer. There is a lack of longitudinal qualitative research studying women’s experiences of ductal carcinoma in situ, especially among newly diagnosed patients, and how experiences change over time.

Methods.  Forty‐five women took part in an initial interview following a diagnosis of ductal carcinoma in situ and 27 took part in a follow‐up interview 9–13 months later. Data were collected between January 2007 and October 2008. Transcripts were analysed using a hybrid approach to thematic analysis.

Findings.  Women’s early perceptions of ductal carcinoma in situ merged and sometimes conflicted with their lay beliefs of breast cancer. Perceptions and experiences of the condition shifted over time. These overriding aspects were evident in four themes identified across the interviews: (i) perceptions of ductal carcinoma in situ vs. breast cancer, (ii) from paradox to acceptance, (iii) personal impact, and (iv) support and interactions with others.

Conclusion.  This study represents one of the few longitudinal qualitative studies with newly diagnosed patients, capturing women’s initial and shifting experiences and perceptions of the condition. The issues identified need to be recognized in clinical practice and supported appropriately.
Why the Maternal Brain?
Authors: Kinsley C. H. , Amory‐Meyer E.
Published: July 2011

In the rat, the change from a virgin/nulliparous female to the maternal animal takes place at many levels. A subtle developmental wave washes over the female nervous system and transforms her from largely self‐centred to offspring‐directed, from personal care and protection to care of genetically‐related offspring, from indifference to ardour. Such change is preceded by substantial and apparently permanent neural alterations, the depth of which results in the maternal brain, and is the basis of the present review. The neuroplasticity of pregnancy, inherent to the female brain and, we believe, representative of the full expression of the female nervous system’s capacity, is a result of significant hormonal and other neurochemical actions. It results in the striking brain changes that are associated with, and necessary for, successful reproduction. We discuss some of these changes and their ramifications. Collectively, they represent the culmination of mammalian evolution and have led to the development of the social brain characteristic of higher orders of mammal, including the human. We also examine different facets of the maternal brain, beginning with a review of the genes involved in maternal behaviour, and in the subsequent ‘expression’ of the maternal brain. We next discuss olfaction and the manner in which this major sense draws from the rich sensory milieu of the mother to regulate and support maternal behaviour. Last, we discuss the ‘whys’ of maternal behaviour, a theoretical foray into the reasons for such substantial maternal brain alterations. We focus on the male’s potential role as theraison d’etrefor the manifest alterations in his mate’s brain. In the end, it is clear that the female brain undergoes a significant reorganisationen routeto motherhood, the results of which are deep and enduring.
A larger transcript is required for the synthesis of the smaller isoform of ferredoxin:NADP oxidoreductase
Authors: Omairi‐Nasser Amin , de Gracia Adrienne Gomez , Ajlani Ghada
Published: July 2011

Ferredoxin:NADP oxidoreductases (FNRs) constitute a family of flavoenzymes that catalyse the exchange of electrons between ferredoxin and NADP(H). In cyanobacteria FNR provides NADPH for photoautotrophic metabolism, but the enzyme is also capable of oxidizing NADPH providing reduced ferredoxin. In the cyanobacterium Synechocystis sp. strain PCC6803, the unique petH gene has two translation products depending on growth conditions. As a consequence two isoforms of the FNR accumulate – FNRL and FNRS. In the present work, analysis of petH expression reveals that different transcriptional start points (tsp) are responsible for this differential translation initiation. Under standard conditions (where FNRL accumulates), two tsps were found at −52 and −34 relative to the first translation start site. Under nitrogen‐starvation conditions (where FNRS accumulates) a tsp was mapped at −126 relative to the first translation start site. Therefore, the transcript responsible for FNRS translation is longer than that producing FNRL. In addition, expression of the short or long transcript in E. coli resulted in the accumulation of FNRL or FNRS respectively. This result demonstrates that translation can initiate at two different sites, 336‐bases apart (ATG‐1 to ATG‐113), depending only on the 5′UTR structure.
The Polymorphisms of C‐Reactive Protein Gene Modify the Association Between Central Obesity and Lung Function in Taiwan Asthmatics
Authors: Wang T.‐N. , Wu C.‐C. , Huang M.‐S. , Wang C.‐C. , Huang C.‐C. , Wang T.‐H. , Lien T.‐C. , Ko Y.‐C. , Lin M.‐C.
Published: July 2011

High‐sensitivity C‐reactive protein (hs‐CRP) concentrations and obesity are proposed to have a significant relationship with impairment of lung function, but little has been reported to date on the association between CRP gene and lung function. We studied the association of three tagSNPs (tag single nucleotide polymorphisms) of CRP gene and their interactions with central obesity on lung function. A total of 384 asthmatic adults and 384 controls who were 1:1 matched by sex and age were recruited for this study. Three tagSNPs polymorphisms for CRP rs1417938, rs1800947 and rs1205 were selected from HapMap data and genotyping by using TaqMan allelic discrimination assay. A questionnaire interview, body composition and pulmonary function tests were performed. CRP single nucleotide polymorphisms (SNPs) did not increase the risk of asthma, but CRP rs1205 CC genotype significantly decreased the predictive value of forced vital capacity (FVC) in the asthma group (adjusted mean change = −7.54%, 95% CI = −13.82 to −1.25%). Waist‐to‐hip ratio, not body mass index, also decreased the predictive value of FVC in asthmatics. The subjects with central obesity who carried CRP SNPs have a significant reduction effect in lung function. The current results suggest that central obesity may play a major role in lung function, and these effects were modified significantly by the polymorphisms for CRP gene.
Tumour Necrosis Factor Gene Polymorphism and Disease Prevalence
Authors: Qidwai T. , Khan F.
Published: July 2011

Tumour necrosis factor (TNF), an important proinflammatory cytokine, plays a role in the regulation of cell differentiation, proliferation and death, as well as in inflammation, innate and adaptive immune responses, and also implicated in a wide variety of human diseases. The presence of DNA sequence variations in regulatory region might interfere with transcription of TNF gene, influencing the circulating level of TNF and thus increases the susceptibility to human diseases (infectious, cancer, autoimmune, neurodegenerative and other diseases). In this review, we have comprehensively analysed various published case–control studies of different types of human diseases, in which TNF gene polymorphism played a role, and computationally predicted several single nucleotide polymorphisms (SNPs) lie in transcription factor–binding sites (TFBS) of transcription factors (TFs). It has been observed that TNF enhancer polymorphism is implicated in several diseases, and TNF rs1800629 and rs361525 SNPs are the most important in human disease susceptibility as these might influence the transcription of TNF gene. Thirty‐two SNPs lies in TFBS of 20 TFs have been detected in the TNF upstream region. It has been found that TNF enhancer polymorphism influences the serum level of TNF in different human diseases and thus affects the susceptibility to diseases. The presence of DNA sequence variation in TNF gene causes the modification of transcriptional regulation and thus responsible for association of susceptibility/resistance with human diseases.