| 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. |
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| 3. |
- Brisuda, Antonín, et al.
(författare)
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Bladder cancer therapy using a conformationally fluid tumoricidal peptide complex
- 2021
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Partially unfolded alpha-lactalbumin forms the oleic acid complex HAMLET, with potent tumoricidal activity. Here we define a peptide-based molecular approach for targeting and killing tumor cells, and evidence of its clinical potential (ClinicalTrials.gov NCT03560479). A 39-residue alpha-helical peptide from alpha-lactalbumin is shown to gain lethality for tumor cells by forming oleic acid complexes (alpha1-oleate). Nuclear magnetic resonance measurements and computational simulations reveal a lipid core surrounded by conformationally fluid, alpha-helical peptide motifs. In a single center, placebo controlled, double blinded Phase I/II interventional clinical trial of non-muscle invasive bladder cancer, all primary end points of safety and efficacy of alpha1-oleate treatment are reached, as evaluated in an interim analysis. Intra-vesical instillations of alpha1-oleate triggers massive shedding of tumor cells and the tumor size is reduced but no drug-related side effects are detected (primary endpoints). Shed cells contain alpha1-oleate, treated tumors show evidence of apoptosis and the expression of cancer-related genes is inhibited (secondary endpoints). The results are especially encouraging for bladder cancer, where therapeutic failures and high recurrence rates create a great, unmet medical need.
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| 4. |
- Mai, Tam T., et al.
(författare)
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An overview of grid-edge control with the digital transformation
- 2021
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Ingår i: Electrical Engineering. - : Springer Science and Business Media LLC. - 1432-0487 .- 0948-7921. ; 103:4, s. 1989-2007
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Tidskriftsartikel (refereegranskat)abstract
- Distribution networks are evolving to become more responsive with increasing integration of distributed energy resources (DERs) and digital transformation at the grid edges. This evolution imposes many challenges to the operation of the network, which then calls for new control and operation paradigms. Among others, a so-called grid-edge control is emerging to harmonise the coexistence of the grid control system and DER’s autonomous control. This paper provides a comprehensive overview of the grid-edge control with various control architectures, layers, and strategies. The challenges and opportunities for such an approach at the grid edge with the integration of DERs and digital transformation are summarised. The potential solutions to support the network operation by using the inherent controllability of DER and the availability of the digital transformation at the grid edges are discussed.
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| 5. |
- Thang, Truong Cong, et al.
(författare)
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Design and implementation of an e-Health system for depression detection
- 2015
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Konferensbidrag (refereegranskat)abstract
- We present the design and implementation of a cost-effective e-Health system for automatic depression detection. The system is based on a client-server architecture, where clients are popular mobile devices. For practical deployment, various factors that affect the accuracy and speed of depression detection are discussed and evaluated with extensive experiments.
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| 6. |
- Tran, Minh Quan, et al.
(författare)
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MPC-Based Coordinated Voltage Control in LV Distribution Systems: A Case Study in Chalmers Campus Network
- 2023
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Ingår i: Conference Proceedings - 2023 IEEE Asia Meeting on Environment and Electrical Engineering, EEE-AM 2023.
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Konferensbidrag (refereegranskat)abstract
- This paper presents detailed analysis results of a model predictive control (MPC)-based coordinated voltage control demonstrated in a real low voltage network, the Chalmers campus in Sweden. First, the modeling of the MPC is presented, and the state space mode is obtained by linearization of the power flow equation around the operation point. Thus, an updated voltage vector in the grid is calculated through the sensitivity gain corresponding to reactive power deviation in the grid. Second, the developed MPC model is integrated into an Internet of Things (IoT) platform developed under the European FlexiGrid project. The state measurements in the Chalmers campus network are collected through the IoT platform as the input for the MPC model. Then, the optimal setpoints for distributed energy resources (DERs) are calculated and sent to DERs via the IoT platform. Lastly, onsite demonstration results are analyzed, showing the performance of the MPC-based voltage control in low-voltage distribution systems.
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| 7. |
- Tran, Minh Quan, et al.
(författare)
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Self-adaptive Controllers for Renewable Energy Communities Based on Transformer Loading Estimation
- 2022
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Ingår i: 2022 IEEE International Conference on Environment and Electrical Engineering and 2022 IEEE Industrial and Commercial Power Systems Europe, EEEIC / I and CPS Europe 2022.
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Konferensbidrag (refereegranskat)abstract
- In this paper, self-adaptive controllers for renewable energy communities based on data-driven approach are proposed to mitigate the voltage rise and transformer congestion at the community level. In the proposed approach, the transformer loading percentage is estimated by the trained data-driven model, which uses the extreme gradient boosting regression algorithm based on a measurement set acquired from critical coupling points of the communities. To avoid voltage rise issues, the droop control parameters (i.e., voltage threshold for P - V, Q - V curves) are adaptively tuned based on the solar irradiance availability and estimated transformer loading. The proposed approach has been tested in the IEEE European LV distribution network. Results showed that the control approach could effectively reduce 22.2 % of the total overloaded instances, while still keeping voltage magnitude in the operation range. This method can help DSOs manage voltage violation and congestion without further communication.
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| 8. |
- Dittrich, Laura, et al.
(författare)
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Retention of noble and rare isotope gases in plasma-facing components-Experience from the JET tokamak with the ITER-like wall
- 2023
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Ingår i: Fusion engineering and design. - : Elsevier BV. - 0920-3796 .- 1873-7196. ; 192
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Tidskriftsartikel (refereegranskat)abstract
- Plasma edge cooling, ion cyclotron wall conditioning and disruption mitigation techniques involve massive gas injection (by puffs or pellets) to the torus. A certain fraction remains in plasma-facing components (PFC) due to co-deposition and implantation. An uncontrolled release/desorption of such retained species affects the stability of plasma operation. The aim of this work was to determine the lateral and depth distribution of noble (3He, 4He, Ne, Ar), seeded (N2, Ne, Ar) and tracer gases (15N, 18O) in PFC retrieved from the JET tokamak with the ITER-Like Wall (JET-ILW) after three experimental campaigns (ILW-1, ILW-2, ILW-3). Results regarding the retention of those gases are shown as well as a comparison to the deuterium retention in the studied areas. Heavy ion elastic recoil detection analysis was used, being the only technique capable of detection and quantitative assessment of all elements, especially low-Z isotopes. Helium was found on the divertor Tile 5, locally up to 44.1015 3He cm-2 and 12.1015 4He cm-2, and on the limiters as well. Neon was found in two positions on the limiters, with up to 10.1015 Ne cm-2 and the 15N tracer on Be limiters exposed to ILW-3. A correlation of N retention with the N seeding rates for each campaign has also been found.
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| 9. |
- Gandhi, Hemi H., et al.
(författare)
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Gold-Hyperdoped Germanium with Room-Temperature Sub-Band-Gap Optoelectronic Response
- 2020
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Ingår i: Physical Review Applied. - : AMER PHYSICAL SOC. - 2331-7019. ; 14:6
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Tidskriftsartikel (refereegranskat)abstract
- Short-wavelength-infrared (SWIR; 1.4-3.0 mu m) photodetection is important for various applications. Inducing a low-cost silicon-compatible material, such as germanium, to detect SWIR light would be advantageous for SWIR applications compared with using conventional (III-V or II-VI) SWIR materials. Here, we present a scalable nonequilibrium method for hyperdoping germanium with gold for dopant-mediated SWIR photodetection. Using ion implantation followed by nanosecond pulsed laser melting, we obtain a single-crystal material with a peak gold concentration of 3 x 10(19) cm(-3) (10(3) times the solubility limit). This hyperdoped germanium has fundamentally different optoelectronic properties from those of intrinsic and conventionally doped germanium. This material exhibits sub-band-gap absorption of light up to wavelengths of at least 3 mu m, with a sub-band-gap optical absorption coefficient comparable to that of commercial SWIR photodetection materials. We show that germanium hyperdoped with gold exhibits sub-band-gap SWIR photodetection at room temperature, in contrast with previous doped-germanium photodetector studies, which only show a low-temperature response. This material is a potential pathway to low-cost room-temperature silicon-compatible SWIR photodetection.
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| 10. |
- Pham, Tuan D, et al.
(författare)
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Fuzzy information fusion of classification models for high-throughput image screening of cancer cells in time-lapse microscopy
- 2007
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Ingår i: Journal of Knowledge-based & Intelligent Engineering Systems. - : IOS Press. - 1327-2314 .- 1875-8827. ; 11:4, s. 237-246
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Tidskriftsartikel (refereegranskat)abstract
- Bioimaging at molecular and cellular levels requires specific image analysis methods to help life scientists develop methodologies and hypotheses in biology and biomedicine. In particular, this is true when dealing with microscopic images of cells and vessels. To facilitate the automation of cell screening, we have developed methods based on vector quantization and Markov model for classification of cellular phases using time-lapse fluorescence microscopic image sequences. Because of ambiguity inherently existing in the labeling of cell-phase feature vectors, we proposed to use relaxation labeling technique to reduce uncertainty among cell-phase models having overlapping properties. To further improve the classification rate we applied a fuzzy fusion strategy for combining individual results obtained from multiple classifiers. Our proposed image-classification methods can be useful for the task of high-content cell-cycle screening which is essential for biomedical research in the study of structures and functions of cells and molecules.
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| 11. |
- 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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| 12. |
- Ström, Petter, et al.
(författare)
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Synthesis of ferromagnetic thin films and engineering of their magnetic properties by Fe ion implantation in polycrystalline Pd
- 2022
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Ingår i: Journal of Magnetism and Magnetic Materials. - : Elsevier. - 0304-8853 .- 1873-4766. ; 552
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Tidskriftsartikel (refereegranskat)abstract
- Ferromagnetic thin films were synthesized by implantation of Fe ions with energies between 40 keV and 120 keV in 60 nm of polycrystalline Pd. The possibility to engineer magnetic properties in such films through the Fe concentration depth profile was demonstrated. In-plane magnetic moments were measured both while varying the sample temperature at constant applied magnetic field, and varying the applied field at constant temperature. All samples were explicitly shown to exhibit ferromagnetism at sufficiently low temperature, with threshold temperatures in the range from 35 K to 140 K. Saturation moments at 5 K were between 3.5 and 4.6 Bohr magnetons per implanted Fe atom for implantation fluences between 5 × 1015 and 2.3 × 1016 ions/cm2. Coercivities were between 1 and 3 mT. The samples included in the study were carefully characterized with Rutherford backscattering spectrometry, and selected samples with elastic recoil detection analysis and cross-sectional transmission electron microscopy, providing information on Fe concentration profiles, impurity fractions, structure as well as sample modification during implantation. A new model was proposed to calculate the scaling of the films’ magnetic moments with temperature from the Fe concentration profiles. The model qualitatively reproduced the data and quantitative differences were explained. It can thus be applied to predict the modification of the magnetic moment at a given temperature for a similar film when the implantation parameters are varied.
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| 13. |
- Tran, Dat T, et al.
(författare)
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A combined Markov and noise clustering modeling method for cell phase classification
- 2006
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Ingår i: WSEAS Transactions on Biology and Biomedicine. - : World Scientific and Engineering Academy and Society. - 1109-9518 .- 2224-2902. ; 3:3, s. 161-166
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Tidskriftsartikel (refereegranskat)abstract
- This paper proposes a classification method of cell nuclei in different mitotic phases using a combined Markov and noise clustering modeling technique. The method was tested with the data set containing 379519 cells in 892 cell sequences for 5 phases extracted from real image sequences recorded at every fifteen minutes with a time-lapse fluorescence microscopy. Experimental results showed that the proposed method performed better than the k-means modeling method.
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| 14. |
- Tran, Dat T, et al.
(författare)
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Recent advances in cell classification for cancer research and drug discovery
- 2009
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Ingår i: Computational Biology. - New York, NY : Springer-Verlag New York. - 9781441908100 - 9781441908117 ; , s. 205-226
-
Bokkapitel (refereegranskat)abstract
- Drug effects on cancer cells are investigated through measuring cell cycle progression in individual cells as a function of time. This investigation requires the processing and analysis of huge amounts of image data obtained in time-lapse microscopy. Manual image analysis is very time consuming thus costly, potentially inaccurate, and poorly reproducible. Stages of an automated cellular imaging analysis consist of segmentation, feature extraction, classification, and tracking of individual cells in a dynamic cellular population. The feature extraction and classification of cell phases are considered the most difficult tasks of such analysis. We review several techniques for feature extraction and classification. We then present our work on an automated feature weighting technique for feature selection and combine this technique with cellular phase modeling techniques for classification. These combined techniques perform the two most difficult tasks at the same time and enhance the classification performance. Experimental results have shown that the combined techniques are effective and have potential for higher performance.
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| 15. |
- Tran, Tuan T., et al.
(författare)
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A contactless single-step process for simultaneous nanoscale patterning and cleaning of large-area graphene
- 2023
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Ingår i: 2D Materials. - : Institute of Physics Publishing (IOPP). - 2053-1583. ; 10:2
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Tidskriftsartikel (refereegranskat)abstract
- The capability to structure two-dimensional materials (2DMs) at the nanoscale with customizable patterns and over large areas is critical for a number of emerging applications, from nanoelectronics to 2D photonic metasurfaces. However, current technologies, such as photo- and electron-beam lithography, often employing masking layers, can significantly contaminate the materials. Large-area chemical vapour deposition-grown graphene is known to have non-ideal properties already due to surface contamination resulting from the transferring process. Additional contamination through the lithographic process might thus reduce the performance of any device based on the structured graphene. Here, we demonstrate a contactless chemical-free approach for simultaneous patterning and cleaning of self-supporting graphene membranes in a single step. Using energetic ions passing through a suspended mask with pre-defined nanopatterns, we deterministically structure graphene with demonstrated feature size of 15 nm, approaching the performance of small-area focused ion beam techniques and extreme ultraviolet lithography. Our approach, however, requires only a broad beam, no nanoscale beam positioning and enables large area patterning of 2DMs. Simultaneously, in regions surrounding the exposed areas, contaminations commonly observed on as-grown graphene targets, are effectively removed. This cleaning mechanism is attributed to coupling of surface diffusion and sputtering effects of adsorbed surface contaminants. For applications using 2DMs, this simultaneous patterning and cleaning mechanism may become essential for preparing the nanostructured materials with improved cleanliness and hence, quality.
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| 16. |
- Tran, Tuan T., et al.
(författare)
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In-situ nanoscale characterization of composition and structure during formation of ultrathin nickel silicide
- 2021
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Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 536
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Tidskriftsartikel (refereegranskat)abstract
- We characterize composition and structure of ultrathin nickel silicide during formation from 3 nm Ni films on Si(1 0 0) using in-situ high-resolution ion scattering and high-resolution transmission electron microscopy. We show the transition to occur in discrete steps, in which an intermediate phase is observed within a narrow range of temperature from 230 °C to 290 °C. The film composition of this intermediate phase is found to be 50% Ni:50% Si, without evidence for long-range structure, indicating the film to be a homogeneous monosilicide NiSi phase. The final phase is resemblant of the cubic disilicide NiSi2, but with slightly off-stoichiometric composition of 38% Ni and 62% Si. Along the [1 0 0] axis, the lattices of the film and the substrate are found in perfect alignment. Due to the epitaxial growth of the silicide, a contraction of the c lattice constant of the film by 0.7–1% is detected.
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| 17. |
- 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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| 18. |
- Tran, Tuan T., et al.
(författare)
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Suppression of ion-implantation induced porosity in germanium by a silicon dioxide capping layer
- 2016
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 109:8
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Tidskriftsartikel (refereegranskat)abstract
- Ion implantation with high ion fluences is indispensable for successful use of germanium (Ge) in the next generation of electronic and photonic devices. However, Ge readily becomes porous after a moderate fluence implant (∼1×1015 ion cm−2) at room temperature, and for heavy ion species such as tin (Sn), holding the target at liquid nitrogen (LN2) temperature suppresses porosity formation only up to a fluence of 2×1016 ion cm−2. We show, using stylus profilometry and electron microscopy, that a nanometer scale capping layer of silicon dioxide significantly suppresses the development of the porous structure in Ge during a Sn− implant at a fluence of 4.5×1016 ion cm−2 at LN2 temperature. The significant loss of the implanted species through sputtering is also suppressed. The effectiveness of the capping layer in preventing porosity, as well as suppressing sputter removal of Ge, permits the attainment of an implanted Sn concentration in Ge of ∼15 at.%, which is about 2.5 times the maximum value previously attained. The crystallinity of the Ge-Sn layer following pulsed-laser-melting induced solidification is also greatly improved compared with that of uncapped material, thus opening up potential applications of the Ge-Sn alloy as a direct bandgap material fabricated by an ion beam synthesis technique.
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| 19. |
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| 20. |
- 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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