104 research outputs found

    Effects of Irradiation Temperature and Dose Rate on the Mechanical Properties of Self-Ion Implanted Fe and Fe-Cr Alloys

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    Pure Fe and model Fe-Cr alloys containing 5, 10 and 14%Cr were irradiated with Fe+ ions at a maximum energy of 2MeV to the same dose of 0.6dpa at temperatures of 300 C, 400 C and 500 C, and at dose rates corresponding to 6 x 10-4 dpa/s and 3 x 10-5 dpa/s. All materials exhibited an increase in hardness after irradiation at 300 C. After irradiation at 400 C, hardening was observed only in Fe-Cr alloys, and not in the pure Fe. After irradiation at 500 C, no hardening was observed in any of the materials tested. For irradiations at both 300 C and 400 C, greater hardening was found in the Fe-Cr alloys irradiated at the lower dose rate. Transmission electron microscopy and atom probe tomography of Fe 5%Cr identified larger dislocation loop densities and sizes in the alloy irradiated with the high dose rate and Cr precipitation in the alloy irradiated with the low dose rate.Comment: 42 pages, 6 figure

    Aging Skin: Nourishing from the Inside Out, Effects of Good Versus Poor Nitrogen Intake on Skin Health and Healing

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    Skin is the outermost defense organ which protects us from the environment, constituting around 8 % of an adult’s body weight. Healthy skin contains one-eighth of the body’s total proteins. The balance of turnover and synthesis of skin proteins is primarily dependent on the availability of sufficient nitrogen-containing substrates, namely, amino acids, essential for protein metabolism in any other tissue and body organs. The turnover of skin proteins has been shown to be rapid, and the mobilization of amino acids at the expense of skin proteins is relevant in experimental models of protein malnutrition. As a result, alterations in nutritional status should be suspected, diagnosed, and eventually treated for any skin lesions. Protein malnutrition has a dramatic prevalence in patients aged >70 or more, independent of the reason for hospitalization. The quality of nutrition and content of essential amino acids are strictly connected to skin health and integrity of its protein components. Collagen fiber deposition is highly and rapidly influenced by alterations in the essential to nonessential amino acid ratios. The most relevant nutritional factor of skin health is the prevalence of essential amino acids

    Aging Skin: Nourishing from Out-In. Lessons from Wound Healing

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    Skin lesion therapy, peculiarly in the elderly, cannot be isolated from understanding that the skin is an important organ consisting of different tissues. Furthermore, dermis health is fundamental for epidermis integrity, and so adequate nourishment is mandatory in maintaining skin integrity. The dermis nourishes the epidermis, and a healthy epidermis protects the dermis from the environment, so nourishing the dermis through the epidermal barrier is a technical problem yet to be resolved. This is also a consequence of the laws and regulations restricting cosmetics, which cannot have properties that pass the epidermal layer. There is higher investment in cosmetics than in the pharmaceutical industry dealing with skin therapies, because the costs of drug registration are enormous and the field is unprofitable. Still, wound healing may be seen as an opportunity to “feed” the dermis directly. It could also verify whether providing substrates could promote efficient healing and test optimal skin integrity maintenance, if not skin rejuvenation, in an ever aging population

    Chimeric aptamers in cancer cell-targeted drug delivery

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    Aptamers are single-stranded structured oligonucleotides (DNA or RNA) that can bind to a wide range of targets ("apatopes") with high affinity and specificity. These nucleic acid ligands, generated from pools of random-sequence by an in vitro selection process referred to as systematic evolution of ligands by exponential enrichment (SELEX), have now been identified as excellent tools for chemical biology, therapeutic delivery, diagnosis, research, and monitoring therapy in real-time imaging. Today, aptamers represent an interesting class of modern Pharmaceuticals which with their low immunogenic potential mimic extend many of the properties of monoclonal antibodies in diagnostics, research, and therapeutics. More recently, chimeric aptamer approach employing many different possible types of chimerization strategies has generated more stable and efficient chimeric aptamers with aptamer-aptamer, aptamer-nonaptamer biomacromolecules (siRNAs, proteins) and aptamer-nanoparticle chimeras. These chimeric aptamers when conjugated with various biomacromolecules like locked nucleic acid (LNA) to potentiate their stability, biodistribution, and targeting efficiency, have facilitated the accurate targeting in preclinical trials. We developed LNA-aptamer (anti-nucleolin and EpCAM) complexes which were loaded in iron-saturated bovine lactofeerin (Fe-blf)-coated dopamine modified surface of superparamagnetic iron oxide (Fe3O4) nanoparticles (SPIONs). This complex was used to deliver the specific aptamers in tumor cells in a co-culture model of normal and cancer cells. This review focuses on the chimeric aptamers, currently in development that are likely to find future practical applications in concert with other therapeutic molecules and modalities

    Study of e+e−→ppˉe^+e^- \rightarrow p\bar{p} in the vicinity of ψ(3770)\psi(3770)

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    Using 2917 pb−1\rm{pb}^{-1} of data accumulated at 3.773~GeV\rm{GeV}, 44.5~pb−1\rm{pb}^{-1} of data accumulated at 3.65~GeV\rm{GeV} and data accumulated during a ψ(3770)\psi(3770) line-shape scan with the BESIII detector, the reaction e+e−→ppˉe^+e^-\rightarrow p\bar{p} is studied considering a possible interference between resonant and continuum amplitudes. The cross section of e+e−→ψ(3770)→ppˉe^+e^-\rightarrow\psi(3770)\rightarrow p\bar{p}, σ(e+e−→ψ(3770)→ppˉ)\sigma(e^+e^-\rightarrow\psi(3770)\rightarrow p\bar{p}), is found to have two solutions, determined to be (0.059±0.032±0.0120.059\pm0.032\pm0.012) pb with the phase angle ϕ=(255.8±37.9±4.8)∘\phi = (255.8\pm37.9\pm4.8)^\circ (<<0.11 pb at the 90% confidence level), or σ(e+e−→ψ(3770)→ppˉ)=(2.57±0.12±0.12\sigma(e^+e^-\rightarrow\psi(3770)\rightarrow p\bar{p}) = (2.57\pm0.12\pm0.12) pb with ϕ=(266.9±6.1±0.9)∘\phi = (266.9\pm6.1\pm0.9)^\circ both of which agree with a destructive interference. Using the obtained cross section of ψ(3770)→ppˉ\psi(3770)\rightarrow p\bar{p}, the cross section of ppˉ→ψ(3770)p\bar{p}\rightarrow \psi(3770), which is useful information for the future PANDA experiment, is estimated to be either (9.8±5.79.8\pm5.7) nb (<17.2<17.2 nb at 90% C.L.) or (425.6±42.9)(425.6\pm42.9) nb

    Modelling Z → ττ processes in ATLAS with τ-embedded Z → ΌΌ data

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    This paper describes the concept, technical realisation and validation of a largely data-driven method to model events with Z→ττ decays. In Z→ΌΌ events selected from proton-proton collision data recorded at √s=8 TeV with the ATLAS experiment at the LHC in 2012, the Z decay muons are replaced by τ leptons from simulated Z→ττ decays at the level of reconstructed tracks and calorimeter cells. The τ lepton kinematics are derived from the kinematics of the original muons. Thus, only the well-understood decays of the Z boson and τ leptons as well as the detector response to the τ decay products are obtained from simulation. All other aspects of the event, such as the Z boson and jet kinematics as well as effects from multiple interactions, are given by the actual data. This so-called τ-embedding method is particularly relevant for Higgs boson searches and analyses in ττ final states, where Zarrowττ decays constitute a large irreducible background that cannot be obtained directly from data control samples. In this paper, the relevant concepts are discussed based on the implementation used in the ATLAS Standard Model H→ττ analysis of the full datataset recorded during 2011 and 2012
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