| 1. |
- Thoresen, Petter Paulsen, et al.
(author)
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On the understanding of bio-oil formation from the hydrothermal liquefaction of organosolv lignin isolated from softwood and hardwood sawdust
- 2023
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In: Sustainable Energy & Fuels. - : Royal Soc Chemistry. - 2398-4902. ; 7:22, s. 5361-5373
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Journal article (peer-reviewed)abstract
- Conversion of organosolv lignins isolated with and without an inorganic acid catalyst (H2SO4) from hard- and softwood (birch and spruce) into bio-oil through hydrothermal liquefaction has been investigated. Furthermore, fractions of the isolated bio-oils were catalytically deoxygenated to improve the bio-oil properties. As elucidated through NMR, both biomass source and extraction mode influence the bio-oil product distribution. Depending on whether the lignins carry a high content of native structures, or are depolymerized and subsequently condensed in the presence of sugar dehydration products, will dictate heavy oil (HO) and light oil (LO) distribution, and skew the HO product composition, which again will influence the requirements upon catalytical deoxygenation.
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| 2. |
- Athlin, Simon, 1971-, et al.
(author)
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Pneumococcal urinary antigen testing for antimicrobial guidance in community-acquired pneumonia : A register-based cohort study
- 2022
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In: Journal of Infection. - : Elsevier. - 0163-4453 .- 1532-2742. ; 85:2, s. 167-173
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Journal article (peer-reviewed)abstract
- OBJECTIVES: To evaluate the effect of pneumococcal urinary antigen test (UAT) usage on broad-spectrum antibiotic treatment in community-acquired pneumonia (CAP).METHODS: Patients admitted to 32 Swedish hospitals between 2011 and 2014 were retrospectively included from the Swedish National Quality Register of CAP. Using propensity score matched data, stratified by CRB-65 score, we studied the effect of performing UAT and of positive test results on treatment with broad-spectrum β-lactam monotherapy (BSBM) and antibiotics with coverage for atypical bacteria compared to narrow-spectrum β-lactam monotherapy (NSBM).RESULTS: UAT was performed for 4,995/14,590 (34.2%) patients, 603/4,995 (12.1%) of whom had positive test results. At day three, performing UAT was not associated with decreased use of BSBM (OR 1.07, 95% CI 0.94-1.23) but was associated with increased atypical coverage among patients with CRB-65 score 2 (OR 1.47, 95% CI 1.06-2.02). A positive UAT was associated with decreased BSBM use (OR 0.39, 95% CI 0.25-0.60) and decreased atypical coverage (OR 0.25, 95% CI 0.16-0.37), predominantly in non-severe CAP. At day one, performing UAT was associated with atypical coverage among patients with CRB-65 scores 2 (OR 2.60, 95% CI 1.69-3.98) and 3-4 (OR 3.69, 95% CI 1.55-8.79), and a positive test reduced the odds of BSBM treatment among CRB-65 score 3-4 patients (OR 3.49, 95% CI 1.02-12.0).CONCLUSIONS: Performing UAT had no overall effect on decreasing the use of BSBM treatment by day three of hospitalization, yet non-severely ill patients with positive UAT results were less likely to be treated with BSBM and antibiotics with atypical coverage.
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| 3. |
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| 4. |
- Bonaglia, Stefano, et al.
(author)
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Activated carbon stimulates microbial diversity and PAH biodegradation under anaerobic conditions in oil-polluted sediments
- 2020
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In: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 248
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Journal article (peer-reviewed)abstract
- Biodegradation by microorganisms is a useful tool that helps alleviating hydrocarbon pollution in nature. Microbes are more efficient in degradation under aerobic than anaerobic conditions, but the majority of sediment by volume is generally anoxic. Incubation experiments were conducted to study the biodegradation potential of naphthalene-a common polycyclic aromatic hydrocarbon (PAH)-and the diversity of microbial communities in presence/absence of activated carbon (AC) under aerobic/anaerobic conditions. Radio-respirometry experiments with endogenous microorganisms indicated that degradation of naphthalene was strongly stimulated (96%) by the AC addition under anaerobic conditions. In aerobic conditions, however, AC had no effects on naphthalene biodegradation. Bioaugmentation tests with cultured microbial populations grown on naphthalene showed that AC further stimulated (92%) naphthalene degradation in anoxia. Analysis of the 16S rRNA gene sequences implied that sediment amendment with AC increased microbial community diversity and changed community structure. Moreover, the relative abundance of Geobacter, Thiobacillus, Sulfuricurvum, and methanogenic archaea increased sharply after amendment with AC under anaerobic conditions. These results may be explained by the fact that AC particles promoted direct interspecies electron transfer (DIET) between microorganisms involved in PAH degradation pathways. We suggest that important ecosystem functions mediated by microbes-such as hydrocarbon degradation-can be induced and that AC enrichment strategies can be exploited for facilitating bioremediation of anoxic oil-contaminated sediments and soils.
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| 5. |
- Cardenas, Edgar, et al.
(author)
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Microstructural evolution of condensed aggregates during the crystallization of ZSM-5 from a heterogeneous system
- 2021
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In: Journal of Crystal Growth. - : Elsevier. - 0022-0248 .- 1873-5002. ; 568–569
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Journal article (peer-reviewed)abstract
- The microstructural evolution of precursors of ZSM-5 zeolite crystallized from a heterogeneous system using fumed silica, sodium aluminate and tetrapropylammonium ions as reagents is investigated. Entities previously described by Ren et al. (Chem. Mater. 2012, 24, 10, 1726–1737) as condensed aggregates, were extensively studied using scanning electron microscopy, and energy dispersive spectroscopy. It was observed that the condensed aggregates first comprise a core of nanocrystals that is enveloped by a shell of amorphous gel phase. During crystallization, the amorphous shell surrounding the core is converted into ZSM-5 crystals that grow to a film surrounding the core. The crystals in the film grow competitively with nutrients provided by the liquid phase from the surroundings, while the nanocrystals in the core show little or no signs of growth.
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| 6. |
- Geng, Shiyu, et al.
(author)
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Monolithic carbon aerogels from bioresources and their application for CO2 adsorption
- 2021
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In: Microporous and Mesoporous Materials. - : Elsevier. - 1387-1811 .- 1873-3093. ; 323
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Journal article (peer-reviewed)abstract
- Monolithic binder-free CO2 adsorbents with high adsorption capacity, selectivity, adsorption-desorption kinetics, and regenerability are highly desired to both reduce the environmental impact of anthropogenic CO2 emissions and purify valuable gases from CO2. Herein, we report a strategy to prepare monolithic carbonaceous CO2 adsorbents from low-cost and underutilized bioresources, which enabled the formation of a delicate anisotropic, hierarchical porous structure. With optimized material composition and processing conditions, the biobased carbon adsorbent demonstrated a CO2 adsorption capacity of 4.49 mmol g-1 at 298 K and 100 kPa, relatively weak adsorbent-adsorbate affinity, good CO2/N2 selectivity, and advantageous hydrophobicity against water vapor. Moreover, the unique anisotropic porous structure provided high stiffness and good flexibility to the adsorbent in the axial and radial directions, respectively. We confirmed that this type of carbon adsorbent could be packed in a column for dynamic CO2 capture independent of any binders, indicating its promising future for further development toward widespread utilization.
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| 7. |
- Geng, Shiyu, et al.
(author)
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Multifunctional Carbon Aerogels with Hierarchical Anisotropic Structure Derived from Lignin and Cellulose Nanofibers for CO2 Capture and Energy Storage
- 2020
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In: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 12:6, s. 7432-7441
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Journal article (peer-reviewed)abstract
- In current times, CO2 capture and light-weight energy storage are receiving significant attention and will be vital functions in next-generation materials. Porous carbonaceous materials have great potential in these areas, whereas most of the developed carbon materials still have significant limitations, such as non-renewable resources, complex and costly processing or the absence of tailorable structure. In this study, a new strategy is developed for using the currently under-utilized lignin and cellulose nanofibers, which can be extracted from renewable resources to produce high-performance multifunctional carbon aerogels with a tailorable, anisotropic pore structure. Both the macro- and microstructure of the carbon aerogels can be simultaneously controlled by discreetly tuning the weight ratio of lignin to cellulose nanofibers in the carbon aerogel precursors, which considerably influences their final porosity and surface area. The designed carbon aerogels demonstrate excellent performance in both CO2 capture and capacitive energy storage, and the best results exhibit a CO2 adsorption capacity of 5.23 mmol g-1 at 273 K and 100 kPa, and a specific electrical double layer capacitance of 124 F g-1 at a current density of 0.2 A g-1, indicating that they have great future potential in the relevant applications.
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| 8. |
- Grahn, Mattias, et al.
(author)
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Small ZSM-5 crystals with low defect density as an effective catalyst for conversion of methanol to hydrocarbons
- 2020
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In: Catalysis Today. - : Elsevier B.V.. - 0920-5861 .- 1873-4308. ; 345, s. 136-146
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Journal article (peer-reviewed)abstract
- This work presents the synthesis of nearly defect-free ZSM-5 nanosized crystals, prepared in fluoride medium by seeding with silicalite-1. This material was carefully characterized and its catalytic performances in the methanol to hydrocarbons (MTH) reaction were assessed. Such fluoride-based material was compared to a reference ZSM-5, produced through a conventional alkaline synthesis but from the same seeding. Despite both the materials show closely identical morphology and they have a comparable acid site population, the catalyst prepared using the fluoride route showed significantly longer lifetime in MTH compared to the catalyst prepared using conventional synthesis at high pH. The slower deactivation for the samples prepared using the fluoride route was ascribed, thanks to a thorough in situ IR spectroscopy study, to its lower density of internal defects. According to the UV-Raman characterization of coke on the spent catalyst, the fluoride-based ZSM-5 catalyst produces less molecular coke species, most probably because of the absence of enlarged cavities/channels as due to the presence of internal defects. On the basis of these observations, the deactivation mechanism in the ZSM-5 synthesized by fluoride medium could be mostly related to the deposition of an external layer of bulk coke, whereas in the alkali-synthesized catalyst an additional effect from molecular coke accumulating within the porous network accelerates the deactivation process.
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| 9. |
- Gyger, Samuel, et al.
(author)
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Metropolitan single-photon distribution at 1550 nm for random number generation
- 2022
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 121:19, s. 194003-
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Journal article (peer-reviewed)abstract
- Quantum communication networks will connect future generations of quantum processors, enable metrological applications, and provide security through quantum key distribution. We present a testbed that is part of the municipal fiber network in the greater Stockholm metropolitan area for quantum resource distribution through a 20 km long fiber based on semiconductor quantum dots emitting in the telecom C-band. We utilize the service to generate random numbers passing the NIST test suite SP800-22 at a subscriber 8 km outside of the city with a bit rate of 23.4 kbit/s.
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| 10. |
- Gyger, Samuel, et al.
(author)
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Metropolitan Single-Photon Distribution at 1550 nm for Random Number Generation
- 2023
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In: 2023 Conference on Lasers and Electro-Optics, CLEO 2023. - : Institute of Electrical and Electronics Engineers Inc..
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Conference paper (peer-reviewed)abstract
- Quantum communication networks are used for QKD and metrological applications. We present research connecting two nodes ≈ 20 kilometers apart over the municipal fiber network using semiconductor quantum dots emitting at 1550 nm.
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