Effect of graphene substrate on the SERS Spectra of Aromatic bifunctional molecules on metal nanoparticles

The design of molecular sensors plays a very important role within nanotechnology and especially in the development of different devices for biomedical applications. Biosensors can be classified according to various criteria such as the type of interaction established between the recognition element and the analyte or the type of signal detection from the analyte (transduction). When Raman spectroscopy is used as an optical transduction technique the variations in the Raman signal due to the physical or chemical interaction between the analyte and the recognition element has to be detected. Therefore any significant improvement in the amplification of the optical sensor signal represents a breakthrough in the design of molecular sensors. In this sense, Surface-Enhanced Raman Spectroscopy (SERS) involves an enormous enhancement of the Raman signal from a molecule in the vicinity of a metal surface. The main objective of this work is to evaluate the effect of a monolayer of graphene oxide (GO) on the distribution of metal nanoparticles (NPs) and on the global SERS enhancement of paminothiophenol (pATP) and 4-mercaptobenzoic acid (4MBA) adsorbed on this substrate. These aromatic bifunctional molecules are able to interact to metal NPs and also they offer the possibility to link with biomolecules. Additionally by decorating Au or Ag NPs on graphene sheets, a coupled EM effect caused by the aggregation of the NPs and strong electronic interactions between Au or Ag NPs and the graphene sheets are considered to be responsible for the significantly enhanced Raman signal of the analytes [1-2]. Since there are increasing needs for methods to conduct reproducible and sensitive Raman measurements, Grapheneenhanced Raman Scattering (GERS) is emerging as an important method [3].Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Smartphones in the teaching of Physics Laws: Projectile motion

New technologies are called upon to play an important role as beneficial tools for meaningful learning in the classroom. In particular, smartphones can be regarded as pocket computers that, in addition to a remarkable memory and computing capacity, incorporate sensors such as accelerometers, gyroscopes, magnetometers, light sensors, etc., which turn them into easily available measurement instruments for practical classes in an educational environment. In this study, the suitability of these devices for demonstrating Classical Mechanics, minimizing the use of resources and class time, has been assessed in two real classrooms (with 16 to 19 year-old students) by conducting experiments related to projectile motion (vertical free fall and parabolic motion). A simple methodology that only involves a mobile phone, a free burst camera application and open-source tools (GIMP and OpenOffice Calc) for data processing is presented. The results obtained in non-perfected conditions led to an estimate of the acceleration of gravity with an error lower than 2%. Further analyses and alternative procedures are also suggested in the discussion section. No major difficulties were encountered with the high school students or with the first year university ones, and a high degree of satisfaction was found

Relationships between Water Status, Leaf Chlorophyll Content and Photosynthetic Performance in Tempranillo Vineyards

The aims of this work were (i) to study the relationships between leaf water potential, foliar chlorophyllcontent and photosynthetic performance of grapevines under field conditions, and (ii) to evaluate thefeasibility of chlorophyll fluorescence parameters to assess water status in commercial vineyards. Duringthree consecutive seasons (2011 to 2013), 20 non-irrigated “Tempranillo” vineyard subzones were monitoredin Ribera del Duero, Spain. Data on foliar chlorophyll content, midday and predawn leaf water potential,net assimilation and chlorophyll fluorescence parameters were measured at fruit set, pre-véraison andvéraison. The results show that the water potential indicated weak to moderate stress in the study yearsand decreased along the vegetative cycle, while foliar chlorophyll contents showed an increasing trend. Thecorrelation between both variables was not consistent. Linear regression of the chlorophyll fluorescenceparameters in dark-adapted leaves, Fo, Fv and Fv/Fm, over chlorophyll content was strong in all thestudy years (higher determination coefficients for Fv/Fm at fruit set in 2012 and 2013). In general, thewater potential with low coefficients of variation showed a low effect on photosynthesis activity, althoughvalues in variables such as Fm, Fv, Fv/Fm, Fs/Fo and ΦPSII registered an increasing trend when middayleaf water potential decreased in the pre-véraison and véraison stages. These variables could be useful toestimate water status in commercial vineyards for application in precision viticulture

Density-Matrix approach to a Strongly Coupled Two-Component Bose-Einstein Condensate

The time evolution equations for average values of population and relative phase of a strongly coupled two component BEC is derived analytically. The two components are two hyper-fine states coupled by an external laser that drives fast Rabi oscillations between these states. Specifically, this derivation incorporates the two-mode model proposed in [1] for the strongly coupled hyper-fine states of Rb. The fast Rabi cycle is averaged out and rate equations are derived that represents the slow dynamics of the system. These include the collapse and revival of Rabi oscillations and their subsequent dependence on detuning and trap displacement as reported in experiments of [1]. A proposal to create stable vortices is also given.Comment: 11 Latex pages, 2 figures (Figure 3 was removed and the text chnaged accordingly

Hierarchical strategies for efficient fault recovery on the reconfigurable PAnDA device

A novel hierarchical fault-tolerance methodology for reconfigurable devices is presented. A bespoke multi-reconfigurable FPGA architecture, the programmable analogue and digital array (PAnDA), is introduced allowing fine-grained reconfiguration beyond any other FPGA architecture currently in existence. Fault blind circuit repair strategies, which require no specific information of the nature or location of faults, are developed, exploiting architectural features of PAnDA. Two fault recovery techniques, stochastic and deterministic strategies, are proposed and results of each, as well as a comparison of the two, are presented. Both approaches are based on creating algorithms performing fine-grained hierarchical partial reconfiguration on faulty circuits in order to repair them. While the stochastic approach provides insights into feasibility of the method, the deterministic approach aims to generate optimal repair strategies for generic faults induced into a specific circuit. It is shown that both techniques successfully repair the benchmark circuits used after random faults are induced in random circuit locations, and the deterministic strategies are shown to operate efficiently and effectively after optimisation for a specific use case. The methods are shown to be generally applicable to any circuit on PAnDA, and to be straightforwardly customisable for any FPGA fabric providing some regularity and symmetry in its structure

The myelodysplastic syndrome: in vitro growth characteristics of hemopoietic progenitor cells.

Blood cell formation results from the continuous proliferation, differentiation and maturation of pluripotent hemopoietic stem cells located in the human bone marrow. In vitro culture assays, developed in the last twenty years, have enabled the identification of the various pluripotent and committed progenitor cells present in human bone marrow by their capacity to form colonies of mature blood cells in vitro. Colony formation dependens on the presence of hemopoietic growth factors in the culture medium, which have become known as the colony stimulating factors (CSFs). At present a number of CSFs can be produced on a large scale through recombinant DNA technology and their biological activities have subsequently been defined. In chapter 1.1 and 1.2 the general principles of hemopoiesis are introduced, i.e., the different models of stem cell renewal and commitment, the various in vitro clonogenic assays for normal as well as for leukemic colony forming cells and the effects of the CSF on progenitor cells and mature blood cells. The myelodysplastic syndrome (MDS) comprises a group of acquired disorders, which are characterized by an ineffective hemopoiesis resulting in cytopenia of one or more cell lineages. Cytogenetic and G-6-PD studies have demonstrated that MDS is a clonal disease of the hemopoietic stem celL The results of some studies suggest that normal hemopoiesis is replaced by the abnormal clone already in an early stage of the disease. Up to fourty percent of the MDS patients eventually develop an acute myeloblastic leukemia. The preleukemic nature of the MDS makes this syndrome of particular interest in the study of leukemogenesis. In chapter 1.3 the clinical, morphological and in vitro growth characteristics of the MDS are introduced

qˉq{\bar {q}}q condensate for light quarks beyond the chiral limit

We determine the ${\bar{q}}q$ condensate for quark masses from zero up to that of the strange quark within a phenomenologically successful modelling of continuum QCD by solving the quark Schwinger-Dyson equation. The existence of multiple solutions to this equation is the key to an accurate and reliable extraction of this condensate using the operator product expansion. We explain why alternative definitions fail to give the physical condensate.Comment: 13 pages, 8 figure