Charge transfer mechanism and Tc(x) dependence in Y0.8(Ca)0.2Ba2Cu3O6+x

We propose a model for charge transfer mechanism in Y0.8(Ca)0.2Ba2Cu3O6+x to count hole doping of CuO2 planes and x dependence of critical transition temperature T_c. It is assumed the total number of doped holes in the planes is sum of holes that are introduced through two separate channels: substitution of Y3+ by Ca2+ and from CuO chains that are longer than a minimal (critical) length l_min needed for charge transfer to take place. The T_c(x) dependence is obtained by combining calculated x dependence of doping, p(x), and universal T_c versus p relation. Although calculated T_c(x) dependences for l_min=3 and l_min=4 both remarkably correlate to the experimental T_c(x), we argue that the value l_min=4 gives a reasonable overall agreement.Comment: Four pages of text, 2 figures, corrected typing error in abstract: Y2+ and Ca3+ replaced by Y3+ and Ca2+. Thw word "each" added in page 3, line 4. Accepted in Superconductor Science and Technology, on 07.Apr.2008, after having been considerably revise

Humanitarian aid for ethnic reconciliation

Mission: Promote rebuilding of a multi-ethnic society in rebrenica, Bosnia-Herzegovina Methods: The group organizes events to engage Clemson students to collect aid for the students in Srebrenica. This is a small city, which was the site of the genocide in 1995 and ethnically cleansed, and it is recovering very slowly. There is an effort to build ethnic tolerance and it starts with youth. The forms of aid have been determined based on their needs and our capability. Close relationship has been established with The House of Confidence, a local NGO in Srebrenica. Their work is focused on children and young people many of whom are thinking about leaving because of lack of jobs, and also ethnically motivated political struggles. This past May twelve suitcases filled with clothing, school supplies, and other necessities were transported to the town and handed out to different groups of children ages 5-teens. Conclusion: Our group hopes to shed light and expose the Clemson community to the Balkan region. We want to build support in Clemson for the people of Srebrenica

On the influence of the "donor"/"acceptor" presence on the excitation states in molecular chains: non-adiabatic polaron approach

In the paper, we considered a molecular structure that consists of a molecular chain and an additional molecule ("donor"/"acceptor") that can inject (or remove) single excitation (vibron, electron, e.t.c.) onto the molecular chain. We assumed that the excitation forms a self-trapped state due to the interaction with mechanical oscillations of chain structure elements. We analyzed the energy spectra of the excitation and showed that its state (when it migrates to the molecular chain) has the properties of the non-adiabatic polaron state. The conditions under which the excitation can migrate from one subsystem to another were considered. It was shown that the presence of a "donor" molecule cannot significantly change the properties of the excitation located on the molecular chain. At the same time, the molecular chain can affect the position of the energy level of the excitation localized on the "donor" subsystem. Indirectly, this can influence the process of excitation migration from one subsystem to another one. The influence of basic energy parameters of the system and the environment temperature on this process are discussed. The entire system was assumed to be in thermal equilibrium with the environment

The microRNA analysis portal is a next-generation tool for exploring and analyzing miRNA-focused data in the literature.

MicroRNAs constitute a class of noncoding small RNAs involved in the posttranscriptional regulation of many biological pathways. In recent years, microRNAs have also been associated with regulation across kingdoms, demonstrating that exogenous miRNAs can function in mammals in a fashion similar to mammalian miRNAs. The growing interest in microRNAs and the increasing amount of literature and molecular and biomedical data available make it difficult to identify records of interest and keep up to date with novel findings. For these reasons, we developed the microRNA Analysis Portal (MAP). MAP selects relevant miRNA-focused articles from PubMed, links biomedical and molecular data and applies bioinformatics modules. At the time of this writing, MAP represents the richest, most complete and integrated database focused on microRNAs. MAP also integrates an updated version of MirCompare (2.0), a computational platform used for selecting plant microRNAs on the basis of their ability to regulate mammalian genes. Both MAP and MirCompare functionalities were used to predict that microRNAs from Moringa oleifera have putative roles across kingdoms by regulating human genes coding for proteins of the immune system. Starting from a selection of 94 human microRNAs, MirCompare selected 6 Moringa oleifera functional homologs. The subsequent prediction of human targets and areas of functional enrichment highlighted the central involvement of these genes in regulating immune system processes, particularly the host-virus interaction processes in hepatitis B, cytomegalovirus, papillomavirus and coronavirus. This case of use showed how MAP can help to perform complex queries without any computational background. MAP is available at http://stablab.uniroma2.it/MAP

Observation of the onset of strong scattering on high frequency acoustic phonons in densified silica glass

The linewidth of longitudinal acoustic waves in densified silica glass is obtained by inelastic x-ray scattering. It increases with a high power alpha of the frequency up to a crossover where the waves experience strong scattering. We find that \alpha is at least 4, and probably larger. Resonance and hybridization of acoustic waves with the boson-peak modes seems to be a more likely explanation for these findings than Rayleigh scattering from disorder.Comment: 4 pages, 4 figures, to appear in Phys. Rev. Letter

Neural superposition and oscillations in the eye of the blowfly

Neural superposition in the eye of the blowfly Calliphora erythrocephala was investigated by stimulating single photoreceptors using corneal neutralization through water immersion. Responses in Large Monopolar Cells (LMCs) in the lamina were measured, while stimulating one or more of the six photoreceptors connected to the LMC. Responses to flashes of low light intensity on individual photoreceptors add approximately linearly at the LMC. Higher intensity light flashes produce a maximum LMC response to illumination of single photoreceptors which is about half the maximum response to simultaneous illumination of the six connecting photoreceptors. This observation indicates that a saturation can occur at a stage of synaptic transmission which precedes the change in the post-synaptic membrane potential. Stimulation of single photoreceptors yields high frequency oscillations (about 200 Hz) in the LMC potential, much larger in amplitude than produced by simultaneous stimulation of the six photoreceptors connected to the LMC. It is discussed that these oscillations also arise from a mechanism that precedes the change in the postsynaptic membrane potential.

Electro-Chemo-Mechanical Modeling of Artificial Solid Electrolyte Interphase to Enable Uniform Electrodeposition of Lithium Metal Anodes

Nonuniform electrodeposition of lithium during charging processes is the key issue hindering development of rechargeable Li metal batteries. This deposition process is largely controlled by the solid electrolyte interphase (SEI) on the metal surface and the design of artificial SEIs is an essential pathway to regulate electrodeposition of Li. In this work, an electro-chemo-mechanical model is built and implemented in a phase-field modelling to understand the correlation between the physical properties of artificial SEIs and deposition of Li. The results show that improving ionic conductivity of the SEI above a critical level can mitigate stress concentration and preferred deposition of Li. In addition, the mechanical strength of the SEI is found to also mitigate non-uniform deposition and influence electrochemical kinetics, with a Young\u27s modulus around 4.0\ua0GPa being a threshold value for even deposition of Li. By comparison of the results to experimental results for artificial SEIs it is clear that the most important direction for future work is to improve the ionic conductivity without compromising mechanical strength. In addition, the findings and methodology presented here not only provide detailed guidelines for design of artificial SEI on Li-metal anodes but also pave the way to explore strategies for regulating deposition of other metal anodes

In-Field LAMP Detection of Flavescence Dorée Phytoplasma in Crude Extracts of the Scaphoideus titanus Vector

One of the most destructive diseases affecting grapevine in Europe is caused by Flavescence Dorée phytoplasma (FDp), which belongs to the 16Sr-V group and is a European Union quarantine pathogen. Although many molecular techniques such as loop-mediated isothermal amplification (LAMP) are widely used for the rapid detection of FDp in infected grapevine plants, there is no developed isothermal amplification assay for FDp detection in the insect vectors that are fundamental for the spread of the disease. For this reason, a simple in-field real-time LAMP protocol was optimized and developed for the specific detection of FDp in the insect vector Scaphoideus titanus. The LAMP assay was optimized to work with crude insect extracts obtained by manually shaking a single insect in a buffer for 5 min. Such a simple, sensitive, specific, economic, and user-friendly LAMP assay allowed the detection of FDp in S. titanus in less than half an hour, directly in the field. The developed insect tissue preparation procedure, combined with the LAMP protocol, promptly revealed the presence of FDp in infected S. titanus directly in the vineyards, allowing for monitoring of the spread of the pathogen in the field and to apply timely strategies required for the mandatory control of this pathogen

EARLY DEVELOPMENT OF SYNCHRONY IN CORTICAL ACTIVATIONS IN THE HUMAN

Peer reviewe