bluuebunny/crossref_metadata_2025 huggingface dataset:
Computation of Sets of Rational Points of Genus-3 Curves via the Dem'Janenko–Manin Method
Authors: Girard Martine , Kulesz Leopoldo
Published: August 2013

The authors construct two families of genus-3 curves defined over Q(t) with three independent morphisms to an elliptic curve of rank at most two. They give explicit examples of an application of the Dem'janenko-Manin method that completely determines both the set of the Q(t)-rational points of the curves under consideration, and the set of Q-rational points of some specialisations.
On Homogenous Minimal Involutive Varieties
Authors: Almeida L. C. O. , Coutinho S. C.
Published: August 2013

Ѕ(2n,k) be the variety of homogeneous polynomials of degree k in 2n variables. The authors of this paper give a computer-assisted proof that there is an analytic open set Ω of Ѕ(4,3) such that the surface F = 0 is a minimal homogeneous involutive variety of ℂ4 for all F ∈ Ω. As part of the proof, they give an explicit example of a polynomial with rational coefficients that belongs to Ω.
Computing the Decay of a Simple Reversible Sub-Markov Semigroup
Authors: Davies E. B.
Published: August 2013

Two different numerical methods for solving a non-self-adjoint evolution equation are compared in this paper. If the intial function lies in the domain of the operator, a recently proposed method that combines pseudospectral ideas and semigroup theory is shown to be considerably more accurate than a standard discretization method. One example is worked out in detail, but the methodsa used are of much wider applicability.
Upper Bounds for Norms of Products of Binomials
Authors: Cipu Mihai
Published: August 2013

This paper deals with the problem of finding the least length of a product of n binomials. A theorem of R. Maltby has shown that the problem is algorithmically solvable for any fixed n. Here, a different proof is presented for this result, and yields improved complexity. The author reports the results of computations of the upper bounds on the least length or Euclidean norm of a product of binomials.
On Tensor-Factorisation Problems,I: The Combinatorial Problem
Authors: Neumann Peter M. , Praeger Cheryl E.
Published: August 2013

A k-multiset is an unordered k-tuple, perhaps with repetitions. If x is an r-multiset {x1, …, xr} and y is an s-multiset {y1, …, ys} with elements from an abelian group A the tensor product x ⊗ y is defined as the rs-multiset {xi yj | 1 ≤ i ≤ r, 1 ≤ j ≤ s}. The main focus of this paper is a polynomial-time algorithm to discover whether a given rs-multiset from A can be factorised. The algorithm is not guaranteed to succeed, but there is an acceptably small upper bound for the probability of failure. The paper also contains a description of the context of this factorisation problem, and the beginnings of an attack on the following division-problem: is a given rs-multiset divisible by a given r-multiset, and if so, how can division be achieved in polynomially bounded time?
Easy Decision Diffie-Hellman Groups
Authors: Galbraith Steven D. , Rotger Victor
Published: August 2013

The decision Diffie-Hellman problem (DDH) is a central computational problem in cryptography. It is known that the Weil and Tate pairings can be used to solve many DDH problems on elliptic curves. Distortion maps are an important tool for solving DDH problems using pairings, and it is known that distortion maps exist for all super-singular elliptic curves. An algorithm is presented here to construct suitable distortion maps. The algorithm is efficient on the curves that are usable in practice, and hence all DDH problems on these curves are easy. The issue of which DDH problems on ordinary curves are easy is also discussed.
Cross Orbits
Authors: Rowley Peter
Published: August 2013

This paper contains a variety of results about the action of Con way‘s largest simple group upon the crosses in the Leech lattice. These results are tailor-made for use in ‘A Monster Graph, I'(Proc. London Math. Soc. (3) 90 (2005) 42-60), where a graph related to the Monster simple group is studied.
An Algorithmic Analysis of the Intersection Property
Authors: Jacobs Pascale , Leemans Dimitri
Published: August 2013

In this paper, efficient algorithms are given to test the intersection property and some of its variations on flag-transitive coset geometries. These algorithms are then applied to geometries of some sporadic groups, namely the Mathieu groups M11, M12, M22and M23, the Janko groups J1, J2and J3 and the Higman-Sims group HS.
A Bound on the Number of Endpoints of the Cut Locus
Authors: Sinclair Robert , Tanaka Minoru
Published: August 2013

We provide strong experimental evidence for an upper bound on the number of endpoints of the cut locus from a point on a 2-surface of revolution. This bound is equal to the minimal number of intervals of monotone non-increasing or non-decreasing Gaussian curvature along one meridian from one pole to the other.
On Polynomial Interpolations related to Verheul Homomorphisms
Authors: Satoh Takakazu
Published: August 2013

The Verheul homomorphism is a group homomorphism from a finite subgroup of the multiplicative group of a field to an elliptic curve. The hardness of computation of the Verheul homomorphism was shown by Verheul to be closely related to the hardness of the computational Diffie-Hellman problem. Let p ≥ 5 be a prime, and let N be a prime satisfying √(12p) < N < 2p / √3, where N ≠ p. Let E be an ordinary elliptic curve over Fp, and let C ⊂ E be a cyclic subgroup of order N. Let H be the group of all Nth roots of unity (contained in the algebraic closure of Fp), and let phi be the Verheul isomorphism from H to C.

We consider a polynomial P such that P(z) is the X-coordinate of phi(z) for all z ∈ H – {1}. We show that, for at least approximately 58% of pairs (E, C), none of the coefficients of the non-constant terms of P vanishes.
Simple Lie Algebras of Low Dimension Over GF (2)
Authors: Vaughan-Lee Michael
Published: August 2013

We classify the simple Lie algebras of dimension at most 9 over GF(2). There is one of dimension 3 and one of dimension 6, there are two of dimension 7 and two of dimension 8, and there is one of dimension 9. The two simple Lie algebras of dimension 8 are restricted Lie algebras. If we extend the ground field to GF(4), then the six-dimensional algebra is no longer simple, and if we extend the ground field to GF(8) then the nine-dimensional algebra is no longer simple. But the other algebras are all central simple.
Resolving the Multitude of Microscale Interactions Accurately Models Stochastic Partial Differential Equations
Authors: Roberts A. J.
Published: August 2013

Constructing numerical models of noisy partial differential equations is a very delicate task. Our long-term aim is to use modern dynamical systems theory to derive discretisations of dissipative stochastic partial differential equations. As a second step, we consider here a small domain, representing a finite element, and derive a one-degree-of-freedom model for the dynamics in the element; stochastic centre manifold theory supports the model. The approach automatically parametrises the microscale structures induced by spatially varying stochastic noise within the element. The crucial aspect of this work is that we explore how a multitude of microscale noise processes may interact in nonlinear dynamical systems. The analysis finds that noise processes with coarse structure across a finite element are the significant noises for the modelling. Further, the nonlinear dynamics abstracts effectively new noise sources over the macroscale time-scales resolved by the model.
Lens Spaces, Isospectral on Forms but not on Functions
Authors: Gornet Ruth , McGowan Jeffrey
Published: August 2013

We study the p-form spectrum of the Laplace-Beltrami operator acting on lens spaces as considered by Ikeda [Geometry of manifolds (Academic Press, Boston, MA, 1989) 383–417]. Ikeda gave examples of such spaces that are non-isometric but isospectral for all p ≤ p0. In this paper we exhibit examples of such spaces that are not isometric, and are isospectral for various, but not for all. values of p. In particular, examples are given of non-isometric lens spaces that are isospectral for some values of p but not for the case p = 0.
Improved Bounds for the Spread of Sporadic Groups
Authors: Bradley J. D. , Holmes P. E.
Published: August 2013

The spread of a group G is the greatest number r such that, for every set of non-trivial elements {x1,…,xr}, there exists an element y with the property that 〈xi, y〉 = G for 1 ≤ i ≤ r. In this paper we obtain good upper bounds for the spread of fourteen sporadic simple groups computationally, and we determine the value of the spread of M11 by hand.
On the Computation of Integral Closures of Cyclic Extensions of Function Fields
Authors: Fraatz Robert
Published: August 2013

LetSbe a non-empty proper subset of the set of places of a global function fieldFandEa cyclic Kummer or Artin–Schreier–Witt extension ofF. We present a method of efficiently computing the ring of elements ofEwhich are integral at all places ofS. As an important tool, we include an algorithmic version of the strong approximation theorem. We conclude with several examples.
The Character Table of a Maximal Subgroup of the Monster
Authors: Barraclough R. W. , Wilson R. A.
Published: August 2013

We calculate the character table of the maximal subgroup of the Monster N(3B) isomorphic to a group of shape 3+1+12 · 2 · Suz: 2, and also of the group 31+12 : 6 · Suz · 2, which has the former as a quotient. The strategy is to induce characters from the inertia groups in 31+12 : 6 · Suz : 2 of characters of 31+12. We obtain the quotient map to N(3B) computationally, and our careful concrete approach allows us to produce class fusions between our tables and various tables in the GAP library.
Categorical Models of Syntactic Control of Intereference Revisited, Revisited
Authors: McCusker Guy
Published: August 2013

The question of what categorical structure is required to give semantics to O‘Hearn et al.'s type system Syntactic Control of Interference Revisited (SCIR) is considered. The previously proposed notion of bireflective model is rejected as being too restrictive to accommodate important concrete models based on game semantics and object spaces; furthermore it is argued that the existing proof-sketch of the important property of coherence for these models is incorrect. A new, more general notion of model is proposed and the coherence property proved.
Generating Series in the Cohomology of Hilbert Schemes of Points on Surfaces
Authors: Boissière Samuel , Nieper-Wisskirchen Marc A.
Published: August 2013

In the study of the rational cohomology of Hilbert schemes of points on a smooth surface, it is particularly interesting to understand the characteristic classes of the tautological bundles and the tangent bundle. In this note we pursue this study. We first collect all results appearing separately in the literature and prove some new formulas using Ohmoto's results on orbifold Chern classes on Hilbert schemes. We also explain the algorithmic counterpart of the topic: the cohomology space is governed by a vertex algebra that can be used to compute characteristic classes. We present an implementation of the vertex operators in the rewriting logic system MAUDE, and address observations and conjectures obtained after symbolic computations.
Fast Jacobian Group Operations for C3,4 Curves over a Large Finite Field
Authors: Abu Salem Fatima K. , khuri-makdisi Kamal
Published: August 2013

Let C be an arbitrary smooth algebraic curve of genus g over a large finite field F. The authors of this paper revisit fast addition algorithms in the Jacobian of C due to Khuri-Makdisi [math.NT/0409209, to appear in Mathematics of Computation]. The algorithms, which reduce to linear algebra in vector spaces of dimension O(g) once |K| ≫ g and which asymptotically require O(g2.376) field operations using fast linear algebra, are shown to perform efficiently even for certain low genus curves. Specifically, the authors provide explicit formulae for performing the group law on Jacobians of C3,4 curves of genus 3. They show show that, typically, the addition of two distinct elements in the Jacobian of a C3,4 curve requires 117 multiplications and 2 inversions in K, and an element can be doubled using 129 multiplications and 2 inversions in K. This represents an improvement of approximately 20% over previous methods.
A Polynomial with Galois Groups SL2(F16)
Authors: Bosman Johan
Published: August 2013

In this paper we display an explicit polynomial having Galois group SL2(F16), filling in a gap in the tables of Jürgen Klüners and Gunter Malle. Furthermore, the polynomial has small Galois root discriminant; this fact answers a question of John Jones and David Roberts. The computation of this polynomial uses modular forms and their Galois representations.
The Tropicalj-Invariant
Authors: Katz Eric , Markwig Hannah , Markwig Thomas
Published: August 2013

If (Q,A) is a marked polygon with one interior point, then a general polynomialfbelonging toK[x,y] with supportAdefines an elliptic curveCfon the toric surfaceXA. IfKhas a non-archimedean valuation intoRwe can tropicalizeCfto get a tropical curve Trop(Cf). If in the Newton subdivision induced byfis a triangulation and the interior point occurs as the vertex of a triangle, then Trop(Cf) will be a graph of genus one and we show that the lattice length of the cycle of that graph is the negative of the valuation of thej-invariant ofCf.
A Point Counting Algorithm Using Cohomology with Compact Support
Authors: Chatel Gweltaz , Lubicz David
Published: August 2013

We describe an algorithm to count the number of rational points of an hyperelliptic curve defined over a finite field of odd characteristic which is based upon the computation of the action of the Frobenius morphism on a basis of the Monsky-Washnitzer cohomology with compact support. This algorithm follows the vein of a systematic exploration of potential applications of cohomology theories to point counting.

Our algorithm decomposes in two steps. A first step which consists of the computation of a basis of the cohomology and then a second step to obtain a representation of the Frobenius morphism. We achieve aÕ(g4n3) time complexity andO(g3n3) memory complexity wheregis the genus of the curve andnis the absolute degree of its base field. We give a detailed complexity analysis of the algorithm as well as a proof of correctness.
Modular Polynomials for Genus 2
Authors: Bröker Reinier , Lauter Kristin
Published: August 2013

Modular polynomials are an important tool in many algorithms involving elliptic curves. In this article we investigate their generalization to the genus 2 case following pioneering work by Gaudry and Dupont. We prove various properties of these genus 2 modular polynomials and give an improved way to explicitly compute them.
Single-class genera of positive integral lattices
Authors: Lorch David , Kirschmer Markus
Published: August 2013

We give an enumeration of all positive definite primitive $ \mathbb{Z} $-lattices in dimension $n\geq 3$ whose genus consists of a single isometry class. This is achieved by using bounds obtained from the Smith–Minkowski–Siegel mass formula to computationally construct the square-free determinant lattices with this property, and then repeatedly calculating pre-images under a mapping first introduced by G. L. Watson.

We hereby complete the classification of single-class genera in dimensions 4 and 5 and correct some mistakes in Watson’s classifications in other dimensions. A list of all single-class primitive $ \mathbb{Z} $-lattices has been compiled and incorporated into the Catalogue of Lattices.
Defining the neurocircuitry of exercise hyperpnoea
Authors: Paterson David J.
Published: August 2013

One hundred years ago in this journal, Krogh and Lindhard published a seminal paper highlighting the importance of the brain in the control of breathing during exercise. This symposium report reviews the historical developments that have taken place since 1913, and attempts to place the detailed neurocircuitry thought to underpin exercise hyperpnoea into context by focusing on key structures that might form the command network. With the advent of enhanced neuroimaging and functional neurosurgical techniques, a unique window of opportunity has recently arisen to target potential circuits in humans. Animal studies have identified a priori sites of interest in mid‐brain structures, in particular the subthalamic locomotor region (subthalamic nucleus, STN) and the periaqueductal grey (PAG), which have now been recorded from in humans during exercise. When all data are viewed in an integrative manner, the PAG, in particular the lateral PAG, and aspects of the dorsal lateral PAG, appear to be key communicating circuitry for ‘central command’. Moreover, the PAG also fulfils many requirements of a command centre. It has functional connectivity to higher centres (dorsal lateral prefrontal cortex) and the basal ganglia (in particular, the STN), and receives a sensory input from contracting muscle, but, importantly, it sends efferent information to brainstem nuclei involved in cardiorespiratory control.
A CFD Study of Pressure Fluctuations to Determine Fluidization Regimes in Gas–Solid Beds
Authors: Deza Mirka , Battaglia Francine
Published: August 2013

Reliable computational methods can provide valuable insight into gas–solid flow processes and can be used as a design tool. Of particular interest in this study is the hydrodynamics of a binary mixture of sand–biomass in a fluidized bed. Biomass particulates vary in size, shape, and density, which inevitably alter how well the particles fluidize. Our study will use computational fluid dynamics (CFD) to interpret the hydrodynamic states of a fluidized bed by analyzing the local pressure fluctuations of beds of sand and a binary mixture of cotton stalks and sand over long time periods. Standard deviation of pressure fluctuations will be compared with experimental data to determine different fluidization regimes at inlet gas velocities ranging from two to nine times the minimum fluidization velocity. We will use Bode plots to present the pressure spectra and reveal characteristic frequencies that describe the bed hydrodynamics for different fluidization regimes. This work will present CFD as a useful tool to perform that analysis. Other important contributions include the study of pressure fluctuations of a fluidized bed in bubbling, slugging, and turbulent regimes, and the analysis of a binary mixture using CFD.
Pressure Drop Predictions for Laminar Fully-Developed Flows of Purely-Viscous Non-Newtonian Fluids in Circular Ducts
Authors: Brewster Robert A.
Published: August 2013

This paper provides the results of numerical calculations of pressure drops and centerline velocities for laminar fully-developed flows of non-Newtonian fluids in circular ducts. The particular non-Newtonian fluid model considered is the Cross model, which has shown the ability to model the behavior of time-independent purely-viscous fluids over a wide range of shear rates. It is shown that the Cross model is equivalent to the more recently proposed extended modified power law (EMPL) model, and an alternative formulation of the nondimensional parameters arising from the use of these models is explored. Results are presented for friction factors and nondimensional centerline velocities over a wide range of fluid and flow conditions, and it is shown that simpler constitutive models can be used in cases where the ratios of the limiting Newtonian viscosities are extreme. The implications of the results to the design and analysis of piping systems is considered, and simple and accurate correlations are provided for engineering calculations.
Detection of Laminar Flow Separation and Transition on a NACA-0012 Airfoil Using Surface Hot-Films
Authors: Rudmin Daniel , Benaissa Azemi , Poirel Dominique
Published: August 2013

A method for mapping the separation and transition of flow over a slowly pitching airfoil with high angular resolution is presented. An array of surface-mounted hot-film sensors is used to record simultaneous corresponding voltages. The method makes use of windowed correlation and spectral signatures of hot-film sensor voltages in synchronization with a servo-motor controlling airfoil pitch angle. Results are given for a NACA-0012 airfoil at three airspeeds at pitch angles of less than 6 deg. The airspeeds correspond to a region of known aeroelastic instability; they are situated between chord Reynolds numbers of 50,000 and 130,000. Tests in static and quasi-static pitch motion schedules were conducted. The quasi-static airfoil was sinusoidally pitching at 0.025 Hz between −6 deg and +6 deg (corresponding to a half-chord based reduced frequency between 0.0011 and 0.0020) and the detected separation and transition agreed very well with the static case. These results constitute a verification of the method used and provide insight into the size and location of the laminar separation bubble at transitional Reynolds numbers.
Numerical Simulation and Modeling of Laminar Developing Flow in Channels and Tubes With Slip
Authors: Muzychka Y. S. , Enright R.
Published: August 2013

Analytical solutions for slip flows in the hydrodynamic entrance region of tubes and channels are examined. These solutions employ a linearized axial momentum equation using Targ's method. The momentum equation is subjected to a first order Navier slip boundary condition. The accuracy of these solutions is examined using computational fluid dynamics (CFD) simulations. CFD simulations utilized the full Navier–Stokes equations, so that the implications of the approximate linearized axial momentum equation could be fully assessed. Results are presented in terms of the dimensionless mean wall shear stress, τ⋆, as a function of local dimensionless axial coordinate, ξ, and relative slip parameter, β. These solutions can be applied to either rarefied gas flows when compressibility effects are small or apparent liquid slip over hydrophobic and superhydrophobic surfaces. It has been found that, under slip conditions, the minimum Reynolds number should be ReDh>100 in order for the approximate linearized solution to remain valid.
Experimental Study on a Medium Consistency Pump
Authors: Ma X. D. , Li Z. F. , Yu H. , Wu D. Z. , Wang L. Q.
Published: August 2013

An experimental testing rig is built to study the performance of a centrifugal pump used in medium consistency technology (MC technology). Pump performances are tested in different pulp concentration, degas pressure differential, and tip clearance ratio. The results show that in medium concentration, pump head and efficiency decreases with increase of pulp concentration. There is a critical concentration above which pump performance drops. Gas separation effect is influenced by the pressure differential over the degas system and the air content in the pulp suspension. In high concentration and small tip clearance conditions, friction loss increases a great deal and results in an efficiency reduction.
Nonlinear Interactions in Systems of Multiple Order Centrifugal Pendulum Vibration Absorbers
Authors: Vidmar Brendan J. , Shaw Steven W. , Feeny Brian F. , Geist Bruce K.
Published: August 2013

We consider nonlinear interactions in systems of order-tuned torsional vibration absorbers with sets of absorbers tuned to different orders. In all current applications, absorber systems are designed to reduce torsional vibrations at a single order. However, when two or more excitation orders are present and absorbers are introduced to address different orders, nonlinear interactions become possible under certain resonance conditions. Under these conditions, a common example of which occurs for orders n and 2n, crosstalk between the absorbers, acting through the rotor inertia, can result in instabilities that are detrimental to system response. In order to design absorber systems that avoid these interactions, and to explore possible improved performance with sets of absorbers tuned to different orders, we develop predictive models that allow one to examine the effects of absorber mass distribution and tuning. These models are based on perturbation methods applied to the system equations of motion, and they yield system response features, including absorber and rotor response amplitudes and stability, as a function of parameters of interest. The model-based analytical results are compared against numerical simulations of the complete nonlinear equations of motion, and are shown to be in good agreement. These results are useful for the selection of absorber parameters to achieve desired performance. For example, they allow for approximate closed form expressions for the ratio of absorber masses at the two orders that yield optimal performance. It is also found that utilizing multiple order absorber systems can be beneficial for system stability, even when only a single excitation order is present.
Modulation Spectroscopy of Acoustic Waves in Solids Containing Contact-Type Cracks
Authors: Tszeng T. C.
Published: August 2013

This study examined the characteristics of sidebands in modulation spectroscopy on a high-frequency wave interacting with a defect that imposes a simple switching type disruption caused by a low-frequency, high-amplitude vibration. A simple close form of sideband amplitude is obtained by convolution of a high-frequency probing wave with harmonics of a pulse wave. This study also proposes an experimental procedure based on sideband phases for determining the crack parameters.
On the Poisson's Ratio of the Nucleus Pulposus
Authors: Farrell M. D. , Riches P. E.
Published: August 2013

Existing experimental data on the Poisson's ratio of nucleus pulposus (NP) tissue is limited. This study aims to determine whether the Poisson's ratio of NP tissue is strain-dependent, strain-rate-dependent, or varies with axial location in the disk. Thirty-two cylindrical plugs of bovine tail NP tissue were subjected to ramp-hold unconfined compression to 20% axial strain in 5% increments, at either 30 μm/s or 0.3 μm/s ramp speeds and the radial displacement determined using biaxial video extensometry. Following radial recoil, the true Poisson's ratio of the solid phase of NP tissue increased linearly with increasing strain and demonstrated strain-rate dependency. The latter finding suggests that the solid matrix undergoes stress relaxation during the test. For small strains, we suggest a Poisson's ratio of 0.125 to be used in biphasic models of the intervertebral disk.
Fast direct estimation of the blood input function and myocardial time activity curve from dynamic SPECT projections via reduction in spatial and temporal dimensions
Authors: Zan Yunlong , Boutchko Rostyslav , Huang Qiu , Li Biao , Chen Kewei , Gullberg Grant T.
Published: August 2013

Purpose:

Reconstruction of parametric images from dynamic single photon emission computed tomography (SPECT) data acquired with slow rotating cameras is a challenge because the estimation of the time–activity curves (TACs) may involve fitting data to an inconsistent underdetermined system of equations. This work presents a novel algorithm for the estimation of the blood input function and myocardial TAC with high accuracy and high efficiency directly from these projections.

Methods:

In the proposed dynamic reconstruction method, the information from the segmentation of functional regions from the static reconstructed image was used as a prior to construct a sparse matrix, through which the spatial distribution of the radioactive tracer was represented. Then the temporal distribution of the radioactive tracer was modeled by nonuniform B‐spline basis functions which were determined according to a new selection rule. With reduction in both the spatial and temporal dimensions of the reconstructed image, the blood input function and myocardial TAC were estimated using the 4D maximum likelihood expectation maximization algorithm. The method was validated using data from both digital phantom simulations and an experimental rat study.

Results:

Compared with the conventional dynamic SPECT reconstruction method without the reduction in spatial dimensions, the proposed method provides more accurate TACs with less computation time in both phantom simulation studies and a rat experimental study.

Conclusions:

The proposed method is promising in both providing more accurate time–activity curves and reducing the computation time, which makes it practical for small animal studies using clinical systems with slow rotating cameras.
Science Signaling
Podcast: 6 August 2013
Authors: Lauffenburger Douglas A. , VanHook Annalisa M.
Published: August 2013

Amplification of the receptor tyrosine kinase AXL correlates with resistance to ErbB inhibitors in cancer cells.
Bacterial Subversion Tactics
Authors: Hurtley Stella M.
Published: August 2013

The bacterial pathogen
Listeria monocytogenes
exploits histone modifications to reprogram its host.
Modification Without Enzymes
Authors: Ray L. Bryan
Published: August 2013

A reactive intermediate formed during glycolysis reacts nonenzymatically to inhibit glycolytic enzymes.
Yap Methylated
Authors: VanHook Annalisa M.
Published: August 2013

The methyltransferase Set7 promotes cytoplasmic retention of the transcriptional coactivator Yap.
Painful Long Noncoding RNA
Authors: Gough Nancy R.
Published: August 2013

Peripheral nerve injury induces an lncRNA that reduces the abundance of a potassium channel, thereby increasing neuronal excitability.
SbcCD-Mediated Processing of Covalent Gyrase-DNA Complex in Escherichia coli
Authors: Aedo Sandra , Tse-Dinh Yuk-Ching
Published: August 2013

Quinolones trap the covalent gyrase-DNA complex in
Escherichia coli
, leading to cell death. Processing activities for trapped covalent complex have not been characterized. A mutant strain lacking SbcCD nuclease activity was examined for both accumulation of gyrase-DNA complex and viability after quinolone treatment. Higher complex levels were found in Δ
sbcCD
cells than in wild-type cells after incubation with nalidixic acid and ciprofloxacin. However, SbcCD activity protected cells against the bactericidal action of nalidixic acid but not ciprofloxacin.
Antimicrobial Peptide GL13K Is Effective in Reducing Biofilms of Pseudomonas aeruginosa
Authors: Hirt Helmut , Gorr Sven-Ulrik
Published: August 2013

Human parotid secretory protein (PSP; BPIF2A) is predicted to be structurally similar to bactericidal/permeability-increasing protein and lipopolysaccharide (LPS)-binding protein. Based on the locations of known antimicrobial peptides in the latter two proteins, potential active peptides in the PSP sequence were identified. One such peptide, GL13NH
2
(PSP residues 141 to 153) was shown previously to interfere with LPS binding and agglutinate bacteria without bactericidal activity. By introducing three additional positively charged lysine residues, the peptide was converted to the novel bactericidal cationic peptide GL13K (MIC for
Pseudomonas aeruginosa
, 8 μg/ml [5.6 μM]). We investigated the antibiofilm activity of GL13K against static, monospecies biofilms of
P. aeruginosa
PAO1. Two-hour exposure of a 24-h biofilm to 64 μg/ml (44.8 μM) GL13K reduced biofilm bacteria by 10
2
, and 100 μg/ml (70 μM) GL13K reduced bacteria by 10
3
. Similar results could be achieved on 48-h-old biofilms. Lower concentrations of GL13K (32 μg/ml [22.4 μM]) were successful in reducing biofilm cell numbers in combination with tobramycin. This combination treatment also achieved total eradication of the biofilm in a majority (67.5%) of tested samples. An alanine scan of GL13K revealed the importance of the leucine residue in position six of the peptide sequence, where replacement led to a loss of antibiofilm activity, whereas the impact of replacing charged residues was less pronounced. Bacterial metalloproteases were found to partially inactivate GL13K but not a
d
amino acid version of the peptide.
Bioluminescence-Based Neuraminidase Inhibition Assay for Monitoring Influenza Virus Drug Susceptibility in Clinical Specimens
Authors: Marjuki Henju , Mishin Vasiliy P. , Sleeman Katrina , Okomo-Adhiambo Margaret , Sheu Tiffany G. , Guo Lizheng , Xu Xiyan , Gubareva Larisa V.
Published: August 2013

The QFlu prototype bioluminescence-based neuraminidase (NA) inhibition (NI) assay kit was designed to detect NA inhibitor (NAI)-resistant influenza viruses at point of care. Here, we evaluated its suitability for drug susceptibility assessment at a surveillance laboratory. A comprehensive panel of reference viruses (
n
= 14) and a set of 90 seasonal influenza virus A and B isolates were included for testing with oseltamivir and/or zanamivir in the QFlu assay using the manufacturer-recommended protocol and a modified version attuned to surveillance requirements. The 50% inhibitory concentrations (IC
50
s) generated were compared with those of NI assays currently used for monitoring influenza drug susceptibility, the fluorescent (FL) and chemiluminescent (CL) assays. To provide proof of principle, clinical specimens (
n
= 235) confirmed by real-time reverse transcription (RT)-PCR to contain influenza virus A(H1N1)pdm09 and prescreened for the oseltamivir resistance marker H275Y using pyrosequencing were subsequently tested in the QFlu assay. All three NI assays were able to discriminate the reference NA variants and their matching wild-type viruses based on the difference in their IC
50
s. Unless the antigenic types were first identified, certain NA variants (e.g., H3N2 with E119V) could be detected among seasonal viruses using the FL assays only. Notably, the QFlu assay identified oseltamivir-resistant A(H1N1)pdm09 viruses carrying the H275Y marker directly in clinical specimens, which is not feasible with the other two phenotypic assays, which required prior virus culturing in cells. Furthermore, The QFlu assay allows detection of the influenza virus A and B isolates carrying established and potential NA inhibitor resistance markers and may become a useful tool for monitoring drug resistance in clinical specimens.
Population Pharmacokinetics of Colistin Methanesulfonate in Rats: Achieving Sustained Lung Concentrations of Colistin for Targeting Respiratory Infections
Authors: W. S. Yapa Shalini , Li Jian , Porter Christopher J. H. , Nation Roger L. , Patel Kashyap , McIntosh Michelle P.
Published: August 2013

Colistin methanesulfonate (CMS), the inactive prodrug of colistin, is administered by inhalation for the management of respiratory infections. However, limited pharmacokinetic data are available for CMS and colistin following pulmonary delivery. This study investigates the pharmacokinetics of CMS and colistin following intravenous (i.v.) and intratracheal (i.t.) administration in rats and determines the targeting advantage after direct delivery into the lungs. In addition to plasma, bronchoalveolar lavage (BAL) fluid was collected to quantify drug concentrations in lung epithelial lining fluid (ELF). The resulting data were analyzed using a population modeling approach in S-ADAPT. A three-compartment model described the disposition of both compounds in plasma following i.v. administration. The estimated mean clearance from the central compartment was 0.122 liters/h for CMS and 0.0657 liters/h for colistin. Conversion of CMS to colistin from all three compartments was required to fit the plasma data. The fraction of the i.v. dose converted to colistin in the systemic circulation was 0.0255. Two BAL fluid compartments were required to reflect drug kinetics in the ELF after i.t. dosing. A slow conversion of CMS (mean conversion time [MCT
CMS
] = 3.48 h) in the lungs contributed to high and sustained concentrations of colistin in ELF. The fraction of the CMS dose converted to colistin in ELF (
f
m,ELF =
0.226) was higher than the corresponding fractional conversion in plasma after i.v. administration. In conclusion, pulmonary administration of CMS achieves high and sustained exposures of colistin in lungs for targeting respiratory infections.
Rapid Emergence of Resistance to Linezolid and Mutator Phenotypes in Staphylococcus aureus Isolates from an Adult Cystic Fibrosis Patient
Authors: Tazi Asmaa , Chapron Jeanne , Touak Gerald , Longo Magalie , Hubert Dominique , Collobert Gislène , Dusser Daniel , Poyart Claire , Morand Philippe C.
Published: August 2013

Linezolid has emerged as an important therapeutic option for the treatment of
Staphylococcus aureus
in patients with cystic fibrosis. We report the rapid emergence, upon treatment with linezolid, of linezolid-resistant
S. aureus
clinical isolates through the accumulation of resistance-associated 23S rRNA mutations, together with acquisition of an altered mutator phenotype.
Requirement and Redundancy of the Src Family Kinases Fyn and Lyn in Perforin-Dependent Killing of Cryptococcus neoformans by NK Cells
Authors: Oykhman Paul , Timm-McCann Martina , Xiang Richard F. , Islam Anowara , Li Shu Shun , Stack Danuta , Huston Shaunna M. , Ma Ling Ling , Mody Christopher H.
Published: August 2013

Natural killer (NK) cells directly recognize and kill fungi, such as the pathogenic fungusCryptococcus neoformans, via cytolytic mechanisms. However, the precise signaling pathways governing this NK cell microbicidal activity and the implications for fungal recognition are still unknown. Previously, it was reported that NK cell anticryptococcal activity is mediated through a conserved phosphatidylinositol 3-kinase–extracellular signal-regulated kinase 1/2 (PI3K-ERK1/2) pathway. Using YT (a human NK-like cell line) and primary human NK cells, we sought to identify the upstream, receptor-proximal signaling elements that led to fungal cytolysis. We demonstrate that Src family kinases were activated in response toC. neoformans. Furthermore, pharmacologic inhibition with an Src kinase inhibitor blockedC. neoformans-induced downstream activation of PI3K and ERK1/2 and abrogated cryptococcal killing. At the same time, the inhibitor disrupted the polarization of perforin-containing granules toward the NK cell-cryptococcal synapse but had no effect on conjugate formation between the organism and the NK cell. Finally, small interfering RNA (siRNA) double (but not single) knockdown of two Src family kinases, Fyn and Lyn, blocked cryptococcal killing. Together these data demonstrate a mechanism whereby the Src family kinases, Fyn and Lyn, redundantly mediate anticryptococcal activity through the activation of PI3K and ERK1/2, which in turn facilitates killing by inducing the polarization of perforin-containing granules to the NK cell-cryptococcal synapse.
An Exploratory Review of the Electroacupuncture Literature: Clinical Applications and Endorphin Mechanisms
Authors: Mayor David
Published: August 2013

Electroacupuncture (EA) is widely used in clinical practice and research, as well as in experimental investigations into the mechanisms of acupuncture. This study explores publication trends in clinical and experimental studies of EA (1975–2011) for pain and non-pain research; EA use for different clinical conditions (1974–2012); and the relation of EA research, including stimulation frequency, to opioid peptide mechanisms.

Appropriate PubMed ‘all fields’ searches were conducted, identified studies were classified using PubMed filters and manually, and data extracted into tables. A total of

2916 clinical studies were located, of which 19% involved EA. Additionally, 3344 animal studies were located, of which 48% involved EA. The publication rate of EA studies per year has risen over time, but the percentage of studies of pain has fallen from 60% to 25%. The conditions most commonly treated with EA are musculoskeletal, neurological, obstetric and gastrointestinal, along with intraoperative and postoperative analgesia. EA studies, particularly with low frequency stimulation, are more likely to support the role of endogenous opioid mechanisms than manual acupuncture studies, and opioid release is more likely in the central nervous system than the circulation.

EA is increasingly used in clinical and especially experimental research, particularly for non-pain conditions. Acupuncture does release endogenous opioids, but this probably depends on ‘dosage’, with the evidence more consistent and convincing for EA than for manual acupuncture. Different frequencies of EA appear to activate different endogenous opioid mechanisms.
Association of possible osteopetrosis with acute myeloid leukaemia in a child
Authors: Prasad Rajniti , Jaiswal B P , Mishra O P , Singh Utpal Kant
Published: August 2013

Osteopetrosis is a rare disease characterised by an increase in bone mass, skeletal malformations and bone marrow failure due to defective bone resorption. We report a 3-month-old male child presented with chest infections, failure to thrive and hepatosplenomegaly and diagnosed with osteopetrosis associated with acute myeloid leukaemia M3type (AML-M3). The patient died on day 7 of admission due to respiratory failure. To our knowledge, this is the first case where both osteopetrosis and AML is diagnosed in a patient.
Bleeding associated with acquired factor V inhibitor in a patient on warfarin treated successfully with prednisolone
Authors: Khalafallah Alhossain , Grabek Julian , Hayes Robert , Mohamed Muhajir
Published: August 2013

An 85-year-old man on warfarin for atrial fibrillation presented with skin bleeding. International normalised ratio (INR) and activated partial thromboplastin time (APTT) were elevated and did not correct even after warfarin reversal with vitamin K, prothrombin complex concentrate (PCC) and fresh frozen plasma. Mixing coagulation studies with normal plasma suggested the presence of an inhibitor rather than the multiple coagulation factor deficiencies expected with warfarin. Assays of the common-pathway coagulation factors revealed factor V concentration <2% with inhibitor level elevated to 11 Bethesda units. The bleeding resolved following a course of corticosteroids. Coagulation studies and factor V level returned to normal along with resolution of the inhibitor. We report the case of the diagnostic dilemma posed and successful therapy implemented despite the limited evidence-based data being available for the treatment of this rare condition.
Lung herniation: an uncommon presentation of Poland's syndrome in a neonate at birth
Authors: Chandran Suresh , Revanna Krishna Gopagondanahalli , Ari Dinesh , Rana Aftab Ahmed
Published: August 2013

A term male infant was admitted to the neonatal intensive care unit with an asymmetric chest wall and a herniating mass through the left fourth intercostal space. While crying, the left fourth intercostal space revealed a mass which herniated on expiration and receded on inspiration. On auscultation, the heart sounds were audible on the right side of the chest. Systemic examination was otherwise unremarkable. A roentgenogram of the chest revealed dextrocardia and hyperlucent left lung fields. Echocardiogram showed dextrocardia with a structurally normal heart. A clinical diagnosis of Poland's syndrome was made based on the hypoplasia of the left pectoral muscles, ribs and nipple, dextrocardia and lung herniation. He was thriving well when reviewed at 2 years of age.
Acquired haemophilia A initially diagnosed as angioedema
Authors: Demissie Asmeret , Shahani Lokesh , Khan Aziz , Desai Meghna
Published: August 2013

Acquired haemophilia (AH) is a bleeding diathesis caused by inhibitors to factor VIII. Patients developing AH may present with catastrophic bleeding episodes despite having no prior history of bleeding disorder. The authors report a patient with AH who presented with tongue swelling and was diagnosed with angioedema on presentation. However, the patient started bleeding spontaneously after presentation and was diagnosed with AH and the workup revealed haematoma of the tongue, which was the cause of tongue swelling. As previously reported in the literature, AH in this patient might have been precipitated secondary to exposure to an ear infection or exposure to the penicillin group of antibiotics. Laboratory examination was confirmatory for AH, which was appropriately treated with recombinant activated factor VIIa and immunosuppressive therapy with good outcomes. Understanding the pathophysiology of AH and appropriate management is important to prevent life-threatening bleeding.
Effectiveness of an educational video on concussion knowledge in minor league hockey players: a cluster randomised controlled trial
Authors: Cusimano Michael D , Chipman Mary , Donnelly Peter , Hutchison Michael G
Published: August 2013

Background

With the heightened awareness of concussions in all sports, the development and implementation of effective prevention strategies are necessary. Education has been advocated as an effective injury prevention intervention.

Purpose

To examine the effectiveness of the ‘Smart Hockey: More Safety, More Fun’ video on knowledge transfer among minor league hockey players.

Study Design

Cluster-randomised controlled trial.

Methods

A total of 267 participants from two age divisions and competitive levels were assigned to either avideoorno-videogroup. The video was shown (or not shown) to the entire team as a result of random assignment. To evaluate the effectiveness of the educational video, questionnaires specific to concussion knowledge and players’ attitudes and behaviours were completed.

Results

There was a significant increase in the players’ concussion knowledge scores immediately following exposure to the video (F(1,103)=27.00, p<0.001). However, concussion knowledge at 2 months was not significantly different between thevideoandno-videogroups, after controlling for prior knowledge level, age and competitive level (F(1,115)=0.41, p=0.523). Similarly, players’ attitudes and behaviour scores at 2 months did not differ between groups (F(1,115)=0.41, p=0.507).

Conclusions

We were able to show that a single viewing of an educational video in hockey could immediately improve knowledge about concussion but that this effect was transient and lost at 2-month follow-up. Future prevention endeavours in hockey and other sports should attempt to incorporate strategies and modalities to enhance knowledge retention.
Ideology and disease identity: the politics of rickets, 1929–1982
Authors: Bivins Roberta
Published: August 2013

How can we assess the reciprocal impacts of politics and medicine in the contemporary period? Using the example of rickets in twentieth century Britain, I will explore the ways in which a preventable, curable non-infectious disease came to have enormous political significance, first as a symbol of socioeconomic inequality, then as evidence of racial and ethnic health disparities. Between the 1920s and 1980s, clinicians, researchers, health workers, members of Parliament and later Britain's growing South Asian ethnic communities repeatedly confronted the British state with evidence of persistent nutritional deficiency among the British poor and British Asians. Drawing on bitter memories of the ‘Hungry Thirties’, postwar rickets—so often described as a ‘Victorian’ disease—became a high-profile sign of what was variously constructed as a failure of the Welfare State; or of the political parties charged with its protection; or of ethnically Asian migrants and their descendants to adapt to British life and norms. Here I will argue that rickets prompted such consternation not because of its severity, the cost of its treatment, or even its prevalence; but because of the ease with which it was politicised. I will explore the ways in which this condition was envisioned, defined and addressed as Britain moved from the postwar consensus to Thatcherism, and as Britain's diverse South Asian communities developed from migrant enclaves to settled multigenerational ethnic communities.
HADRONIC τ AND e+e-SPECTRA, CONTRIBUTION TO (g-2)μAND QCD STUDIES
Authors: MALAESCU BOGDAN
Published: August 2013

The dominant contribution to the uncertainty of the theoretical prediction of the (g-2) of the muon comes from the leading order hadronic vacuum polarization part. This contribution is evaluated using either tau or e+e-experimental data. The same experimental data are exploited for QCD studies. We present an update of the ALEPH hadronic spectral functions. This update induces only small changes for the hadronic contribution to the (g-2) of the muon and for the QCD fits. We also present updates of the contributions to g-2 for several channels of e+e-into hadrons.