Thermophysical and elastic properties of Cu50Zr50 and (Cu50Zr50)95Al5 bulk-metallic-glass-forming alloys

By employing a containerless high-temperature high-vacuum electrostatic levitation technique, the thermophysical properties, including the ratio between the specific heat capacity and the hemispherical total emissivity, the specific volume, and the viscosity, of Cu50Zr50 and (Cu50Zr50)95Al5 bulk-metallic-glass (BMG)-forming liquids have been measured. Compared with Cu50Zr50, the improved glass-forming ability of (Cu50Zr50)95Al5 can be attributed to its dense liquid structure and its high value of viscosity. Additionally, the relationship between the viscosity of various BMG forming liquids at the melting temperature and the elastic properties of the corresponding glasses at room temperature will be compared

Dynamics of axial separation in long rotating drums

We propose a continuum description for the axial separation of granular materials in a long rotating drum. The model, operating with two local variables, concentration difference and the dynamic angle of repose, describes both initial transient traveling wave dynamics and long-term segregation of the binary mixture. Segregation proceeds through ultra-slow logarithmic coarsening.Comment: 4 pages, 3 Postscript figures; submitted to PR

Effect of varying dietary zinc levels and environmental temperature on the growth performance, feathering score and feather mineral concentration in commercial broilers

This study aimed to investigate the effects of dietary zinc (Zn), environmental temperatures and Zn× temperature interaction on growth, feathering score and mineral composition of broilers. A total of 256 d-old Avian male broiler chicks were randomly allocated to a 4×2 factorial arrangement with four corn-soybean meal basal diets (containing 44 mg Zn/kg) supplemented with 0, 40, 60 mg/kg Zn (Diets 1, 2 and 3, respectively; 0.8% Ca for these three diets) and non-Zn supplementation, 1.6% Ca (Diet 4)and two temperature conditions (low: 26, 24, 22°C vs. high: 30, 28, 26°C). All birds were given feathering coverage scores for back, breast, wing, under-wing and tail. The wing and tail were further evaluated for the occurrence and severity of defect feathers. Feathers were then pooled for mineral composition analysis. The results showed that in high temp erature conditions, broilers fed Zn-unsupplemented, 0.8% Ca ration (Diet 1) had significantly(p<0.05) lower ADFI and ADG (wk 1-6) than birds under low temperature conditions. However, when the birds were fed 40 and 60 mg/kg Zn supplementation (Diets 2 and 3), the ADFI and ADG in both temperature conditions were not significantly different. In low temperature conditions, the ADFI, ADG (p<0.05), all feather coverage (p<0.01) and tail defect scores (p<0.001) of birds fed Diet 4 (excess Ca) were significantly poorer than those fed Diet 1. More Ca (p<0.05) was retained in the feathers of broilers fed Diet 4 under high temperature conditions. Broilers fed the Zn-unsupplemented ration (D iet 1) had significantly higher feather phosphorus (p<0. 01) and potassium (p<0.05) concentrations than those fed the 60 mg/kg Zn-supplemented ration (Diet 3). A reduction of feather phosphorus (p<0.01) and potassium (p<0.05) and higher manganese (p<0.05) concentrations were observed in Diet 4 broilers as compared to those fed Diet 1.Under high temperature conditions, broilers had lower iron (p<0.05) and higher manganese (p<0.05) concentrations in feathers. Broilers kept in high temperature conditions had a higher Zn requirement and 40 mg/kg Zn supplementation was sufficient for the birds to achieve optimum growth. Suppl emental Zn ameliorated the adverse effect of high temperature on growth and occurrence of tail feather defects. Excess Ca disrupted Zn metabolism to exert a detrimental effect on growth performance and normal feathering and this was elucidated in the birds kept in low temperature conditions

Traveling Granular Segregation Patterns in a Long Drum Mixer

Mixtures of granular media often exhibit size segregation along the axis of a partially-filled, horizontal, rotating cylinder. Previous experiments have observed axial bands of segregation that grow from concentration fluctuations and merge in a manner analogous to spinodal decomposition. We have observed that a new dynamical state precedes this effect in certain mixtures: bi-directional traveling waves. By preparing initial conditions, we found that the wave speed decreased with wavelength. Such waves appear to be inconsistent with simple PDE models which are first order in time.Comment: 11 page

Anti-tumor activity mediated by protein and peptide transduction of HIV viral protein R (Vpr)

Peptides that are capable of traversing the cell membrane, via protein transduction domains (PTDs), are attractive either directly as drugs or indirectly as carriers for the delivery of therapeutic molecules. One such PTD, a HIV-1 Tat derived peptide has successfully delivered a variety of "cargoes" including proteins, peptides and nucleic acids into cells. There also exists other naturally occurring membrane permeable peptides which have potential as PTDs. Specifically, one of the accessory proteins of HIV (viral protein R; i.e., Vpr), which is important in controlling viral pathogenesis, possesses cell transduction domain characteristics. Related to these characteristics, Vpr has also been demonstrated to induce cell cycle arrest and host/target cell apoptosis, suggesting a potential anticancer activity for this protein. In this report we assessed the ability of Vpr protein or peptides, with or without conjugation to a PTD, to mediate anti-cancer activity against several tumor cell lines. Specifically, several Vpr peptides spanning carboxy amino acids 65-83 induced significant (i.e., greater than 50%) in vitro growth inhibition/toxicity of murine B16.F10 melanoma cells. Likewise, in in vitro experiments with other tumor cell lines, conjugation of Vpr to the Tat derived PTD and transfection of this construct into cells enhanced the induction of in vitro apoptosis by this protein when compared to the effects of transfection of cells with unconjugated Vpr. These results underscore the potential for Vpr based reagents as well as PTDs to enhance anti-tumor activity, and warrants further examination of Vpr protein and derived peptides as potential therapeutic agents against progressive cell proliferative diseases such as cancer. ©2009 Landes Bioscience

Dynamic knowledge integration in socio-technical networks: an interpretive study of intranet use for knowledge integration

A major challenge facing firms competing in electronic business markets is the dynamic integration of knowledge within and beyond the firm, enabled by internet-based infrastructure and emergent fluid socio-technical networks. This paper explores how social actors dynamically employ intranets to integrate formal and informal knowledge within evolving socio-technical networks that emerge, permeate and extend beyond the organisational boundary. The paper presents two case studies that illustrate how static intranets can be useful for dynamically integrating knowledge when they are interwoven with other knowledge channels such as e-mail through which flows the informal knowledge needed to make sense of and situate formal organisational knowledge. The findings suggest that businesses should carefully examine how employees integrate intranets with other channels in their work, and the shaping of knowledge outcomes that flows from such use. There are practical implications for the proper skilling of thepeople who share and integrate knowledge in this way. The paper also provides a framework for dynamic knowledge integration in socio-technical networks, which can help underpin future research in this area.<br /

Esperanto for histones : CENP-A, not CenH3, is the centromeric histone H3 variant

The first centromeric protein identified in any species was CENP-A, a divergent member of the histone H3 family that was recognised by autoantibodies from patients with scleroderma-spectrum disease. It has recently been suggested to rename this protein CenH3. Here, we argue that the original name should be maintained both because it is the basis of a long established nomenclature for centromere proteins and because it avoids confusion due to the presence of canonical histone H3 at centromeres