466 research outputs found

    Deep eutectic solvents: a structural point of view on the role of the cation

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    In this work we have developed an analytical procedure to identify metal ion coordination geometries in liquid media based on the calculation of Combined Distribution Functions (CDFs) starting from Molecular Dynamics (MD) simulations. CDFs provide a fingerprint which can be easily and unambiguously assigned to a reference polyhedron. The CDF analysis has been tested on five systems and has proven to reliably identify the correct geometries of several ion coordination complexes. This tool is simple and general and can be efficiently applied to different MD simulations of liquid systems

    Treatment of Palatally Displaced Canines Using Miniscrews for Direct or Indirect Anchorage: A Three-Dimensional Prospective Cohort Study on Tooth Movement Speed

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    Palatally impacted canines are usually challenging to treat in terms of both biomechanics and possible side effects. Different therapeutic approaches have been reported with or without the use of temporary anchorage devices, including the canine-first approach. Two groups of patients with palatally impacted canines were compared, observing their canine movement measured on consecutive CBCTs after three months of treatment. In the control group, impacted canines were treated with direct anchorage on miniscrews, and in the test group with indirect anchorage using a miniscrew-supported transpalatal arch. The primary outcome was the canine movement speed; the secondary outcome was the change in the root length of adjacent teeth. The median monthly apex speed was 1.05 mm in the control group (IR [0.74, 1.64]) and 0.72 mm in the test group (IR [0.27, 1.30]). The median monthly cusp displacement was 1.89 mm in the control group (IR [1.04, 2.84]) and 1.08 mm in the test group (IR [0.81, 1.91]). Approximately 50% of teeth adjacent to an impacted canine underwent a negative root length change of less than 1 mm in the majority of cases, but no significant differences were found in root length changes between groups. No statistically significant differences in the reported speeds were found, and no miniscrew failures were observed in either group

    Optical Channeling of Low Energy Antiprotons in Thin Crystal Targets

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    A relevant aspect of the interactions between charged fermions and crystal targets is coherence, which can exist at both classical and quantum levels. In the case of antiprotons crossing crystal targets, there are theories and measurements of classical-level coherence effects, in particular, channeling effects. For the present study, we assume the existence of a low-energy regime where the electrostatic interactions between an antiproton and the crystal atoms lead to a local loss in the beam flux as their leading effect. We expect this assumption to be well-justified for antiproton (p over bar ) energies below 100 eV, with a progressive transition to a standard "Rutherford regime" in the energy range 100-1000 eV. Under these conditions, the target can be treated as an optical absorber with a periodical structure, which can be simplified by considering a multi-layer planar structure only. As in standard optics, wave absorption is accompanied by interference and diffraction. Assuming sub-nanometer ranges for the relevant parameters and a realistic angular spread for the antiproton beam, we find narrow-angle focusing effects that reproduce the classical channeling effect at a qualitative level. We also find that diffraction dominates over interference, although this may strongly depend on the target details

    Systematic Review of Laser and Other Light Therapy for the Management of Oral Mucositis in Cancer Patients

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    Background The aim of this study was to review the available literature and define clinical practice guidelines for the use of laser and other light therapies for the prevention and treatment of oral mucositis. Methods A systematic review was conducted by the Mucositis Study Group of the Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology. The body of evidence for each intervention, in each cancer treatment setting, was assigned an evidence level. Based onthe evidence level, one of the following three guideline determinations was possible: recommendation, suggestion, and no guideline possible. Results A new recommendation was made for low-level laser (wavelength at 650 nm, power of 40 mW, and each square centimeter treated with the required time to a tissue energy dose of 2 J/cm2 (2 s/point)) for the prevention of oral mucositis in adult patients receiving hematopoietic stem cell transplantation conditioned with high-dose chemotherapy, with or without total body irradiation. A new suggestion was made for low-level laser (wavelength around 632.8 nm) for the prevention of oral mucositis in patients undergoing radiotherapy, without concomitant chemotherapy, for head and neck cancer. No guideline was possible in other populations and for other light sources due to insufficient evidence. Conclusions The increasing evidence in favor of low-level laser therapy allowed for the development of two new guidelines supporting this modality in the populations listed above. Evidence for other populations was also generally encouraging over a range of wavelengths and intensities. However, additional well-designed research is needed to evaluate the efficacy of laser and other light therapies in various cancer treatment settings

    Molybdenum sputtering film characterization for high gradient accelerating structures

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    Technological advancements are strongly required to fulfill the demands of new accelerator devices with the highest accelerating gradients and operation reliability for the future colliders. To this purpose an extensive R&D regarding molybdenum coatings on copper is in progress. In this contribution we describe chemical composition, deposition quality and resistivity properties of different molybdenum coatings obtained via sputtering. The deposited films are thick metallic disorder layers with different resistivity values above and below the molibdenum dioxide reference value. Chemical and electrical properties of these sputtered coatings have been characterized by Rutherford backscattering, XANES and photoemission spectroscopy. We will also present a three cells standing wave section coated by a molybdenum layer \sim 500 nm thick designed to improve the performance of X-Band accelerating systems.Comment: manuscript has been submitted and accepted by Chinese Physics C (2012

    unveiling the complex network of interactions in ionic liquids a combined exafs and molecular dynamics approach

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    The structural properties of geminal dicationic ionic liquids ([Cn (mim)2]Br2)/water mixtures have been investigated by means of extended X-ray absorption fine structure (EXAFS) spectroscopy and Molecular Dynamics (MD) simulations. This synergic approach allowed us to assess the reliability of the MD results and to provide accurate structural information about the first coordination shell of the Br- ion. We found that the local environment around the anion changes as a function of the water concentration, while it is the same independently from the length of the bridge-alkyl chain. Moreover, as regards the long-range structural organization, no tail-tail aggregation occurs with increasing alkyl chain length

    Research on Benefit Evaluation of Advanced Manufacturing Technology

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    先进制造技术投资是一项关系到企业生存与发展的战略投资,其投资质量对企业的技术实力,管理水平,经济效益,竞争能力和长远发展都会产生重大的影响。先进制造技术投资决策的质量在很大程度上取决于人们对其所做的技术经济评价质量,正如国内外专家学者在相关研究中所指出:“影响先进制造技术推广应用的关键原因,并不在于技术而在于管理,而且其中‘如何评价先进制造技术’是影响其应用的最主要原因。”本文首先阐述了先进制造技术项目方面国内外的相关文献,然后分析了先进制造技术的含义、特征与其效益评价目标、原则和方法,构建了经济效益评价、无形效益评价和投资风险评价的综合评价体系,该体系的主要框架为:(1)应用作业成本法思路,...Applying advanced manufacturing technology (AMT) to the enterprise is a really significant strategic investment for the continuous operation and development of company, and the quality of decision-making greatly impacts the technical strength, management quality level, economic efficiency, competitiveness and long-term development of a company. Moreover, the quality of AMT investment decision-maki...学位:管理学硕士院系专业:管理学院会计系_会计学学号:1752006115128
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