183 research outputs found
Layer-By-Layer Assembly of Graphene Oxide on Thermosensitive Liposomes for Photo-Chemotherapy
Stimuli responsive polyelectrolyte nanoparticles have been developed for chemo-photothermal destruction of breast cancer cells. This novel system, called layer by layer Lipo-graph (LBL Lipo-graph), is composed of alternate layers of graphene oxide (GO) and graphene oxide conjugated poly (l-lysine) (GO-PLL) deposited on cationic liposomesencapsulating doxorubicin. Various concentrations of GO and GO-PLL were examined and the optimal LBL Lipo-graph was found to have a particle size of 267.9 ± 13 nm, zeta potentialof +43.9 ± 6.9 mV and encapsulation efficiency of 86.4 ± 4.7%. The morphology of LBL Lipo-graph was examined by cryogenic-transmission electron microscopy (Cryo-TEM), atomic force microcopy (AFM) and scanning electron microscopy (SEM). The buildup of LBL Lipo-graph was confirmed via ultraviolet-visible (UV–Vis) spectrophotometry, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis. Infra-red (IR) response suggests that four layers are sufficient to induce a gel-to-liquid phase transition in response to near infra-red (NIR) laser irradiation. Light-matter interaction of LBL Lipo-graph was studied by calculating the absorption cross section in the frequency domain by utilizing Fourier analysis. Drug release assay indicates that the LBL Lipo-graph releases much faster in an acidic environment than a liposome control. A cytotoxicity assay was conducted to prove the efficacy of LBL Lipo-graph to destroy MD-MB-231 cells in response to NIR laser emission. Also, image stream flow cytometry and two photon microcopy provide supportive data for the potential application of LBL Lipo-graph for photothermal therapy. Study results suggest the novel dual-sensitive nanoparticles allow intracellular doxorubin delivery and respond to either acidic environments or NIR excitation. Statement of Significance Stimuli sensitive hybrid nanoparticles have been synthesized using a layer-by-layer technique and demonstrated for dual chemo-photothermal destruction of breast cancer cells. The hybrid nanoparticles are composed of alternating layers of graphene oxide and graphene oxide conjugated poly-l-lysine coating the surface of a thermosensitive cationic liposome containing doxorubicin as a core. Data suggests that the hybrid nanoparticles may offer many advantages for chemo-photothermal therapy. Advantages include a decrease of the initial burst release which may result in the reduction in systemic toxicity, increase in pH responsivity around the tumor environment and improved NIR light absorption
The perception of fluid properties and how it influences an artistic direction in 3D printing
In this work we explore this fusion of art and technology through the 3D printing of fluid simulations and what
limits the design of such simulations before perception is abstracted. The challenge of 3D printing complex forms
presents itself through the comparison of the artefacts and what was rendered online. The properties of fluid are
controlled using viscosity, speed and collision objects and a static frame of the simulation is 3D printed. This
paper presents the potential pipeline to 3D printing of fluids and the process undergone to achieve aesthetically
pleasing results
Structural or dispositional? An experimental investigation of the experience of winning in social casino games (and impulsivity) on subsequent gambling behaviors
BACKGROUND AND AIMS: In the present research, we experimentally investigated whether the experience of winning (i.e., inflated payout rates) in a social casino game influenced social casino gamers' subsequent decision to gamble for money. Furthermore, we assessed whether facets of dispositional impulsivity - negative and positive urgency in particular - also influenced participants' subsequent gambling. METHODS: Social casino gamers who were also current gamblers (N = 318) were asked to play a social casino game to assess their perceptions of the game in exchange for 3 renumeration in an online roulette game. RESULTS: A total of 280 participants (88.1%) elected to gamble, but no between-condition variation in the decision to gamble emerged. Furthermore, there were no differences in gambling on the online roulette between condition. However, higher levels of both negative and positive urgency increased the likelihood of gambling. Finally, impulsivity did not moderate the re
Randomness at the Edge: Theory of Quantum Hall transport at filling
Current Luttinger liquid edge state theories for filling predict a
non-universal Hall conductance, in disagreement with experiment. Upon inclusion
of random edge tunnelling we find a phase transition into a new
disordered-dominated edge phase. An exact solution of the random model in this
phase gives a quantized Hall conductance of 2/3 and a neutral mode propagating
upstream. The presence of the neutral mode changes the predicted temperature
dependence for tunnelling through a point contact from to .Comment: 12 pages 1 postscript figure appended, REVTEX 3.
A platform for curated products from novel Open Reading Frames (nORFs) prompts reinterpretation of disease variants
Recent evidence from proteomics and deep massively parallel sequencing studies have revealed that eukaryotic genomes contain substantial numbers of as-yet-uncharacterized open reading frames (ORFs). We define these uncharacterized ORFs as novel ORFs (nORFs). nORFs in humans are mostly under 100 codons and are found in diverse regions of the genome, including in long noncoding RNAs, pseudogenes, 3′ UTRs, 5′ UTRs, and alternative reading frames of canonical protein coding exons. There is therefore a pressing need to evaluate the potential functional importance of these unannotated transcripts and proteins in biological pathways and human disease on a larger scale, rather than one at a time. In this study, we outline the creation of a valuable nORFs data set with experimental evidence of translation for the community, use measures of heritability and selection that reveal signals for functional importance, and show the potential implications for functional interpretation of genetic variants in nORFs. Our results indicate that some variants that were previously classified as being benign or of uncertain significance may have to be reinterpreted
Lubrication synergy: Mixture of hyaluronan and dipalmitoylphosphatidylcholine (DPPC) vesicles
AbstractPhospholipids and hyaluronan have been implied to fulfil important roles in synovial joint lubrication. Since both components are present in synovial fluid, self-assembly structures formed by them should also be present. We demonstrate by small angle X-ray scattering that hyaluronan associates with the outer shell of dipalmitoylphophatidylcholine (DPPC) vesicles in bulk solution. Further, we follow adsorption to silica from mixed hyaluronan/DPPC vesicle solution by Quartz Crystal Microbalance with Dissipation measurements. Atomic Force Microscope imaging visualises the adsorbed layer structure consisting of non-homogeneous phospholipid bilayer with hyaluronan/DPPC aggregates on top. The presence of these aggregates generates a long-range repulsive surface force as two such surfaces are brought together. However, the aggregates are easily deformed, partly rearranged into multilayer structures and partly removed from between the surfaces under high loads. These layers offer very low friction coefficient (<0.01), high load bearing capacity (≈23MPa), and self-healing ability. Surface bound DPPC/hyaluronan aggregates provide a means for accumulation of lubricating DPPC molecules on sliding surfaces
Kepler constraints on planets near hot Jupiters
We present the results of a search for planetary companions orbiting near hot Jupiter planet candidates (Jupiter-size candidates with orbital periods near 3 d) identified in the Kepler data through its sixth quarter of science operations. Special emphasis is given to companions between the 2∶1 interior and exterior mean-motion resonances. A photometric transit search excludes companions with sizes ranging from roughly two-thirds to five times the size of the Earth, depending upon the noise properties of the target
star. A search for dynamically induced deviations from a constant period (transit timing variations) also shows no significant signals. In contrast, comparison studies of warm Jupiters (with slightly larger orbits) and hot Neptune-size candidates do exhibit signatures of additional companions with these same tests. These differences
between hot Jupiters and other planetary systems denote a distinctly different formation or dynamical history
Topical Issues for Particle Acceleration Mechanisms in Astrophysical Shocks
Particle acceleration at plasma shocks appears to be ubiquitous in the
universe, spanning systems in the heliosphere, supernova remnants, and
relativistic jets in distant active galaxies and gamma-ray bursts. This review
addresses some of the key issues for shock acceleration theory that require
resolution in order to propel our understanding of particle energization in
astrophysical environments. These include magnetic field amplification in shock
ramps, the non-linear hydrodynamic interplay between thermal ions and their
extremely energetic counterparts possessing ultrarelativistic energies, and the
ability to inject and accelerate electrons in both non-relativistic and
relativistic shocks. Recent observational developments that impact these issues
are summarized. While these topics are currently being probed by
astrophysicists using numerical simulations, they are also ripe for
investigation in laboratory experiments, which potentially can provide valuable
insights into the physics of cosmic shocks.Comment: 13 pages, no figures. Invited review, accepted for publication in
Astrophysics and Space Science, as part of the HEDLA 2006 conference
proceeding
Electrostatic Potentials in Supernova Remnant Shocks
Recent advances in the understanding of the properties of supernova remnant
shocks have been precipitated by the Chandra and XMM X-ray Observatories, and
the HESS Atmospheric Cerenkov Telescope in the TeV band. A critical problem for
this field is the understanding of the relative degree of dissipative
heating/energization of electrons and ions in the shock layer. This impacts the
interpretation of X-ray observations, and moreover influences the efficiency of
injection into the acceleration process, which in turn feeds back into the
thermal shock layer energetics and dynamics. This paper outlines the first
stages of our exploration of the role of charge separation potentials in
non-relativistic electron-ion shocks where the inertial gyro-scales are widely
disparate, using results from a Monte Carlo simulation. Charge density spatial
profiles were obtained in the linear regime, sampling the inertial scales for
both ions and electrons, for different magnetic field obliquities. These were
readily integrated to acquire electric field profiles in the absence of
self-consistent, spatial readjustments between the electrons and the ions. It
was found that while diffusion plays little role in modulating the linear field
structure in highly oblique and perpendicular shocks, in quasi-parallel shocks,
where charge separations induced by gyrations are small, and shock-layer
electric fields are predominantly generated on diffusive scales.Comment: 7 pages, 2 embedded figures, Accepted for publication in Astrophysics
and Space Science, as part of the HEDLA 2006 conference proceeding
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