Quantum theory of spin waves in finite chiral spin chains

We calculate the effect of spin waves on the properties of finite-size spin chains with a chiral spin ground state observed on biatomic Fe chains deposited on iridium(001). The system is described with a Heisenberg model supplemented with a Dzyaloshinskii-Moriya coupling and a uniaxial single ion anisotropy that presents a chiral spin ground state. Spin waves are studied using the Holstein-Primakoff boson representation of spin operators. Both the renormalized ground state and the elementary excitations are found by means of Bogoliubov transformation, as a function of the two variables that can be controlled experimentally, the applied magnetic field and the chain length. Three main results are found. First, because of the noncollinear nature of the classical ground state, there is a significant zero-point reduction of the ground-state magnetization of the spin spiral. Second, there is a critical external field from which the ground state changes from chiral spin ground state to collinear ferromagnetic order. The character of the two lowest-energy spin waves changes from edge modes to confined bulk modes over this critical field. Third, in the spin-spiral state, the spin-wave spectrum exhibits oscillatory behavior as function of the chain length with the same period of the spin helix.

2C-Cas9: a versatile tool for clonal analysis of gene function

CRISPR/Cas9-mediated targeted mutagenesis allows efficient generation of loss-of-function alleles in zebrafish. To date this technology has been primarily used to generate genetic knockout animals. Nevertheless, the study of the function of certain loci might require tight spatiotemporal control of gene inactivation. Here, we show that tissue-specific gene disruption can be achieved by driving Cas9 expression with the Gal4/UAS system. Furthermore, by combining the Gal4/UAS and Cre/loxP systems, we establish a versatile tool to genetically label mutant cell clones, enabling their phenotypic analysis. Our technique has the potential to be applied to diverse model organisms, enabling tissue-specific loss-of-function and phenotypic characterization of live and fixed tissues.

Analysis of an Intervention to Reduce Truck Drivers' Exposure to Whole-Body Vibration

Thesis (Master's)--University of Washington, 2016-06

Function and Regulation of Cytochrome P450 4V2 and the Implications in Bietti’s Crystalline Dystrophy

Thesis (Ph.D.)--University of Washington, 2016-06

Sigmoidal cosine series on the interval

We construct a set of functions, say, psi([r])(n) composed of a cosine function and a sigmoidal transformation gamma(r) of order r > 0. The present functions are orthonormal with respect to a proper weight function on the interval [-1, 1]. It is proven that if a function f is continuous and piecewise smooth on [-1, 1] then its series expansion based on psi([r])(n) converges uniformly to f so long as the order of the sigmoidal transformation employed is 0 < r

Inhibition of iron-catalysed hydroxyl radical formation by inositol polyphosphates: a possible physiological function for myo-inositol hexakisphosphate

1. The ability of myo-inositol polyphosphates to inhibit iron-catalysed hydroxyl radical formation was studied in a hypoxanthine/xanthine oxidase system [Graf, Empson and Eaton (1987) J. Biol. Chem. 262, 11647-11650]. Fe3+ present in the assay reagents supported some radical formation, and a standard assay, with 5 microM Fe3+ added, was used to investigate the specificity of compounds which could inhibit radical generation. 2. InsP6 (phytic acid) was able to inhibit radical formation in this assay completely. In this respect it was similar to the effects of the high affinity Fe3+ chelator Desferral, and dissimilar to the effects of EDTA which, even at high concentrations, still allowed detectable radical formation to take place. 3. The six isomers of InsP5 were purified from an alkaline hydrolysate of InsP6 (four of them as two enantiomeric mixtures) and they were compared with InsP6 in this assay. Ins(1,2,3,4,6)P5 and D/L-Ins(1,2,3,4,5)P5 were similar to InsP6 in that they caused a complete inhibition of iron-catalysed radical formation at > 30 microM. Ins(1,3,4,5,6)P5 and D/L-Ins(1,2,4,5,6)P5, however, were markedly less potent than InsP6, and did not inhibit radical formation completely; even when Ins(1,3,4,5,6)P5 was added up to 600 microM, significant radical formation was still detected. Thus InsP5s lacking 2 or 1/3 phosphates are in this respect qualitatively different from InsP6 and the other InsP5s. 4. scyllo-Inositol hexakisphosphate was also tested, and although it caused a greater inhibition than Ins(1,3,4,5,6)P5, it too still allowed detectable free radical formation even at 600 microM. 5. We conclude that the 1,2,3 (equatorial-axial-equatorial) phosphate grouping in InsP6 has a conformation that uniquely provides a specific interaction with iron to inhibit totally its ability to catalyse hydroxyl radical formation; we suggest that a physiological function of InsP6 might be to act as a 'safe' binding site for iron during its transport through the cytosol or cellular organelles

GPCRTree:online hierarchical classification of GPCR function

G protein-coupled receptors (GPCRs) play important physiological roles transducing extracellular signals into intracellular responses. Approximately 50% of all marketed drugs target a GPCR. There remains considerable interest in effectively predicting the function of a GPCR from its primary sequence.

Characterization of tissue transglutaminase 2 in macrophage function

Programmed cell death, apoptosis, is a highly regulated process that removes damaged or unwanted cells in vivo and has significant immunological implications. Defective clearance of apoptotic cells by macrophages (professional phagocytes) is known to result in chronic inflammatory and autoimmune disease. Tissue transglutaminase 2 (TG2) is a Ca2+-dependent protein cross linking enzyme known to play an important role in a number of cell functions. Up-regulation of TG2 is thought to be involved in monocyte to macrophage differentiation and defective clearance of apoptotic cells by TG2 null mice has been described though in this context the role of TG2 is yet to be fully elucidated. Cell surface-associated TG2 is now recognized as being important in regulating cell adhesion and migration, via its association with cell surface receptors such as syndecan-4, ß1 and ß3 integrin, but its extracellular role in the clearance of apoptotic cells is still not fully explored. Our work aims to characterize the role of TG2 and its partners (e.g. syndecan-4 and ß3 integrin) in macrophage function within the framework of apoptotic cell clearance. Both THP-1 cell-derived macrophage-like cells and primary human macrophages were analyzed for the expression and function of TG2. Macrophage-apoptotic cell interaction studies in the presence of TG2 inhibitors (both cell permeable and impermeable, irreversible and active site directed) resulted in significant inhibition of interaction indicating a possible role for TG2 in apoptotic cell clearance. Macrophage cell surface TG2 and, in particular, its cell surface crosslinking activity was found to be crucial in dictating apoptotic cell clearance. Our further studies demonstrate syndecan-4 association with TG2 and imply possible cooperation of these proteins in apoptotic cell clearance. Knockdown studies of syndecan-4 reveal its importance in apoptotic cell clearance. Our current findings suggest that TG2 has a crucial but yet to be fully defined role in apoptotic cell clearance which seems to involve protein cross linking and interaction with other cell surface receptors.

Characterization of tissue transglutaminase 2 in macrophage function

Apoptosis is a highly regulated process that removes damaged or unwanted cells in vivo and defective clearance of apoptotic cells by macrophages has significant immunological implications. Tissue transglutaminase 2 (TG2) is a Ca2+-dependent protein cross linking enzyme known to play an important role in cell proliferation, differentiation, carcinogenesis, programmed death, and aging. TG2 as a guanosine triphosphate (GTP)-binding or GTP- hydrolyzing protein for mediating signal transduction and as a cell cycle regulator emphasized the importance of this enzyme in aging process. The ubiquitous presence of TG2 compared to the other organ-specific TGases has attracted special attention as a cellular aging device. TG2 activity and expression are known to increase in aging humans suggesting possible involvement in several age-related processes such as decrease in vascular compliance and increased stiffening of conduit arteries, cataract formation, Alzheimer's disease and senescent epidermal keratinocytes. Our work aims to characterize the role of TG2 and its partners (e.g. syndecan-4 and ß3 integrin) in macrophage function. THP-1 cell derived macrophage-like cells and primary human macrophages were analyzed for the expression and function of TG2. Macrophage-apoptotic cell interaction studies in the presence of TG2 inhibitors resulted in significant inhibition of interaction. Macrophage cell surface TG2 and, in particular, its cell surface cross linking activity was found to be crucial in apoptotic cell clearance. Syndecan-4 association with TG2 implies possible cooperation of these proteins and knockdown studies of syndecan-4 reveal its importance in apoptotic cell clearance. Our current findings suggest that TG2 has a crucial but yet to be fully defined role in apoptotic cell clearance.

Can the Q Link Ally,® a form of sympathetic resonance technology (SRT™), sttenuate scute mobile phone-related changes to neural function?

OBJECTIVES: Exposure to active mobile phones (MP) has been shown to affect human neural function as shown by the electroencephalogram (EEG). Although it has not been determined whether such effects are harmful, a number of devices have been developed that attempt to minimize these MP-related effects. One such device, the Q Link Ally® (QL; Clarus Products, International, L.L.C., San Rafael, CA), is argued to affect the human organism in such a way as to attenuate the effect of MPs. The present pilot study was designed to determine whether there is any indication that QL does alter MP-related effects on the human EEG. DESIGN: Twenty-four (24) subjects participated in a single-blind, fully counterbalanced crossover design in which subjects' resting EEG and phase-locked neural responses to auditory stimuli were assessed under conditions of either active MP or active MP plus QL. RESULTS: The addition of QL to the MP condition increased resting EEG in the gamma range and did so as a function of exposure duration, and it attenuated MP-related effects in the delta and alpha range (at trend-level). The addition of the QL also affected phase-locked neural responses, with a laterality reversal in the alpha range and an alteration to changes over time in the delta range, a reduction of the MP-related beta decrease over time at fronto-posterior sites, and a global reduction in the gamma range that increased as a function of exposure duration. No unambiguous relations were found between these changes and either performance or psychologic state. CONCLUSIONS: This pilot study suggests that the addition of the QL to active MP-exposure does affect neural function in humans, altering both resting EEG patterns and the evoked neural response to auditory stimuli, and that there is a tendency for some MP-related changes to the EEG to be attenuated by the QL.

Compactness in the First Baire Class and Baire-1 Operators

For a polish space M and a Banach space E let B1 (M, E) be the space of first Baire class functions from M to E, endowed with the pointwise weak topology. We study the compact subsets of B1 (M, E) and show that the fundamental results proved by Rosenthal, Bourgain, Fremlin, Talagrand and Godefroy, in case E = R, also hold true in the general case. For instance: a subset of B1 (M, E) is compact iff it is sequentially (resp. countably) compact, the convex hull of a compact bounded subset of B1 (M, E) is relatively compact, etc. We also show that our class includes Gulko compact. In the second part of the paper we examine under which conditions a bounded linear operator T : X ∗ → Y so that T |BX ∗ : (BX ∗ , w∗ ) → Y is a Baire-1 function, is a pointwise limit of a sequence (Tn ) of operators with T |BX ∗ : (BX ∗ , w∗ ) → (Y, · ) continuous for all n ∈ N. Our results in this case are connected with classical results of Choquet, Odell and Rosenthal.

Fractional Powers of Almost Non-Negative Operators

Mathematics Subject Classification: Primary 47A60, 47D06.

Comparative Analysis of Viscoelastic Models Involving Fractional Derivatives of Different Orders

Mathematics Subject Classification: 74D05, 26A33

Fractional Integration and Fractional Differentiation of the M-Series

Mathematics Subject Classification: 26A33, 33C60, 44A15

Riemann-Hilbert Problems with Canonical Normalization and Families of Commuting Operators

2010 Mathematics Subject Classification: 35Q15, 31A25, 37K10, 35Q58.