| 1. |
- Angerer, Tina B., 1987, et al.
(author)
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Optimizing sample preparation for anatomical determination in the hippocampus of rodent brain by ToF-SIMS analysis
- 2016
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In: Biointerphases. - : American Vacuum Society. - 1934-8630 .- 1559-4106. ; 11:2
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Journal article (peer-reviewed)abstract
- Lipidomics has been an expanding field since researchers began to recognize the signaling functions of lipids and their involvement in disease. Time-of-flight secondary ion mass spectrometry is a valuable tool for studying the distribution of a wide range of lipids in multiple brain regions, but in order to make valuable scientific contributions, one has to be aware of the influence that sample treatment can have on the results. In this article, the authors discuss different sample treatment protocols for rodent brain sections focusing on signal from the hippocampus and surrounding areas. The authors compare frozen hydrated analysis to freeze drying, which is the standard in most research facilities, and reactive vapor exposure (trifluoroacetic acid and NH3). The results show that in order to preserve brain chemistry close to a native state, frozen hydrated analysis is the most suitable, but execution can be difficult. Freeze drying is prone to produce artifacts as cholesterol migrates to surface, masking other signals. This effect can be partially reversed by exposing freeze dried sections to reactive vapor. When analyzing brain sections in negative ion mode, exposing those sections to NH3 vapor can re-establish the diversity in lipid signal found in frozen hydrated analyzed sections. This is accomplished by removing cholesterol and uncovering sulfatide signals, allowing more anatomical regions to be visualized.
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| 2. |
- Birmpilis, Georgios, 1988, et al.
(author)
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Fabric Investigation of Natural Sensitive Clay from 3D Nano- And Microtomography Data
- 2022
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In: Journal of Engineering Mechanics - ASCE. - 1943-7889 .- 0733-9399. ; 148:2
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Journal article (peer-reviewed)abstract
- The three-dimensional (3D) fabric in natural sensitive clay is quantified from a combination of high resolution nano and microtomographies, scanning electron microscopy, and dynamic light scattering. Although the speckle arising from clay particles and the pores they enclose is discerned in the nanotomography data and compare well with scanning electron microscopy (SEM) images on the same clay, the individual platelet-shaped clay particles cannot be segmented for subsequent quantitative analysis. Regardless, a very wide range of particle sizes - 0.1-300 μm - was detected using the current state-of-the-art in imaging and postprocessing. The measured aspect ratios range was 2.5±1; hence, the particles identified were not clay platelets but, rather, mechanically weathered particles embedded in the clay matrix. Furthermore, the smaller particle sizes <80 μm presented a consistent 22-23° deviation in orientation from the horizontal plane, whereas the larger fractions had a horizontal orientation. The latter finding agrees well with prior findings on the inclination of the clay minerals using small angle X-ray scattering. Finally, the measured mean particle size of 450 nm determined from the nano data is corroborated by an independent determination of particle sizes using dynamic light scattering.
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| 3. |
- Burzio, Cecilia, 1991, et al.
(author)
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Chemical Imaging of Pharmaceuticals in Biofilms for Wastewater Treatment Using Secondary Ion Mass Spectrometry
- 2023
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In: Environmental Science and Technology. - 1520-5851 .- 0013-936X. ; 57:19, s. 7431-7441
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Journal article (peer-reviewed)abstract
- The occurrence of pharmaceuticals in the aquatic environment is a global water quality challenge for several reasons, such as deleterious effects on ecological and human health, antibiotic resistance development, and endocrine-disrupting effects on aquatic organisms. To optimize their removal from the water cycle, understanding the processes during biological wastewater treatment is crucial. Time-of-flight secondary ion mass spectrometry imaging was successfully applied to investigate and analyze the distribution of pharmaceuticals as well as endogenous molecules in the complex biological matrix of biofilms for wastewater treatment. Several compounds and their localization were identified in the biofilm section, including citalopram, ketoconazole, ketoconazole transformation products, and sertraline. The images revealed the pharmaceuticals gathered in distinct sites of the biofilm matrix. While citalopram penetrated the biofilm deeply, sertraline remained confined in its outer layer. Both pharmaceuticals seemed to mainly colocalize with phosphocholine lipids. Ketoconazole concentrated in small areas with high signal intensity. The approach outlined here presents a powerful strategy for visualizing the chemical composition of biofilms for wastewater treatment and demonstrates its promising utility for elucidating the mechanisms behind pharmaceutical and antimicrobial removal in biological wastewater treatment.
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| 4. |
- Burzio, Cecilia, 1991, et al.
(author)
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Sorption of pharmaceuticals to foam and aerobic granular sludge with different morphologies
- 2024
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In: Resources, Environment and Sustainability. - : Elsevier BV. - 2666-9161. ; 15
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Journal article (peer-reviewed)abstract
- In biological wastewater treatment, the sorption process is an important removal pathway of organic micropollutants from the aqueous phase. Beyond the conventional sorption to biomass and particulate matter, organic molecules can also partition to gas bubbles commonly present in aerated biological processes. This study investigated the partitioning behavior of 21 selected pharmaceuticals to two types of aerobic granular sludge, and the foam generated by aeration. Batch sorption experiments were performed with biologically inactive granules of controlled diameters (0.5–1, 1–2, and >2 mm). Removal during sorption tests was observed for four positively charged micropollutants (sertraline, citalopram, clarithromycin, and erythromycin), four neutral compounds (levonorgestrel, estradiol, ethinylestradiol, and ketoconazole), and one negatively charged pharmaceutical (losartan). This highlights the importance of electrostatic interactions and lipophilic affinity with the solids. For some compounds, the removal increased with time, suggesting that sorption in thick biofilm is limited by molecular diffusion into the biofilm matrix. Furthermore, partitioning of pharmaceuticals to aeration-induced foam was confirmed in separate batch tests. Clarithromycin, erythromycin, ketoconazole, losartan, levonorgestrel, and ethinylestradiol exhibited concentrations in the foam 1.0–5.3 times higher than the initial test values, indicating potential adsorption at the liquid/gas interface for these compounds.
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| 5. |
- Ekholm, Jennifer, 1992, et al.
(author)
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Influence of decreasing temperature on aerobic granular sludge - microbial community dynamics and treatment performance
- 2024
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In: Bioresource Technology Reports. - 2589-014X. ; 25
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Journal article (peer-reviewed)abstract
- Municipal wastewater in temperate climates is characterized by seasonal temperature changes. Temperature is a determining factor for biological processes, but the impact of gradually decreasing temperature on aerobic granular sludge (AGS) has been largely unexplored. In this study, the influence of decreasing temperature from 20 °C to 6 °C on AGS was investigated at rates of 0.5 and 1 °C per week. Temperature was a major driver for microbial community change, where the community response could be divided into three main subclusters. Strains within the guilds of ammonium- and nitrite-oxidising bacteria (AOB and NOB) as well as polyphosphate- and glycogen-accumulating organisms (PAOs and GAOs) grouped in different subclusters, indicating variable responses among and between the guilds. The phosphorous removal rate was sufficient for complete removal at all temperatures, presumably due to functional redundancy within the PAOs. The nitrification rate was, however, seriously impaired below 13 °C, despite diversity within AOB and NOB.
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| 6. |
- Induchoodan, Govindan, 1990, et al.
(author)
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The Critical Role of Asphaltene Nanoaggregates in Stabilizing Functionalized Graphene in Crude Oil Derivatives
- 2023
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In: Colloids and Surfaces A: Physicochemical and Engineering Aspects. - : Elsevier BV. - 1873-4359 .- 0927-7757. ; 660
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Journal article (peer-reviewed)abstract
- Graphene derivatives have been seen as an additive to improve the material properties of bitumen, such as thermal conductivity, viscoelasticity, and mechanical strength. However, in our previous work, a critical challenge was identified. When graphene derivatives are incorporated into bitumen, it leads to detrimental effects. This is due to the poor phase compatibility of graphene derivatives with asphaltene aggregates, the intrinsic aggregates that give bitumen its characteristic properties. In this work, we focus on tailoring the surface chemistry of graphene, thorough non-covalent functionalization, to achieve phase compatibility with asphaltene aggregates. In addition, the work also focuses on stabilizing this functionalized graphene in bitumen. To achieve this, the graphene was functionalized with -COOH tethers by the Molecular wedging method. Thereafter, the same molecules that form the asphaltene aggregates were used to stabilize the functionalized graphene by embedding the -COOH tethers in the asphaltene aggregates. As a result, graphene functionalized by this strategy was observed to be stable in bitumen and phase compatible with asphaltene aggregates. Thus, a successful environment-friendly strategy was developed to utilize the potential of graphene to improve the material properties of bitumen.
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| 7. |
- Jansson, Helen, 1964, et al.
(author)
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Carbon enhanced cementitious coatings: Alternative anode materials for impressed current cathodic protection systems intended for reinforced concrete
- 2024
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In: Materials and Corrosion - Werkstoffe und Korrosion. - 1521-4176 .- 0947-5117. ; 75:6, s. 705-718
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Journal article (peer-reviewed)abstract
- In this study, the functionality of self-formulated carbon-based conductive coatings (CBCCs) with incorporation of graphite as the anode in an impressed current cathodic protection system is studied. The anode materials are tested and evaluated for long-term durability and performance by an accelerated durability test method. The results show that the functional time is highly dependent on the acceleration factor, and thus the charge passed through the material during testing, as well as the material composition. From the results, there are also indications that the addition of graphene into the CBCC matrix has a positive effect on the homogeneity of the material, but without any major influence on the conductivity and performance.
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| 8. |
- Li, Xianchan, 1982, et al.
(author)
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Single cell amperometry reveals curcuminoids modulate the release of neurotransmitters during exocytosis from PC12 cells
- 2016
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In: Journal of Electroanalytical Chemistry. - : Elsevier BV. - 1572-6657. ; 781, s. 30-35
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Journal article (peer-reviewed)abstract
- We used single cell amperometry to examine whether curcumin and bisdemethoxycurcumin (BDMC), substances that are suggested to affect learning and memory, can modulate monoamine release from PC12 cells. Our results indicate both curcumin and BDMC need long-term treatment (72 h in this study) to influence exocytosis effectively. By analyzing the parameters calculated from single exocytosis events, it can be concluded that curcumin and BDMC affect exocytosis through different mechanisms. Curcumin accelerates the event dynamics with no significant change of the monoamine amount released from single exocytotic events, whereas BDMC attenuates the amount from single exocytotic event with no significant change of the event dynamics. This comparison of the effect of curcumin and BDMC on exocytosis at the single cell level brings insight into their different mechanisms, which might lead to different biological actions. The effect of curcumin and BDMC on the opening and closing of the exocytotic fusion pore were also investigated. These results might be helpful for understanding the improvement of learning and memory and the anti-depression properties of curcuminoids.
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| 9. |
- Lundberg, Erik, 1981, et al.
(author)
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Controlling and Monitoring Orientation of DNA Nanoconstructs on Lipid Surfaces
- 2013
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In: Langmuir. - : American Chemical Society (ACS). - 1520-5827 .- 0743-7463. ; 29:1, s. 285-293
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Journal article (peer-reviewed)abstract
- Its extraordinary self-assembly property, with potential to form nonperiodic structures with unique addressability, makes DNA ideal for fabrication of advanced nanostructures. We here demonstrate the controllable tethering of a hexagonal DNA nanostructure in two distinct orientations at the lipid bilayer of a liposome functioning as a soft-matter support. With polarized light (linear dichroism) applied to the flow-aligned liposomes, we show that the construct is preferentially in a parallel alignment with the lipid surface when two anchors are attached while with one anchor only a perpendicular orientation is observed.
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| 10. |
- Mohammadi, Amir Saeid, 1984, et al.
(author)
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Gold and silver nanoparticle-assisted laser desorption ionization mass spectrometry compatible with secondary ion mass spectrometry for lipid analysis
- 2014
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In: Surface and Interface Analysis. - : Wiley. - 1096-9918 .- 0142-2421. ; 46:S1, s. 379-382
-
Journal article (peer-reviewed)abstract
- To provide a convenient organic matrix-free spray-on sample preparation for laser desorption ionization (LDI) that is compatible with secondary ion mass spectrometry (SIMS) imaging mass spectrometry (IMS) techniques, silver and gold nanoparticles (NPs) were applied on a 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipid sample. Application of Ag and Au nanoparticles to the POPC sample allowed POPC lipid fragments to be detected using NP-LDI in both positive and negative polarities. In addition, the same sample prepared for NP-LDI experiments was used for C-60 SIMS lipid analysis, and a secondary ion signal enhancement was obtained for the [M+H](+) ion of the POPC lipid as well as for characteristics POPC lipid fragments in positive ion mode.
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