| 1. |
- Sator, Lea, et al.
(author)
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Overdiagnosis of COPD in Subjects With Unobstructed Spirometry A BOLD Analysis
- 2019
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In: Chest. - : Elsevier BV. - 0012-3692 .- 1931-3543. ; 156:2, s. 277-288
-
Journal article (peer-reviewed)abstract
- BACKGROUND: There are several reports on underdiagnosis of COPD, while little is known about COPD overdiagnosis and overtreatment. We describe the overdiagnosis and the prevalence of spirometrically defined false positive COPD, as well as their relationship with overtreatment across 23 population samples in 20 countries participating in the BOLD Study between 2003 and 2012.METHODS: A false positive diagnosis of COPD was considered when participants reported a doctor's diagnosis of COPD, but postbronchodilator spirometry was unobstructed (FEV1/FVC > LLN). Additional analyses were performed using the fixed ratio criterion (FEV1/FVC < 0.7).RESULTS: Among 16,177 participants, 919 (5.7%) reported a previous medical diagnosis of COPD. Postbronchodilator spirometry was unobstructed in 569 subjects (61.9%): false positive COPD. A similar rate of overdiagnosis was seen when using the fixed ratio criterion (55.3%). In a subgroup analysis excluding participants who reported a diagnosis of "chronic bronchitis" or "emphysema" (n = 220), 37.7% had no airflow limitation. The site-specific prevalence of false positive COPD varied greatly, from 1.9% in low- to middle-income countries to 4.9% in high-income countries. In multivariate analysis, overdiagnosis was more common among women, and was associated with higher education; former and current smoking; the presence of wheeze, cough, and phlegm; and concomitant medical diagnosis of asthma or heart disease. Among the subjects with false positive COPD, 45.7% reported current use of respiratory medication. Excluding patients with reported asthma, 34.4% of those with normal spirometry still used a respiratory medication.CONCLUSIONS: False positive COPD is frequent. This might expose nonobstructed subjects to possible adverse effects of respiratory medication.
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| 2. |
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| 5. |
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| 6. |
- Ezzat, Kariem, et al.
(author)
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The viral protein corona directs viral pathogenesis and amyloid aggregation
- 2019
-
In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10
-
Journal article (peer-reviewed)abstract
- Artificial nanoparticles accumulate a protein corona layer in biological fluids, which significantly influences their bioactivity. As nanosized obligate intracellular parasites, viruses share many biophysical properties with artificial nanoparticles in extracellular environments and here we show that respiratory syncytial virus (RSV) and herpes simplex virus type 1 (HSV-1) accumulate a rich and distinctive protein corona in different biological fluids. Moreover, we show that corona pre-coating differentially affects viral infectivity and immune cell activation. In addition, we demonstrate that viruses bind amyloidogenic peptides in their corona and catalyze amyloid formation via surface-assisted heterogeneous nucleation. Importantly, we show that HSV-1 catalyzes the aggregation of the amyloid beta-peptide (A beta(42)), a major constituent of amyloid plaques in Alzheimer's disease, in vitro and in animal models. Our results highlight the viral protein corona as an acquired structural layer that is critical for viral-host interactions and illustrate a mechanistic convergence between viral and amyloid pathologies.
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| 7. |
- Gunnbjornsdottir, M. I., et al.
(author)
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Obesity and nocturnal gastro-oesophageal reflux are related to onset of asthma and respiratory symptoms
- 2004
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In: Eur Respir J. - : European Respiratory Society (ERS). ; 24:1
-
Journal article (peer-reviewed)abstract
- Several studies have identified obesity as a risk factor for asthma in both children and adults. An increased prevalence of asthma in subjects with gastro-oesophageal reflux (GOR) and obstructive sleep apnoea syndrome has also been reported. The aim of this investigation was to study obesity, nocturnal GOR and snoring as independent risk factors for onset of asthma and respiratory symptoms in a Nordic population. In a 5-10 yr follow-up study of the European Community Respiratory Health Survey in Iceland, Norway, Denmark, Sweden and Estonia, a postal questionnaire was sent to previous respondents. A total of 16,191 participants responded to the questionnaire. Reported onset of asthma, wheeze and night-time symptoms as well as nocturnal GOR and habitual snoring increased in prevalence along with the increase in body mass index (BMI). After adjusting for nocturnal GOR, habitual snoring and other confounders, obesity (BMI >30) remained significantly related to the onset of asthma, wheeze and night-time symptoms. Nocturnal GOR was independently related to the onset of asthma and in addition, both nocturnal GOR and habitual snoring were independently related to onset of wheeze and night-time symptoms. This study adds evidence to an independent relationship between obesity, nocturnal gastro-oesophageal reflux and habitual snoring and the onset of asthma and respiratory symptoms in adults.
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| 8. |
- Järver, Peter, et al.
(author)
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Single-Stranded Nucleic Acids Regulate TLR3/4/7 Activation through Interference with Clathrin-Mediated Endocytosis
- 2018
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8
-
Journal article (peer-reviewed)abstract
- Recognition of nucleic acids by endosomal Toll-like receptors (TLR) is essential to combat pathogens, but requires strict control to limit inflammatory responses. The mechanisms governing this tight regulation are unclear. We found that single-stranded oligonucleotides (ssON) inhibit endocytic pathways used by cargo destined for TLR3/4/7 signaling endosomes. Both ssDNA and ssRNA conferred the endocytic inhibition, it was concentration dependent, and required a certain ssON length. The ssON-mediated inhibition modulated signaling downstream ofTLRs that localized within the affected endosomal pathway. We further show that injection of ssON dampens dsRNA-mediated inflammatory responses in the skin of non-human primates. These studies reveal a regulatory role for extracellular ssON in the endocytic uptake of TLR ligands and provide a mechanistic explanation of their immunomodulation. The identified ssON-mediated interference of endocytosis (SOMIE) is a regulatory process that temporarily dampens TLR3/4/7 signaling, thereby averting excessive immune responses.
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| 9. |
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| 10. |
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| 11. |
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| 12. |
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| 13. |
- Torsi, Luisa, et al.
(author)
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Organic thin-film transistors for inorganic substance monitoring
- 2009. - 1
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In: Organic electronics in Sensors and Biotechnology. - New York : McGraw-Hill Companies Inc. - 9780071596756 ; , s. 51-91
-
Book chapter (other academic/artistic)abstract
- Develop high-performance, field-deployable organic semiconductor-based biological, chemical, and physical sensor arrays using the comprehensive information contained in this definitive volume. Organic Electronics in Sensors and Biotechnology presents state-of-the-art technology alongside real-world applications and ongoing R & D.Learn about light, temperature, and pressure monitors, integrated flexible pyroelectric sensors, sensing of organic and inorganic compounds, and design of compact photoluminescent sensors. You will also get full details on organic lasers, organic electronics in memory elements, disease and pathogen detection, and conjugated polymers for advancing cellular biology.Monitor organic and inorganic compounds with OFETsCharacterize organic materials using impedance spectroscopyWork with organic LEDs, photodetectors, and photovoltaic cellsForm flexible pyroelectric sensors integrated with OFETsBuild PL-based chemical and biological sensing modules and arraysDesign organic semiconductor lasers and memory elementsUse luminescent conjugated polymers as optical biosensorsDeploy polymer-based switches and ion pumps at the microfluidic level
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| 14. |
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| 15. |
- Arbab, A., et al.
(author)
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Evaluation of gas mixtures with high-temperature gas sensors based on silicon carbide
- 1994
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In: Sensors and actuators. B, Chemical. - : Elsevier. - 0925-4005 .- 1873-3077. ; 19:1-3, s. 562-565
-
Journal article (peer-reviewed)abstract
- Field-effect devices with a catalytic metal gate are operated as gas sensors over a large temperature range by the use of 6H-silicon carbide (bandgap 2.9 eV) instead of silicon (1.1 eV) as the semiconducting material. We have produced metal-silicon dioxide-silicon carbide (MOSiC) capacitors with platinum as the gate metal that can be operated above 800-degrees-C. The sensitivity of the Pt-MOSiC devices to hydrogen and hydrocarbons was tested in various oxygen atmospheres. The response to mixtures of hydrogen and saturated hydrocarbons indicated the existence of two different sensing mechanisms.
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| 16. |
- Arbab, A., et al.
(author)
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Gas sensors for high temperature operation based on metal oxide silicon carbide (MOSiC) devices
- 1993
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In: Sensors and actuators. B, Chemical. - : Elsevier. - 0925-4005 .- 1873-3077. ; 15:1-3, s. 19-23
-
Journal article (peer-reviewed)abstract
- Catalytic metal gate-silicon dioxide-silicon carbide (MOSiC) capacitors operating to about 800-degrees-C are used as high temperature gas sensor devices. Hydrogen or hydrogen containing molecules, which are dissociated on the catalytic metal surface, create a decrease of the flat band voltage of the MOS capacitor. The MOSiC devices with a platinum gate respond to saturated hydrocarbons in air at concentrations well below the explosion limits.
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| 17. |
- Assadi, A., et al.
(author)
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Interaction of planar polymer Schottky barrier diodes with gaseous substances
- 1994
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In: Sensors and actuators. B, Chemical. - : Elsevier. - 0925-4005 .- 1873-3077. ; 20:1, s. 71-77
-
Journal article (peer-reviewed)abstract
- Conducting polymers appear very attractive as sensor materials either as the gas-sensitive component or as a matrix for easy immobilization of a specific substrate. The planar Schottky barrier diode with poly(3-octylthiophene), P3OT, as the semiconductor is used as a sensor for the detection of different gas species. The shifts in the current-voltage (C-V) characteristics as well as the C-V characteristics of the diodes due to water and ethanol vapour, ammonia gas and nitric oxide gases are studied. Nitric oxide and ammonia give the largest and most specific changes of the C-V characteristics. Nitric oxide has a doping effect, which increases the reverse current, while ammonia is the only gas that causes a negative change in the forward bias current of the I-V curve. The planar configuration of the Schottky barrier diode facilitates the absorption of gaseous species in the environment, and provides a simple method for production of gas sensors.
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| 18. |
- Bastuck, Manuel, et al.
(author)
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Characterizing the Influence of Gate Bias on Electrical and Catalytical Properties of a Porous Platinum Gate on Field Effect Gas Sensors
- 2016
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In: 2016 IEEE SENSORS. - : IEEE. - 9781479982875
-
Conference paper (peer-reviewed)abstract
- In this work, we exposed an MIS capacitor with porous platinum as gate material to different concentrations of CO and NH3. Its capacitance and typical reaction products (water, CO2 and NO) were monitored at high and low oxygen concentration and different gate bias voltages. We found that the gate bias influences the switch-point of the binary CO response usually seen when either changing the temperature at constant gas concentrations or the CO/O-2 ratio at constant temperature. For NH3, the sensor response as well as product reaction rates increase with bias voltages up to 6 V. A capacitance overshoot is observed when switching on or off either gas at low gate bias, suggesting increasing oxygen surface coverage with decreasing gate bias.
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| 19. |
- Bastuck, Manuel, et al.
(author)
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Exploring the selectivity of WO3 with iridium catalyst in an ethanol/naphthalene mixture using multivariate statistics
- 2016
-
In: Thin Solid Films. - : ELSEVIER SCIENCE SA. - 0040-6090 .- 1879-2731. ; 618, s. 263-270
-
Journal article (peer-reviewed)abstract
- Temperature cycled operation and multivariate statistics have been used to compare the selectivity of two gate (i.e. sensitive) materials for gas-sensitive, silicon carbide based field effect transistors towards naphthalene and ethanol in different mixtures of the two substances. Both gates have a silicon dioxide (SiO2) insulation layer and a porous iridium (Ir) electrode. One of it has also a dense tungsten trioxide (WO3) interlayer between Ir and SiO2. Both static and transient characteristics play an important role and can contribute to improve the sensitivity and selectivity of the gas sensor. The Ir/SiO2 is strongly influenced by changes in ethanol concentration, and is, thus, able to quantify ethanol in a range between 0 and 5 ppm with a precision of 500 ppb, independently of the naphthalene concentrations applied in this investigation. On the other hand, this sensitivity to ethanol reduces its selectivity towards naphthalene, whereas Ir/WO3/SiO2 shows an almost binary response to ethanol. Hence, the latter has a better selectivity towards naphthalene and can quantify legally relevant concentrations down to 5 ppb with a precision of 2.5 ppb, independently of a changing ethanol background between 0 and 5 ppm. (C) 2016 Elsevier B.V. All rights reserved.
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| 20. |
- Becker, Elin, 1981, et al.
(author)
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Study of the Sensing Mechanism Towards Carbon Monoxide of Platinum-Based Field Effect Sensors
- 2011
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In: IEEE Sensors Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1558-1748 .- 1530-437X. ; 11:7, s. 1527-1534
-
Journal article (peer-reviewed)abstract
- We have investigated the temperature dependence and the effect of hydrogen on the CO response of MISiC field effect device sensors. The evolution of adsorbates on a model sensor was studied by in situ DRIFT spectroscopy and correlated to sensor response measurements at similar conditions. A strong correlation between the CO coverage of the sensor surface and the sensor response was found. The temperature dependence and hydrogen sensitivity are partly in agreement with these observations, however at low temperatures it is difficult to explain the observed increase in sensor response with increasing temperature. This may be explained by the reduction of a surface oxide or removal of oxygen from the Pt/SiO2 interface at increasing temperatures. The sensing mechanism of MISiC field effect sensors is likely complex, involving several of the factors discussed in this paper.
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| 21. |
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| 22. |
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| 23. |
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| 24. |
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| 25. |
- Bounechada, Djamela, et al.
(author)
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Vibrational analysis of SO2 on Pt / SiO2 system
-
Other publication (other academic/artistic)abstract
- In situ diffuse reflectance infrared Fourier transformed spectroscopy was used to study the interactions of SOx species with Pt/SiO2 between 200 and 400°C, and for SO2 concentrations between 10 and 50 ppm, which represents a concentration range where MISFET sensors exhibit good responses. In parallel, first-principles calculations have been carried out to support the experimental interpretations. It was found that sulfate species were formed on the silica surface, accompanied with removal/rearrangement of silanol groups upon exposure to SO2. Both experimental and theoretical calculations also suggest that the surface species were only formed after SO2 oxidation to SO3 on the metal surface. These evidences support the idea of SO2 oxidation to SO3 as the first step in the process of sulfate formation, followed by spillover of SO3 to the oxide, and finally the formation of sulfate species on the hydroxyl positions on the oxide. The results also indicate that the sulfate formation on silica depends both on the temperature and the SO2 concentration. Furthermore, hydrogen exposure was shown to be efficient for sulfur removal from the silica surface.
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| 26. |
- Darmastuti, Zhafira, et al.
(author)
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Detection mechanism studies of SO2 on Pt / SiO2 system
-
Other publication (other academic/artistic)abstract
- Experiment was performed with Pt-gate SiC-FET sensors to study the detection mechanism of the sensors. The sensing measurement showed that oxygen influenced the response quite strongly. The sensor response became larger in the presence of oxygen. Experiment with mass spectroscopy indicated the formation of SO3 during the sensing measurement. Further experiment with DRIFT spectroscopy showed the formation of sulfate species on the oxide surface, accompanied by the disappearance of the silanol groups. An explanatory model was built based on quantum-chemical calculations. The results strengthened the experimental results by showing that it was more energetically favorable for SO2 to oxidize into SO3 before being adsorbed on the oxide surface. It was also observed that the overall adsorption reaction was exothermic, the activation energy for the SO2 oxidation was 48,75 kJ/mol, and the rate limiting step was the desorption of SO3 from the Pt surface.
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| 27. |
- Darmastuti, Zhafira, et al.
(author)
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SiC-FET based SO2 sensor for power plant emission applications
- 2014
-
In: Sensors and actuators. B, Chemical. - : Elsevier. - 0925-4005 .- 1873-3077. ; 194, s. 511-520
-
Journal article (peer-reviewed)abstract
- Thermal power plants produce SO2 during combustion of fuel containing sulfur. One way to decrease the SO2 emission from power plants is to introduce a sensor as part of the control system of the desulphurization unit. In this study, SiC-FET sensors were studied as one alternative sensor to replace the expensive FTIR (Fourier Transform Infrared) instrument or the inconvenient wet chemical methods. The gas response for the SiC-FET sensors comes from the interaction between the test gas and the catalytic gate metal, which changes the electrical characteristics of the devices. The performance of the sensors depends on the ability of the test gas to be adsorbed, decomposed, and desorbed at the sensor surface. The feature of SO2, that it is difficult to desorb from the catalyst surface, makes it known as catalyst poison. It is difficult to quantify the SO2 with static operation, even at the optimum operation temperature of the sensor due to low response levels and saturation already at low concentration of SO2. The challenge of SO2 desorption can be reduced by introducing dynamic operation in a designed temperature cycle operation (TCO). The intermittent exposure to high temperature can help to desorb SO2. Simultaneously, additional features extracted from the sensor data can be used to reduce the influence of sensor drift. The TCO operation, together with pattern recognition, may also reduce the baseline and response variation due to changing concentration of background gases (4-10% O-2 and 0-70% RH), and thus it may improve the overall sensor performance. In addition to the laboratory experiment, testing in the desulphurization pilot unit was performed. Desulphurization pilot unit has less controlled environment compared to the laboratory conditions. Therefore, the risk of influence from the changing concentration of background gas is higher. In this study, linear discriminant analysis (LDA) and partial least square (PLS) were employed as pattern recognition methods. It was demonstrated that using LDA quantification of SO2 into several groups of concentrations up to 2000 ppm was possible. Additionally, PLS analysis indicated a good agreement between the predicted value from the model and the SO2 concentration from the reference instrument of the pilot plant.
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| 28. |
- Dondalska, Aleksandra, et al.
(author)
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Amelioration of Compound 48/80-Mediated Itch and LL-37-Induced Inflammation by a Single-Stranded Oligonucleotide
- 2020
-
In: Frontiers in Immunology. - : FRONTIERS MEDIA SA. - 1664-3224. ; 11
-
Journal article (peer-reviewed)abstract
- Numerous inflammatory skin disorders display a high prevalence of itch. The Mas-related G protein coupled receptor X2 (MRGPRX2) has been shown to modulate itch by inducing non-IgE-mediated mast cell degranulation and the release of endogenous inducers of pruritus. Various substances collectively known as basic secretagogues, which include inflammatory peptides and certain drugs, can trigger MRGPRX2 and thereby induce pseudo-allergic reactions characterized by histamine and protease release as well as inflammation. Here, we investigated the capacity of an immunomodulatory single-stranded oligonucleotide (ssON) to modulate IgE-independent mast cell degranulation and, more specifically, its ability to inhibit the basic secretagogues compound 48/80 (C48/80)-and LL-37in vitroandin vivo. We examined the effect of ssON on MRGPRX2 activationin vitroby measuring degranulation in a human mast cell line (LAD2) and calcium influx in MRGPRX2-transfected HEK293 cells. To determine the effect of ssON on itch, we performed behavioral studies in established mouse models and collected skin biopsies for histological analysis. Additionally, with the use of a rosacea mouse model and RT-qPCR, we investigated the effect on ssON on LL-37-induced inflammation. We reveal that both mast cell degranulation and calcium influx in MRGPRX2 transfected HEK293 cells, induced by the antimicrobial peptide LL-37 and the basic secretagogue C48/80, are effectively inhibited by ssON in a dose-dependent manner. Further, ssON demonstrates a capability to inhibit LL-37 and C48/80 activationin vivoin two mouse models. We show that intradermal injection of ssON in mice is able to block itch induced via C48/80 in a dose-dependent manner. Histological staining revealed that ssON inhibits acute mast cell degranulation in murine skin treated with C48/80. Lastly, we show that ssON treatment ameliorates LL-37-induced inflammation in a rosacea mouse model. Since there is a need for new therapeutics targeting non-IgE-mediated activation of mast cells, ssON could be used as a prospective drug candidate to resolve itch and inflammation in certain dermatoses.
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| 29. |
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| 30. |
- Fashandi, Hossein, et al.
(author)
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Dirac points with giant spin-orbit splitting in the electronic structure of two-dimensional transition-metal carbides
- 2015
-
In: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 92:15
-
Journal article (peer-reviewed)abstract
- We investigated the structural and electrical properties of 2D MXene sheets by means of firstprinciples density functional theory (DFT) calculations. To describe the Kohn-Sham states, plane wave basis set and projector augmented wave method (PAW) were used as implemented in the Vienna ab initio Simulation Package (VASP). We applied PBE parameterization of the generalized gradient approximation of the exchange and correlation energy functional to account for many-body effects of the interacting electron system. Convergent sampling of the Brillouin-zone was achieved by a Γ-centered 15×15×1 grid. In order to model a single sheet of MXene we ensured at least 30 Å vacuum between the periodically repeated sheets. For the structural optimization 1×10−3 eV/Å force criteria was used. The relativistic spin-orbit coupling effects were also included in our simulations regarding band structure and density of states.
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| 31. |
- Granlund, Margareta, et al.
(author)
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Antimicrobial resistance in colonizing group B Streptococci before the implementation of a Swedish intrapartum antibiotic prophylaxis program.
- 2010
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In: European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology. - : Springer Science and Business Media LLC. - 1435-4373 .- 0934-9723. ; 29:10, s. 1195-201
-
Journal article (peer-reviewed)abstract
- The prevalence of antibiotic resistance and their genetic determinants in colonizing group B streptococci (GBS) sampled in a Swedish nationwide survey was examined. In five GBS isolates (1.3%), kanamycin/amikacin resistance and the presence of the aphA-3 gene was identified. Three of these isolates carried the aad-6 gene and were streptomycin-resistant. Screening with kanamycin and streptomycin 1,000-μg disks enabled a rapid and easy detection of these isolates. In all, 312/396 (79%) GBS were tetracycline-resistant and 95% of the examined isolates harbored the tetM gene. Among the 22 (5.5%) GBS resistant to erythromycin and/or clindamycin, the ermB gene was detected in nine isolates (41%) and erm(A/TR) in ten isolates (45%). A high level of erythromycin and clindamycin resistance with minimum inhibitory concentrations (MICs) >256mg/L was found in four serotype V isolates that harbored ermB. The erythromycin/clindamycin resistance was distributed among all of the common serotypes Ia, Ib, II, III, IV, and V, but was not present in any of the 44 serotype III isolates associated to clonal complex 17. Screening for penicillin resistance with 1-μg oxacillin disks showed a homogenous population with a mean inhibition zone of 20mm. A change in the present oxacillin breakpoints for GBS is suggested.
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| 32. |
- Groß, Rüdiger, et al.
(author)
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Macromolecular Viral Entry Inhibitors as Broad-Spectrum First-Line Antivirals with Activity against SARS-CoV-2
- 2022
-
In: Advanced Science. - : Wiley. - 2198-3844. ; 9:20
-
Journal article (peer-reviewed)abstract
- Inhibitors of viral cell entry based on poly(styrene sulfonate) and its core–shell nanoformulations based on gold nanoparticles are investigated against a panel of viruses, including clinical isolates of SARS-CoV-2. Macromolecular inhibitors are shown to exhibit the highly sought-after broad-spectrum antiviral activity, which covers most analyzed enveloped viruses and all of the variants of concern for SARS-CoV-2 tested. The inhibitory activity is quantified in vitro in appropriate cell culture models and for respiratory viral pathogens (respiratory syncytial virus and SARS-CoV-2) in mice. Results of this study comprise a significant step along the translational path of macromolecular inhibitors of virus cell entry, specifically against enveloped respiratory viruses.
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| 33. |
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| 34. |
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| 35. |
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| 36. |
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| 37. |
- Kalli, K., et al.
(author)
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Room temperature hydrogen gas detection with optically thin palladium films on silicon oxide using photomodulated thermoreflectance
- 1999
-
In: AIP Conference Proceedings. - : American Institute of Physics (AIP). - 0094-243X .- 1551-7616. ; 463, s. 220-222
-
Journal article (peer-reviewed)abstract
- The sensitivity of various thicknesses of optically thin film Pd layers evaporated into a silicon oxide substrate is investigated in the presence of a hydrogen/air atmosphere at room temperature. The magnitude of the resulting reflectivity change is measured using an excite-probe technique, through laser excited photothermal modulation of a probe beam. Data indicates that concentrations of 0.1% hydrogen in a balanced air mixture and at room temperature may be measured with. an 8nm Pd film. Inhomogeneities in the Pd layers lead to anomalous behavior.
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| 38. |
- Kalli, K, et al.
(author)
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Temperature-induced reflectivity changes and activation of hydrogen sensitive optically thin palladium films on silicon oxide
- 1998
-
In: Review of Scientific Instruments. - : American Institute of Physics (AIP). - 0034-6748 .- 1089-7623. ; 69:9, s. 3331-3338
-
Journal article (peer-reviewed)abstract
- The optical properties of several thin metal film palladium-silicon oxide structures are examined at room temperature before and after annealing to 200 degrees C and also at 90 degrees C-in all cases in the presence of hydrogen gas. Multicycling sample activation is shown to occur iii the presence of hydrogen at room temperature with an increase in reflectivity on exposure to hydrogen, in contrast to thicker 80 Angstrom films. The reflectivity change increases with increasing film thickness (1-10 Angstrom). The surface activation at room temperature, before and after annealing to 200 degrees C, is compared with the performance at 90 degrees C, where it is shown that heat treatment strongly influences the behavior of the metal film.
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| 39. |
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| 40. |
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| 41. |
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| 42. |
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| 43. |
- Lutic, D, et al.
(author)
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Catalytic properties of oxide nanoparticles applied in gas sensors
- 2007
-
In: Topics in Catalysis. - : Springer Science and Business Media LLC. - 1572-9028 .- 1022-5528. ; 45:1-4, s. 105-109
-
Journal article (peer-reviewed)abstract
- A series of gas sensing layers based on indium oxide doped with gold were prepared by using the aerosol technology for deposition as the active contact layer in a metal oxide semiconductor capacitive device. The interaction between the measured species and the insulator surface was quantified as the voltage changes at a constant capacitance of the device. The sensor properties were investigated in the presence of H2, CO, NH3, NO, NO2 and C3H6 at temperatures between 100–400 °C. Significant differences in the morphology of the layer and its sensitivity were noted for different preparation methods and different gas environments.
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| 44. |
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| 45. |
- Martinelle, E, et al.
(author)
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FET Transduction of Electric Dipole Changes in Organic Layers
- 2007
-
In: TRANSDUCERS 2007 - 2007 International Solid-State Sensors, Actuators and Microsystems Conference. - : IEEE. - 1424408423 - 1424408415 ; , s. 1895-1898
-
Conference paper (peer-reviewed)abstract
- Modern chemistry makes possibile the production of artificial receptors endowed with interaction sites specific towards selected analytes. To fabricate chemical sensors a transducer able to preserve the selectivity of such sensing layers is requested. We demonstrate the Field Effect Transistors (FET) coated by metalloporphyrins emphasizes the coordination of analytes with the sensing molecules with respect to the weakest forces that tend to cancel the selectivity. Molecular simulations show that coordination of gases such as carbon monoxide and nitric oxide greatly change the porphyrin electric dipole both in magnitude and direction inducing a large FET signal shift.
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| 46. |
- Mikalo, RP, et al.
(author)
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Comparison of HF and ozone treated SiC surfaces
- 2000
-
In: Materials Science Forum. - 0255-5476 .- 1662-9752. ; 353-3, s. 219-222
-
Journal article (peer-reviewed)abstract
- Single crystals of SiC were etched in hydrofluoric acid to remove the native oxide. Ozone exposure at room temperature is shown to give an oxide of about 0.7nm. The differences of interface and bulk oxides regarding their elemental composition and their oxidation states are reported as determined by photoelectron spectroscopy utilizing synchrotron radiation.
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| 47. |
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| 48. |
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| 49. |
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| 50. |
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