11,352 research outputs found

    Albumin-heparin microspheres as carriers for cytostatic agents

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    Much work has been done on adriamycin-loaded albumin microspheres (Alb-MS) for chemoembolization [1–4], the rationale being that site-specific drug delivery may increase the therapeutic efficacy of the drug. Alb-Ms are being investigated because of their biocompatibility and because the degradation products of these microspheres are non-toxic. However, these microspheres have some disadvantages (i.e. drug loading during the microsphere preparation, low payloads, large burst effects). These disadvantages can be overcome by the incorporation of heparin (a highly negatively charged mucopolysaccharide). Albumin-heparin microspheres were prepared (i) by crosslinking of soluble albumin and heparin first using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and subsequently glutaraldehyde (Alb-Hep-MS) and (ii) by crosslinking a preformed soluble conjugate of heparin and albumin with glutaraldehyde (Alb-Hep-Conj-MS). Albumin-heparin microspheres could be loaded with adriamycin after microsphere preparation giving payloads of 15–30%. Preliminary in vitro adriamycin release experiments showed that Alb-Hep-Conj-MS exhibit sustained release properties. Furthermore ion-exchange properties could be observed both with Alb-Hep-MS and Alb-Hep-Conj-MS. In vitro and in vivo toxicity experiments with Alb-Hep-MS showed no adverse effects

    Adriamycin loading and release characteristics of albumin-heparin conjugate microspheres

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    Biodegradable ion-exchange microspheres, prepared from a prefabricated conjugate of albumin and heparin were investigated as carriers for adriamycin. The ion-exchange microspheres could be loaded with adriamycin giving payloads up to 33% w/w, depending on the heparin content of the conjugate. In vitro adriamycin release depended on the ionic strength of the release medium. In ion containing media, for instance saline, 90% of the drug was released within 45 min, whereas in non-ionic media, such as distilled water, only 30% was released. Drug release profiles could be modelled by combining ion-exchange kinetics and diffusion controlled drug release models

    PAMELA's cosmic positron from decaying LSP in SO(10) SUSY GUT

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    We propose two viable scenarios explaining the recent observations on cosmic positron excess. In both scenarios, the present relic density in the Universe is assumed to be still supported by thermally produced WIMP or LSP (\chi). One of the scenarios is based on two dark matter (DM) components (\chi,X) scenario, and the other is on SO(10) SUSY GUT. In the two DM components scenario, extremely small amount of non-thermally produced meta-stable DM component [O(10^{-10}) < n_X /n_\chi] explains the cosmic positron excess. In the SO(10) model, extremely small R-parity violation for LSP decay to e^\pm is naturally achieved with a non-zero VEV of the superpartner of one right-handed neutrino (\tilde{\nu}^c) and a global symmetry.Comment: 6 pages, Talks presented in PASCOS, SUSY, and COSMO/CosPA in 201

    Quantification of Thickness Effects for Circumferential Through-Wall Cracked Pipe Bend with Un-Uniform Thickness under In-Plane Opening Bending

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    AbstractAn Elbow is one of the major component that make up the piping system of a nuclear power plant and chemical plant facilities. In general, the elbow is made by welding a straight pipe and bend part. So, periodic welding inspection is required due to the potential defects in weld zone. Recently, the application of induction heating pipe bend is increasing in order to reduce this problem. Pipe bend made by induction heating band is not necessary welding process because it is made by bending a straight pipe but the intrados thickness and the extrados thickness are different. On the other hand, J-integral is widely used to evaluate a structural integrity (to check crack stability) but the J estimation of pipe bend with un-uniform thickness is very difficult because of the thickness differences in each locations.This paper proposes a reference stress based J estimation scheme of circumferential through-wall cracked pipe bend with un-uniform thickness under in-plane opening bending loading condition. The pipe bend with un-uniform thickness is assumed to have different thickness between intrados and extrados and the crack to be located in the entre of the pipe bend, either at the intrados or extrados

    Quantum Key Distribution Using Quantum Faraday Rotators

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    We propose a new quantum key distribution (QKD) protocol based on the fully quantum mechanical states of the Faraday rotators. The protocol is unconditionally secure against collective attacks for multi-photon source up to two photons on a noisy environment. It is also robust against impersonation attacks. The protocol may be implemented experimentally with the current spintronics technology on semiconductors.Comment: 7 pages, 7 EPS figure

    Energetics of Hydrogen Chemisorbed on Cu(110): A First Principlies Calculations Study

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    In the current study we present a potential energy surface (PES)for atomic hydrogen chemisorbed on Cu(110)at Θ=1/8 monolayer ~ML! obtained from a plane-wave, gradient-corrected, density functional calculation. This PES is markedly different from and significantly more complex than that predicted by empirical embedded atom method (EAM) calculations. Our results, for example, suggest strongly that the hollow (HL)site is not the preferred binding site for this system. In our calculations, both the short bridge (SB)and pseudo-threefold sites are energetically more favorable than the hollow (HL)site. Energetically, we find the SB site to be slightly lower (30 meV)than the pseudo-threefold site. We also find, however, that the calculated vibrational frequencies for the pseudo-threefold site agree more closely with experimental electron energy loss data than for the SB site. In view of the relatively flat region between adjacent pseudo-threefold sites along the cross-channel [001]direction, we speculate that the hydrogen atom motion at low coverages may be two-dimensional rather than quasi-one-dimensional in character

    Unusual Higgs or Supersymmetry from Natural Electroweak Symmetry Breaking

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    This review provides an elementary discussion of electroweak symmetry breaking in the minimal and the next-to-minimal supersymmetric models with the focus on the fine-tuning problem -- the tension between natural electroweak symmetry breaking and the direct search limit on the Higgs boson mass. Two generic solutions of the fine-tuning problem are discussed in detail: models with unusual Higgs decays; and models with unusual pattern of soft supersymmetry breaking parameters.Comment: 23 pages, 6 figures; invited review by MPL
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