Side-Jump Effect in Paramagnetic Amorphous Metals

Journals published by the American Physical Society can be found at http://journals.aps.org/A systematic study of the resistivity (rho), the Hall coefficients (R(H)), and the magnetic susceptibilities (chi) of the Zr-based paramagnetic amorphous alloys suggests a self-consistent explanation for the frequently observed positive values of R(H) that is based on. the side-jump effect. Measurements for chi, R(H), and rho of (Zr0.64Cu0.36)1-xAlx and chi for (Zr0.50Ni0.50)1-xAlx alloys are presented. The odd behavior of the Hall coefficients of these alloys and the anomalous positive Hall coefficients of paramagnetic Zr-based amorphous alloys can be accounted for in terms of the enhanced spin-orbit interaction, which produces the side-jump effect

Ubiquitin sets the timer: impacts on aging and longevity

Protein homeostasis is essential for cellular function, organismal growth and viability. Damaged and aggregated proteins are turned over by two major proteolytic routes of the cellular quality-control pathways: the ubiquitin-proteasome system and autophagy. For both these pathways, ubiquitination provides the recognition signal for substrate selection. This Commentary discusses how ubiquitin-dependent proteolytic pathways are coordinated with stress- and aging-induced signals

RNA Aptamers Generated against Oligomeric Aβ40 Recognize Common Amyloid Aptatopes with Low Specificity but High Sensitivity

Aptamers are useful molecular recognition tools in research, diagnostics, and therapy. Despite promising results in other fields, aptamer use has remained scarce in amyloid research, including Alzheimer's disease (AD). AD is a progressive neurodegenerative disease believed to be caused by neurotoxic amyloid β-protein (Aβ) oligomers. Aβ oligomers therefore are an attractive target for development of diagnostic and therapeutic reagents. We used covalently-stabilized oligomers of the 40-residue form of Aβ (Aβ40) for aptamer selection. Despite gradually increasing the stringency of selection conditions, the selected aptamers did not recognize Aβ40 oligomers but reacted with fibrils of Aβ40, Aβ42, and several other amyloidogenic proteins. Aptamer reactivity with amyloid fibrils showed some degree of protein-sequence dependency. Significant fibril binding also was found for the naïve library and could not be eliminated by counter-selection using Aβ40 fibrils, suggesting that aptamer binding to amyloid fibrils was RNA-sequence-independent. Aptamer binding depended on fibrillogenesis and showed a lag phase. Interestingly, aptamers detected fibril formation with ≥15-fold higher sensitivity than thioflavin T (ThT), revealing substantial β-sheet and fibril formation undetected by ThT. The data suggest that under physiologic conditions, aptamers for oligomeric forms of amyloidogenic proteins cannot be selected due to high, non-specific affinity of oligonucleotides for amyloid fibrils. Nevertheless, the high sensitivity, whereby aptamers detect β-sheet formation, suggests that they can serve as superior amyloid recognition tools

Sign Change of Hall-Coefficients for Amorphous Ni0.80-Xcrxp0.20 Alloys

Journals published by the American Physical Society can be found at http://journals.aps.org/The magnetic susceptibilities, resistivities, and Hall coefficients of amorphous Ni0.80-xCrxPo0.20 (0.00 less-than-or-equal-to x less-than-or-equal-to 0.40) alloys are reported. A sip change with temperature of the Hall coefficient for a single paramagnetic amorphous alloy that correlates with the temperature-dependent valence susceptibility has been observed (x = 0.20), indicating that an extraordinary contribution to R(H) is responsible for the positive Hall effect in these paramagnetic alloys. Also, an unexplained relatively large contribution to R(H) that is linear in T has been observed in some of these alloys. A gradual change in magnetic properties with composition from large cluster-dominant phase to Kondo-impurity phase has been observed

Surface modification with fibrin/hyaluronic acid hydrogel on solid-free form-based scaffolds followed by BMP-2 loading to enhance bone regeneration

Bone tissue engineering often requires a well-defined scaffold that is highly porous. The multi-head deposition system (MHDS), a form of solid freeform fabrication, has raised great interest as a method for fabricating scaffolds, since it yields a highly porous inter-connective structure without the use of cytotoxic solvents, and permits the diffusion of nutrients and oxygen. However, this method is not suitable for introducing proteins, as it includes a heating process. Hydrogels incorporated with protein coating of the scaffold surface could overcome this MHDS limitation. In the present study, the surface of a scaffold fabricated using MHDS was coated with a mixture of fibrin and hyaluronic acid (HA) and used as a vehicle for delivery of both bone morphogenetic protein-2 (BMP-2) and adipose-derived stromal cells (ASCs). Fibrin/HA coating of the scaffold significantly enhanced initial cell attachment. Furthermore, the in vitro release of BMP-2 from fibrin/HA-coated scaffolds was sustained for 3 days and it stimulated the alkaline phosphatase activity of ASCs seeded on the scaffold for 10 days more actively and continuously than did the soluble BMP-2 that was added to the culture media, not the scaffold itself. Importantly, the transplantation of undifferentiated ASCs inoculated on BMP-2-loaded, fibrin/HA-coated scaffolds resulted in more improved bone formation and mineralization than did the transplantation of undifferentiated ASCs seeded on uncoated scaffolds or on fibrin/HA-coated scaffolds without BMP-2, but containing BMP-2 in the cell suspension medium. These results show that BMP-2-loaded, fibrin/HA-coated scaffolds fabricated using MHDS may be useful in stimulating bone regeneration from undifferentiated ASCs in vivo. (C) 2010 Elsevier Inc. All rights reserved.X117671sciescopu

An Adenovirus-Vectored Nasal Vaccine Confers Rapid and Sustained Protection against Anthrax in a Single-Dose Regimen

Bacillus anthracis is the causative agent of anthrax, and its spores have been developed into lethal bioweapons. To mitigate an onslaught from airborne anthrax spores that are maliciously disseminated, it is of paramount importance to develop a rapid-response anthrax vaccine that can be mass administered by nonmedical personnel during a crisis. We report here that intranasal instillation of a nonreplicating adenovirus vector encoding B. anthracis protective antigen could confer rapid and sustained protection against inhalation anthrax in mice in a single-dose regimen in the presence of preexisting adenovirus immunity. The potency of the vaccine was greatly enhanced when codons of the antigen gene were optimized to match the tRNA pool found in human cells. In addition, an adenovirus vector encoding lethal factor can confer partial protection against inhalation anthrax and might be coadministered with a protective antigen-based vaccine