Off-forward parton distributions and Shuvaev's transformations

We review Shuvaev's transformations, that relate off-forward parton distributions (OFPDs) to so-called effective forward parton distributions (EFPDs). The latter evolve like conventional forward partons. We express nonforward amplitudes, depending on OFPDs, directly in terms of EFPDs and construct a model for the EFPDs, which allows to consistently express them in terms of the conventional forward parton distributions and nucleon form factors. Our model is self-consistent for arbitrary x, xi, mu, and t.Comment: 13 pages, 7 eps-figures, LaTeX2e, added references, corrected typo

Classical pion fields in the presence of source

Classical pion field similar to Disoriented Chiral Condensate (DCC) is considered in the presence of the external source. This field is similar to DCC in the sense that its isotopic orientation is specified with a single vector at the whole space. We study the classical field solutions in the nonlinear sigma-model both in the chiral limit with massless pion and for the finite pion mass. In both cases the field resembles the Coulomb field of charged particle however the nonlinear pion interactions lead to the existence of several solutions. In the massless case and for the very small size of the source there is the lot of classical solutions with finite discrete energies. In the more realistic situation of large nucleus (heavy ion) there are no stable solutions of the above type, but there is the possibility for the formation of the quasistationary states. They can live for a long time slowly decaying through the emission of very soft pions. The structure and the energies of these solutions is investigated numerically.Comment: 10 pages, LaTeX, 1 figure, epsfig.sty, corrected typos, added reference

Bivalent engagement of endothelial surface antigens is critical to prolonged surface targeting and protein delivery in vivo

Targeted drug delivery to the endothelium has the potential to generate localized therapeutic effects at the blood- tissue interface. For some therapeutic cargoes, it is essential to maintain contact with the bloodstream to exert protective effects. The pharmacokinetics (PK) of endothelial surface- targeted affinity ligands and biotherapeutic cargo remain a largely unexplored area, despite obvious translational implications for this strategy. To bridge this gap, we site- specifically radiolabeled mono- (scFv) and bivalent (mAb) affinity ligands specific for the endothelial cell adhesion molecules, PECAM- 1 (CD31) and ICAM- 1 (CD54). Radiotracing revealed similar lung biodistribution at 30 minutes post- injection (79.3% ± 4.2% vs 80.4% ± 10.6% ID/g for αICAM and 58.9% ± 3.6% ID/g vs. 47.7% ± 5.8% ID/g for αPECAM mAb vs. scFv), but marked differences in organ residence time, with antibodies demonstrating an order of magnitude greater area under the lung concentration vs. time curve (AUCinf 1698 ± 352 vs. 53.3 ± 7.9 ID/g*hrs for αICAM and 1023 ± 507 vs. 114 ± 37 ID/g*hrs for αPECAM mAb vs scFv). A physiologically based pharmacokinetic model, fit to and validated using these data, indicated contributions from both superior binding characteristics and prolonged circulation time supporting multiple binding- detachment cycles. We tested the ability of each affinity ligand to deliver a prototypical surface cargo, thrombomodulin (TM), using one- to- one protein conjugates. Bivalent mAb- TM was superior to monovalent scFv- TM in both pulmonary targeting and lung residence time (AUCinf 141 ± 3.2 vs 12.4 ± 4.2 ID/g*hrs for ICAM and 188 ± 90 vs 34.7 ± 19.9 ID/g*hrs for PECAM), despite having similar blood PK, indicating that binding strength is more important parameter than the kinetics of binding. To maximize bivalent target engagement, we synthesized an oriented, end- to- end anti- ICAM mAb- TM conjugate and found that this therapeutic had the best lung residence time (AUCinf 253 ± 18 ID/g*hrs) of all TM modalities. These observations have implications not only for the delivery of TM, but also potentially all therapeutics targeted to the endothelial surface.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156501/3/fsb220760_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156501/2/fsb220760-sup-0001-Supinfo.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156501/1/fsb220760.pd

Symmetry breaking, conformal geometry and gauge invariance

When the electroweak action is rewritten in terms of SU(2) gauge invariant variables, the Higgs can be interpreted as a conformal metric factor. We show that asymptotic flatness of the metric is required to avoid a Gribov problem: without it, the new variables fail to be nonperturbatively gauge invariant. We also clarify the relations between this approach and unitary gauge fixing, and the existence of similar transformations in other gauge theories.Comment: 11 pages. Version 2: typos corrected, discussion of Elitzur's theorem added. Version to appear in J.Phys.

DALMATIAN: An Algorithm for Automatic Cell Detection and Counting in 3D

Current 3D imaging methods, including optical projection tomography, light-sheet microscopy, block-face imaging, and serial two photon tomography enable visualization of large samples of biological tissue. Large volumes of data obtained at high resolution require development of automatic image processing techniques, such as algorithms for automatic cell detection or, more generally, point-like object detection. Current approaches to automated cell detection suffer from difficulties originating from detection of particular cell types, cell populations of different brightness, non-uniformly stained, and overlapping cells. In this study, we present a set of algorithms for robust automatic cell detection in 3D. Our algorithms are suitable for, but not limited to, whole brain regions and individual brain sections. We used watershed procedure to split regional maxima representing overlapping cells. We developed a bootstrap Gaussian fit procedure to evaluate the statistical significance of detected cells. We compared cell detection quality of our algorithm and other software using 42 samples, representing 6 staining and imaging techniques. The results provided by our algorithm matched manual expert quantification with signal-to-noise dependent confidence, including samples with cells of different brightness, non-uniformly stained, and overlapping cells for whole brain regions and individual tissue sections. Our algorithm provided the best cell detection quality among tested free and commercial software

Dynamical Dzyaloshinsky-Moriya Interaction in KCuF3

The spin dynamics of the prototypical quasi one-dimensional antiferromagnetic Heisenberg spin S=1/2 chain KCuF3 is investigated by electron spin resonance spectroscopy. Our analysis shows that the peculiarities of the spin dynamics require a new dynamical form of the antisymmetric anisotropic spin-spin interaction. This dynamical Dzyaloshinsky-Moriya interaction is related to strong oscillations of the bridging fuorine ions perpendicular to the crystallographic c axis. This new mechanism allows to resolve consistently the controversies in observation of the magnetic and structural properties of this orbitally ordered perovskite compound.Comment: 4 pages, 3 figure

Helicity skewed quark distributions of the nucleon and chiral symmetry

We compute the helicity skewed quark distributions $\widetilde{H}$ and $\widetilde{E}$ in the chiral quark-soliton model of the nucleon. This model emphasizes correctly the role of spontaneously broken chiral symmetry in structure of nucleon. It is based on the large-N_c picture of the nucleon as a soliton of the effective chiral lagrangian and allows to calculate the leading twist quark- and antiquark distributions at a low normalization point. We discuss the role of chiral symmetry in the helicity skewed quark distributions $\widetilde{H}$ and $\widetilde{E}$. We show that generalization of soft pion theorems, based on chiral Ward identities, leads in the region of -\xi < x < \xi to the pion pole contribution to $\widetilde{E}$ which dominates at small momentum transfer.Comment: 22 pages, 5 figure

Unusual magnetoelectric effect in paramagnetic rare-earth langasite

Violation of time reversal and spatial inversion symmetries has profound consequences for elementary particles and cosmology. Spontaneous breaking of these symmetries at phase transitions gives rise to unconventional physical phenomena in condensed matter systems, such as ferroelectricity induced by magnetic spirals, electromagnons, non-reciprocal propagation of light and spin waves, and the linear magnetoelectric (ME) effect - the electric polarization proportional to the applied magnetic field and the magnetization induced by the electric field. Here, we report the experimental study of the holmium-doped langasite, Ho$_{x}$La$_{3-x}$Ga$_5$SiO$_{14}$, showing a puzzling combination of linear and highly non-linear ME responses in the disordered paramagnetic state: its electric polarization grows linearly with the magnetic field but oscillates many times upon rotation of the magnetic field vector. We propose a simple phenomenological Hamiltonian describing this unusual behavior and derive it microscopically using the coupling of magnetic multipoles of the rare-earth ions to the electric field.Comment: 8 pages, 3 figure

The dual parametrization for gluon GPDs

We consider the application of the dual parametrization for the case of gluon GPDs in the nucleon. This provides opportunities for the more flexible modeling unpolarized gluon GPDs in a nucleon which in particular contain the invaluable information on the fraction of nucleon spin carried by gluons. We perform the generalization of Abel transform tomography approach for the case of gluons. We also discuss the skewness effect in the framework of the dual parametrization. We strongly suggest to employ the fitting strategies based on the dual parametrization to extract the information on GPDs from the experimental data.Comment: 37 pages, 2 figure