| 1. |
- Tran, Dien M., et al.
(författare)
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High prevalence of colonisation with carbapenem-resistant Enterobacteriaceae among patients admitted to Vietnamese hospitals : Risk factors and burden of disease
- 2019
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Ingår i: Journal of Infection. - : Saunders Elsevier. - 0163-4453 .- 1532-2742. ; 79:2, s. 115-122
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundCarbapenem-resistant Enterobacteriaceae (CRE) is an increasing problem worldwide, but particularly problematic in low- and middle-income countries (LMIC) due to limitations of resources for surveillance of CRE and infection prevention and control (IPC).MethodsA point prevalence survey (PPS) with screening for colonisation with CRE was conducted on 2233 patients admitted to neonatal, paediatric and adult care at 12 Vietnamese hospitals located in northern, central and southern Vietnam during 2017 and 2018. CRE colonisation was determined by culturing of faecal specimens on selective agar for CRE. Risk factors for CRE colonisation were evaluated. A CRE admission and discharge screening sub-study was conducted among one of the most vulnerable patient groups; infants treated at an 80-bed Neonatal ICU from March throughout June 2017 to assess CRE acquisition, hospital-acquired infection (HAI) and treatment outcome.ResultsA total of 1165 (52%) patients were colonised with CRE, most commonly Klebsiella pneumoniae (n=805), Escherichia coli (n=682) and Enterobacter spp. (n=61). Duration of hospital stay, HAI and treatment with a carbapenem were independent risk factors for CRE colonisation. The PPS showed that the prevalence of CRE colonisation increased on average 4.2 % per day and mean CRE colonisation rates increased from 13% on the day of admission to 89% at day 15 of hospital stay. At the NICU CRE colonisation increased from 32% at admission to 87% at discharge, mortality was significantly associated (OR 5•5, P < 0•01) with CRE colonisation and HAI on admission.ConclusionThese data indicate that there is an epidemic spread of CRE in Vietnamese hospitals with rapid transmission to hospitalised patients.
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| 2. |
- Wolf, Philipp M., et al.
(författare)
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An in situ ToF-LEIS characterization of the surface of Ti-based thin films under oxygen exposure and at elevated temperatures
- 2023
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 638
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Tidskriftsartikel (refereegranskat)abstract
- Ti-based coatings are utilized in a wide variety of applications, from biomedical implants to mechanical tools. Insight into initial stages of processes triggered by gas exposure and temperature change in the near-surface region of such coatings is essential for the understanding of their macroscopic behavior. We present an in situ time-of-flight low-energy ion scattering (ToF-LEIS) approach for the non-destructive and depth-resolved study of composition and morphology of the immediate surface region with sub-nm resolution. Ti-based coatings, with increasing compositional complexity, starting from in situ grown Ti, followed by ex situ grown Ti, TiN, and (Ti,Al) N, are studied concerning effects of exposure to oxygen and elevated temperatures. On the clean in situ deposited Ti surface, a 1.9 nm thick oxide layer is observed after exposure to 4000 Langmuir oxygen at room temperature. In contrast, for ex situ grown samples, an oxidic surface layer not removable by surface ion sputtering is found to limit effects of further oxygen exposure. TiN does not show significant changes when exposed to oxygen at 370 & DEG;C. For (Ti,Al)N, a nm-thick Al-rich surface layer is observed at annealing temperatures above 600 & DEG;C, both in ultra-high vacuum and in 1.0 x 10-3 Pa of oxygen.
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| 3. |
- Arama, Charles, et al.
(författare)
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Genetic Resistance to Malaria Is Associated With Greater Enhancement of Immunoglobulin (Ig)M Than IgG Responses to a Broad Array of Plasmodium falciparum Antigens
- 2015
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Ingår i: Open forum infectious diseases. - : Oxford University Press (OUP). - 2328-8957. ; 2:3
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Tidskriftsartikel (refereegranskat)abstract
- Background. People of the Fulani ethnic group are more resistant to malaria compared with genetically distinct ethnic groups, such as the Dogon people, in West Africa, and studies suggest that this resistance is mediated by enhanced antibody responses to Plasmodium falciparum antigens. However, prior studies measured antibody responses to < 0.1% of P falciparum proteins, so whether the Fulani mount an enhanced and broadly reactive immunoglobulin (Ig) M and IgG response to P falciparum remains unknown. In general, little is known about the extent to which host genetics influence the overall antigen specificity of IgM and IgG responses to natural infections. Methods. In a cross-sectional study in Mali, we collected plasma from asymptomatic, age-matched Fulani (n = 24) and Dogon (n = 22) adults with or without concurrent P falciparum infection. We probed plasma against a protein microarray containing 1087 P falciparum antigens and compared IgM and IgG profiles by ethnicity. Results. We found that the breadth and magnitude of P falciparum-specific IgM and IgG responses were significantly higher in the malaria-resistant Fulani versus the malaria-susceptible Dogon, and, unexpectedly, P falciparum-specific IgM responses more strongly distinguished the 2 ethnic groups. Conclusions. These findings point to an underappreciated role for IgM in protection from malaria, and they suggest that host genetics may influence the antigen specificity of IgM and IgG responses to infection.
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| 4. |
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| 5. |
- Pitthan, Eduardo, et al.
(författare)
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Thin films sputter-deposited from EUROFER97 in argon and deuterium atmosphere : Material properties and deuterium retention
- 2023
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Ingår i: Nuclear Materials and Energy. - : Elsevier. - 2352-1791. ; 34
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Tidskriftsartikel (refereegranskat)abstract
- Sputter-deposited thin films (33–1160 nm) from EUROFER97 were obtained on different substrates (C, Si, W, MgO) in argon and a mix of argon and deuterium atmosphere. The composition, microstructure, and mechanical properties of the films were analyzed and compared to those of the bulk material. The films feature lower density (-10%), higher hardness (+79%), and smaller crystallites in comparison to the bulk. Despite such differences, the elemental atomic composition of the films and the bulk was very similar, as determined by ion beam analysis. Deposition in deuterium-containing atmosphere resulted in a low deuterium incorporation (0.28% of atomic content), indicating low retention of hydrogen-isotopes in the deposited material.
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| 6. |
- Tran, Tuan T., et al.
(författare)
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Ion beam synthesis and photoluminescence study of supersaturated fully-relaxed Ge-Sn alloys
- 2020
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Ingår i: Materials Science & Engineering. - : Elsevier BV. - 0921-5107 .- 1873-4944. ; 262
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Tidskriftsartikel (refereegranskat)abstract
- Direct-bandgap germanium-tin (Ge-Sn) alloys are highly sought-after materials for applications in silicon photonic integrated circuits. Other than crystal quality, two main factors determine the transition from the indirect to direct bandgap: the high Sn concentration and the strain relaxation in the materials. Using ion implantation and pulsed laser melting, we demonstrate a fully-relaxed Ge-Sn alloy with a Sn concentration of 6at.%. This concentration is at least 10 times higher than the equilibrium solubility of Sn in Ge. Cross-sectional transmission electron microscopy shows unconventional threading-like defects in the film as the mechanism for the strain relaxation. Due to the high degree of strain relaxation and the good crystal quality, photoluminescence could be obtained from the samples to examine the indirect-direct bandgap transition in the alloys.
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| 7. |
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| 8. |
- Wolf, Philipp M., et al.
(författare)
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Direct Transition from Ultrathin Orthorhombic Dinickel Silicides to Epitaxial Nickel Disilicide Revealed by In Situ Synthesis and Analysis
- 2022
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Ingår i: Small. - : Wiley-VCH Verlagsgesellschaft. - 1613-6810 .- 1613-6829. ; 18:14
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Tidskriftsartikel (refereegranskat)abstract
- Understanding phase transitions of ultrathin metal silicides is crucial for the development of nanoscale silicon devices. Here, the phase transition of ultrathin (3.6 nm) Ni silicides on Si(100) substrates is investigated using an in situ synthesis and characterization approach, supplemented with ex situ transmission electron microscopy and nano-beam electron diffraction. First, an ultrathin epitaxial layer and ordered structures at the interface are observed upon room-temperature deposition. At 290 °C, this structure is followed by formation of an orthorhombic δ-Ni2Si phase exhibiting long-range order and extending to the whole film thickness. An unprecedented direct transition from this δ-Ni2Si phase to the final NiSi2−x phase is observed at 290 °C, skipping the intermediate monosilicide phase. Additionally, the NiSi2−x phase is found epitaxial on the substrate. This transition process substantially differs from observations for thicker films. Furthermore, considering previous studies, the long-range ordered orthorhombic δ-Ni2Si phase is suggested to occur regardless of the initial Ni thickness. The thickness of this ordered δ-Ni2Si layer is, however, limited due to the competition of different orientations of the δ-Ni2Si crystal. Whether the formed δ-Ni2Si layer consumes all deposited nickel is expected to determine whether the monosilicide phase appears before the transition to the final NiSi2−x phase.
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