Effects of silicon on mechanical properties of AM60 magnesium alloy

Silicon was added to improve the tensile, wear and creep behaviors of AM60 magnesium alloy in this study. The investigation has been undertaken by means of universal testing machine, HBE-3000A Brinell hardness tester, M-2000 friction-wear machine, DMA-Q800 creep machine, optical microscopy (OM) and scanning electron microscopy (SEM). The results indicate that the Chinese script type Mg2Si particles are formed by adding Si into the AM60 magnesium alloy. The ultimate tensile strength and hardness of the AM60 magnesium alloy increases with the Si addition, and the ultimate tensile strength and hardness of the AM60+1.0wt.%Si alloy are increased by 12% and 19.8%, respectively in comparison with that of the AM60 magnesium alloy. The wear property and the high temperature creep property of the AM60 magnesium alloy are also improved with Si addition. The wear mechanisms of the AM60 and AM60+1.0wt.%Si alloys are adhesive wear and abrasion wear, respectively. While, the elongation of the AM60 magnesium alloy decreases with the addition of Si. The optimum Si addition content is 1.0wt.%

Genome-wide screen for modifiers of Parkinson's disease genes in Drosophila

<p>Abstract</p> <p>Background</p> <p>Mutations in <it>parkin </it>and <it>PTEN-induced kinase 1 </it>(<it>Pink1) </it>lead to autosomal recessive forms of Parkinson's disease (PD). <it>parkin </it>and <it>Pink1 </it>encode a ubiquitin-protein ligase and a mitochondrially localized serine/threonine kinase, respectively. Recent studies have implicated Parkin and Pink1 in a common and evolutionarily conserved pathway for protecting mitochondrial integrity.</p> <p>Results</p> <p>To systematically identify novel components of the PD pathways, we generated a genetic background that allowed us to perform a genome-wide F1 screen for modifiers of <it>Drosophila parkin </it>(<it>park</it>) and <it>Pink1 </it>mutant phenotype. From screening ~80% of the fly genome, we identified a number of cytological regions that interact with <it>park </it>and/or <it>Pink1</it>. Among them, four cytological regions were selected for identifying corresponding PD-interacting genes. By analyzing smaller <it>deficiency </it>chromosomes, available transgenic RNAi lines, and P-element insertions, we identified five PD-interacting genes. Among them, <it>opa1 </it>and <it>drp1 </it>have been previously implicated in the PD pathways, whereas <it>debra (dbr), Pi3K21B </it>and <it>β4GalNAcTA </it>are novel PD-interacting genes.</p> <p>Conclusions</p> <p>We took an unbiased genetic approach to systematically isolate modifiers of PD genes in <it>Drosophila</it>. Further study of novel PD-interacting genes will shed new light on the function of PD genes and help in the development of new therapeutic strategies for treating Parkinson's disease.</p

The SH2/SH3 Adaptor Protein Dock Interacts with the Ste20-like Kinase Misshapen in Controlling Growth Cone Motility

AbstractRecent studies suggest that the SH2/SH3 adaptor Dock/Nck transduces tyrosine phosphorylation signals to the actin cytoskeleton in regulating growth cone motility. The signaling cascade linking the action of Dock/Nck to the reorganization of cytoskeleton is poorly understood. We now demonstrate that Dock interacts with the Ste20-like kinase Misshapen (Msn) in the Drosophila photoreceptor (R cell) growth cones. Loss of msn causes a failure of growth cones to stop at the target, a phenotype similar to loss of dock, whereas overexpression of msn induces pretarget growth cone termination. Physical and genetic interactions between Msn and Dock indicate a role for Msn in the Dock signaling pathway. We propose that Msn functions as a key controller of growth cone cytoskeleton in response to Dock-mediated signals

N-Benzyl­idenenordehydro­abietylamine

The title compound [systematic name: (1R,4aS,10aR,E)-N-benzyl­idene-7-isopropyl-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octa­hydro­phenanthren-1-amine], C26H33N, has been synthesized from nor-dehydro­abietylamine and benzaldehyde. The two cyclo­hexane rings form a trans ring junction with classic chair and half-chair conformations, respectively, the two methyl groups are on the same side of tricyclic hydro­phenanthrene structure. The dihedral angle between two benzene rings is 44.2 (4)°. The C=N bond is in an E configuration

The R Coronae Borealis stars - carbon abundances from forbidden carbon lines

Spectra of several R Coronae Borealis (RCB) stars at maximum light were examined for the [C I] 9850 A and 8727 A absorption lines. The 9850 A line is variously blended with a Fe II and CN lines but positive identifications of the [C I] line are made for R CrB and SU Tau. The 8727 A line is detected in the spectrum of the five stars observed in this wavelength region. Carbon abundances are derived from the [C I] lines using the model atmospheres and atmospheric parameters used by Asplund et al. (2000). Although the observed strength of a C I line is constant from cool to hot RCB stars, the strength is weaker than predicted by an amount equivalent to a factor of four reduction of a line's gf-value. Asplund et al. dubbed this 'the carbon problem' and discussed possible solutions. The [C I] 9850 A line seen clearly in R CrB and SU Tau confirms the magnitude of the carbon problem revealed by the C I lines. The [C I] 8727 A line measured in five stars shows an enhanced carbon problem. The gf-value required to fit the observed [C I] 8727 A line is a factor of 15 less than the well-determined theoretical gf-value. We suggest that the carbon problem for all lines may be alleviated to some extent by a chromospheric-like temperature rise in these stars. The rise far exceeds that predicted by our non-LTE calculations, and requires a substantial deposition of mechanical energy.Comment: 11 pages (embedded 5 figures and 3 tables), accepted for publication in MNRA

Bringing E-Government into the Classroom: A Case of E-Commerce Education

The paper discusses a novel educational initiative in e-commerce pedagogy where students work on an e-government project. The paper describes a two-semester joint e-government project conducted by the town of Amherst, NY, and the State University of New York at Buffalo. During the first semester, students in a graduate e-commerce course in the School of Management were instructed to identify and analyze management issues valuable for small or middle size local government. In the second semester graduate students from the Department of Computer Science and Engineering designed and implemented prototypes of three e-government portals: an on-line action site for governmental procurement (E-Procurement), a portal for reservation of community recreation facilities (E-Recreation), and a portal for online dog registration (E-DogRegistration) combining a central registry of dog owners with distributed veterinarian databases. The objective of this initiative is twofold. First, it saves the local government resources by eliminating duplication of services and by using students as developers. Second, it provides students with real life hands-on experience. The paper discusses both the technical issues involved in the implementation of the project, and the management issues that need to be taken into account to enhance the e-commerce experience for the ordinary citizen and local governments