985 research outputs found

    The magnetofection method: Using magnetic force to enhance gene delivery

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    In order to enhance and target gene delivery we have previously established a novel method, termed magnetofection, which uses magnetic force acting on gene vectors that are associated with magnetic particles. Here we review the benefits, the mechanism and the potential of the method with regard to overcoming physical limitations to gene delivery. Magnetic particle chemistry and physics are discussed, followed by a detailed presentation of vector formulation and optimization work. While magnetofection does not necessarily improve the overall performance of any given standard gene transfer method in vitro, its major potential lies in the extraordinarily rapid and efficient transfection at low vector doses and the possibility of remotely controlled vector targeting in vivo

    Dolichopoda cave crickets from Peloponnese (Orthoptera, Rhaphidophoridae): molecular and morphological investigations reveal four new species for Greece

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    Three species belonging to the genus Dolichopoda (Orthoptera; Rhaphidopohoridae) are known so far from the Peloponnese, all endemic to the area. In particular, D. matsakisi is known from two mountains in the North, while D. dalensi is present in the east region. The third species, D. unicolor, is distributed in the southern part of the Peloponnese, inhabiting caves on Mt Taygetos and Mani Peninsula. Recently, extensive sampling work in most of the Peloponnese has led to the discovery of new taxa, morphologically differentiated by the above three known species. To investigate the delimitation of the Peloponnesian species of Dolichopoda, we performed both morphological and molecular analyses. Morphological analysis was carried out by considering diagnostic characters generally used to distinguish different taxa, as the shape of epiphallus in males and the subgenital plate in females. Molecular analysis was performed by sequencing three mitochondrial genes, 12S rRNA, 16S rRNA, and COI, and one nuclear gene, 28S rRNA. Results from both morphological and molecular analyses were used to revise the taxonomic arrangement of the Peloponnesian species. On the whole, we were able to distinguish seven lineages of Peloponnesian Dolichopoda species, of which D. kofinasi n.sp., D.epidavrii n.sp., D. poseidonica n.sp., and D. propanti n.sp. are described as new species

    Magnetization of polydisperse colloidal ferrofluids: Effect of magnetostriction

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    We exploit magnetostriction in polydisperse ferrofluids in order to generate nonlinear responses, and apply a thermodynamical method to derive the desired nonlinear magnetic susceptibility. For an ideal gas, this method has been demonstrated to be in excellent agreement with a statistical method. In the presence of a sinusoidal ac magnetic field, the magnetization of the polydisperse ferrofluid contains higher-order harmonics, which can be extracted analytically by using a perturbation approach. We find that the harmonics are sensitive to the particle distribution and the degree of field-induced anisotropy of the system. In addition, we find that the magnetization is higher in the polydisperse system than in the monodisperse one, as also found by a recent Monte Carlo simulation. Thus, it seems possible to detect the size distribution in a polydisperse ferrofluid by measuring the harmonics of the magnetization under the influence of magnetostriction.Comment: 23 pages, 4 figures. To be accepted for publication in Phys. Rev.

    Quantization effects and stabilization of the fast-Kalman algorithm

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    The exact and actual cause of the failure of the fast-Kalman algorithm due to the generation and propagation of finite-precision or quantization error is presented. It is demonstrated that out of all the formulas that constitute this fast Recursive Least Squares (RLS) scheme only three generate an amount of finite-precision error that consistently propagates in the subsequent iterations and eventually makes the algorithm fail after a certain number of recursions. Moreover, it is shown that there is a very limited number of specific formulas that transmit the generated finite-precision error, while there is another class of formulas that lift or "relax" this error. In addition, a number of general propositions is presented that allow for the calculation of the exact number of erroneous digits with which the various quantities of the fast-Kalman scheme are computed, including the filter coefficients. On the basis of the previous analysis a method of stabilization of the fast-Kalman algorithm is developed and is presented here, a method that allows for the fast-Kalman algorithm to follow very difficult signals such as music, speech, environmental noise, and other nonstationary ones. Finally, a general methodology is pointed out, that allows for the development of new algorithms which, intrinsically, suffer far less of finite-precision problems.</p

    Quantum-mechanical calculation of Stark widths of Ne VII n=3, Δn=0\Delta n=0 transitions

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    The Stark widths of the Ne VII 2s3s-2s3p singlet and triplet lines are calculated in the impact approximation using quantum-mechanical Convergent Close-Coupling and Coulomb-Born-Exchange approximations. It is shown that the contribution from inelastic collisions to the line widths exceeds the elastic width contribution by about an order of magnitude. Comparison with the line widths measured in a hot dense plasma of a gas-liner pinch indicates a significant difference which may be naturally explained by non-thermal Doppler effects from persistent implosion velocities or turbulence developed during the pinch implosion. Contributions to the line width from different partial waves and types of interactions are discussed as well.Comment: 8 pages, 3 figures; accepted by Phys. Rev.

    Drivers of the real effective exchange rates in high and upper-middle income countries

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    This paper revisits the nexus between real effective exchange rate (REER) and total factor productivity (TFP) by controlling for trade openness, financial development and natural resources rents. We use a sample of 60 high‐income and upper‐middle income countries over the period 1995–2015 and employ the GMM estimation framework. Our results advance the empirical knowledge on the drivers of REER by providing robust evidence that the impact of TFP is not uniform across different country clusters. We find that in high‐income countries, increasing productivity causes the REER to depreciate hence becoming more trade competitive while the opposite is true for upper‐middle income countries. Furthermore, financial development and natural resources rents have no meaningful impact in the case of upper‐middle income countries but retain a significant effect in high‐income countries. Trade openness plays a key role in explaining the variation in REER in both country clusters

    The Effect of Fused 12-Membered Nickel Metallacrowns on DNA and their Antibacterial Activity

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    The synthesis, characterization and the biological study of a series of Ni(ll)2(carboxylato)2 [12- MCNi(II)N(shi)2(pko)2-4][12-MCNi(ii)N(sh03(pko)-4] (CH3OH)3(H3O) fused 12-membered metallacrowns with 10 metal ions and commercial available herbicides or anti-inflammatory drugs as carboxylato ligands are reported. All the compounds have a mixed ligand composition with salicylhydroxamic acid and di-2-pyridylketonoxime as chelate agents. The compounds construct metallacrown cores {[12-MCNi(n)N(sj02(pko)2-4][12-MCNi(ll)N(shO3(pko)-4]}2+ following the pattern [-Ni-O-N-]4. The neutral decanuclear [Ni(II)(A)]2[12-MCNi(II)N(shi)2(pko)2-4][12-MCNi(II)N(pko)3(pko)-4] fused metallacrown, consists of two [12-MCM(ox)N(ligand)-4] units the {Ni(ll)(A)[12-MCNi(II)N(shi)2(pko)2-4]} and {Ni(II)(A)[12-MCNi(II)N(shi)3(pko)-4]} with 1+ and 1- charge, respectively. Each metallacrown unit has four ring Ni(II) ions and one additional encapsulated Ni(II) ion in planar arrangement. The anionic unit is bonded with cationic one creating binuclear moieties. The herbicide or antiiflammatory carboxylato ligands are bridging the central octahedral nickel atom with a ring metal ion in a bindetate fashion. The effect on DNA and their antibacterial activity was examined. The changes in the mobility can be attributed to the altered structures of the pDNA treated with Ni(II) complexes. Evaluating the data of the antibacterial activity of the compounds tested, we can conclude that nickel complexes present strong antibacterial activity

    Anti-C1q Autoantibodies Are Frequently Detected in Patients With Systemic Sclerosis Associated With Pulmonary Fibrosis

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    BACKGROUND: Anti-C1q autoantibodies (autoAbs) are associated with systemic lupus erythematosus (SLE) but their presence in other rheumatic diseases has not been adequately investigated. OBJECTIVE: We aim to assessanti-C1q autoAbs and circulating immune complexes (CICs) in systemic sclerosis (SSc). METHODS: One hundred twenty four patients with SSc (106 females; median age 59.4 years, range 25-81.4; 75(60.5%) with limited cutaneous SSc[lcSSc], and 49(39.5%) with diffuse cutaneous SSc[dcSSc]), were studied. Twenty-five patients with Sjögren\u27s syndrome (SjS), 29 with rheumatoid arthritis (RA), and 38 patients with systemic lupus erythematosus (SLE) and 53 healthy controls (NC) were also included. ELISAs with high and low salt buffers the former allowing IgGFc binding to C1q, the latter not allowing IgGFc binding and anti-C1q Ab binding to C1q were used to measure anti-C1q Abs and CICs. RESULTS: Anti-C1q Abs were present in20/124 (16.1%) SSc patients [5 had high levels (\u3e80 RU/mL) and 10 patients (50%) had moderate levels (40-80 RU/mL)] compared to 1/25 (4%) SjS, 1/29 (3.4%) RA patients (p CONCLUSIONS: Anti-C1q autoAbs were frequently detected in patients with SSc and their high levels predict the co-occurrence of pulmonary fibrosis or pulmonary arterial hypertension
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