329 research outputs found
Apolipoprotein-induced conversion of phosphatidylcholine bilayer vesicles into nanodisks
AbstractApolipoprotein mediated formation of nanodisks was studied in detail using apolipophorin III (apoLp-III), thereby providing insight in apolipoproteinâlipid binding interactions. The spontaneous solubilization of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) vesicles occured only in a very narrow temperature range at the gelâliquidâcrystalline phase transition temperature, exhibiting a net exothermic interaction based on isothermal titration calorimetry analysis. The resulting nanodisks were protected from proteolysis by trypsin, endoproteinase Glu-C, chymotrypsin and elastase. DMPC solubilization and the simultaneous formation of nanodisks were promoted by increasing the vesicle diameter, protein to lipid ratio and concentration. Inclusion of cholesterol in DMPC dramatically enhanced the rate of nanodisk formation, presumably by stabilization of lattice defects which form the main insertion sites for apolipoprotein α-helices. The presence of fully saturated acyl chains with a length of 13 or 14 carbons in phosphatidylcholine allowed the spontaneous vesicle solubilization upon apolipoprotein addition. Nanodisks with C13:0-phosphatidylcholine were significantly smaller with a diameter of 11.7±3.1nm compared to 18.5±5.6nm for DMPC nanodisks determined by transmission electron microscopy. Nanodisk formation was not observed when the phosphatidylcholine vesicles contained acyl chains of 15 or 16 carbons. However, using very high concentrations of lipid and protein (>10mg/ml), 1,2,-dipalmitoyl-sn-glycero-3-phosphocholine nanodisks could be produced spontaneously although the efficiency remained low
Magnetic moments of antidecuplet pentaquarks
We analyze the magnetic moment of the exotic pentaquarks of the flavor
antidecuplet in the constituent quark model for the case in which the ground
state is in an orbital L(p)=0(+) or a L(p)=1(-) state. We derive sum rules for
the magnetic moments. The magnetic moment of the Theta(1540) is found to be
0.38, 0.09 and 1.05 mu_N for J(p)=1/2(-), 1/2(+) and 3/2(+), respectively,
which is compared with the results obtained in other approaches.Comment: 15 pages, 1 figure, 3 tables. Revised version, extended introduction
and discussion, accepted for publication in Physics Letters
Assembling and (Re)assembling critical infrastructure resilience in Khulna City, Bangladesh
Extreme Weather Events continue to cause shocking losses of life and long-term damage at scales, depths and complexities that elude robust and accountable calculation, expression and reparation. Cyclones and storm surges can wipe out entire towns, and overwhelm vulnerable built and lived environments. It was storm surges that was integral to the destructive power of Hurricane Katrina in the USA (2005), Typhoon Haiyan in the Philippines (2013), as well as Cyclone Nargis (2008) and the 1970 Bhola Cyclone in the Bay of Bengal. This paper report on work which concerns itself with the question of, given what we know already about such extreme weather events, and their associated critical infrastructure impacts and recovery trajectories, what scenarios, insights and tools might we develop to enable critical infrastructures which are resilient?
With several of the worldâs most climate vulnerable cities situated in well-peopled and rapidly growing urban areas near coasts, our case study of Khulna City speaks globally into a resilience discourse, through critical infrastructure, disaster risk reduction, through spatial data science and high visualisation. With a current population of 1.4 million estimated to rise to 2.9 million by 2030, dense historical Khulna City may well continue to perform a critical role in regional economic development and as well as a destination for environmental refugees.
Working as part of the EUâCIRCLE consortium, we conduct a case study into cyclones and storm surges affecting the critical infrastructure then discuss salient developments of loss modelling. The research aims to contribute towards a practical framework that stimulates adaptive learning across multiple stakeholders and organisational genres
Abelian gauge potentials on cubic lattices
The study of the properties of quantum particles in a periodic potential
subject to a magnetic field is an active area of research both in physics and
mathematics; it has been and it is still deeply investigated. In this review we
discuss how to implement and describe tunable Abelian magnetic fields in a
system of ultracold atoms in optical lattices. After discussing two of the main
experimental schemes for the physical realization of synthetic gauge potentials
in ultracold set-ups, we study cubic lattice tight-binding models with
commensurate flux. We finally examine applications of gauge potentials in
one-dimensional rings.Comment: To appear on: "Advances in Quantum Mechanics: Contemporary Trends and
Open Problems", G. Dell'Antonio and A. Michelangeli eds., Springer-INdAM
series 201
and from QCD sum rules
and are calculated using a QCD sum rule
motivated method used by Reinders, Rubinstein and Yazaki to extract Hadron
couplings to goldstone bosons. The SU(3) symmetry breaking effects are taken
into account by including the contributions from the strange quark mass and
assuming different values for the strange and the up down quark condensates. We
find and Comment: 14 pages (REVTeX) and 2 PS figure
Evolution of the differential transverse momentum correlation function with centrality in Au+Au collisions at GeV
We present first measurements of the evolution of the differential transverse
momentum correlation function, {\it C}, with collision centrality in Au+Au
interactions at GeV. {\it C} exhibits a strong dependence
on collision centrality that is qualitatively similar to that of number
correlations previously reported. We use the observed longitudinal broadening
of the near-side peak of {\it C} with increasing centrality to estimate the
ratio of the shear viscosity to entropy density, , of the matter formed
in central Au+Au interactions. We obtain an upper limit estimate of
that suggests that the produced medium has a small viscosity per unit entropy.Comment: 7 pages, 4 figures, STAR paper published in Phys. Lett.
The incidence of fatal breast cancer measures the increased effectiveness of therapy in women participating in mammography screening
Background: Women and their health care providers need a reliable answer to this important question: If a woman chooses to participate in regular mammography screening, then how much will this choice improve her chances of avoiding a death from breast cancer compared with women who choose not to participate?Methods: To answer this question, we used comprehensive registries for population, screening history, breast cancer incidence, and diseaseâspecific death data in a defined population in Dalarna County, Sweden. The annual incidence of breast cancer was calculated along with the annual incidence of breast cancers that were fatal within 10 and within 11 to 20 years of diagnosis among women aged 40 to 69 years who either did or did not participate in mammography screening during a 39âyear period (1977â2015). For an additional comparison, corresponding data are presented from 19 years of the prescreening period (1958â1976). All patients received stageâspecific therapy according to the latest national guidelines, irrespective of the mode of detection.Results: The benefit for women who chose to participate in an organized breast cancer screening program was a 60% lower risk of dying from breast cancer within 10 years after diagnosis (relative risk, 0.40; 95% confidence interval, 0.34â0.48) and a 47% lower risk of dying from breast cancer within 20 years after diagnosis (relative risk, 0.53; 95% confidence interval, 0.44â0.63) compared with the corresponding risks for nonparticipants.Conclusions: Although all patients with breast cancer stand to benefit from advances in breast cancer therapy, the current results demonstrate that women who have participated in mammography screening obtain a significantly greater benefit from the therapy available at the time of diagnosis than do those who have not participated.</p
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