| 1. |
- Abrahamsson, Thomas, et al.
(författare)
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Low diversity of the gut microbiota in infants with atopic eczema
- 2012
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Ingår i: Journal of Allergy and Clinical Immunology. - New York, USA : Elsevier BV. - 0091-6749 .- 1097-6825. ; 129:2, s. 434-U244
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: It is debated whether a low total diversity of the gut microbiota in early childhood is more important than an altered prevalence of particular bacterial species for the increasing incidence of allergic disease. The advent of powerful, cultivation-free molecular methods makes it possible to characterize the total microbiome down to the genus level in large cohorts. OBJECTIVE: We sought to assess microbial diversity and characterize the dominant bacteria in stool during the first year of life in relation to atopic eczema development. METHODS: Microbial diversity and composition were analyzed with barcoded 16S rDNA 454-pyrosequencing in stool samples at 1 week, 1 month, and 12 months of age in 20 infants with IgE-associated eczema and 20 infants without any allergic manifestation until 2 years of age (ClinicalTrials.gov ID NCT01285830). RESULTS: Infants with IgE-associated eczema had a lower diversity of the total microbiota at 1 month (P= .004) and a lower diversity of the bacterial phylum Bacteroidetes and the genus Bacteroides at 1 month (P= .02 and P= .01) and the phylum Proteobacteria at 12 months of age (P= .02). The microbiota was less uniform at 1 month than at 12 months of age, with a high interindividual variability. At 12 months, when the microbiota had stabilized, Proteobacteria, comprising gram-negative organisms, were more abundant in infants without allergic manifestation (Empirical Analysis of Digital Gene Expression in R edgeR test: P= .008, q= 0.02). CONCLUSION: Low intestinal microbial diversity during the first month of life was associated with subsequent atopic eczema.
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| 2. |
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| 3. |
- Afshari, Davood, et al.
(författare)
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An approach in prediction of failure in resistance spot welded aluminum 6061-T6 under quasi-static tensile test
- 2012
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Ingår i: Proceedings of the Institution of mechanical engineers. Part B, journal of engineering manufacture. - : SAGE Publications. - 0954-4054 .- 2041-2975. ; 226:B6, s. 1026-1032
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this article is to predict the failure load in resistance spot welded aluminum 6061-T6 sheets with 2mm thickness under quasi-static tensile test. Various welding parameters, e. g. welding current, welding time and electrode force are selected to produce welded joints with different quality. The results show that for all the samples in this study only interfacial failure mode was observed in tensile-shear test and no pull-out mode was observed. According to the failure mode, an empirical equation was used for the prediction of failure load based on nugget size and hardness of failure line. Microstructure study has been carried out to investigate microstructural changes in the welded joints. For determination of the minimum hardness, microhardness tests have been carried out to find hardness profiles. The minimum hardness value was observed for a thin layer around the nugget with large and coarse grains. The results show that by using the presented empirical equation, the failure can be predicted with a good agreement only by measuring nugget size.
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| 4. |
- Ahlroth, Sofia, et al.
(författare)
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Weighting and valuation in selected environmental systems analysis tools - suggestions for further developments
- 2011
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526 .- 1879-1786. ; 19:2-3, s. 145-156
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Tidskriftsartikel (refereegranskat)abstract
- In environmental systems analysis tools like Life Cycle Assessment, strategic environmental assessment, cost benefit analysis and environmental management systems, results need to be presented in a comprehensible way to make alternatives easily comparable. One way of doing this is to aggregate results to a manageable set by using weighting methods.. In this paper, we explore how weighting methods are used in some selected Environmental Systems Analysis Tools (ESATs), and suggest possible developments of their use. We examine the differences in current use patterns, discuss the reasons for and implications of such differences, and investigate whether observed differences in use are necessary. The result of our survey shows that weighting and valuation is broadly used in the examined ESATs. The use of weighting/valuation methods is different in different tools, but these differences are not always related to the application; rather, they are related to traditions and views on valuation and weighting. Also, although the requirements on the weights/values may differ between tools, there are intersections where they coincide. Monetary weights, using either endpoint or midpoint methods, are found to be useful in all the selected tools. Furthermore, the inventory shows that that there is a common need for generic sets of weights. There is a need for further research focusing on the development of consistent value sets derived with a wide range of methods. In parallel to the development of weighting methods it is important with critical evaluations of the weighting sets with regard to scientific quality, consistency and data gaps.
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| 5. |
- Ahrén, Maria, et al.
(författare)
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A simple polyol-free synthesis route to Gd 2O 3 nanoparticles for MRI applications : An experimental and theoretical study
- 2012
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Ingår i: Journal of nanoparticle research. - : Springer. - 1388-0764 .- 1572-896X. ; 14:8
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Tidskriftsartikel (refereegranskat)abstract
- Chelated gadolinium ions, e.g., Gd-DTPA, are today used clinically as contrast agents for magnetic resonance imaging (MRI). An attractive alternative contrast agent is composed of gadolinium oxide nanoparticles as they have shown to provide enhanced contrast and, in principle, more straightforward molecular capping possibilities. In this study, we report a new, simple, and polyol-free way of synthesizing 4-5-nm-sized Gd 2O 3 nanoparticles at room temperature, with high stability and water solubility. The nanoparticles induce high-proton relaxivity compared to Gd-DTPA showing r 1 and r 2 values almost as high as those for free Gd 3+ ions in water. The Gd 2O 3 nanoparticles are capped with acetate and carbonate groups, as shown with infrared spectroscopy, near-edge X-ray absorption spectroscopy, X-ray photoelectron spectroscopy and combined thermogravimetric and mass spectroscopy analysis. Interpretation of infrared spectroscopy data is corroborated by extensive quantum chemical calculations. This nanomaterial is easily prepared and has promising properties to function as a core in a future contrast agent for MRI.
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| 6. |
- Aid, Graham, 1980-, et al.
(författare)
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Improvement of aggregate cycles in Stockholm and the Baltic Region : Activities and results of the BRA initiative
- 2012
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Ingår i: WASCON 2012 Conference proceedings. - : Swedish Geotechnical Institute. ; , s. 1-9, s. 1-9
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Konferensbidrag (refereegranskat)abstract
- From 2009 until 2011 project BRA (Bygg-och Rivningsavfall i Stockholms Län) “Construction and Demolition (C&D) waste in Stockholm County” was coordinated from the division of Industrial Ecology, KTH. This project was focused on actively improving (from plural perspectives) the cycles of C&D (specifically non-metallic inert) materials in the region. In response to the normative aim and inter-systems complexity, a highly participative action research procedure was adopted. Through processes of network communication, workshops, a course, and an international symposium - a number of issues (such as market development, recycled product quality, greenhouse gas impacts, collaborative planning, and statistics) were prioritized, researched, and acted upon. Indicators for measuring progress in selected areas were developed and preliminary action plans created. At a final co-organized symposium Swedish delegates laid the groundwork for the establishment of a Swedish C&D recycling b ranch organization. This initiative of continued collaboration between and within sectors is seen as a vehicle for the priorities and action requirements identified in BRA to be further enabled and held in focus. Furthermore, these actors taking ownership of the process is seen as a success in accordance to the original aims and the need for further cycles of evaluation, planning, and action.
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| 7. |
- Aiempanakit, Montri, 1977-, et al.
(författare)
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Understanding the discharge current behavior in reactive high power impulse magnetron sputtering of oxides
- 2013
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 113:13, s. 133302-
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Tidskriftsartikel (refereegranskat)abstract
- The discharge current behavior in reactive high power impulse magnetron sputtering (HiPIMS) of Ti-O and Al-O is investigated. It is found that for both metals, the discharge peak current significantly increases in the oxide mode in contrast to the behavior in reactive direct current magnetron sputtering where the discharge current increases for Al but decreases for Ti when oxygen is introduced. In order to investigate the increase in the discharge current in HiPIMS-mode, the ionic contribution of the discharge in the oxide and metal mode is measured using time-resolved mass spectrometry. The energy distributions and time evolution are investigated during the pulse-on time as well as in the post-discharge. In the oxide mode, the discharge is dominated by ionized oxygen, which has been preferentially sputtered from the target surface. The ionized oxygen determines the discharge behavior in reactive HiPIMS.
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| 8. |
- Aijaz, Asim, et al.
(författare)
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A strategy for increased carbon ionization in magnetron sputtering discharges
- 2012
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Ingår i: Diamond and related materials. - : Elsevier BV. - 0925-9635 .- 1879-0062. ; 23, s. 1-4
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Tidskriftsartikel (refereegranskat)abstract
- A strategy that facilitates a substantial increase of carbon ionization in magnetron sputtering discharges is presented in this work. The strategy is based on increasing the electron temperature in a high power impulse magnetron sputtering discharge by using Ne as the sputtering gas. This allows for the generation of an energetic C+ ion population and a substantial increase in the C+ ion flux as compared to a conventional Ar-HiPIMS process. A direct consequence of the ionization enhancement is demonstrated by an increase in the mass density of the grown films up to 2.8 g/cm(3); the density values achieved are substantially higher than those obtained from conventional magnetron sputtering methods.
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| 9. |
- Ajmal, Muhammad, et al.
(författare)
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Trading Quality of Transmission for Improved Blocking Performance in All-Optical Networks
- 2013
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Ingår i: Asia Communications and Photonics Conference 2013. - 9781557529893 ; , s. AF4E.5-
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Konferensbidrag (refereegranskat)abstract
- We propose a connection provisioning strategy in dynamic all-optical networks, which exploit the possibility to allow a tolerable signal quality degradation during a small fraction of holding-time resulting in a significant improvement of blocking performance.
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| 10. |
- Al-Saidi, W. A., et al.
(författare)
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Resonance raman spectra of TNT and RDX using vibronic theory, excited-state gradient, and complex polarizability approximations
- 2012
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Ingår i: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 116:30, s. 7862-7872
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Tidskriftsartikel (refereegranskat)abstract
- Geometries, UV absorption bands, and resonance Raman (RR) cross sections of TNT and RDX are investigated using density functional theory (DFT) in conjunction with the Coulomb attenuated B3LYP exchange-correlation functional. The absorption and RR spectra are determined with use of vibronic (VB) theory, excited-state gradient, and complex polarizability (CPP) approximations. We examined low-energy isomers (two for TNT and four for RDX) whose energies differ by less than 1 kcal/mol, such that they would appreciably be populated at room temperature. The two TNT isomers differ by an internal rotation of the methyl group, while the four conformers of RDX differ by the arrangements of the nitro group relative to the ring. Our theoretical optical properties of the TNT and RDX isomers are in excellent agreement with experimental and recent CCSD-EOM results, respectively. For the two TNT isomers, the ultraviolet RR (UVRR) spectra are similar and in good agreement with recently measured experimental results. Additionally, the UVRR spectra computed using the excited-state and CPP approaches compare favorably with the VB theory results. On the other hand, the RR spectra of the RDX conformers differ from one another, reflecting the importance of the positioning of the NO 2 groups with respect to the ring. In the gas phase or in solution, RDX would give a spectrum associated with a conformationally averaged structure. It is encouraging that the computed spectra of the conformers show similarities to recent measured RDX spectra in acetonitrile solution, and reproduce the 10-fold decrease in the absolute Raman cross sections of RDX compared to TNT for the observed 229 nm excitation. We show that in TNT and RDX vibrational bands that couple to NO 2 or the ring are particularly resonance enhanced. Finally, the computed RDX spectra of the conformers present a benchmark for understanding the RR spectra of the solid-phase polymorphs of RDX.
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