Detection of low-abundance protein phosphorylation by selective (18)o labeling and mass spectrometry

Reversible phosphorylation regulates the majority of intracellular networking and pathways. The study of this widely explored post-translational modification is usually challenged by low stoichiometric levels of modification. Many approaches have been developed to overcome this problem and to achieve rigorous characterization of protein phosphorylation. We describe a method for enhanced detection of low-abundance protein phosphorylation that uses selective introduction of (18)O label into phosphorylation sites with H(2)(18)O and mass spectrometric detection. The method was applied to introduce (18)O label into bacterially expressed Aurora A kinase phosphorylation sites and resulted in the representation of phosphorylated peptides as doublets or triplets according to the number of phosphate groups. A total of 28 phosphopeptides were observed by this method.     

Synthesis of conducting transparent few-layer graphene directly on glass at 450 °C

Post-growth transfer and high growth temperature are two major hurdles that research has to overcome to get graphene out of research laboratories. Here, using a plasma-enhanced chemical vapour deposition process, we demonstrate the large-area formation of continuous transparent graphene layers at temperatures as low as 450?°C. Our few-layer graphene grows at the interface between a pre-deposited 200 nm Ni catalytic film and an insulating glass substrate. After nickel etching, we are able to measure the optical transmittance of the layers without any transfer. We also measure their sheet resistance directly and after inkjet printing of electrical contacts: sheet resistance is locally as low as 500 Ω sq?1. Finally the samples equipped with printed contacts appear to be efficient humidity sensors.     

Changes in rumen bacterial and archaeal communities over the transition period in primiparous Holstein dairy cows

In the present study, we hypothesized that the rumen bacterial and archaeal communities would change significantly over the transition period of dairy cows, mainly as an adaptation to the classical use of low-grain prepartum and high-grain postpartum diets. Bacterial 16S rRNA gene amplicon sequencing of rumen samples from 10 primiparous Holstein dairy cows revealed no changes over the transition period in relative abundance of genera such as Ruminococcus, Butyrivibrio, Clostridium, Coprococcus, and Pseudobutyrivibrio. However, other dominant genus-level taxa, such as Prevotella, unclassified Ruminococcaceae, and unclassified Succinivibrionaceae, showed distinct changes in relative abundance from the prepartum to the postpartum period. Overall, we observed individual fluctuation patterns over the transition period for a range of bacterial taxa that, in some cases, were correlated with observed changes in the rumen short-chain fatty acids profile. Combined results from clone library and terminal-restriction fragment length polymorphism (T-RFLP) analyses, targeting the methyl-coenzyme M reductase α-subunit (mcrA) gene, revealed a methanogenic archaeal community dominated by the Methanobacteriales and Methanomassiliicoccales orders, particularly the genera Methanobrevibacter, Methanosphaera, and Methanomassiliicoccus. As observed for the bacterial community, the T-RFLP patterns showed significant shifts in methanogenic community composition over the transition period. Together, the composition of the rumen bacterial and archaeal communities exhibited changes in response to particularly the dietary changes of dairy cows over the transition period.     

Mobility impact in IEEE 802.11p infrastructureless vehicular networks

Vehicular ad hoc networks (VANETs) are an extreme case of mobile ad hoc networks (MANETs). High speed and frequent network topology changes are the main characteristics of vehicular networks. These characteristics lead to special issues and challenges in the network design, especially at the medium access control (MAC) layer. In this paper, we provide a comprehensive evaluation of mobility impact on the IEEE 802.11p MAC performance. The study evaluates basic performance metrics such as packet delivery ratio, throughput, and delay. An unfairness problem due to the relative speed is identified for both broadcast and unicast scenarios. We propose two dynamic contention window mechanisms to alleviate network performance degradation due to high mobility. The first scheme provides dynamic level of service priority via adaptation to the number of neighboring nodes, while the second scheme provides service priority based on node relative speed. Extensive simulation results demonstrate a significant impact of mobility on the IEEE 802.11p MAC performance, the unfairness problem in the vehicle-to-vehicle (V2V) communications, and the effectiveness of the proposed MAC schemes.     

Surface enhanced Raman scattering of neurotransmitter release in neuronal cells using antibody conjugated gold nanoparticles

This study demonstrated the potential feasibility of using antibody-conjugated gold nanoparticles as highly sensitive and homogeneous sensing probes for biological monitoring of neurotransmitters in neuronal cells. Bands at 1152 and 1322 cm(-1) were also similar to SERS of metal catecholates, and could be assigned to catechol ring vibration and carbon-oxygen stretches.     

Fabrication of nanoconcave surface for cell immobilization in cell-based chip

Nanostructured surface such as nanoconcave shape can be utilized as a bioplatform to immobilize cells. In this study, we present fabrication of Au-coated nanoconcave surface and some possibility of cell immobilization. Long-range ordered periodic patterns with concave shape were formed on aluminum substrate by electrochemical anodization process. The morphology and topography of nanoconcave surface was investigated by atomic force microscopy and scanning electron microscopy. The pore-pore distance and the pore depth of nanoconcave pattern were measured at 105 +/- 5 nm and 30 +/- 2 nm, respectively. After Au deposition, the pore depth within Au-coated concave surface was 15 +/- 2 nm. The topography of HeLa cells immobilized on the nanoconcave surface was observed by AFM combined with confocal microscopy. The result expected that the Au-coated nanoconcave surface may be used as new culture substrate for cells immobilization in cell-based chip.     

Electrochemical sensor to detect neurotransmitter using gold nano-island coated ITO electrode

Parkinson disease is a chronic neurodegenerative disorder characterized by the loss of dopamine, which is a neurotransmitter in the substantia nigra. In this study, a simple, rapid and inexpensive method to fabricate gold nano-island film (GNIF) coated ITO electrode has been developed based on electrochemical deposition of Au onto ITO substrate. The nanostructured film surface was characterized by scanning electron microscopy (SEM). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to evaluate the electrochemical behavior of induvidul dopamine and uric acid solution were studied. Moreover, GNIF/ITO electrode was applied to detecte DA in the presence of Bovine Serum Albumin (50 microM) as an interference. These results demonstrate that, interfering component has no effect on the determination of DA at GNIF electrode, hence this GNIF electrode is suitable for the determination of DA with high sensitivity and selectivity. Then, GNIF coated ITO electrode was applied to monitor the electrochemical simultaneous detection of dopamine and uric acid mixtures based on CV and DPV with high sensitivity. GNIF-modified ITO electrode showed a linear range for the determination of dopamine concentration from 0.1 microM to 40 microM in the presence of 50 microM of uric acid. Based on these results, the proposed technique can be a promising method to construct a highly sensitive biosensor as well as highly efficient protein chip.     

Surface-enhanced Raman scattering of dopamine on self-assembled gold nanoparticles

Dopamine, a potent neurotransmitter in the brain, influences a variety of motivated behaviors and plays a major role in Parkinson's disease. In this study, the Raman signal of dopamine was detected on a fabricated nanoparticle-immobilized glass surface by surface-enhanced raman spectroscopy (SERS). Amine-modified glass was prepared by the self-assembly of amine-terminated silane on substrate, followed by the deposition of gold nanoparticles. The gold nanoparticles deposited on the glass surface were functionalized by anti-dopamine or dopamine. The antigen-dopamine was captured by antibody-assembled gold substrate and detected by SERS. The optical properties and morpology of the glass substrate with immobilized gold nanoparticles were analyzed by scanning electron microscopy and UV-VIS absorption spectroscopy. The Raman spectrum of dopamine displayed broad bands at 1267, 1331, 1158, 1478, 1578 and 1584 cm(-1). The strongest peaks in the spectra (at 1267 and 1478 cm(-1)) were identified as phenolic carbon-oxygen and phenyl C=C stretches, respectively. A working curve of the SERS signal constructed from cathecol ring vibration versus antigen-dopamine concentration was obtained at 1478 cm(-1), and the non-optimized detection limit for anti-dopamine surface antigen was as low as 1 ng/ml. These results suggest that SERS-based immunosensor can be a promising tool for the detection and screening of neurotransmitters.     

Synthesis and characterization of PVA/YBCO nanocomposite for improvement of solar energy conversion

The development of nano‐metal oxide materials with unique optoelectronic properties such as highly solar energy absorption and generation of dense amount of electrons is one of the hottest topics now days. The incorporation of these nanomaterials into polymers results in an improvement of the properties of these polymers. Therefore, the understanding of their electronic properties is an essential demand to introduce these nanocomposites into service life. In this work, Yttrium barium copper oxide (YBCO) nanopowders with a uniform particle size of around 11 nm was prepared, sintered, and blended with polyvinyl alcohol (PVA) by casting technique. The characteristics of the structure and morphology of PVA/YBCO nanocomposite films are studied using X‐ray diffraction and transmission electron microscopy. The influence of YBCO nanoparticles on the thermal stability of PVA showed that the YBCO enhanced the thermal stability and reduced the rate of thermal degradation of PVA nanocomposites. Current–voltage behavior of PVA/YBCO nanocomposite films was measured at different temperatures. An explanation for the charge carrier concentration in the conduction band with the calculation of the barrier height, activation energy, and conversion and their dependence on temperature and applied field is presented.POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers     

The metamorphosis of the urban fabric in Arab-Muslim City: Riyadh, Saudi Arabia

Saudi Arabia has experienced rapid growth inurban development since the 1960s. This urbangrowth is not based on the traditional urbanplanning principles which have been followed inSaudi Arabia for many centuries. Instead,various imported urban forms and planningregulations have been implemented in thecountry. These relate neither to thetraditional built environment and culture norto the local climate of the city. As a result,major cultural and climatic problems haveoccurred. The aim of this paper is to identify andanalyze the types of built environment inRiyadh, as an example of Saudi Arabia's cities,and discuss the cultural conflicts resultingfrom the use of imported planning principlesand regulations. In light of this analysis anddiscussion, the planning regulations will bereviewed and recommendations will be made foramendments.