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We propose a simplified and computationally feasible model accounting for the dielectric confinement in arbitrarily shaped many-electron quantum dots, within the local spin density approximation. The model yields quite a good agreement with full configuration interaction calculations including exact dielectric confinement. The model is used to study the influence of the dielectric confinement on the electronic charge distribution of elongated quantum dots in the low density regime. [ABSTRACT FROM AUTHOR]

A consistent extension of local spin density approximation (LSDA) to account for mass and dielectric mismatches in nanocrystals is presented. The extension accounting for variable effective mass is exact. Illustrative comparisons with available configuration interaction calculations show that the approach is also very reliable when it comes to account for dielectric mismatches. The modified LSDA is as fast and computationally low demanding as LSDA. Therefore, it is a tool suitable to study large particle systems in inhomogeneous media without much effort. [ABSTRACT FROM AUTHOR]

The calcium-sensing receptor regulates various parathyroid gland functions, including hormone secretion, gene transcription, and chief cell hyperplasia through G alpha q- and G alpha i-dependent signaling pathways. To determine the specific function of G alpha q in these processes, we generated transgenic mice using the human parathyroid hormone promoter to drive overexpression of a dominant negative G alpha q loop minigene to selectively disrupt G alpha q function in the parathyroid gland. The G alpha q loop mRNA was highly expressed in the parathyroid gland but not in other tissues of these transgenic mice. Gross appearance, body weight, bone mineral density, and survival of the transgenic mice were indistinguishable from those of their wild-type littermates. Adult transgenic mice, however, exhibited an increase in parathyroid hormone mRNA and in its basal serum level as well as in gland size. The response of the parathyroid gland to hypocalcemia was found to be reduced in sensitivity in the transgenic mice when compared to their wild-type controls. Abnormalities of the parathyroid gland function in these transgenic mice were similar to those of heterozygous G alpha q(+/-) and calcium sensing receptor(+/-) mice. These studies demonstrate the feasibility of selectively targeting the parathyroid gland to investigate signaling mechanisms downstream of the calcium receptor. [ABSTRACT FROM AUTHOR]

Fractal image coding is a block-based scheme that exploits the self-similarity hiding within an image. Fractal parameters generated by the block-based scheme are quantitative measurements of self-similarity, and therefore they can be used to construct image signatures. By combining fractal parameters and collage error, a set of new statistical fractal signatures, such as histogram of collage error (HE), joint histogram of contrast scaling and collage error (JHSE), and joint histogram of range block mean and contrast scaling and collage error (JHMSE) is proposed. These fractal signatures effectively extract and reflect the statistical properties intrinsic in texture images. Hence, they provide new statistical features for use in texture image retrieval and identification. Furthermore, in order to reduce computational complexity of the JHMSE signature, the JHMSE signature is simplified to HM (histogram of range block mean) +JHSE and HM+HS (histogram of contrast scaling) +HE, based on the independence and distance equivalence. Mathematical analysis of the simplification scheme is also carried out. The proposed fractal signatures are compared with the existing fractal signatures. Experimental results show that the proposed signatures, HM+JHSE and HM+HS+HE, achieve a higher retrieval rate with a lower computational complexity. [ABSTRACT FROM AUTHOR]

Within finite temperature Density Functional Theory, we have calculated the energy of the transitions from the ground state to the first two excited states in the electron bubbles in liquid helium at pressures from zero to about the solidification pressure. For 4He at low temperatures, our results are in very good agreement with infrared absorption experiments. We have found that the 1s – 2p transition energies are sensitive not only to the size of the electron bubble, but also to its surface thickness. We also present results for the infrared transitions in the case of liquid 3He. [ABSTRACT FROM AUTHOR]

SUMMARY CD14, a GPI-linked membrane protein, is a component of the lipopolysaccharide (LPS) receptor complex, one of the pattern-recognizing receptors (PRR) expressed by myeloid lineage cells. Here we report that CD14, the functionally linked toll-like receptor molecules, TLR2 and TLR4, and the associated molecule MD-2 are expressed in endocrine cells of the human pancreatic islets. CD14 expression in human pancreatic islets was determined by immunofluorescence staining of tissue sections and primary cultures, and confirmed by flow cytometry of dispersed normal islets and SV40-transformed islet cells (HP62). The latter cells synthesized and secreted CD14 in response to lipopolysaccharide (LPS) in a time- and dose-dependent manner. Reverse transcription polymerase chain reaction (RT-PCR)-Southern was positive for CD14, TLR2, TLR4 and MD-2 in human pancreas, purified islets and HP62 cells. In vitro experiments using rat islets (also positive for CD14 by RT-PCR) and HP62 cells showed that LPS regulates glucose-dependent insulin secretion and induces inflammatory cytokines [interleukin (IL)-1α , IL-6 and tumour necrosis factor (TNF)-α ]. The functional expression of CD14 and associated molecules in islet β cells adds a new pathway that islet cells may follow to adjust their function to endotoxaemia situations and become vulnerable to the inflammatory events that occur during diabetogenic insulitis. [ABSTRACT FROM AUTHOR]

One of the paradoxes of insulin-dependent diabetes mellitus is that the destruction of the pancreatic islets' endocrine cells is restricted to the insulin-producing β cells, whereas the main autoantibodies, islet cell antibodies (ICA), are directed against all endocrine islet cells. GAD has recently been proposed as the main target of the humoral and cellular autoimmune attack to the islets, and since in rat pancreas this enzyme was expressed only in the β cells, this provided an explanation for the cell specificity of the destructive process. The finding of GAD-positive cells in the islets of two diabetic patients, one of whom had completely lost the β cells, led us to study in detail the distribution of GAD in normal human islet cells using a panel of GAD antisera and the double indirect immunofluorescence technique on cryostat sections, monolayer cultures and cytosmears. The results showed that GAD is present not only in the cytoplasm of β cells but also in 69% of the α and 27% of the δ cells. GAD was not present, however, on the surface of the islet cells. These results suggest that the cellular distribution of GAD can not by itself explain the selectivity of β cell destruction in insulin-dependent diabetes mellitus. [ABSTRACT FROM AUTHOR]

We have investigated the collision ofHe drops in the normal phase by means of the Vlasov equation. The structure and dynamics of the drops have been described by a density functional that takes properly into account relevant properties of the homogeneous liquid. Results forHe-He collisions at different energies and impact parameters are presented. [ABSTRACT FROM AUTHOR]

We have computed the density of states and the evaporation rate ofHe clusters, paying special attention to finite size effects which modify theHe level density parameter and chemical potential from their bulk values. Ready-to-use liquid-drop expansions of these quantities are given. [ABSTRACT FROM AUTHOR]

Abstract: We present an exact numerical calculation of the spin phase diagram of a two-electron quantum ring as a function of an applied in-plane electric field and a perpendicular magnetic field B. In general, large and B favour, respectively, singlet and triplet states. At low fields, however, the spin phase diagram shows singlet–triplet oscillations and the formation of spin islands surrounded by the complementary phase. Calculations of the density dipole excitation spectrum as a function of the electric field are also reported. [Copyright &y& Elsevier]

We have studied physical aspects of the charge and spin density responses of nanoscopic rings that might be detected by Raman spectroscopy. We have taken an InAs–GaAs ring as a case of study with N=10 electrons and several values of the on-plane transferred momentum q. Distinct monopole to quadrupole modes appear in the spin density, and especially in the charge density channel. We have found that both channels are coupled if the ground-state is ferromagnetic. [Copyright &y& Elsevier]

An extension of the spin density functional theory simultaneously accounting for dielectric mismatch between neighboring materials and nonparabolicity corrections originating from interactions between conduction and valence bands is presented. This method is employed to calculate ground state and addition energy spectra of homogeneous and multishell spherical quantum dots. Our calculations reveal that corrections become especially relevant when they come into play simultaneously in strong regimes of spatial confinement. [ABSTRACT FROM AUTHOR]

Within finite-range density-functional theory, we have addressed the photo-ejection of electrons hosted in He bubbles as a function of pressure at zero temperature. It is shown that, besides the 1 s→1 p and 1 s→2 p transitions that show up in the whole pressure range up to solidification, there is another transition to a loosely bound 3 p state that disappears at a pressure P above 1.7 bar. Realistic predictions for the electron photo-ejection cross section are made using a model that has been proven to reproduce the experimental infrared absorption transitions as a function of pressure. [ABSTRACT FROM AUTHOR]

An analysis of helium cluster properties at finite temperature using a phenomenological free energy density has been carried out. We have studied in detail the energetics and the density profile characteristics of hot drops of both helium isotopes containing 70, 112, 168, 240 and 330 atoms. A finite temperature mass formula including volume, surface and curvature terms has been derived. [ABSTRACT FROM AUTHOR]

The dipole surface plasmon for K clusters is analyzed using the RPA sum-rule technique within a semiclassical Density Functional Theory and the spherical jellium model. The theoretical frequencies are blue shifted as compared to the experimental ones. The discrepancies between theory and experiment are reduced when considering non-local energy contributions in the density functional and phenomenologically including atomic lattice effects by means of an electron effective mass and a static dielectric constant. [ABSTRACT FROM AUTHOR]

We present a combined ion imagingand density functional theorystudy of the dynamics of the desorption process of rubidium and cesiumatoms off the surface of helium nanodroplets upon excitation of theperturbed 6s and 7s states, respectively. Both experimental and theoreticalresults are well represented by the pseudodiatomic model for effectivemasses of the helium droplet in the desorption reaction of meff/mHe≈10 (Rb) and 13 (Cs). Deviations from this model are found for Rb excitedto the 6p state. Photoelectron spectra indicate that the dopant–dropletinteraction induces relaxation into low-lying electronic states ofthe desorbed atoms in the course of the ejection process. [ABSTRACT FROM AUTHOR]

Objective: CD4 T-cells secreting interleukin (IL)-17 are implicated in several human autoimmune diseases, but their role in type 1 diabetes has not been defined. To address the relevance of such cells, we examined IL-17 secretion in response to β-cell autoantigens, IL-17A gene expression in islets, and the potential functional consequences of IL-17 release for β-cells.Research Design and Methods: Peripheral blood CD4 T-cell responses to β-cell autoantigens (proinsulin, insulinoma-associated protein, and GAD65 peptides) were measured by IL-17 enzyme-linked immunospot assay in patients with new-onset type 1 diabetes (n = 50). mRNA expression of IL-17A and IFNG pathway genes was studied by qRT-PCR using islets obtained from subjects who died 5 days and 10 years after diagnosis of disease, respectively, and from matched control subjects. IL-17 effects on the function of human islets, rat β-cells, and the rat insulinoma cell line INS-1E were examined.Results: A total of 27 patients (54%) showed IL-17 reactivity to one or more β-cell peptides versus 3 of 30 (10%) control subjects (P = 0.0001). In a single case examined close to diagnosis, islet expression of IL17A, RORC, and IL22 was detected. It is noteworthy that we show that IL-17 mediates significant and reproducible enhancement of IL-1β/interferon (IFN)-γ-induced and tumor necrosis factor (TNF)-α/IFN-γ-induced apoptosis in human islets, rat β-cells, and INS-1E cells, in association with significant upregulation of β-cell IL17RA expression via activation of the transcription factors STAT1 and nuclear factor (NF)-κB.Conclusions: Circulating IL-17(+) β-cell-specific autoreactive CD4 T-cells are a feature of type 1 diabetes diagnosis. We disclose a novel pathway to β-cell death involving IL-17 and STAT1 and NF-κB, rendering this cytokine a novel disease biomarker and potential therapeutic target. [ABSTRACT FROM AUTHOR]

A finite-temperature density functional approach to describe the properties of parahydrogen in the liquid-vapor coexistence region is presented. The first proposed functional is zero-range, where the density-gradient term is adjusted so as to reproduce the surface tension of the liquid-vapor interface at low temperature. The second functional is finite-range and, while it is fitted to reproduce bulk pH2 properties only, it is shown to yield surface properties in good agreement with experiments. These functionals are used to study the surface thickness of the liquid-vapor interface, the wetting transition of parahydrogen on a planar Rb model surface, and homogeneous cavitation in bulk liquid pH2. [ABSTRACT FROM AUTHOR]

We investigate the wetting behavior of helium on nanostructured alkali metal surfaces, at temperatures below and slightly above the bulk superfluidity threshold. Starting from a determination of the phase diagram of helium on semiinfinite planar Cs up to 3 K, performed within finite-range, temperature-dependent density functional theory, we examine the modifications of the isotherms introduced by an infinite array of nanocavities. We compare the hysterectic loops of helium on nonwettable Cs surfaces and on wettable Na substrates in the same temperature range. [ABSTRACT FROM AUTHOR]

Dendritic cells (DCs) are powerful antigen-presenting cells capable of maintaining peripheral tolerance. The possibility to generate tolerogenic DCs opens new therapeutic approaches in the prevention or remission of autoimmunity. There is currently no treatment inducing long-term tolerance and remission in type 1 diabetes (T1D), a disease caused by autoimmunity towards β cells. An ideal immunotherapy should inhibit the autoimmune attack, avoid systemic side effects and allow islet regeneration. Apoptotic cells – a source of autoantigens – are cleared rapidly by macrophages and DCs through an immunologically silent process that contributes to maintaining tolerance. Our aims were to prevent T1D and to evaluate the re-establishment of peripheral tolerance using autologous DCs pulsed in vitro with apoptotic bodies from β cells. Immature DCs derived from bone marrow of non-obese diabetic (NOD) mice were obtained and pulsed with antigen-specific apoptotic bodies from the β cell line NIT-1. Those DCs that phagocytosed apoptotic cells diminished the expression of co-stimulatory molecules CD40 and CD86 and reduced secretion of proinflammatory cytokines. Moreover, these cells were resistant to increase the expression of co-stimulatory molecules after lipopolysaccharide activation. The administration of these cells to NOD transgenic mice expressing interferon-β in their insulin-producing cells, a model of accelerated autoimmune diabetes, decreased diabetes incidence significantly and correlated positively with insulitis reduction. DCs pulsed with apoptotic cells that express disease-associated antigens constitutes a promising strategy to prevent T1D. [ABSTRACT FROM AUTHOR]

Type 1 diabetes (T1D) is caused by the selective destruction of the insulin-producing β cells of the pancreas by an autoimmune response. Due to ethical and practical difficulties, the features of the destructive process are known from a small number of observations, and transcriptomic data are remarkably missing. Here we report whole genome transcript analysis validated by quantitative reverse transcription–polymerase chain reaction (qRT–PCR) and correlated with immunohistological observations for four T1D pancreases (collected 5 days, 9 months, 8 and 10 years after diagnosis) and for purified islets from two of them. Collectively, the expression profile of immune response and inflammatory genes confirmed the current views on the immunopathogenesis of diabetes and showed similarities with other autoimmune diseases; for example, an interferon signature was detected. The data also supported the concept that the autoimmune process is maintained and balanced partially by regeneration and regulatory pathway activation, e.g. non-classical class I human leucocyte antigen and leucocyte immunoglobulin-like receptor, subfamily B1 (LILRB1). Changes in gene expression in islets were confined mainly to endocrine and neural genes, some of which are T1D autoantigens. By contrast, these islets showed only a few overexpressed immune system genes, among which bioinformatic analysis pointed to chemokine (C-C motif) receptor 5 (CCR5) and chemokine (CXC motif) receptor 4) (CXCR4) chemokine pathway activation. Remarkably, the expression of genes of innate immunity, complement, chemokines, immunoglobulin and regeneration genes was maintained or even increased in the long-standing cases. Transcriptomic data favour the view that T1D is caused by a chronic inflammatory process with a strong participation of innate immunity that progresses in spite of the regulatory and regenerative mechanisms. [ABSTRACT FROM AUTHOR]

Within density functional theory, we have addressed the solvation onset of Ca atoms in small, mixed helium drops. As a case of study, we have considered a Ca@4He50 droplet to which we have first added one single 3He atom. Next, the structure of spin-saturated Ca@3He N3+4He50 droplets with N3=18, 32, 50 and 68 is determined and used to infer the number of 3He atoms needed to solvate the Ca atom for that particular system. [ABSTRACT FROM AUTHOR]

We report studies of adsorption of helium in translationally invariant polygonal pores at zero temperature, with emphasis on the route to capillary condensation and the appearance of metastable states. We analyze hysteresis and hysterectic-like phenomena associated to the existence of multiple equilibrium states in a rhombic pore and examine the effects of the angular geometry, as opposed to the smooth curvature of cylindrical tubes. [ABSTRACT FROM AUTHOR]

The destruction of β cells by the islet infiltrating lymphocytes causes type 1 diabetes. Transgenic mice models expressing interferon (IFN)-β in β cells, in the non-obese diabetic (NOD) strain and in a diabetes-free, major histocompatibility complex-matched, homologous strain, the non-obese resistant (NOR) mice, developed accelerated type 1 diabetes after 3 weeks of age. Our aim was to determine if natural killer (NK) cells could affect the acceleration of the disease. We determined the amount of NK cells in the pancreas, spleen and lymph nodes from NOD rat insulin promoter (RIP)-IFN-β mice. Pancreatic cytokines were assessed by quantitative real-time polymerase chain reaction and protein arrays. To confirm the relevance of NK cells in the acceleration of autoimmune diabetes this subset was depleted with anti-asialo GM1 antibodies. An increase of intrapancreatic NK cells characterized the accelerated onset of diabetes both in NOD and NOR RIP-IFN-β transgenic models. Cytokines involved in NK function and migration were found to be hyperexpressed in the pancreas from accelerated diabetic mice. Interestingly, the depletion of NK cells in vivo abolished completely the acceleration of diabetes. NK cells connect innate to adaptive immunity and might play a role in autoimmunity. We report here that NK cells are required critically in the pancreas for accelerated diabetes. This model links inflammation to acceleration of β cell-specific autoimmunity mediated by NK cells. [ABSTRACT FROM AUTHOR]

We investigate the adsorption of helium in alkali wedges at zero temperature within a fully unrestricted density–functional theory. We have found a sequence of shapes that includes one filling transition on the nonwettable Cs and one emptying transition for every alkali, as well as a threshold for metastable configurations where helium does not populate the wedge apex. [ABSTRACT FROM AUTHOR]

Pancreatic islet transplantation has been proposed as an attractive option for the treatment of type I diabetes. Transplantation into different sites has been investigated, among them those that are immunologically privileged (e.g., thymus, uterus, brain, anterior eye chamber, and testicle). Because of their characteristics, seminal vesicles could be considered as immunologically privileged organs, but there is no worldwide experience that can confirm it. The purpose of the present study is to assess the viability and functionality of islet transplantation into seminal vesicles of diabetic rats. One hundred ninety inbred adult male syngeneic Lewis rats were used as donors (n = 72), receptors (ii = 36), and controls (n = 11). Diabetes was chemically induced through a single intraperitoneal injection of streptozotocin. Groups of 1200 purified islets were introduced in the right seminal vesicle of diabetic rats. Diabetic control rats were sham transplanted. Body weight and glycemia were monitored every 2 d. Of transplanted rats, 16.7% achieved a good function due to islet engraftment, while 30.6% achieved a partially good response, and 52.7% were considered as nonresponding. This is the first report about islet transplantation into seminal vesicles of diabetic animals. Our results indicate that islet transplantation into rat seminal vesicles is technically possible, and that islets can function normally after engraftment into the wall of the seminal vesicle. [ABSTRACT FROM AUTHOR]

We investigate integer filling factor phases of many-N-electron vertically coupled semiconductor quantum dot artificial molecules when the inter-dot coupling is strong and weak. The experimental results are analyzed within local-spin density- functional theory. Maximum density droplets composed of electrons in both bonding and anti-bonding, or just bonding states are revealed. Interesting isospin physics (i.e., isospin transitions) can occur particularly when the inter-dot coupling is reduced. [Copyright &y& Elsevier]

Local spin density functional theory calculations for double quantum dots are compared with experimental data to explain the evolution of addition energy spectra with the interdot distance. Realistic features such as finite thickness and nonidentical constituent dots are included in the calculation. We can thus evaluate the heteronuclear character of the diatomic artificial quantum molecules due to a small unavoidable mismatch introduced in their fabrication. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2003 [ABSTRACT FROM AUTHOR]

We investigate the dissociation of few-electron circular vertical semiconductor double quantum dot artificial molecules at 0 T as a function of interdot distance. Slight mismatch introduced in the fabrication of the artificial molecules from materials with nominally identical constituent quantum wells induces localization. This offsets the energy levels in the quantum dots by up to 2 meV, and can play a crucial role in the appearance of the addition energy spectra as a function of coupling strength particularly in the weak coupling limit. [Copyright &y& Elsevier]

Using an effectiveHe-He interaction, we have investigated the fission and fusion ofHe drops from a static point of view. Our calculations show that a fission barrier develops for these neutral systems, and that their saddle configurations are rather elongate. The transition from oblate to prolate shapes as a function of the angular momentum L, as well as critical values for fission and fusion are discussed for some selected cases. We show that a kind of proximity potential can be extracted from the drop-drop interaction potentials. [ABSTRACT FROM AUTHOR]

Full configuration interaction calculations demonstrate the existence of mixed correlation phases in truly three-dimensional elongated nanocrystals subject to inhomogeneous spatial confining potentials. In such phases, the electron density behaves like a Fermi liquid in some regions, while, simultaneously, other more dilute regions display the typical quasi-classical Wigner distribution. The present results confirm and strengthen previous local spin-density functional theory predictions [Ballester et al., Phys. Rev. B 82, 115405 (2010)]. Additionally, simulation of the in-plane and z-polarized modes of the absorption spectra reveals the different correlation regimes occurring in these systems. [ABSTRACT FROM AUTHOR]

We have investigated the static fission and fusion ofHe drops using a density functional. Our calculations show that a fission barrier develops for these neutral systems, and that their saddle configurations are rather elongate. We show that a kind of proximity potential can be extracted from the drop-drop interaction potentials. [ABSTRACT FROM AUTHOR]