bluuebunny/crossref_metadata_2025 huggingface dataset:
Nuclear factor κB (NF-κB) activation primes cells to a pro-inflammatory polarized response to a Toll-like receptor 7 (TLR7) agonist
Authors: Lee Jongdae , Hayashi Masaaki , Lo Jeng-Fan , Fearns Colleen , Chu Wen-Ming , Luo Yunping , Xiang Rong , Chuang Tsung-Hsien
Published: May 2009

TLR7 (Toll-like receptor 7) mediates anti-viral immunity by recognizing ssRNA (single-stranded RNA) viruses. Small-molecular-mass TLR7 agonists have been approved, or are being evaluated, for treatment of cancers or infectious diseases. Although TLR7 is predominantly expressed in a restricted set of immune cell types, including pDCs (plasmacytoid dendritic cells), it is also expressed in non-native expressing cells (e.g. hepatocytes) under certain circumstances. To elucidate the molecular basis of TLR7 induction by pro-inflammatory stimulation and the subsequent cellular responses in these non-native TLR7-expressing cell types, we first cloned and characterized the 5′-promoter region of TLR7. The proximal region of this promoter drives the transcription of the TLR7 gene. Pro-inflammatory stimuli activated TLR 7 transcription via a NF-κB (nuclear factor κB)-binding motif in this region, and this activation could be blocked by mutation of the NF-κB binding site or addition of NF-κB inhibitors. Further studies showed that pretreatment of the Hep3B hepatocytes with TNF-α (tumour necrosis factor-α) or IL-1 (interleukin-1) rendered them responsive to TLR7 activation by a TLR7 agonist. However, distinct from TLR7 activation in pDCs, which respond to stimulation with Th1 polarized cytokine production, TLR7 induction by pro-inflammatory signals in hepatocytes reconstitutes the NF-κB-dependent cascade but not the IRF7 (interferon regulatory factor 7)-dependent cascade, resulting in a pro-inflammatory polarized response rather than a Th1 polarized response. These results indicate that inflammatory stimulation is capable of priming cells to respond to TLR7 agonist with an immune response that differs from that in native TLR7-expressing cells.
The carbohydrate-binding domain on galectin-1 is more extensive for a complex glycan than for simple saccharides: implications for galectin–glycan interactions at the cell surface
Authors: Miller Michelle C. , Nesmelova Irina V. , Platt David , Klyosov Anatole , Mayo Kevin H.
Published: May 2009

gal-1 (galectin-1) mediates cell–cell and cell–extracellular matrix adhesion, essentially by interacting with β-galactoside-containing glycans of cell-surface glycoconjugates. Although most structural studies with gal-1 have investigated its binding to simple carbohydrates, in particular lactose and N-acetyl-lactosamine, this view is limited, because gal-1 functions at the cell surface by interacting with more complex glycans that are heterogeneous in size and composition. In the present study we used NMR spectroscopy to investigate the interaction of human gal-1 with a large (120 kDa) complex glycan, GRG (galactorhamnogalacturonate glycan), that contains non-randomly distributed mostly terminal β(1→4)-linked galactose side chains. We used 15N–1H-HSQC (heteronuclear single quantum coherence) NMR experiments with 15N-enriched gal-1 to identify the GRG-binding region on gal-1 and found that this region covers a large surface area on gal-1 that includes the quintessential lactose-binding site and runs from that site through a broad valley or cleft towards the dimer interface. HSQC and pulsed-field-gradient NMR diffusion experiments also show that gal-1 binds GRG with a gal-1:GRG stoichiometry of about 5:1 (or 6:1) and with average macroscopic and microscopic equilibrium dissociation constants (Kd) of 8×10−6 M and 40×10−6 M (or 48×10−6 M) respectively, indicating stronger binding than to lactose (Kd=520×10−6 M). Although gal-1 may bind GRG in various ways, the glycan can be competed for by lactose, suggesting that there is one major mode of interaction. Furthermore, even though terminal motifs on GRG are Gal-β(1→4)-Gal rather than the traditional Gal-β(1→4)-Glc/GlcNAc (where GlcNAc is N-acetylglucosamine), we show that the disaccharide Gal-β(1→4)-Gal can bind gal-1 at the lactose-binding domain. In addition, gal-1 binding to GRG disrupts inter-glycan interactions and decreases glycan-mediated solution viscosity, a glycan decongestion effect that may help explain why gal-1 promotes membrane fluidity and lateral diffusion of glycoconjugates within cell membranes. Overall, our results provide an insight into the function of galectin in situ and have potential significant biological consequences.
Antiparallel β-sheet: a signature structure of the oligomeric amyloid β-peptide
Authors: Cerf Emilie , Sarroukh Rabia , Tamamizu-Kato Shiori , Breydo Leonid , Derclaye Sylvie , Dufrêne Yves F. , Narayanaswami Vasanthy , Goormaghtigh Erik , Ruysschaert Jean-Marie , Raussens Vincent
Published: May 2009

AD (Alzheimer's disease) is linked to Aβ (amyloid β-peptide) misfolding. Studies demonstrate that the level of soluble Aβ oligomeric forms correlates better with the progression of the disease than the level of fibrillar forms. Conformation-dependent antibodies have been developed to detect either Aβ oligomers or fibrils, suggesting that structural differences between these forms of Aβ exist. Using conditions which yield well-defined Aβ-(1–42) oligomers or fibrils, we studied the secondary structure of these species by ATR (attenuated total reflection)–FTIR (Fouriertransform infrared) spectroscopy. Whereas fibrillar Aβ was organized in a parallel β-sheet conformation, oligomeric Aβ displayed distinct spectral features, which were attributed to an antiparallel β-sheet structure. We also noted striking similarities between Aβ oligomers spectra and those of bacterial outer membrane porins. We discuss our results in terms of a possible organization of the antiparallel β-sheets in Aβ oligomers, which may be related to reported effects of these highly toxic species in the amyloid pathogenesis associated with AD.
Non-esterified fatty acids increase arterial pressure via central sympathetic activation in humans
Authors: Florian John P. , Pawelczyk James A.
Published: May 2009

Previous studies have shown that acute increases in plasma NEFAs (non-esterified fatty acids) raise SVR (systemic vascular resistance) and BP (blood pressure). However, these studies have failed to distinguish between CNS (central nervous system) mechanisms that raise sympathetic activity and paracrine mechanisms that increase SVR directly, independent of CNS involvement. The aim of the present study was to directly determine whether the sympathetic nervous system contributes to the pressor response to NEFAs. On 2 days separated by at least 2 weeks, 17 lean healthy volunteers (ten male/seven female; age, 22±1 years; body mass index, 23±1 kg/m2; values are means±S.E.M.) received a 4-h intravenous infusion of 20% Intralipid® or placebo (in a single-blind randomized balanced order). MSNA (muscle sympathetic nerve activity), HR (heart rate), BP (oscillometric brachial measurement) and (cardiac output; acetylene rebreathing) were measured before and throughout infusion. The change in HR (+8.2±1.0 and +2.4±1.2 beats/min), systolic BP (+14.0±1.6 and +3.2±2.5 mmHg) and diastolic BP (+8.2±1.0 and −0.1±1.7 mmHg) were significantly greater after the 4-h infusion of Intralipid® compared with placebo (P<0.001). The change in BP with Intralipid® resulted from an increase in SVR (/mean arterial pressure; P<0.001) compared with baseline, without a change in . MSNA burst frequency increased during Intralipid® infusion compared with baseline (+4.9±1.3 bursts/min; P<0.05), and total MSNA (frequency×amplitude) was augmented 65% (P<0.001), with no change during placebo infusion. Lipid infusion increased insulin, aldosterone and F2-isoprostane, but not leptin, concentrations. On the basis of the concomitant increase in BP, MSNA and SVR, we conclude that central sympathetic activation contributes to the pressor response to NEFAs.
Schottky-Ohmic transition in metal-all-around electrical contacts to silicon nanowires
Authors: Wang Zhong-Rui , Zhang Gang , Pey Kin-Leong , Tung Chih-Hang , Lo Guo-Qiang
Published: May 2009

In this paper, systematic study on electrical contacts to silicon nanowires (SiNWs) is performed using a developed Schottky barrier simulator. At room temperature, the SiNW-metal contact is always characterized by Schottky behaviors, with the barrier height exhibiting a minimum at a diameter of about 4 nm. At ultralow temperature of 138 K, a Schottky-Ohmic transition is found in SiNW, which originates from the limited extent of the depletion region in SiNW as a result of its small geometrical dimension. The generality of diameter dependent barrier heights for different material configurations, impacts of doping in SiNW, and interfacial oxide layer between the metal and SiNW is also studied to understand the influence of the SiNW size on the contact properties including Schottky barrier height, band profile, and specific contact resistance.
Spin-glasslike behavior of K+-containing α-MnO2 nanotubes
Authors: Luo J. , Zhu H. T. , Zhang F. , Liang J. K. , Rao G. H. , Li J. B. , Du Z. M.
Published: May 2009

Magnetic properties of K+-containing α-MnO2 nanotubes have been systematically investigated by dc magnetic measurements. Zero-field-cooled and field-cooled susceptibilities display divergences at low temperature, and a spin-glass temperature of 33.1 K is determined from the de Almedia–Thouless line by extrapolating the applied field to zero. The dc magnetic measurements, such as the field dependent magnetic susceptibility, hysteresis effect, thermoremanent magnetization, and memory effect, further confirm the spin-glass feature of the tetragonal α-MnO2 sample, which can be attributed to the geometrical frustration on the triangular lattices and the mixed valence of Mn3+ and Mn4+.
Particle migration and suspension structure in steady and oscillatory plane Poiseuille flow
Authors: Yapici K. , Powell R. L. , Phillips R. J.
Published: May 2009

A structure-tensor-based model is used to compute the microstructure and velocity field of concentrated suspensions of hard spheres in a fully developed, pressure-driven channel flow. The model is comprised of equations governing conservation of mass and momentum in the bulk suspension, conservation of particles, and conservation of momentum in the particle phase. The equations governing the relation between structure and stress in hard-sphere suspensions were developed previously and were shown to reproduce quantitatively results obtained by Stokesian dynamics simulations of linear shear flows. In nonhomogeneous, pressure-driven flows, the divergence of the particle contribution to the stress is nonzero and acts as a body force that causes particles to migrate across streamlines. Under steady conditions, the model predicts that the resulting migration causes particles to move to the center of the channel, where the concentration approaches the maximum packing for hard-sphere suspensions. In oscillatory flow, the behavior depends strongly on the amplitude of the strain. For oscillations with large strains, the particles migrate to the channel center. However, when the strain is small, the maximum concentration is located either at a position between the channel center and walls or, in the limit of very small strains, at the wall. The migration to the wall induced by small-strain oscillation occurs in conjunction with the suspension microstructure becoming ordered. This behavior agrees qualitatively with experimental observations reported in the literature. However, the predicted rate of migration toward the wall in the simulations is significantly slower than what is observed experimentally.
Silicon nanowire sensors for Hg2+ and Cd2+ ions
Authors: Luo Linbao , Jie Jiansheng , Zhang Wenfeng , He Zhubing , Wang Jianxiong , Yuan Guodong , Zhang Wenjun , Wu Lawrence Chi Man , Lee Shuit-Tong
Published: May 2009

High-sensitivity detection of toxic heavy metal cations such as Hg2+ and Cd2+ ions was demonstrated using single silicon nanowire field-effect transistors (SiNW-FETs). The conduct-ance of FET fabricated from thermally oxidized SiNWs functionalized with 3-mercaptopropyltriethoxysilane showed high sensitivity to Hg2+ and Cd2+ ions at a concentration down to 10−7 and 10−4M, respectively. Linear relationship between the logarithmic concentration of metal ions and the current change was observed. The SiNW sensor could be recycled to regain nearly the same sensitivity. Comparative experiments showed that SiNW-FET sensors have great selectivity for detecting Hg2+ and Cd2+ over other metal cations.
Quasi-one-dimensional kinetic theory model of laser ablation of carbon
Authors: Shusser Michael
Published: May 2009

The paper compares the predictions of the quasi-one-dimensional and one-dimensional kinetic theory models of laser ablation of carbon based on the moment solution of the Boltzmann equation for arbitrary strong evaporation. The quasi-one-dimensional model still assumes one-dimensional flow but tries to account for more realistic spatial distribution of the laser intensity. Both models estimate the total ablated mass reasonably well. However, comparison of the predictions of the models shows that the pure one-dimensional results represent spatially averaged values that ignore considerable radial nonuniformity existing in the physical situation. The radial motion due to this nonuniformity can be accounted only in the full two-dimensional calculation.
Temperature dependence of the O+I(P21/2)→O+I(P23/2) quenching rate constant
Authors: Mikheyev Pavel A. , Postell David J. , Heaven Michael C.
Published: May 2009

The rate constant for quenching of I(P21/2) by O(P3) has been measured for the temperature range 295–360 K. Pulsed laser photolysis of mixtures N2O and I2 was used to examine the kinetics. O(P3) atoms were produced by the photoinitiated reaction sequences N2O+hν→O(D1)+N2 and O(D1)+M→O(P3)+M, while singlet oxygen was generated by the secondary reaction O(D1)+N2O→O2(a 1Δ)+N2. Iodine atoms were produced by I2 photodissociation and from the secondary reactions of I2 with O(P3) atoms. Subsequent excitation of I by O2(a Δ1) led to I(P21/2) formation, with I(P21/2) concentrations monitored using time-resolved 1315 nm emission. The rate constant of the quenching process was determined by fitting a kinetic model to the observed emission traces. Special attention was given to the gas flow conditions. A modest temperature dependence of the quenching rate constant was found, and this was well represented by the equation k=(6.5±1)×10−12(T/300)1.76 cm3 s−1. The room temperature rate constant differs from previous experimental determinations but agrees well with the value determined by modeling of the data from discharge driven oxygen-iodine lasers.
Electronic structure and exciton states in the freestanding ZnO nanorods
Authors: Xiong Wen , Li Shu-Shen
Published: May 2009

The electronic structure and exciton states of cylindrical ZnO nanorods with radius from 2 to 6 nm are investigated based on the framework of the effective-mass theory. Using the adiabatic approximation, the exciton binding energies taking account of the dielectric mismatch are solved exactly when the total angular momentum of the exciton states L=0 and L=±1. We find that the exciton binding energies can be enhanced greatly by the dielectric mismatch and the calculated results are almost consistent with the experimental data. Meanwhile, we obtain the optical transition rule when the small spin-obit splitting Δso of ZnO is neglected. Furthermore, the radiative lifetime and linear optical susceptibilities χ(w) of the exciton states are calculated theoretically. The theoretical results are consistent with the experimental data very well.
On the importance of nuclear quantum motions in near edge x-ray absorption fine structure spectroscopy of molecules
Authors: Schwartz Craig P. , Uejio Janel S. , Saykally Richard J. , Prendergast David
Published: May 2009

We report the effects of sampling nuclear quantum motion with path integral molecular dynamics (PIMD) on calculations of the nitrogen K-edge spectra of two isolated organic molecules. s-triazine, a prototypical aromatic molecule occupying primarily its vibrational ground state at room temperature, exhibits substantially improved spectral agreement when nuclear quantum effects are included via PIMD, as compared to the spectra obtained from either a single fixed-nuclei based calculation or from a series of configurations extracted from a classical molecular dynamics trajectory. Nuclear quantum dynamics can accurately explain the intrinsic broadening of certain features. Glycine, the simplest amino acid, is problematic due to large spectral variations associated with multiple energetically accessible conformations at the experimental temperature. This work highlights the sensitivity of near edge x-ray absorption fine structure (NEXAFS) to quantum nuclear motions in molecules, and the necessity of accurately sampling such quantum motion when simulating their NEXAFS spectra.
Static analysis of possible emittance growth of intense charged particle beams with thermal equilibrium distribution
Authors: Kikuchi Takashi , Horioka Kazuhiko
Published: May 2009

Possible emittance growths of intense, nonuniform beams during a transport in a focusing channel are derived as a function of nonlinear field energy and space charge tune depression factors. The nonlinear field energy of the beam with thermal equilibrium distribution is estimated by considering the particle distribution across the cross section of the beam. The results show that the possible emittance growth can be suppressed by keeping the beam particle in thermal equilibrium distribution during the beam transport.
Effect of impurity molecules on the low-temperature vibrational dynamics of polyisobutylene: Investigation by single-molecule spectroscopy
Authors: Eremchev I. Yu. , Naumov A. V. , Vainer Yu. G. , Kador L.
Published: May 2009

The influence of impurity chromophore molecules—tetra-tert-butylterrylene (TBT) and dibenzo-anthanthrene (DBATT)—on the vibrational dynamics of the amorphous polymer polyisobutylene (PIB) has been studied via single-molecule spectroscopy. The measurements were performed in the temperature region of 7–30 K, where the interaction of the chromophores with quasilocalized low-frequency vibrational modes (LFMs) determines the observed spectral line broadening. The analysis of the individual temperature dependences of the linewidths for a large number of single probe molecules yielded effective frequency values of those LFMs which are located near the respective chromophores. In this way the distributions of the LFM frequencies were measured for the two systems, and they were found to be similar. Moreover, they are in good agreement with the vibrational density of states as measured in pure PIB by inelastic neutron scattering. This allows us to conclude that, at least in the case of PIB, doping with low concentrations of the nonpolar and neutral molecules TBT and DBATT does not affect the vibrational dynamics of the matrix markedly.
Surface charge density of the track-etched nanopores in polyethylene terephthalate foils
Authors: Xue Jianming , Xie Yanbo , Yan Yu , Ke Jin , Wang Yugang
Published: May 2009

Surface charge is one of the most important properties of nanopores, which determines the nanopore performance in many practical applications. We report the surface charge densities of track-etched nanopores, which were obtained by measuring the streaming current and pore conductance, respectively. Experimental results reveal that surface charge densities depend significantly on the salt concentrations. In addition the values obtained with the pore conductance were always several times higher than those calculated with the streaming current, and the gel-like surface layer on the nanopore was considered to be responsible for this discrepancy.
Effects of enhanced cathode electron emission on Hall thruster operation
Authors: Raitses Y. , Smirnov A. , Fisch N. J.
Published: May 2009

Interesting discharge phenomena are observed that have to do with the interaction between the magnetized Hall thruster plasma and the neutralizing cathode. The steady-state parameters of a highly ionized thruster discharge are strongly influenced by the electron supply from the cathode. The enhancement of the cathode electron emission above its self-sustained level affects the discharge current and leads to a dramatic reduction in the plasma divergence and a suppression of large amplitude, low frequency discharge current oscillations usually related to an ionization instability. These effects correlate strongly with the reduction in the voltage drop in the region with the fringing magnetic field between the thruster channel and the cathode. The measured changes in the plasma properties suggest that the electron emission affects the electron cross-field transport in the thruster discharge. These trends are generalized for Hall thrusters of various configurations.
Solute dispersion in channels with periodically varying apertures
Authors: Bolster Diogo , Dentz Marco , Le Borgne Tanguy
Published: May 2009

We study solute dispersion in channels with periodically varying apertures. Based on an approximate analytical solution of the flow equation, we study the impact of the geometry and molecular diffusion on effective solute dispersion analytically using the method of local moments. We also study the problem numerically using a random walk particle tracking method. For transport in parallel shear flow, the effective dispersion coefficient is dependant on the square of the Peclet number. Here, when the fluctuation of the channel aperture becomes comparable with the channel width, the effective dispersion coefficients show a more complex dependence on the Peclet number and the pore geometry. We find that for a fixed flow rate, periodic fluctuations of the channel aperture can lead to both a decrease and an increase in effective dispersion.
Semiclassical description of vibrational quantum coherence in a three dimensional I2Arn (n≤6) cluster: A forward-backward initial value representation implementation
Authors: Tao Guohua , Miller William H.
Published: May 2009

The semiclassical (SC) initial value representation (IVR) has been applied to describe true quantum coherence effects in a complex molecular system in full three dimensional space. The specific quantity considered is the time-dependent probability distribution of the I2 vibrational coordinate following photoexcitation of I2 in a rare gas cluster. The “forward-backward” version of the IVR method is shown to be capable of capturing detailed quantum coherence in this quantity, coherence that cannot be described by a classical Wigner model (which is equivalent to a linearized approximation to the more general SC-IVR). Solvent effects on this vibrational quantum coherence have also been investigated for a I2Arn (n=1,6) cluster. A solvent cage consisting of six argon atoms reduces the fraction of iodine molecules that dissociate (an example of the “cage effect”) and also diminishes, but does not entirely eliminate, quantum coherence in the vibrational motion of the molecules that remain undissociated.
Coarse-grained description of localized inelastic deformation in amorphous metals
Authors: Demetriou Marios D. , Johnson William L. , Samwer Konrad
Published: May 2009

The sequence of shear transformation events that lead to a shear band transition in amorphous metals is described by a spatially random coarse-grained model calibrated to obey the thermodynamic scaling relations that govern flow in a real glass. The model demonstrates that shear banding is a consequence of local shear transformation events that self-organize along planes of maximum resolved shear stress to form extended bands of highly localized deformation. This description suggests that shear band formation is incipient during the early stages of deformation of a randomly inhomogeneous material.
First-principles prediction of mechanical properties of gamma-boron
Authors: Jiang Chao , Lin Zhijun , Zhang Jianzhong , Zhao Yusheng
Published: May 2009

The structural and mechanical properties of γ-B28 are investigated using first-principles density functional calculations. The single-crystal elastic constants calculations show that γ-B28 is mechanically stable under ambient conditions. The predicted bulk and shear moduli of γ-B28 are comparable to those of boron suboxide, suggesting that γ-B28 can be a superhard material. We also obtained the ideal tensile strength for γ-B28 through deformation from the elastic regime to structural instability. We find that the breaking of B1–B1 and B1–B2 bonds is responsible for the failure of γ-B28 under ⟨100⟩ and ⟨010⟩ tensile deformation, respectively.
Improved semipolar (112¯2) GaN quality using asymmetric lateral epitaxy
Authors: de Mierry P. , Kriouche N. , Nemoz M. , Nataf G.
Published: May 2009

Semipolar (112¯2) GaN films were obtained by epitaxial lateral overgrowth from (112¯2) GaN templates patterned with SiO2 stripes 7 μm wide with 3 μm spacing, oriented along the [11¯00] GaN in-plane direction. The growth conditions were optimized in order to promote a fast growth rate along the +c [0001] direction. The crystal expands both laterally and vertically until a situation where it overgrows the adjacent crystal, thus stopping the propagation of stacking faults and threading dislocations. The growth anisotropy and filtering of defects is observed by cross-sectional scanning electron microscopy and cathodoluminescence. The lowering of defect density is confirmed by x-ray diffraction measurements. The photoluminescence spectrum of the coalesced epitaxial lateral overgrowth of the (112¯2) epilayers exhibits a strong band edge emission and a low emission band at 3.41 eV, assigned to the remaining stacking faults.
A model of Sn whisker growth by coupled plastic flow and grain boundary diffusion
Authors: Buchovecky Eric J. , Du Ningning , Bower Allan F.
Published: May 2009

Finite element simulations are used to calculate the rate of whisker growth due to intermetallic formation in a Sn film with columnar grain structure on a Cu substrate. The simulations account for plastic flow by dislocation motion within the grains, as well as diffusion along grain boundaries. Grains with a slightly lower yield stress than their neighbors are shown to act as sinks for material and are progressively extruded from the film. A simple analytical model is developed to estimate the resulting whisker growth rate, and is shown to be in good agreement with experimental measurements.
Effect of rheological properties on drag reduction in turbulent boundary layer flow
Authors: Tamano Shinji , Itoh Motoyuki , Hotta Shintaro , Yokota Kazuhiko , Morinishi Yohei
Published: May 2009

Direct numerical simulation of a zero-pressure gradient drag-reducing turbulent boundary layer of viscoelastic fluids was systematically performed at the momentum-thickness Reynolds number Reθ0=500 and Weissenberg number We=25 using constitutive equation models such as the Oldroyd-B, the finitely extensible nonlinear elastic Peterlin model at the maximum chain extensibility parameters L2=100, 1000, and 10 000, and the Giesekus model at the mobility factors α=0.01, 0.001, and 0.0001, where the ratios of solvent viscosity to zero shear rate solution viscosity, β, were 0.9, 0.99, and 0.999. For the case that the elongational viscosity for the steady elongational flow was identical, the streamwise variation in the drag reduction (DR) was thoroughly investigated, and then the effects of rheological properties such as the elongational and shear viscosities and the first and the second normal stress differences on DR were clarified. It is found that the streamwise profile of DR shifts downstream with the decrease in the first normal stress difference. The shear-thinning property and the first normal stress difference slightly affect the maximum DR, while the decrease in the magnitude of the second normal stress difference results in the decrease in the maximum DR.
Brahman and Brahman crossbred cattle grown on pasture and in feedlots in subtropical and temperate Australia. 2. Meat quality and palatability
Authors: Schutt K. M. , Burrow H. M. , Thompson J. M. , Bindon B. M.
Published: May 2009

Market demand for a reliable supply of beef of consistently high eating quality led the Cooperative Research Centre for Cattle and Beef Industry (Meat Quality) to initiate a crossbreeding progeny test program to quantify objective and sensory meat quality differences between straightbred and first-cross Brahman cattle. Brahman, Belmont Red, Santa Gertrudis, Angus, Hereford, Shorthorn, Charolais and Limousin sires were mated to Brahman females over 3 years to produce 1346 steers and heifers in subtropical northern Australia. Calves were assigned within sire by age and weight to one of three market endpoints (domestic, Korean or Japanese), one of two finishing environments (subtropical or temperate) and one of two finishing diets (pasture or feedlot). Average carcass weights were 227, 288 and 327 kg for domestic, Korean and Japanese markets respectively. Only steers were finished for the Japanese market. The effects of sire breed, finishing regime, market endpoint and sex on sensory meat quality of four attributes score (CMQ4), ossification score and Warner-Bratzler shear force (SF), instron compression (IC), ultimate pH and percent cooking loss (CL) on the M. longissimus thoracis et lumborum (LT) and M. semitendinosus (ST) were determined. Straightbred Brahmans had the highest SFLT (5.39 ± 0.07; P < 0.001), ICLT (1.89 ± 0.02; P < 0.05) and CL in both muscles (P < 0.05). Straightbred Brahmans were the only genotype that failed to meet minimum CMQ4 grading standards (38.3; P < 0.001). Progeny with up to 75% Brahman content successfully met minimum objective and sensory meat quality consumer thresholds for tenderness (IC <2.2 kg, SF <5.0 kg; CMQ4 >46.5). There was little difference between crossbred progeny for most meat quality traits. All feedlot-finished animals were slaughtered at domestic, Korean and Japanese market weights by 24 months of age, with minimal differences in objective measures of meat quality between markets. The IC measures for all sire breeds were below 2.2 kg, indicating connective tissue toughness was not an important market consideration in feedlot-finished animals slaughtered by 24 months of age. Pasture finishing adversely affected all meat quality traits (P < 0.001) except CLST, with Korean and Japanese market animals having unacceptably tough SF, IC and CMQ4 measures. This was attributed to their older age at slaughter (31 and 36 months respectively), resulting from their seasonally interrupted growth path. While domestic animals slaughtered at 25 months of age off pasture had unacceptably high SF and IC, CMQ4 was acceptable. Subtropical feedlot animals had slightly more desirable (n.s.) SF and IC relative to temperate feedlot animals, whereas temperate feedlot animals had higher CMQ4 (P < 0.001). Genotype × environment interactions were not important.
Effect of postweaning growth and bulls selected for extremes in retail beef yield and intramuscular fat on progeny liveweight and carcass traits
Authors: Graham J. F. , Byron J. , Clark A. J. , Kearney G. , Orchard B.
Published: May 2009

The present study is a component of a multi-site experiment, using Bos taurus cattle generated at four locations across southern Australia, designed to examine postweaning growth pathways for progeny whose sires were extreme in retail beef yield and intramuscular fat. Treatment and interaction effects on beef production and meat quality were examined within and across sites. The present paper describes the effect of postweaning growth and sire carcass type on liveweight and carcass traits at the Hamilton site. Angus sires selected on estimated breeding values for extremes in retail beef yield (RBY%), intramuscular fat (IMF%) (estimated breeding values for IMF% are derived by using live-animal ultrasound scanning) or both and sire breed types considered to be more extreme in those traits (Limousin, and Belgian Blue for yield, and Wagyu for intramuscular fat) were joined to crossbred and straight-bred cows. After weaning, the resultant 645 steer and heifer progeny were grown on a fast and slow growth path to ~550 kg and slaughtered, averaging 0.68 kg/day and 22.2 months, and 0.49 kg/day and 27.8 months for growth rate and age at slaughter, respectively. Growth path, sire carcass type and sex affected carcass traits; however, there were no sire carcass type by growth treatment interactions. The fast growth-path cattle were fatter, had more intramuscular fat (measured chemically), a higher Meat Standards of Australia (MSA) USA and AUS marble score, and a higher predicted MSA eating-quality score. Progeny of Wagyu sires were lighter at weaning and slaughter and had a lower hot standard carcass weight than the other sire carcass types. The Belgian Blue and Limousin progeny had a higher dressing percentage, a higher RBY% and a lower P8 and rib-fat depth and lower IMF% than the other sire breed types. Progeny of the high RBY% Angus had a lower rib-fat depth, a lower IMF% and higher RBY% than those selected for high IMF%. There was no difference in IMF% between the Wagyu or the high IMF% Angus. Progeny from the Belgian Blue, Limousin and Wagyu had a larger eye muscle area than the other sire breeds. The results indicate that simultaneous selection for supposedly antagonistic traits of IMF% and RBY% would result in carcass having high values of both measurements. Females were lighter than steers at slaughter, had a lower hot standard carcass weight, were fatter at the P8 and rib, and had a higher marble score and IMF%, a lower yield and a lower MSA-predicted eating-quality score than did steers. There was no interaction between postweaning growth and sire carcass type. These results indicate that with the use of appropriate sire carcass types and BREEDPLAN, and post-weaning nutrition, beef producers can confidently change carcass parameters to suit market specifications.
Performance of steer progeny of sires differing in genetic potential for fatness and meat yield following postweaning growth at different rates. 2. Carcass traits
Authors: McKiernan W. A. , Wilkins J. F. , Irwin J. , Orchard B. , Barwick S. A.
Published: May 2009

The steer progeny of sires genetically diverse for fatness and meat yield were grown at different rates from weaning to feedlot entry and effects on growth, carcass and meat-quality traits were examined. The present paper, the second of a series, reports the effects of genetic and growth treatments on carcass traits. A total of 43 sires, within three ‘carcass class’ categories, defined as high potential for meat yield, marbling or both traits, was used. Where available, estimated breeding values for the carcass traits of retail beef yield (RBY%) and intramuscular fat (IMF%) were used in selection of the sires, which were drawn from Angus, Charolais, Limousin, Black Wagyu and Red Wagyu breeds, to provide a range of carcass sire types across the three carcass classes. Steer progeny of Hereford dams were grown at either conventional (slow: ~0.5 kg/day) or accelerated (fast: ~0.7 kg/day) rates from weaning to feedlot entry weight, with group means of ~400 kg. Accelerated and conventionally grown groups from successive calvings were managed to enter the feedlot at similar mean feedlot entry weights at the same time for the 100-day finish under identical conditions. Faster-backgrounded groups had greater fat levels in the carcass than did slower-backgrounded groups. Dressing percentages and fat colour were unaffected by growth treatment, whereas differences in ossification score and meat colour were explained by age at slaughter. There were significant effects of sire type for virtually all carcass traits measured in the progeny. Differences in hot standard carcass weight showed a clear advantage to European types, with variable outcomes for the Angus and Wagyu progeny. Sire selection by estimated breeding values (within the Angus breed) for yield and/or fat traits resulted in expected differences in the progeny for those traits. There were large differences in both meat yield and fatness among the types of greatest divergence in genetic potential for those traits, with the Black Wagyu and the Angus IMF clearly superior for IMF%, and the European types for RBY%. The Angus IMF progeny performed as well as that of the Black Wagyu for all fatness traits. Differences in RBY% among types were generally reflected by similar differences in eye muscle area. Results here provide guidelines for selecting sire types to target carcass traits for specific markets. The absence of interactions between growth and genetic treatments ensures that consistent responses can be expected across varying management and production systems.
Biogeography of theSulfolobus islandicuspan-genome
Authors: Reno Michael L. , Held Nicole L. , Fields Christopher J. , Burke Patricia V. , Whitaker Rachel J.
Published: May 2009

Variation in gene content has been hypothesized to be the primary mode of adaptive evolution in microorganisms; however, very little is known about the spatial and temporal distribution of variable genes. Through population-scale comparative genomics of 7Sulfolobus islandicusgenomes from 3 locations, we demonstrate the biogeographical structure of the pan-genome of this species, with no evidence of gene flow between geographically isolated populations. The evolutionary independence of each population allowed us to assess genome dynamics over very recent evolutionary time, beginning ≈910,000 years ago. On this time scale, genome variation largely consists of recent strain-specific integration of mobile elements. Localized sectors of parallel gene loss are identified; however, the balance between the gain and loss of genetic material suggests thatS. islandicusgenomes acquire material slowly over time, primarily from closely relatedSulfolobusspecies. Examination of the genome dynamics through population genomics inS. islandicusexposes the process of allopatric speciation in thermophilic Archaea and brings us closer to a generalized framework for understanding microbial genome evolution in a spatial context.
Rigidity percolation and the spatial heterogeneity of soft modes in disordered materials
Authors: de Souza Vanessa K. , Harrowell Peter
Published: May 2009

We show how the spatial character of unconstrained motion in a network of bonds can be directly inferred from the topological arrangement of constraints. Relaxation time scales of these soft modes are determined, and from this information we generate spatial maps of the heterogeneous distribution of relaxation times in the disordered network. We show that the nature of the dynamic heterogeneity and its sensitivity to changes in bond configuration depends dramatically on the proximity of the system to the rigidity percolation point.
Re-thinking balanced bilingualism
Authors: Juarros-Daussà Eva , Lanz Tilman
Published: May 2009

Traditionally, Catalonia is seen as a successful example of language revitalization, through the achievement and maintenance of a fairly stable Castilian/Catalan bilingualism for the last thirty years or so. Recently, however, Catalonia has experienced significant immigration in the context of globalization. The autonomous government is now supporting an agenda in which Catalan alone is presented as the national language, the language of convergence, while Castilian, despite its long historical presence in the region, is portrayed as one of three hundred languages spoken there today. We examine how this policy interacts with everyday linguistic realities and with a preservationist agenda. Catalan speakers are divided between those who feel liberated from the imposition of Spanish identity and culture and those who fear an exclusivist nationalism which they feel would be anachronistic in the globalized world of today. Spanish speakers, in turn, feel threatened and targeted. New immigrants, coming from all corners of the world, are caught in a climate in which official language policies hardly reflect their own needs. Linguistic policies have to be re-thought to tend to the needs of immigrants while also ensuring the survival of Catalan.
Irish and Scottish Gaelic
Authors: Ó Riain Seán
Published: May 2009

This survey discusses the motives and consequences of the 13 June 2005 decision to include Irish among the EU’s official and working languages, and the 15 July 2008 decision to upgrade the status of languages recognised by law in the UK, such as Welsh and Scottish Gaelic. It also looks at the current state of Irish and Scottish Gaelic. Irish’s new EU status coincides with increased support at the top political level in Ireland. A tentative conclusion is that this happy coincidence could enhance the practical role of Irish, which in turn could exercise a knock-on positive effect on Scottish Gaelic. The continuing decrease in the use of Irish by young people in the Gaeltacht (Irish speaking regions), due to the unrelenting pressure of English, is a matter for deep concern, as is the failure of the authorities over many years to appreciate that language use, and not just language learning, needs to be planned. This may now be changing: expanded use of Irish in the electronic media, the structures put in place by the Official Languages Act of 2003, and Irish Government work on a 20-year strategic plan for Irish, together with continuing progress at EU level, give grounds for hope. To sum up: much has been done, but much remains to be done.
Tending to the “Native Word”: Teachers and the Soviet Campaign for Ukrainian-Language Schooling, 1923–1930
Authors: Pauly Matthew D.
Published: May 2009

In the 1920s, the Ukrainian Commissariat of Education and a circle of progressive educators aimed to radically transform the educational system in Ukraine, and, as a consequence, the skills and mentality of its graduates. To do this, they would have to teach students in a language they understood. For nearly three-quarters of the juvenile population of Ukraine, this meant instruction in Ukrainian. Although this may have sounded like a simple proposition, it was not. Throughout the pre-revolutionary period, schools had educated Ukrainian children in Russian, and teachers, regardless of their ethnicity, were trained and accustomed to teaching in it. Pre-revolutionary publications, still widely used in Soviet schools, and even the early Soviet primers were overwhelmingly written in Russian. Ukrainian national leaders had made an attempt to set up a network of Ukrainian-language schools during the country's short-lived period of independence, but their attempts were disrupted by the chaos of civil war and the fall of successive governments. It was under Soviet patronage that the “Ukrainization” of the schools reached its greatest extent; however, it was an achievement that required effort, and real qualitative change in the language of instruction was gradual.
Public Service Provision in a Failed State: Looking Beyond Predation in the Democratic Republic of Congo
Authors: Trefon Theodore
Published: May 2009

‘The state is dying but not yet dead’ and ‘the state is so present, but so useless’ are also commonly heard refrains. These popular sentiments, inexorably expressed in all of the country's languages by the poor and the well-to-do, have been described by development experts and political scientists as state failure. But why is the state still so powerful and omnipresent in the daily lives of these people wronged by colonial oppression, dictatorship, economic underdevelopment and more recently, unresolved political transition? How, concretely, does the state manifest itself? Does theraison d’êtreof the Congolese state go beyond the violence of exploitation and predation? The objective of this article is to respond to these questions, contributing to our understanding of the function and dysfunction of the Congolese state, notably during the post-Mobutu transition.
The End of a ‘Special Relationship’? The New EU–ACP Economic Partnership Agreements
Authors: Flint Adrian
Published: May 2009

The WTO-sanctioned waiver for the extension of the Lomé system of preferences to the African, Caribbean Pacific (ACP) countries expired in December 2007. This deadline coincided with the scheduled conclusion of the EU–ACP Economic Partnership Agreement (EPA) negotiations, initiated in 2002. The origins of the EU–ACP relationship stretch back to the early days of the European Community, and were formalised in 1975 with the signing of the Georgetown Agreement. However, there has been a notable ‘cooling’ of the relationship since the signing of the Cotonou Partnership Agreement in 2000. For many, the new EPA framework is perceived as a diktat rather than a true partnership agreement. This article reviews the culmination of six years of talks between the two sides and the EU's apparent ‘rationalisation’ of a decades-old partnership.
The Political Economy of Nigeria's Post-military Elections, 1999–2007
Authors: Amuwo Adekunle
Published: May 2009

This article is a structural and empirical analysis of the interface between the economics and the politics of elections in post-military Nigeria. Structures and strictures of contemporary economic globalisation and market reforms have weakened nationalistic fractions of the state/political elite, led to the emergence of a largely externally-oriented national bourgeoisie and virtually removed politics from the public sphere. The result has been the increased alienation of the popular classes from politics and the apparent inability of the state/political elite to satisfactorily deal with this alienation. Market reforms during the Obasanjo years, 1999–2007, fuelled astonishing corporate and private profit for transnational capital and the state/political elite through the misuse and abuse of the oil industry. The character of the superintending state, the democracy it purveyed and the elections it organised were anything but redemptive. This article makes a case for a democracy with social relevance through the agency of political struggles whose objective will be to recover the state and politics from the stranglehold of globalisation-induced structural relations of power; they should be re-inserted into the public space where they really belong and used for public purposes such as social justice, credible and legitimate elections and participatory democracy.
Echoes of Divergence Within: The Politics and Politicisation of Nigeria's Debt Relief
Authors: Nwozor Agaptus
Published: May 2009

Nigeria has been weighed down over the years by a huge debt overhang and has had to contend with several reform programmes prescribed by the multilateral institutions of the IMF and the World Bank. Ordinary people, especially women, children and the under-privileged, have been the worst victims of the fallout from these reforms. Recently, Nigeria was granted debt relief to the tune of US$18 billion by the Paris Club of creditors, with the proviso that the country would pay a total of US$12 billion of its remaining debt, in two equal instalments, within a specified period to the Club. Nigeria has since met this obligation and exited from the Paris Club debt trap. However, debt relief, which ought to have elicited public gratitude, instead unleashed a wave of cynicism. Opposition to the relief package emanated from popular perception of the Paris Club members as institutional loan sharks and authors of the gross contradictions in the Nigerian economy. This article distils these contradictory opinions. It argues that the optimism which the Paris Club of creditors expressed in their press release, and which the Nigerian Government holds as a sacred economic truth, namely that the debt trade-off would free resources for the rapid development of Nigeria, was hopeful at best and manipulative at worst.