Stress and displacement fields in soft cylindrical multilayers

AbstractMultilayered gels play an important role in biomedical engineering as drug delivery vehicles, replacement tissues and bio-mimetic substrates for cell cultures. It has been established that the gel elasticity strongly influences the intended functionalities. In view of this, second-order elastic solutions for the stresses and displacements in cylindrical multilayered hydrogels subjected to various dilatation profiles are developed in this paper. The results emphasize the importance of nonlinearity in gel mechanics, and suggest the possibility of a rational selection of layer elasticities, layer thicknesses and dilatation profiles for improved mechanical responses such as maximum/minimum swelling and multiaxial stress states

Individual and competitive adsorption of MSMA and phosphate onto iron and non-iron soil

Title from PDF of title page (University of Missouri--Columbia, viewed on May 30, 2013).The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical general description, or public abstract, appears in the public.pdf file.Thesis advisor: Dr. Baolin DengIncludes bibliographical references.M.S. University of Missouri-Columbia 2012."May 2012"Monosodium monomethylarsenate (MSMA (V)) is a common constitute in herbicides and pesticides used widely in the world, and yet its mobility and transport properties are still a relatively understudied area. Knowledge of the MSMA (V) sorption process is a key to understanding the properties. This research investigated the adsorption of MSMA (V) of soil samples collected at the USDA-ARS Dale Bumpers National Rice Research Center located near Stuttgart, Arkansas. Batch experiments were performed to evaluate the effect of Fe, phosphate, and pH conditions on MSMA (V) adsorption. The results indicate: 1) MSMA (V) was strongly adsorbed onto the whole soil ( no Fe removed), implying that adsorption is an important process controlling the MSMA (V) mobility in environments; 2) the reductive removal of iron minerals from the soil effectively eliminated MSMA (V) adsorption indicating that iron oxides in the soil are primarily responsible for MSMA (V) adsorption; 3) the presence of phosphate in aqueous solutions inhibited MSMA (V) adsorption as a result of competitive adsorption between phosphate and MSMA (V); and 4) MSMA (V) adsorption and apparent adsorption extent were strongly influenced by pH indicating that surface complexation on amphoteric sorption sites in the soil was responsible for MSMA (V) adsorption

A theorem for the beam splitter entangler

It is conjectured that the an entanglement output states from a beam splitter requires the nonclassicality in the input state(M.S. Kim, W. Son, V. Buzek and P. L. Knight, Phys. Rev. A, 65, 032323(2002)). Here we give a proof for this conjecture.Comment: Two relevant literatures added. To appear in Phys. Rev.

Static and dynamic traversable wormhole geometries satisfying the Ford-Roman constraints

It was shown by Ford and Roman in 1996 that quantum field theory severely constrains wormhole geometries on a macroscopic scale. The first part of this paper discusses a wide class of wormhole solutions that meet these constraints. The type of shape function used is essentially generic. The constraints are then discussed in conjunction with various redshift functions. Violations of the weak energy condition and traversability criteria are also considered. The second part of the paper analyzes analogous time-dependent (dynamic) wormholes with the aid of differential forms. It is shown that a violation of the weak energy condition is not likely to be avoidable even temporarily.Comment: 16 pages AMSTe

Properties of a beam splitter entangler with Gaussian input states

An explicit formula is given for the quantity of entanglement in the output state of a beam splitter, given the squeezed vacuum states input in each mode.Comment: To appear in Phys. Rev.

Functional properties of two mutants of human glucose 6-phosphate dehydrogenase, R393G and R393H, corresponding to the clinical variants G6PD Wisconsin and Nashville

AbstractTwo severe Class I human glucose-6-phosphate dehydrogenase (G6PD, EC1.1.1.49) mutations, G6PDWisconsin (nt1177 C→G, R393G) and G6PDNashville (nt1178 G→A, R393H), affect the same codon, altering a residue in the dimer interface close to the “structural” NADP+ site. These mutations are predicted to influence interaction with the bound “structural” NADP+, long supposed to be crucial for enzyme stability. Recombinant proteins corresponding to these mutants have been constructed, expressed and purified to homogeneity. Steady-state kinetic parameters of the mutant enzymes were comparable to those of normal human G6PD, indicating that the mutations do not alter catalytic efficiency drastically. However, investigations of thermostability, urea denaturation, protease digestion, and hydrophobic exposure demonstrated that G6PD R393H is less stable than normal G6PD or R393G, and stability was more NADP+-dependent. Apoenzymes were prepared by removal of “structural” NADP+. Again the G6PDNashville protein was markedly less stable, and its dissociation constant for “structural” NADP+ is ∼500 nM, about 10 times higher than values for R393G (53 nM) and normal G6PD (37 nM). These results, together with structural information, suggest that the instability of the R393H protein, enhanced by the weakened binding of “structural” NADP+, is the likely cause of the severe clinical manifestation observed for G6PDNashville. They do not, however, explain the basis of disease in the case of G6PDWisconsin

Fiber depolymerization

Depolymerization is, by definition, a crucial process in the reversible assembly of various biopolymers. It may also be an important factor in the pathology of sickle cell disease. If sickle hemoglobin fibers fail to depolymerize fully during passage through the lungs then they will reintroduce aggregates into the systemic circulation and eliminate or shorten the protective delay (nucleation) time for the subsequent growth of fibers. We study how depolymerization depends on the rates of end- and side-depolymerization, kend and kside, which are, respectively, the rates at which fiber length is lost at each end and the rate at which new breaks appear per unit fiber length. We present both an analytic mean field theory and supporting simulations showing that the characteristic fiber depolymerization time View the MathML source depends on both rates, but not on the fiber length L, in a large intermediate regime 1 much less-than ksideL2/kend much less-than (L/d)2, with d the fiber diameter. We present new experimental data which confirms that both mechanisms are important and shows how the rate of side depolymerization depends strongly on the concentration of CO, acting as a proxy for oxygen. Our theory remains rather general and could be applied to the depolymerization of an entire class of linear aggregates, not just sickle hemoglobin fibers

Testing Gluino Spin with Three-Body Decays

We examine the possibility of distinguishing a supersymmetric gluino from a Kaluza-Klein gluon of universal extra dimensions (UED) at the Large Hadron Collider (LHC). We focus on the case when all kinematically allowed tree-level decays of this particle are 3-body decays into two jets and a massive daughter (typically weak gaugino or Kaluza-Klein weak gauge boson). We show that the shapes of the dijet invariant mass distributions differ significantly in the two models, as long as the mass of the decaying particle mA is substantially larger than the mass of the massive daughter mB. We present a simple analysis estimating the number of events needed to distinguish between the two models under idealized conditions. For example, for mA/mB=10, we find the required number of events to be of order several thousand, which should be available at the LHC within a few years. This conclusion is confirmed by a parton level Monte Carlo study which includes the effects of experimental cuts and the combinatoric background.Comment: 19 pages, 10 figure

Transverse oscillations of coronal loops

On 14 July 1998 TRACE observed transverse oscillations of a coronal loop generated by an external disturbance most probably caused by a solar flare. These oscillations were interpreted as standing fast kink waves in a magnetic flux tube. Firstly, in this review we embark on the discussion of the theory of waves and oscillations in a homogeneous straight magnetic cylinder with the particular emphasis on fast kink waves. Next, we consider the effects of stratification, loop expansion, loop curvature, non-circular cross-section, loop shape and magnetic twist. An important property of observed transverse coronal loop oscillations is their fast damping. We briefly review the different mechanisms suggested for explaining the rapid damping phenomenon. After that we concentrate on damping due to resonant absorption. We describe the latest analytical results obtained with the use of thin transition layer approximation, and then compare these results with numerical findings obtained for arbitrary density variation inside the flux tube. Very often collective oscillations of an array of coronal magnetic loops are observed. It is natural to start studying this phenomenon from the system of two coronal loops. We describe very recent analytical and numerical results of studying collective oscillations of two parallel homogeneous coronal loops. The implication of the theoretical results for coronal seismology is briefly discussed. We describe the estimates of magnetic field magnitude obtained from the observed fundamental frequency of oscillations, and the estimates of the coronal scale height obtained using the simultaneous observations of the fundamental frequency and the frequency of the first overtone of kink oscillations. In the last part of the review we summarise the most outstanding and acute problems in the theory of the coronal loop transverse oscillations

Entanglement capability of self-inverse Hamiltonian evolution

We determine the entanglement capability of self-inverse Hamiltonian evolution, which reduces to the known result for Ising Hamiltonian, and identify optimal input states for yielding the maximal entanglement rate. We introduce the concept of the operator entanglement rate, and find that the maximal operator entanglement rate gives a lower bound on the entanglement capability of a general Hamiltonian.Comment: 4 pages, no figures. Version 3: small change