bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sensitivity enhancement of CE and CE‐MS for the analysis of peptides by a dynamic pH junction
Authors: Hasan Md. Nabiul , Park Soo Hyun , Oh Eulsik , Song Eun Joo , Ban Eunmi , Yoo Young Sook 
Published: November 2010

AbstractAn analytical method of CE‐MS and CE with an online preconcentration technique induced by a dynamic pH junction, addition of organic solvent and large volume injection was developed for sensitive determination of peptides in biological samples. Leucine enkephalin, methionine enkephalin, dynorphin A, β‐endorphin and angiotensin II were used as model peptides. The optimal online preconcentration conditions were obtained at a sample matrix consisting of 100 mM borate buffer (pH 10.0) with 50% v/v acetonitrile and a BGE containing 1 M formic acid at pH 2.0, along with a 25‐cm injection length. Under the optimized conditions, a 4.0×103–1.1×104‐fold increase in peak intensity was achieved without degrading the peak shape. This online preconcentration method was applied to analyze the intracellular angiotensin II within the peptides extracted from HL1 cells and approximately increase of 1×104‐fold sensitivity was achieved compared to normal condition. Thus, the developed method could be applied to the analysis of various peptides for peptidomics study in biological samples.
Development and optimization of an LC‐MS/MS‐based method for simultaneous quantification of vitamin D2, vitamin D3, 25‐hydroxyvitamin D2 and 25‐hydroxyvitamin D3
Authors: Adamec Jiri , Jannasch Amber , Huang Jianjie , Hohman Emily , Fleet James C. , Peacock Munro , Ferruzzi Mario G. , Martin Berdine , Weaver Connie M. 
Published: November 2010

AbstractSimultaneous and accurate measurement of vitamin D and 25‐hydroxyvitamin D in biological samples is a barrier limiting our ability to define “optimal” vitamin D status. Thus, our goal was to optimize conditions and evaluate an LC‐MS method for simultaneous detection and quantification of vitamin D2, vitamin D3, 25‐hydroxyvitamin D2 and 25‐hydroxyvitamin D3 in serum. Extraction and separation of vitamin D forms were achieved using acetone liquid–liquid extraction and by a reversed phase C8 column, respectively. Detection was performed on a triple quadrupole tandem mass spectrometer (QQQ‐MS/MS) equipped with atmospheric pressure photo ionization source. The LOQs for all analytes tested were 1 ng/mL for hydroxylated molecules and 2 ng/mL for the parent vitamin Ds. RSD at lower LOQ (2 ng/mL) and in medium (80 ng/mL) and high (200 ng/mL) quality control samples did not exceed 20 and 15% CV, respectively. Accuracy of the method for determination of hydroxylated molecules was also validated using National Institutes of Standards and Technology standard samples and found to be in the range of 90.9–111.2%. In summary, a sensitive and reproducible method is reported for simultaneous quantification of vitamin D2, vitamin D3, 25‐hydroxyvitamin D2 and 25‐hydroxyvitamin D3 molecules in biological samples.
Connectivity in Lattice‐Ordered Spaces
Authors: Erné M. , Vainio R. 
Published: November 2010

AbstractThe classical order‐theoretical characterizations of compact and connected chains, respectively, are extended to wider classes of lattices, using the fact that compactness and (path‐) connectedness of maximal chains are closely related to the corresponding properties of the whole lattice (as was already pointed out in an earlier paper due to the second author). Here we replace maximal chains by “links” and study several new types of connectedness in ordered convergence spaces, such as path‐connectedness, link‐connectedness and 1‐connectedness. As a useful framework for these studies, we introduce the concept of “connectivity systems”.
Mean Values of Weighted Cells of Stationary Poisson Hyperplane Tessellations of IRd
Authors: Favis Wassilis , Weiß Viola 
Published: November 2010

AbstractThis paper deals with stationary Poisson hyperplane tessellations. Weighted distributions are considered, where the weights are the volume of the cell and the total volume of all faces of the cell. A randomly chosen cell according to such a weighted distribution will be called volume weighted cell and face content weighted cell, respectively. Mean values of cell characteristics for such weighted cells are calculated. These results are connected with second‐order quantities for the typical cell of a stationary Poisson hyperplane tessellation. There are no suppositions to the isotropy of the tessellation, stationarity is sufficient. In case of isotropy already known results for planar tessellations from [AMS], [Mi1] and [Mi2] will be confirmed. A stereological interpretation of weighted cells is given by the aid of suitable intersections.
Tauberian Theorems for Sequences linked by a Convolution
Authors: Warlimont Richard 
Published: November 2010

AbstractGiven sequences g, λ: IN0 → C, g (0) = 1, linked by the convolution λ g = g′1 (g′1(n)= (n + 1) g (n + 1)) we study what can be inferred about λ (n → ∞) from some concrete information about the behaviour of g (n → ∞).
A New Proof of a Theorem of Beorchia on the Genus of Space Curves
Authors: Schlesinger Enrico 
Published: November 2010

AbstractWe give a new proof of a theorem of Beorchia which provides a bound P(d, t) for the maximum genus of a locally Cohen ‐ Macaulay space curve of degree d which does not lie on a surface of degree t ‐ 1.
Asymptotics of Heat Kernels on Projective Spaces of Large Dimensions and on Disk Hypergroups
Authors: Voit Michael 
Published: November 2010

AbstractIn this note we give exact asymptotic rates of convergence of Brownian motions on complex and quaternionic projective spaces to the uniform distribution when the dimension of these spaces tends to infinity. Similar results are also established for the symmetric spaces U(n)/U(n‐1) and disk hypergroups. Proofs will be based on a comparision of heat kernels with Poisson kernels together with a central limit result for Poisson kernels.
On the Eigenvalue Behaviour for a Class of Differential Operators on Semiaxis
Authors: Birman M. Sh. , Laptev A. , Solomyak M. 
Published: November 2010

AbstractWe study the eigenvalue behaviour of a class of ODE acting on the semiaxis. Using interpolation of quasinormed spaces as one of our main tools, we obtain sharp estimates of the counting function of eigenvalues n(λ). In particular, some of our results become reversible if a matrix‐valued “weight” ‐function is nonnegative. The asymptotic behaviour of n(λ) is also discussed.
Absolute Continuity for Curvature Measures of Convex Sets I
Authors: Hug Daniel 
Published: November 2010

AbstractLet us denote by Cr(K, ·), r ∈ {0,…, d ‐ 1}, the curvature measures of a convex body K in the Euclidean space ℝd with d ≥ 2. According to Lebesgue's decomposition theorem the curvature measure of order r of K, Cr(K, ·), can be written as the sum of an absolutely continuous measure, Car(K, ·), and a singular measure, Csr(K, ·), with respect to (d ‐ 1) ‐ dimensional Hausdorff measure. For example, if K is a polytope, then Car(K, ·) = 0 and if K is sufficiently smooth, then Csr(K, ·) = 0. For a general convex body K, a description of Car(K, ·) in terms of geometric quantities is known. In the present paper, we provide a corresponding explicit representation for the singular part Csr(K, .). Further, denote by Σr (K) the set of r‐singular boundary points of the convex body K· It is known that Σr(K) has σ‐finite, but possibly infinite, r ‐ dimensional Hausdorff measure. Provided that the singular part Csr(K, ·) of the curvature measure of order r vanishes, for a given convex body K, we prove that the r ‐ dimensional Hausdorff measure of Σr (K) also vanishes. Examples show that in a certain sense this result is sharp. Analogous results are established for surface area measures and singular normal vectors.
Hypersurfaces of E4 with Harmonic Mean Curvature Vector
Authors: Leuven Filip Defever Of 
Published: November 2010

AbstractA submanifold Mn of a Euclidean space Em is said to have harmonic mean curvature vector field if Δ H, where H denotes the mean curvature vector. B.‐Y. Chen conjectured that the only submanifolds of Euclidean spaces with harmonic mean curvature vector field, are the minimal ones. In this paper, we give a proof of the theorem that every hypersurface of E4 with harmonic mean curvature vector field is minimal. The method gives insight in the role of the principal curvatures.
Translative and Kinematic Formulae for Curvature Measures of Flat Sections
Authors: Rataj Jan 
Published: November 2010

AbstractLet X be a set of positive reach in the d‐dimensional Euclidean space. We present formulae for the integrals of the curvature measures of flat sections of X with respect to all translations/Euclidean motions of the sectioning flat. We consider the (generalized) curvature measures supported by the corresponding unit normal bundle. As a special case we obtain formulae for the spherical area measures.
Inertia Theorems for Hilbert Space Operators Based on Lyapunov and Stein Equations
Authors: Lerer Leonid , Rodman Leiba 
Published: November 2010

AbstractInequalities between the inertias of X and of A, are proved for Hilbert space operators X = X* and A such that AX + XA* is positive semidefinite or such that X ‐ A* XA is positive semidefinite. A weak version of the controllability property is assumed.
On the Relation between Linear Difference and Differential Equations with Polynomial Coefficients
Authors: Immink G. K. 
Published: November 2010

AbstractThis paper represents the third part of a contribution to the “dictionary” of homogeneous linear differential equations with polynomial coefficients on one hand and corresponding difference equations on the other. In the first part (cf. [4]) we studied the case that the differential equation (D) has at most regular singularities at O and at ∞, and arbitrary singularities in the rest of the complex plane. We constructed fundamental systems of solutions of a corresponding difference equation (A), using integral transforms of microsolutions of (D) at its singular points in ℂ. In the second part ([5]) we considered differential equations having at most a regular singularity at O and an irregular one at O. We used integral transforms of asymptotically flat solutions of (D) to define it fundamental system of solutions of (Δ), holomorphic in a right half plane, and integral transforms of sections of the sheaf of solutions of (D) modulo solutions with moderate growth as t → 0 in some sector, to define a fundamental system of (Δ), holomorphic in a left half plane. In this final part we combine the techniques and results of the preceding papers to deal with the general case.
Harmonic Analysis of Fractal Processes viaC* ‐ Algebras
Authors: Jorgensen Palle E. T. 
Published: November 2010

AbstractWe construct a harmonic analysis of iteration systems which include those which arise from wavelet algorithms based on multiresolutions. While traditional discretizations lead to asymptotic formulas, we argue here for a direct Fourier duality; but it is based on a non ‐ commutative harmonic analysis, specifically on representations of the CuntzC* ‐algebras. With this approach the waling from the wavelet takes the form of an endomorphism ofB(H), Ha Hilbert space derived from the lattice of translations. We use this to describe, and to calculate, new invariants for the wavelets. those iteration systems which arise from wavelets and from Julia sets, we show that the associated endomorphisms are in fact Powers shifts.
Pseudodifferential Operators in Function Spaces with Exponential Weights
Authors: Schott Thomas 
Published: November 2010

AbstractThis paper is a continuation of [17]. We study weighted function spaces of type Bapq(u) and Fapq(u) on the Euclidean space ℝn, where u is a weight function of at most exponential growth. In particular, u(x) = exp(±|x|) is an admissible weight. We consider symbols which belong to the Hörmander class Su1,δ, where u ∈ ℝ and 0 ≤ δ ≤ 1. We give sufficient conditions for the boundedness of the corresponding pseudodifferential operators in the above function spaces. As a main tool, we use molecular decompositions of these spaces. Furthermore, we prove that the spaces Bapq (u) and Fapq(u) have the lift property.
On Higher Order Embeddings and n ‐ Connectedness
Authors: Beltrametti M. C. , Di Rocco S. , Lanteri A. 
Published: November 2010

AbstractLet L be a very ample line bundle on a smooth complex projective surface. The relations between the higher order embedding properties of L, like k ‐ spannedness, k ‐ very ampleness, k ‐ jet ampleness, and the higher numerical connectedness properties of divisors D ε |L| are Investigated. Some applications to adjoint bundles as well as pluricanonical bundles are discussed.
Biliaison Classes of Rank Two Reflexive Sheaves on P3
Authors: Buraggina Antonella 
Published: November 2010

AbstractA biliaison theory for rank two reflexive sheaves on projective 3 ‐ space is established, In analogy with the existing theory for curves and, more generally, for 2 ‐ codimensional subschemes of projective n ‐ space. By definition two such sheaves are in the same biliaison class if their first cohomology modules are isomorphic. A parametrization of these classes is given. It is then shown that any class not corresponding to the zero module has a structure described by the Lazarsfeld ‐ Rao property. In particular, it is shown that vector bundles are precisely the minimal elements (in the of the LR ‐ property) in their biliaison classes.
Curves in P3 with Quasi‐‐Linear Resolution
Authors: Franco Davide 
Published: November 2010

AbstractOur main result is Theorem 1.3 which gives sufficient conditions for the global generation of some classes of vector bundles which arise as kernels of special morphisms between splitting vector bundles of Pn.Following the paper [3], we apply our result to the construction of space curves admitting quasilinear resolution (see Theorem 1.1).
Operator Interpretation of Resonances Arising in Spectral Problems for 2 × 2 Operator Matrices
Authors: Mennicken Reinhard , Motovilov Alexander K. 
Published: November 2010

AbstractWe consider operator matrices \documentclass{article}\pagestyle{empty}\begin{document}${\rm{H = }}\left( {{_{B_{10} }^{A{_0}}} {_{A_{1} }^{B{_{01}}}} } \right)$\end{document} with self ‐ adjoint entries Ai, i = 0,1, and bounded B10 = B10 acting in the orthogonal sum μ=μ0 ⊕ μ1 of Hilbert spaces μ0 and μ1. We are especially interested in the case where the spectrum of, say, A1 is partly or totally embedded into the continuous spectrum of A0 and the transfer function V1(z) = B10 where (χ ‐ A0)−1 B01, admits analytic continuation (as an operator ‐ valued function) through the cuts along branches of the continuous spectrum of the entry A0 into the unphysical sheet(s) of the spectral parameter plane. The values of χ in the unphysical sheets where M1−1(z) and consequently the resolvent (H ‐ z)−1 have poles are usually called resonances. A main goal of the present work is to find non ‐ selfadjoint operators whose spectra include the resonances as well as to study the completeness and basis properties of the resonance eigenvectors of M1(z) in μ1. To this end we first construct an operator ‐ valued function V1(Y) on the space of operators in μ1 possessing the property: V1(Y)ϕ1 = V1(z)ϕ1 for any eigenvector ϕ1 of Y corresponding to an eigenvalue z and then study the equation H1 = A1 + V1(H1). We prove the solvability of this equation even in the case where the spectra of A0 and A1 overlap. Using the fact that the root vectors of the solutions H1 are at the same time such vectors for M1(z), we prove completeness and even basis properties for the root vectors (including those for the resonances).
Descriptions of Some K Functionals for Three Spaces and Reiteration
Authors: Ericsson Stefan 
Published: November 2010

AbstractWe prove some equivalence formulas for the K functional for three spaces. In particular we calculate K(t, s, f, Lp0, Lp1, Lp2). We also give an integral formula connecting the K functional for triples of the type (A0, A1, A2), where A1 is of class C(θ, A0,A2), with the K functional for the pair (A0, A2). This formula is used to prove a reiteration formula for interpolation of the triple (A0, Al, A2) when Ai is of class C(θi, X, Y)
The Khinchin Inequality for Generalized Rademacher Functions
Authors: Meléndez Yolanda , Tonge Andrew 
Published: November 2010

AbstractWe give a new proof of the Khinchin inequality for the sequence
equation image
of k‐Rademacher functions:
equation image
We obtain constants which are independent of k. Although the constants are not best possible, they improve estimates of Floret and Matos [4] and they do have optimal dependence on p as p → ∞.
Holomorphic Connections and Extension of Complex Vector Bundles
Authors: Buchdahl N. P. , Harris Adam 
Published: November 2010

AbstractLet
equation image
be a regular, surjective holomorphic map between complex manifolds such that for all t ∈ Y, π−1(t) is a connected, simply connected Riemann surface. Let K C X be compact, and E ⊂ X \ K a holomorphic vector bundle, equipped with a holomorphic relative connection along the fibres of π. The main result of this note establishes unique existence of a holomorphic vector bundle extension Ê→ X under the added assumptions that π (K) is a proper subset of Y, and π−1 (t) ∪ (X \ K) is always non‐empty and connected. As a corollary of the main theorem, it follows that if X is an arbitrary complex manifold, and A C X is an analytic subset of co dimension at least two, then E → X \ A admits a unique extension if there exists a holomorphic connection ▽:Ox (E) → Ω(E).
Convolutions and the Geometry of Multifractal Measures
Authors: Falconer K. J. , O'Neil T. C. 
Published: November 2010

AbstractThis paper relates multifractal features of a measure μ on IRn to those of the projection of the measure onto m‐ dimensional subspaces. We achieve this through the study of appropriately defined convolution kernels. This provides a unified approach to projections of measures and leads to new results on multifractal properties as well as alternative derivations of some existing formulae. These include formulae and estimates for the local dimensions and generalised q‐ dimensions of projected measures as well as more precise information about the limiting behaviour of multifractal expressions. We consider briefly how similar ideas may be applied to sections of a measure by (n ‐ m)‐dimensional planes.
New criterion to aid manual and automatic selection of the arterial input function in dynamic susceptibility contrast MRI
Authors: Bleeker Egbert J. W. , van Osch Matthias J. P. , Connelly Alan , van Buchem Mark A. , Webb Andrew G. , Calamante Fernando 
Published: November 2010

AbstractDynamic susceptibility contrast‐MRI requires an arterial input function (AIF) to obtain cerebral blood flow, cerebral blood volume, and mean transit time. The current AIF selection criteria discriminate venous, capillary, and arterial profiles based on shape and timing characteristics of the first passage. Unfortunately, partial volume effects can lead to shape errors in the bolus passage, including a narrower and higher peak, which might be selected as a “correct” AIF. In this study, a new criterion is proposed that detects shape errors based on tracer kinetic principles for computing cerebral blood volume. This criterion uses the ratio of the steady‐state value to the area‐under‐the‐curve of the first passage, which should result in an equal value for tissue and arterial responses. By using a reference value from tissue, partial volume effects–induced shape errors of the AIF measurement can be detected. Different factors affecting the ratio were investigated using simulations. These showed that the new criterion should only be used in studies with T1‐insensitive acquisition. In vivo data were used to evaluate the proposed approach. The data showed that the new criterion enables detection of shape errors, although false positives do occur, which could be easily avoided when combined with current AIF selection criteria. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.
Relaxivity‐iron calibration in hepatic iron overload: Probing underlying biophysical mechanisms using a Monte Carlo model
Authors: Ghugre Nilesh R. , Wood John C. 
Published: November 2010

AbstractIron overload is a serious condition for patients with β‐thalassemia, transfusion‐dependent sickle cell anemia, and inherited disorders of iron metabolism. MRI is becoming increasingly important in noninvasive quantification of tissue iron, overcoming the drawbacks of traditional techniques (liver biopsy). Effective transverse relaxation rate (1/effective transverse relaxation time) rises linearly with iron while transverse relaxation rate (1/T2) has a curvilinear relationship in human liver. Although recent work has demonstrated clinically valid estimates of human liver iron, the calibration varies with MRI sequence, field strength, iron chelation therapy, and organ imaged, forcing recalibration in patients. To understand and correct these limitations, a thorough understanding of the underlying biophysics is of critical importance. Toward this end, a Monte Carlo‐based approach, using human liver as a “model” tissue system, was used to determine the contribution of particle size and distribution on MRI signal relaxation. Relaxivities were determined for hepatic iron concentrations ranging from 0.5 to 40 mg iron per gram dry tissue weight. Model predictions captured the linear and curvilinear relationship of effective transverse relaxation rate and transverse relaxation rate with hepatic iron concentrations, respectively, and were within in vivo confidence bounds; contact or chemical exchange mechanisms were not necessary. A validated and optimized model will aid understanding and quantification of iron‐mediated relaxivity in tissues where biopsy is not feasible (heart and spleen). Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.
Rapid MR‐ARFI method for focal spot localization during focused ultrasound therapy
Authors: Kaye Elena A. , Chen Jing , Pauly Kim Butts 
Published: November 2010

AbstractMR‐guided focused ultrasound (FUS) is a noninvasive therapy for treating various pathologies. MR‐based acoustic radiation force imaging (MR‐ARFI) measures tissue displacement in the focal spot due to acoustic radiation force. MR‐ARFI also provides feedback for adaptive focusing algorithms that could correct for phase aberrations caused by the skull during brain treatments. This work developed a single‐shot echo‐planar imaging–based MR‐ARFI method that reduces scan time and ultrasound energy deposition. The new method was implemented and tested in a phantom and ex vivo brain tissue. The effect of the phase aberrations on the ultrasound focusing was studied using displacement maps obtained with echo‐planar imaging and two‐dimensional spin‐warp MR‐ARFI. The results show that displacement in the focal spot can be rapidly imaged using echo‐planar imaging–based MR‐ARFI with high signal‐to‐noise ratio efficiency and without any measurable tissue heating. Echo‐planar imaging–based displacement images also demonstrate sufficient sensitivity to phase aberrations and can serve as rapid feedback for adaptive focusing in brain treatments and other applications. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.