| 1. |
- Garpvall, K., et al.
(författare)
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Admission screening and cohort care decrease carbapenem resistant enterobacteriaceae in Vietnamese pediatric ICUs
- 2021
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Ingår i: Antimicrobial Resistance and Infection Control. - : BMC. - 2047-2994. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Objectives To assess if admission screening for Carbapenem Resistant Enterobacteriaceae (CRE) and cohort care can reduce CRE acquisition (CRE colonization during hospital stay), Hospital Acquired Infections (HAI), hospital-stay, mortality, and costs in three Intensive Care Units (ICUs) at the Vietnamese National Childrens Hospital. Method CRE screening using rectal swabs and ChromIDCarbas elective culture at admission and if CRE negative, once weekly. Patients were treated in cohorts based on CRE colonization status. Results CRE colonization at baseline point-prevalence screening was 76.9% (103/134). Of 941 CRE screened at admission, 337 (35.8%) were CREpos. 694 patients met inclusion criteria. The 244 patients CRE negative at admission and screened > 2 times were stratified in 8 similar size groups (periods), based on time of admission. CRE acquisition decreased significant (OR - 3.2, p < 0.005) from 90% in period 2 (highest) to 48% in period 8 (last period). Patients with CRE acquisition compared to no CRE acquisition had a significantly higher rate of culture confirmed HAI, n = 20 (14%) vs. n = 2 (2%), longer hospital stays, 3.26 vs. 2.37 weeks, and higher total treatment costs, 2852 vs. 2295 USD. Conclusion Admission CRE screening and cohort care in pediatric ICUs significantly decreased CRE acquisition, cases of HAI and duration of hospital-stay.
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| 2. |
- Badel, Xavier, et al.
(författare)
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Formation of pn junctions in deep silicon pores for X-ray imaging detector applications
- 2003
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - 0168-9002 .- 1872-9576. ; 509:1-3, s. 96-101
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Tidskriftsartikel (refereegranskat)abstract
- The formation of pn junctions in deep silicon pores has been studied for a new concept of X-ray imaging detectors. The sensitive part of the device is an array of CsI(Tl) columns formed by filling a silicon matrix of pores having pn junctions in their walls. Under X-ray illumination, the CsI(TI) scintillator emits photons that are collected by the pn junctions. Relatively high signal collection efficiency is expected. However, the formation of pn junctions inside pore walls represents a challenging step in the detector fabrication. In this work pore matrices were fabricated in n-type silicon by deep reactive ion etching and by photo-electrochemical etching. The pn junctions were formed either by boron diffusion or deposition of boron doped poly-silicon. Various techniques were used to analyze the transverse depth profiles of boron atoms at different pore depths. The study shows successful results for pn-junctions formed both by diffusion and by poly-silicon deposition.
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| 3. |
- Badel, Xavier, et al.
(författare)
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Metallized and oxidized silicon macropore arrays filled with a scintillator for CCD-based X-ray imaging detectors
- 2004
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Ingår i: IEEE Transactions on Nuclear Science. - : IEEE. - 0018-9499 .- 1558-1578. ; 51:3, s. 1001-1005, s. 1006-1010
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Tidskriftsartikel (refereegranskat)abstract
- Silicon charge-coupled devices (CCDs) covered with a scintillating film are now available on the market for use in digital medical imaging. However, these devices could still be improved in terms of sensitivity and especially spatial resolution by coating the CCD with an array of scintillating waveguides. In this paper, such waveguides were fabricated by first etching pores in silicon, then performing metallization or oxidation of the pore walls and finally filling the pores with CsI(TI). The resulting structures were observed using scanning electron microscopy and tested under X-ray exposure. Theoretical efficiencies of macropore arrays filled with CsI(TI) were also calculated, indicating that the optimal pore depth for metallized macropore arrays is about 80 mum while it is around 350 mum for oxidized ones. This result, together with the roughness of the metal coating, explains why lower SNR values were measured with the metallized macropores. Indeed, the macropore arrays had depths in the range of 210-390 mum, which is favorable to oxidized structures.
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| 4. |
- Badel, Xavier, et al.
(författare)
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Performance of scintillating waveguides for CCD-based X-ray detectors
- 2006
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Ingår i: IEEE Transactions on Nuclear Science. - 0018-9499 .- 1558-1578. ; 53:1, s. 3-8
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Tidskriftsartikel (refereegranskat)abstract
- Scintillating films are usually used to improve the sensitivity of CCD-based X-ray imaging detectors. For an optimal spatial resolution and detection efficiency, a tradeoff has to be made on the film thickness. However, these scintillating layers can also be structured to provide a pixellated screen. In this paper, the study of CsI(TI)-filled pore arrays is reported. The pores are first etched in silicon, then oxidized and finally filled with CsI(TI) to form scintillating waveguides. The dependence of the detector sensitivity on pore depth, varied from 40 to 400 mu m here, follows rather well theoretical predictions. Most of the detectors produced in this work have a detective quantum efficiency of the incoming X-ray photons of about 25%. However, one detector shows that higher efficiency can be achieved approaching almost the theoretical limit set by Poisson statistics of the incoming X-rays. Thus, we conclude that it is possible to fabricate scintillating waveguides with almost ideal performance. Imaging capabilities of the detectors are demonstrated.
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| 5. |
- Cavallaro, Sara, et al.
(författare)
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Label-Free Surface Protein Profiling of Extracellular Vesicles by an Electrokinetic Sensor
- 2019
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Ingår i: ACS Sensors. - : AMER CHEMICAL SOC. - 2379-3694. ; 4:5, s. 1399-1408
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Tidskriftsartikel (refereegranskat)abstract
- Small extracellular vesicles (sEVs) generated from the endolysosomal system, often referred to as exosomes, have attracted interest as a suitable biomarker for cancer diagnostics, as they carry valuable biological information and reflect their cells of origin. Herein, we propose a simple and inexpensive electrical method for label-free detection and profiling of sEVs in the size range of exosomes. The detection method is based on the electrokinetic principle, where the change in the streaming current is monitored as the surface markers of the sEVs interact with the affinity reagents immobilized on the inner surface of a silica microcapillary. As a proof-of-concept, we detected sEVs derived from the non-small-cell lung cancer (NSCLC) cell line H1975 for a set of representative surface markers, such as epidermal growth factor receptor (EGFR), CD9, and CD63. The detection sensitivity was estimated to be similar to 175000 sEVs, which represents a sensor surface coverage of only 0.04%. We further validated the ability of the sensor to measure the expression level of a membrane protein by using sEVs displaying artificially altered expressions of EGFR and CD63, which were derived from NSCLC and human embryonic kidney (HEK) 293T cells, respectively. The analysis revealed that the changes in EGFR and CD63 expressions in sEVs can be detected with a sensitivity in the order of 10% and 3%, respectively, of their parental cell expressions. The method can be easily parallelized and combined with existing microfluidic-based EV isolation technologies, allowing for rapid detection and monitoring of sEVs for cancer diagnosis.
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| 6. |
- Cavallaro, Sara, et al.
(författare)
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Multiparametric Profiling of Single Nanoscale Extracellular Vesicles by Combined Atomic Force and Fluorescence Microscopy : Correlation and Heterogeneity in Their Molecular and Biophysical Features
- 2021
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 17:14
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Tidskriftsartikel (refereegranskat)abstract
- Being a key player in intercellular communications, nanoscale extracellular vesicles (EVs) offer unique opportunities for both diagnostics and therapeutics. However, their cellular origin and functional identity remain elusive due to the high heterogeneity in their molecular and physical features. Here, for the first time, multiple EV parameters involving membrane protein composition, size and mechanical properties on single small EVs (sEVs) are simultaneously studied by combined fluorescence and atomic force microscopy. Furthermore, their correlation and heterogeneity in different cellular sources are investigated. The study, performed on sEVs derived from human embryonic kidney 293, cord blood mesenchymal stromal and human acute monocytic leukemia cell lines, identifies both common and cell line-specific sEV subpopulations bearing distinct distributions of the common tetraspanins (CD9, CD63, and CD81) and biophysical properties. Although the tetraspanin abundances of individual sEVs are independent of their sizes, the expression levels of CD9 and CD63 are strongly correlated. A sEV population co-expressing all the three tetraspanins in relatively high abundance, however, having average diameters of <100 nm and relatively low Young moduli, is also found in all cell lines. Such a multiparametric approach is expected to provide new insights regarding EV biology and functions, potentially deciphering unsolved questions in this field.
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| 7. |
- Cavallaro, Sara, et al.
(författare)
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Multiplexed electrokinetic sensor for detection and therapy monitoring of extracellular vesicles from liquid biopsies of non-small-cell lung cancer patients
- 2021
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Ingår i: Biosensors & bioelectronics. - : Elsevier. - 0956-5663 .- 1873-4235. ; 193
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Tidskriftsartikel (refereegranskat)abstract
- Liquid biopsies based on extracellular vesicles (EVs) represent a promising tool for treatment monitoring of tumors, including non-small-cell lung cancers (NSCLC). In this study, we report on a multiplexed electrokinetic sensor for surface protein profiling of EVs from clinical samples. The method detects the difference in the streaming current generated by EV binding to the surface of a functionalized microcapillary, thereby estimating the expression level of a marker. Using multiple microchannels functionalized with different antibodies in a parallel fluidic connection, we first demonstrate the capacity for simultaneous detection of multiple surface markers in small EVs (sEVs) from NSCLC cells. To investigate the prospects of liquid biopsies based on EVs, we then apply the method to profile sEVs isolated from the pleural effusion (PE) fluids of five NSCLC patients with different genomic alterations (ALK, KRAS or EGFR) and applied treatments (chemotherapy, EGFR- or ALKtyrosine kinase inhibitors). The vesicles were targeted against CD9, as well as EGFR and PD-L1, two treatment targets in NSCLC. The electrokinetic signals show detection of these markers on sEVs, highlighting distinct interpatient differences, e.g., increased EGFR levels in sEVs from a patient with EGFR mutation as compared to an ALK-fusion one. The sensors also detect differences in PD-L1 expressions. The analysis of sEVs from a patient prior and post ALK-TKI crizotinib treatment reveals significant increases in the expressions of some markers (EGFR and PD-L1). These results hold promise for the application of the method for tumor treatment monitoring based on sEVs from patient liquid biopsies.
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| 8. |
- Galeckas, A., et al.
(författare)
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Combined photoluminescence-imaging and deep-level transient spectroscopy of recombination processes at stacking faults in 4H-SiC
- 2006
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 74:23
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Tidskriftsartikel (refereegranskat)abstract
- We report on electronic properties of single- and double-layer stacking faults in 4H-SiC and provide an insight into apparent distinctions of recombination-enhanced defect reactions at these faults. Photoluminescence imaging spectroscopy and deep-level transient spectroscopy experiments reveal key constituents of radiative recombination and also provide firm evidence of nonradiative centers at E-V+0.38 eV responsible for recombination-enhanced mobility of silicon-core partial dislocations. A comprehensive energy level model is proposed allowing for a qualitative description of recombination activity at different types of stacking faults and the corresponding bounding partial dislocations.
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| 9. |
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| 10. |
- Li, F., et al.
(författare)
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Fabrication and assembly behavior of square microcapsules
- 2006
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Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 18:3, s. 270-
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Tidskriftsartikel (refereegranskat)abstract
- Square microcapsules have been fabricated within porous silicon membranes. The capsules float in water when released from the membrane (see Figure). Dry capsules float with one of their edges pointing down, but after uptake of water, they float face down; the edge-down capsules assemble end-to-end while the face-down capsules assemble face-to-face.
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