15,278 research outputs found
Solid superheating observed in two-dimensional strongly-coupled dusty plasma
It is demonstrated experimentally that strongly-coupled plasma exhibits solid
superheating. A 2D suspension of microspheres in dusty plasma, initially
self-organized in a solid lattice, was heated and then cooled rapidly by
turning laser heating on and off. Particles were tracked using video
microscopy, allowing atomistic-scale observation during melting and
solidification. During rapid heating, the suspension remained in a solid
structure at temperatures above the melting point, demonstrating solid
superheating. Hysteresis diagrams did not indicate liquid supercooling in this
2D system.Comment: 9 pages text, 3 figures, in press Physical Review Letters 200
Recommended from our members
A Novel Aptamer LL4A Specifically Targets Vemurafenib-Resistant Melanoma through Binding to the CD63 Protein.
Melanoma is a highly aggressive tumor with a poor prognosis, and half of all melanoma patients harbor BRAF mutations. A BRAF inhibitor, vemurafenib (PLX4032), has been approved by the US Food and Drug Administration (FDA) and European Medicines Agency (EMA) to treat advanced melanoma patients with BRAFV600E mutation. However, the efficacy of vemurafenib is impeded by adaptive resistance in almost all patients. In this study, using a cell-based SELEX (systematic evolution of ligands by exponential enrichment) strategy, we obtained a DNA aptamer (named LL4) with high affinity and specificity against vemurafenib-resistant melanoma cells. Optimized truncated form (LL4A) specifically binds to vemurafenib-resistant melanoma cells with dissociation constants in the nanomolar range and with excellent stability and low toxicity. Meanwhile, fluorescence imaging confirmed that LL4A significantly accumulated in tumors formed by vemurafenib-resistant melanoma cells, but not in control tumors formed by their corresponding parental cells in vivo. Further, a transmembrane protein CD63 was identified as the binding target of aptamer LL4A using a pull-down assay combined with the liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. CD63 formed a supramolecular complex with TIMP1 and β1-integrin, activated the nuclear factor кB (NF-кB) and mitogen-activated protein kinase (MAPK) signaling pathways, and contributed to vemurafenib resistance. Potentially, the aptamer LL4A may be used diagnostically and therapeutically in humans to treat targeted vemurafenib-resistant melanoma
First-principles prediction of coexistence of magnetism and ferroelectricity in rhombohedral Bi2FeTiO6
First principles calculations based on the density functional theory within
the local spin density approximation plus U(LSDA+U)scheme, show rhombohedral
BiFeTiO is a potential multiferroic in which the magnetism and
ferroelectricity coexist . A ferromagnetic configuration with magnetic moment
of 4 per formula unit have been reported with respect to the minimum
total energy. Spontaneous polarization of 27.3 C/cm, caused mainly by
the ferroelectric distortions of Ti, was evaluated using the berry phase
approach in the modern theory of polarization. The Bi-6s stereochemical
activity of long-pair and the `d-ness' criterion in off-centring of Ti were
coexisting in the predicted new system. In view of the oxidation state of
Bi,Fe,Ti, and O from the orbital-resolved density
of states of the Bi-6p, Fe-3d,Ti-3d, and O-2p states,the valence state of
BiFeTiO in the rhombohedral phase was found to be
BiFeTiO.Comment: 22 pages, 9 figures. submitted to Physics Letters
Recommended from our members
Towards High-Quality Selective Beam Melting Technologies: Modeling and Experiments of Single Track Formations
Additive manufacturing technologies are promising but still not widely used. One major
problem is the unsatisfying quality e.g. surface roughness and dimensional accuracy. The
discontinuous droplets and distortions in single track formations, which influence both surface
roughness and dimensional accuracy, were investigated. The physical mechanisms of the
formations of the droplets and distortions were proposed and the heat transfer simulations based
on the Finite Element Method were established to predict the possibility of the droplet formation
and the magnitude of the distortion. Experiments using Electron Beam Melting were then
conducted to validate the physical and numerical models. The good agreements of the simulated
and experimental results demonstrated that the proposed models are simple and efficient to provide
quantitative predictions of the distortions.Mechanical Engineerin
Exploring the relationship between work stress and work-related rumination.
Current studies lack adequate analysis of the antecedents of the two forms of work-related rumination. However, understanding the relationship between different types of stress and the two forms of rumination is of profound significance for eliminating the influence of negative rumination. In this project, three studies were conducted to investigate the cumulative and immediate effects of challenge and hindrance stress on affective rumination and problem-solving rumination based on one-time, two-time points and daily measurements. Participants were 1109, 605 and 111 employees from a variety of jobs in Chinese mainland. The results showed the relationship between hindrance stress and affective rumination varies over different time course. There was no significant correlation between hindrance stress and problem-solving rumination over any time course. The relationship between challenge stress and two forms of work-related rumination varies over different time course. The results of this study suggest that the antecedent analysis of work-related rumination should not only give attention to the type of work stress, but also consider the time of work stress when analyzing its aftereffects
Tumor microenvironment in pancreatic ductal adenocarcinoma: Implications in immunotherapy
Pancreatic ductal adenocarcinoma is one of the most aggressive and lethal cancers. Surgical resection is the only curable treatment option, but it is available for only a small fraction of patients at the time of diagnosis. With current therapeutic regimens, the average 5-year survival rate is less than 10% in pancreatic cancer patients. Immunotherapy has emerged as one of the most promising treatment options for multiple solid tumors of advanced stage. However, its clinical efficacy is suboptimal in most clinical trials on pancreatic cancer. Current studies have suggested that the tumor microenvironment is likely the underlying barrier affecting immunotherapy drug efficacy in pancreatic cancer. In this review, we discuss the role of the tumor microenvironment in pancreatic cancer and the latest advances in immunotherapy on pancreatic cancer
Hard and soft spectral states of ULXs
I discuss some differences between the observed spectral states of
ultraluminous X-ray sources (ULXs) and the canonical scheme of spectral states
defined in Galactic black holes. The standard interpretation of ULXs with a
curved spectrum, or a moderately steep power-law with soft excess and
high-energy downturn, is that they are an extension of the very high state, up
to luminosities ~ 1 to 3 L_{Edd}. Two competing models are Comptonization in a
warm corona, and slim disk; I suggest bulk motion Comptonization in the
radiatively-driven outflow as another possibility. The interpretation of ULXs
with a hard power-law spectrum is more problematic. Some of them remain in that
state over a large range of luminosities; others switch directly to a curved
state without going through a canonical high/soft state. I suggest that those
ULXs are in a high/hard state not seen in Galactic black holes; that state may
overlap with the low/hard state at lower accretion rates, and extend all the
way to Eddington accretion rates. If some black holes can reach Eddington
accretion rates without switching to a standard-disk-dominated state, it is
also possible that they never quench their steady jets.Comment: 6 pages, accepted for publication in the Astronomische Nachrichten,
to appear in the proceedings of the conference "Ultra-Luminous X-ray sources
and Middle Weight Black Holes" (Madrid, May 24-26, 2010
Long-term temporal dependence of droplets transiting through a fixed spatial point in gas-liquid twophase turbulent jets
We perform rescaled range analysis upon the signals measured by Dual Particle
Dynamical Analyzer in gas-liquid two-phase turbulent jets. A novel rescaled
range analysis is proposed to investigate these unevenly sampled signals. The
Hurst exponents of velocity and other passive scalars in the bulk of spray are
obtained to be 0.590.02 and the fractal dimension is hence 1.41
0.02, which are in remarkable agreement with and much more precise than
previous results. These scaling exponents are found to be independent of the
configuration and dimensions of the nozzle and the fluid flows. Therefore, such
type of systems form a universality class with invariant scaling properties.Comment: 16 Elsart pages including 8 eps figure
A Microbiome-Based Index for Assessing Skin Health and Treatment Effects for Atopic Dermatitis in Children.
A quantitative and objective indicator for skin health via the microbiome is of great interest for personalized skin care, but differences among skin sites and across human populations can make this goal challenging. A three-city (two Chinese and one American) comparison of skin microbiota from atopic dermatitis (AD) and healthy pediatric cohorts revealed that, although city has the greatest effect size (the skin microbiome can predict the originated city with near 100% accuracy), a microbial index of skin health (MiSH) based on 25 bacterial genera can diagnose AD with 83 to ∼95% accuracy within each city and 86.4% accuracy across cities (area under the concentration-time curve [AUC], 0.90). Moreover, nonlesional skin sites across the bodies of AD-active children (which include shank, arm, popliteal fossa, elbow, antecubital fossa, knee, neck, and axilla) harbor a distinct but lesional state-like microbiome that features relative enrichment of Staphylococcus aureus over healthy individuals, confirming the extension of microbiome dysbiosis across body surface in AD patients. Intriguingly, pretreatment MiSH classifies children with identical AD clinical symptoms into two host types with distinct microbial diversity and treatment effects of corticosteroid therapy. These findings suggest that MiSH has the potential to diagnose AD, assess risk-prone state of skin, and predict treatment response in children across human populations.IMPORTANCE MiSH, which is based on the skin microbiome, can quantitatively assess pediatric skin health across cohorts from distinct countries over large geographic distances. Moreover, the index can identify a risk-prone skin state and compare treatment effect in children, suggesting applications in diagnosis and patient stratification
- …