Density functional theory for a model quantum dot: Beyond the local-density approximation

We study both static and transport properties of model quantum dots, employing density functional theory as well as (numerically) exact methods. For the lattice model under consideration the accuracy of the local-density approximation generally is poor. For weak interaction, however, accurate results are achieved within the optimized effective potential method, while for intermediate interaction strengths a method combining the exact diagonalization of small clusters with density functional theory is very successful. Results obtained from the latter approach yield very good agreement with density matrix renormalization group studies, where the full Hamiltonian consisting of the dot and the attached leads has to be diagonalized. Furthermore we address the question whether static density functional theory is able to predict the exact linear conductance through the dot correctly - with, in general, negative answer.Comment: 8 page

Identification of a non-purple tartrate-resistant acid phosphatase: an evolutionary link to Ser/Thr protein phosphatases?

BACKGROUND Tartrate-resistant acid phosphatases (TRAcPs), also known as purple acid phosphatases (PAPs), are a family of binuclear metallohydrolases that have been identified in plants, animals and fungi. The human enzyme is a major histochemical marker for the diagnosis of bone-related diseases. TRAcPs can occur as a small form possessing only the ~35 kDa catalytic domain, or a larger ~55 kDa form possessing both a catalytic domain and an additional N-terminal domain of unknown function. Due to its role in bone resorption the 35 kDa TRAcP has become a promising target for the development of anti-osteoporotic chemotherapeutics. FINDINGS A new human gene product encoding a metallohydrolase distantly related to the ~55 kDa plant TRAcP was identified and characterised. The gene product is found in a number of animal species, and is present in all tissues sampled by the RIKEN mouse transcriptome project. Construction of a homology model illustrated that six of the seven metal-coordinating ligands in the active site are identical to that observed in the TRAcP family. However, the tyrosine ligand associated with the charge transfer transition and purple color of TRAcPs is replaced by a histidine. CONCLUSION The gene product identified here may represent an evolutionary link between TRAcPs and Ser/Thr protein phosphatases. Its biological function is currently unknown but is unlikely to be associated with bone metabolism.This work was funded by the Royal Society of Tropical Medicine and Hygiene through a Dennis Burkitt Fellowship to JJM. ARD is supported by the Economic and Social Research Council. JJM is supported by a Wellcome Trust Research Training Fellowship (GR074833MA)

Physical Approach to Ferroelectric Impedance Spectroscopy: The Rayleigh Element

The Rayleigh law describes the linear dependence of the permittivity of a ferroelectric on the applied ac electric field amplitude due to irreversible motions of domain walls. We show that this gives rise to a new equivalent-circuit element predestined to fit the impedance spectra of ferroelectrics based on an accepted physical model. Such impedance spectroscopy is a powerful tool to obtain a dielectric and resistive representation of the entire sample structure. The superiority of the Rayleigh analysis based on impedance spectroscopy compared to the common single-frequency approach is demonstrated for a ferroelectric Si : HfO₂ thin fil

Ice-Melting Characteristics of Calcium Magnesium Acetate

DTFH61-83-C-00041Pertinent chemical and physical properties of calcium magnesium acetate (CMA) were determined. Included were comparisons of ratios of calcium to magnesium varying from 100% CaAc2 to 100% MgAc2. The objective was to determine the optimum composition of CMA for road deicing. In a 12-month study involving wetting/drying tests with 11 ratios of Ca/Mg and five pH's, it was found that CMA at pH's above 7.0 and at any Ca/Mg ratio produced no more harm to portland cement concrete than did NaCl. In addition, with compositions containing Mg at levels equal to or greater than Ca, the damage to concrete was significantly reduced

Characterization of the binding site of the histamine H3 receptor. 1. Various approaches to the synthesis of 2-(1H-imidazol-4-yl)cyclopropylamine and histaminergic activity of (1R,2R)-and (1S,2S)-2-(1H-imidazol-4-yl)-cyclopropylamine.

Various approaches to the synthesis of all four stereoisomers of 2-(1H- imidazol-4-yl)cyclopropylamine (cyclopropylhistamine) are described. The rapid and convenient synthesis and resolution of trans-cyclopropylhistamine is reported. The absolute configuration of its enantiomers was determined by single-crystal X-ray crystallographic analysis. The distinct transcyclopropylhistamine enantiomers were tested for their activity and affinity on the histamine

A Combined Patch-Clamp and Electrorotation Study of the Voltage- and Frequency-Dependent Membrane Capacitance Caused by Structurally Dissimilar Lipophilic Anions

Interactions of structurally dissimilar anionic compounds with the plasma membrane of HEK293 cells were analyzed by patch clamp and electrorotation. The combined approach provides complementary information on the lipophilicity, preferential affinity of the anions to the inner/outer membrane leaflet, adsorption depth and transmembrane mobility. The anionic species studied here included the well-known lipophilic anions dipicrylamine (DPA−), tetraphenylborate (TPB−) and [W2(CO)10(S2CH)]−, the putative lipophilic anion \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{B}}{\left( {{\text{CF}}_{3} } \right)}^{ - }_{4}$$\end{document} and three new heterocyclic W(CO)5 derivatives. All tested anions partitioned strongly into the cell membrane, as indicated by the capacitance increase in patch-clamped cells. The capacitance increment exhibited a bell-shaped dependence on membrane voltage. The midpoint potentials of the maximum capacitance increment were negative, indicating the exclusion of lipophilic anions from the outer membrane leaflet. The adsorption depth of the large organic anions DPA−, TPB− and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{B}}{\left( {{\text{CF}}_{3} } \right)}^{ - }_{4}$$\end{document} increased and that of W(CO)5 derivatives decreased with increasing concentration of mobile charges. In agreement with the patch-clamp data, electrorotation of cells treated with DPA− and W(CO)5 derivatives revealed a large dispersion of membrane capacitance in the kilohertz to megahertz range due to the translocation of mobile charges. In contrast, in the presence of TPB− and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{B}}{\left( {{\text{CF}}_{3} } \right)}^{ - }_{4}$$\end{document} no mobile charges could be detected by electrorotation, despite their strong membrane adsorption. Our data suggest that the presence of oxygen atoms in the outer molecular shell is an important factor for the fast translocation ability of lipophilic anions

A 15-year perspective of the fabry outcome survey

The Fabry Outcome Survey (FOS) is an international long-term observational registry sponsored by Shire for patients diagnosed with Fabry disease who are receiving or are candidates for therapy with agalsidase alfa (agala). Established in 2001, FOS provides long-term data on agala safety/efficacy and collects data on the natural history of Fabry disease, with the aim of improving clinical management. The FOS publications have helped establish prognostic and severity scores, defined the incidence of specific disease variants and implications for clinical management, described clinical manifestations in special populations, confirmed the high prevalence of cardiac morbidity, and demonstrated correlations between ocular changes and Fabry disease severity. These FOS data represent a rich resource with utility not only for description of natural history/therapeutic effects but also for exploratory hypothesis testing and generation of tools for diagnosis/management, with the potential to improve future patient outcomes

(I) Early Alterations of Apoptosis and Cell Proliferation in Azoxymethane-initiated Rat Colonic Epithelium (II) Expression of Bcl-2, Bax and Bcl-XL proteins in the azoxymethane-induced rat colonic adenocarcinomas

(I) Early Alterations of Apoptosis and Cell Proliferation in Azoxymethane-initiated Rat Colonic Epithelium(II) Expression of Bcl-2, Bax and Bcl-XL proteins in the azoxymethane-induced rat colonic adenocarcinoma