The Relationship between Working Memory and Cognitive Functioning in Children

One-hundred and forty-four Year 1 children (51% boys and 49% girls, mean age 6) from Queensland State primary schools participated in a study to investigate the relationship between working memory and cognitive functioning. Children were given two tests of cognitive functioning (the School-Years Screening Test for the Evaluation of Mental Status (SYSTEMS) and the Kaufman Brief Intelligence Test (K-BIT)) and six subtests of working memory from the Working Memory Test Battery for Children (WMTB-C) (Backward Digit Recall, Listening Recall, Digit Recall, Word List Matching, Word List Recall and Non-word List Recall). The two cognitive tests correlated at r = .50. Results showed a high correlation between SYSTEMS and the Phonological Loop (PL) component of working memory. The K-BIT also correlated highly with PL component. The SYSTEMS and K-BIT showed various levels of correlation with the working memory sub-tests. A measurement model utilising Confirmatory Factor Analysis method showed a strong relationship between working memory and cognitive functioning, the degree of fit for the model was very high at GFI = .996

Evaluation of photografted charged sites within polymer monoliths in capillary columns using contactless conductivity detection

Capacitively coupled contactless conductivity detection (C4D) is presented as a novel and versatile means of visualising discrete zones of charged functional groups grafted onto polymer based monoliths. Monoliths were formed within 100 μm UV transparent fused silica capillaries and photografting methods were subsequently used to graft a charged functional monomer, 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) onto discrete regions of the “generic” monolith using a photomask. Post-modification monolith evaluation involves scanning the C4D detector along the length of the monolith to obtain a profile of the exact spatial location of grafted charged functionalities with millimetre accuracy. The methodology was extended to the visualisation of several zones of immobilised protein (bovine serum albumin) using photografted azlactone groups to enable covalent attachment of the protein to the monolith at precise locations along its length. In addition, the extent of non-specific binding of protein to the ungrafted regions of the monolith due to hydrophobic interactions could be monitored as an increase in background conductivity of the stationary phase. Finally, the technique was cross-validated using fluorescence microscopy by immobilising green fluorescent protein (GFP) in discrete zones and comparing the profiles obtained using both complementary techniques

Radiation from an Oscillating Dipole in the Presence of Photon-Sector CPT and Lorentz Violation

We examine one of the standard loci for studying electromagnetic wave emission -- the radiation from an oscillating electric dipole -- in a model in which the electromagnetic sector is modified to include novel CPT- and Lorentz-violating propagation effects involving a preferred axial vector background. We evaluate the vacuum-birefringent radiation fields, including nonperturbative terms where appropriate. In general, the energy-momentum carried by the fields in this model is known to have a complicated nonperturbative structure, which cannot be captured by naive power series expansions in the components of preferred background vector. However, we nevertheless find that at the lowest nontrivial orders, there are actually no modifications to the Larmor expressions for the energy-momentum emission.Comment: 20 page

AuNP-Agglomerated monoliths in pipette tips for lectin affinity extraction of glycoproteins

• To in situ fabricate ethylene dimethacrylate porous polymer monoliths within the confines of a commercial 20 μL polypropylene pipette tips. • To enhance the monolith surface area by immobilising AuNPs and then functionalise the AuNPs with ECL lectin for selective extraction of galactosylated proteins from complex media

Gold nano-particle modified silica monolithic micro-columns for selected chromatographic and biological applications.

Monolithic microcolumns and especially silica monoliths are showing several advantages compared to classical particle packed and organic polymeric monolithic columns: ease of production and functionalisation, excellent mechanical and thermal stability. Morphology of the monolithic columns can easily be tuned by simply changing the compositions of reaction mixtures. High porosity and interconnected flow-through pores ensure low back pressures at higher flow rates so increasing reaction speeds. High salt resistance allows use water based buffer solutions without any swelling of the stationary phase, large biomolecules can be utilised and conditions to prevent denaturation and comformation changes of these biomolecules can be maintained. Introduction of gold nano-particles on the surfaces of silica monoliths allows increase of the surface areas and alows creation of new, exotic surfaces. Gold shows strong affinity towards thiol groups, which can be found in different biomolecules so utilisation of this phenomena would allow production of micro-reactors and bioreactors in order to mimic biological reactions happening in living organisms and large biological systems. Silica monoliths were synthesised using classical sol-gel process. In order to immobilise gold nano-particles, surfaces of the silica monoliths were amminated using standard silanisation reaction with 3-aminopropyl-methyl-diethoxysilane. 20 nm citrate stabilised gold nano-particles were immobilised on the surfaces afterwards. Depending on the desired application, gold nano-oparticle modified silica monoliths were functionalised afterwards. Immobilisation of ionic species such as amino acids and small peptides would allow creation of stationary phase for ion chromatography, retention of enzymes and other biologically active molecules would allow to create micro-reactors. Leaving gold nano-particles unmodified would make ideal stationary phase for micro-extraction. These modified monoliths were characterised using microscopy techniques, such as scanning electron microscopy (SEM) and field emission SEM. They were used to characterise morphology of the monoliths as well as to evaluate the coverage of the surface with gold nano-particles. The fabricated stationary phases were used for selected biological and chromatographic applications (incorporanting classical chromatographic techniques in order to evaluate the performance of these new modified monolithic materials)

Neutron star-black hole mergers with a nuclear equation of state and neutrino cooling: Dependence in the binary parameters

We present a first exploration of the results of neutron star-black hole mergers using black hole masses in the most likely range of $7M_\odot-10M_\odot$, a neutrino leakage scheme, and a modeling of the neutron star material through a finite-temperature nuclear-theory based equation of state. In the range of black hole spins in which the neutron star is tidally disrupted ($\chi_{\rm BH}\gtrsim 0.7$), we show that the merger consistently produces large amounts of cool ($T\lesssim 1\,{\rm MeV}$), unbound, neutron-rich material ($M_{\rm ej}\sim 0.05M_\odot-0.20M_\odot$). A comparable amount of bound matter is initially divided between a hot disk ($T_{\rm max}\sim 15\,{\rm MeV}$) with typical neutrino luminosity $L_\nu\sim 10^{53}\,{\rm erg/s}$, and a cooler tidal tail. After a short period of rapid protonization of the disk lasting $\sim 10\,{\rm ms}$, the accretion disk cools down under the combined effects of the fall-back of cool material from the tail, continued accretion of the hottest material onto the black hole, and neutrino emission. As the temperature decreases, the disk progressively becomes more neutron-rich, with dimmer neutrino emission. This cooling process should stop once the viscous heating in the disk (not included in our simulations) balances the cooling. These mergers of neutron star-black hole binaries with black hole masses $M_{\rm BH}\sim 7M_\odot-10M_\odot$ and black hole spins high enough for the neutron star to disrupt provide promising candidates for the production of short gamma-ray bursts, of bright infrared post-merger signals due to the radioactive decay of unbound material, and of large amounts of r-process nuclei.Comment: 20 pages, 19 figure

Parallel analysis of glycoproteins using lectin-functionalised monoPLOT columns integrated in micro-fluidic chips

Glycoprotein isolation, purification and analysis is critical in the production of biologics. Therefore, there is a growing interest in new methods and techniques that allow ultra fast analytical characterisation and detection of glycoproteins and their glycoforms in the biological samples employed within the biopharmaceutical industry. In that context, micro-fluidic devices offer a great potential owing to the very fast analysis they allow, the low sample/reagent consumption, the disposability, and the ease of integration with other analytical systems, among others. In this work, a micro-fluidic device integrating porous layer open tubular columns based on dimethacrylate monoliths (monoPLOT) and functionalised with Erythrina cristagalli lectin (ECL) were used for extraction of selected glycoproteins. Polymer monoliths are very versatile materials as they can be prepared with different porosities, pore sizes, and a wide variety of functionalities using many different precursors and chemistries. The monoPLOT columns were fabricated and functionalised off-chip, and then bonded to the channel walls before final channel lamination. In order to increase the monolith surface area, immobilisation of gold nano-particles (AuNPs) was carried out prior to covalent attachment of the ECL to the AuNPs. Detection was carried out with capacitively coupled contactless conductivity detection (C4D)