| 1. |
-
5-HT1A targeting PARCEST agent DO3AM-MPP with potential for receptor imaging : Synthesis, physico-chemical and MR studies
- 2021
-
Ingår i: Bioorganic chemistry. - : Elsevier. - 0045-2068. ; 106
-
Tidskriftsartikel (refereegranskat)abstract
- Contrast enhancement in MRI using magnetization or saturation transfer techniques promises better sensitivity, and faster acquisition compared to T-1 or T-2 contrast. This work reports the synthesis and evaluation of 5-HT1A targeted PARACEST MRI contrast agent using 1,4,7,10-tetraazacycloDOdecane-4,7,10-triacetAMide (DO3AM) as the bifunctional chelator, and 5-HT1A-antagonist methoxyphenyl piperazine (MPP) as a targeting unit. The multistep synthesis led to the MPP conjugated DO3AM with 60% yield. CEST-related physicochemical parameters were evaluated after loading DO3AM-MPP with paramagnetic MRI active lanthanides: Gadolinium (Gd-DO3AM-MPP) and Europium (Eu-DO3AM-MPP). Luminescence lifetime measurements with Eu-DO3AM-MPP and computational DFT studies using Gd-DO3AM-MPP revealed the coordination of one water molecule (q = 1.43) with metal-water distance (r(M)-H2O) of 2.7 angstrom and water residence time (tau(m)) of 0.23 ms. The dissociation constant of K-d 62 +/- 0.02 pM as evaluated from fluorescence quenching of 5-HT1A (protein) and docking score of -4.81 in theoretical evaluation reflect the binding potential of the complex Gd-DO3AM-MPP with the receptor 5-HT1A. Insights of the docked pose reflect the importance of NH2 (amide) and aromatic ring in Gd-DO3AM-MPP while interacting with Ser 374 and Phe 370 in the antagonist binding pocket of 5-HT1A. Gd-DO3AM-MPP shows longitudinal relaxivity 5.85 mM(-1)s(-1) with a water residence lifetime of 0.93 ms in hippocampal homogenate containing 5-HT1A. The potentiometric titration of DO3AM-MPP showed strong selectivity for Gd3+ over physiological metal ions such as Zn2+ and Cu2+. The in vitro and in vivo studies confirmed the minimal cytotoxicity and presential binding of Gd-DO3AM-MPP with 5-HT1A receptor in the hippocampus region of the mice. Summarizing, the complex Gd-DO3AM-MPP can have a potential for CEST imaging of 5-HT1A receptors.
|
|
| 2. |
- A. B. Marçal, L., et al.
(författare)
-
Spatially resolved structural and chemical properties of the white layer in machined Inconel 718 super alloy
- 2024
-
Ingår i: Materials and Design. - 0264-1275. ; 239
-
Tidskriftsartikel (refereegranskat)abstract
- Inconel 718 is one type of nickel-based alloy used for a large range of applications, including gas turbines and aeroengines components. Although mechanical and thermodynamic properties of this material have been deeply studied in the past years, a method able to investigate local properties of the thin white layer formed on the alloy surface after machining remains challenging. Here, a 90 nm X-ray beam is used to probe the local strain, crystal orientation, and chemical composition of grains in the white layer. Data reveals mosaicity induced by the tool during machining. The high spatial resolution, combined with crystal lattice sensitivity, shows that the average grain size is around 30 nm throughout the white layer, while the strain is anisotropic nearest to the surface. Results provide new insights on the basic properties of the white layer in super alloys, revealing important information about the impact of finish machining which might help to explain fatigue and cracking formation on these materials during their usage phase.
|
|
| 3. |
- A. Bateki, Christian, et al.
(författare)
-
Of milk and mobiles: Assessing the potential of cellphone applications to reduce cattle milk yield gaps in Africa using a case study
- 2021
-
Ingår i: Computers and Electronics in Agriculture. - : Elsevier BV. - 0168-1699. ; 191
-
Tidskriftsartikel (refereegranskat)abstract
- There are growing expectations that Information and Communication Technology (ICT) applications could help improve on-farm yields amongst smallholder farmers in developing countries, and consequently, food and nutrition security. However, few studies have quantified the actual contribution of ICT applications on farmers’ yields, and these studies predominantly focused on crop production. We assessed the potential of ICT applications to close milk yield gaps among small- and medium scale dairy cattle farmers in Africa. First, we developed a theoretical framework summarizing biophysical and socio-economic constraints that foster milk yield gaps and discussed which constraints can be addressed using ICT applications. Second, using a case study of a feeding advice application for dairy cattle pre-tested with farmers in rural Kenya, we analyzed how much stand-alone the application could contribute to close dairy cattle milk yield gaps. Our findings suggest that ICT applications could help address some existing biophysical and socio-economic constraints fostering milk yield gaps, including data collection for breeding programs, feeding management advice, and facilitating access to markets and capital. Our stand-alone ICT application closed yield gaps by 2 % to 6 % on representative farms. Several factors may explain the limited actual contribution of selected ICT applications to reduce existing milk yield gaps, including the quality of the input data and models used in ICT applications, and more structural constraints that cannot be addressed by digital tools. Therefore, although ICT applications could help address constraints to achieving higher milk yields on dairy farms, a significant contribution to improve yields may only be achieved when conditions surrounding their use are adequate.
|
|
| 4. |
- A, Dell'Isola, et al.
(författare)
-
The role of pain and walking difficulties in shaping willingness to undergo joint surgery for osteoarthritis: Data from the Swedish BOA register
- 2021
-
Ingår i: Osteoarthritis and Cartilage Open. - : Elsevier BV. - 2665-9131. ; 3:2
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives: To investigate whether the association between pain intensity and willingness to undergo surgery is explained by walking difficulties, in patients with knee or hip osteoarthritis (OA). Methods: This is an observational study using data from the Better management of patients with Osteoarthritis (BOA) register, which collects data from a publicly financed self-management programme for people with OA in Sweden. We included all patients with knee or hip OA who attended the baseline visit between 2008 and 2016. We conducted separate mediation analyses within a counterfactual framework to estimate the mediation effect of walking difficulties (yes/no) on willingness to undergo surgery (yes/no) for each one-point increase in pain (0–10 on a numeric rating scale), adjusted for relevant confounders. Results: We included 72,131 patients (69% women, mean age 66, mean pain 5.4, 81% had walking difficulties, 27% was willing to undergo surgery). A one-point increase in pain intensity was associated with 1.53 (95% CI: 1.51; 1.55) higher odds of being willing to undergo surgery. Walking difficulties mediated 10%–25% of the effect of one-point increase in pain when pain was <8/10, while at pain ≥8/10 this percentage decreased to 3%. Conclusions: More than 80% of the BOA patients have mild to moderate pain (<8/10) and walking difficulties can mediate up to a quarter of the total effect of pain on the willingness to undergo surgery in these patients. Trials to evaluate the potential to lower surgery demand by reducing walking difficulties in people with these characteristics are needed.
|
|
| 5. |
- A. da Cruz, Márcia G., et al.
(författare)
-
Electrochemical Depolymerization of Lignin in a Biomass-based Solvent
- 2022
-
Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 15:15
-
Tidskriftsartikel (refereegranskat)abstract
- Breaking down lignin into smaller units is the key to generate high value-added products. Nevertheless, dissolving this complex plant polyphenol in an environment-friendly way is often a challenge. Levulinic acid, which is formed during the hydrothermal processing of lignocellulosic biomass, has been shown to efficiently dissolve lignin. Herein, levulinic acid was evaluated as a medium for the reductive electrochemical depolymerization of the lignin macromolecule. Copper was chosen as the electrocatalyst due to the economic feasibility and low activity towards the hydrogen evolution reaction. After depolymerization, high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy revealed lignin-derived monomers and dimers. A predominance of aryl ether and phenolic groups was observed. Depolymerized lignin was further evaluated as an anti-corrosion coating, revealing enhancements on the electrochemical stability of the metal. Via a simple depolymerization process of biomass waste in a biomass-based solvent, a straightforward approach to produce high value-added compounds or tailored biobased materials was demonstrated.
|
|
| 6. |
- A. da Cruz, Marcia Gabriely, et al.
(författare)
-
On the product selectivity in the electrochemical reductive cleavage of 2-phenoxyacetophenone, a lignin model compound
- 2022
-
Ingår i: Green Chemistry Letters and Reviews. - : Informa UK Limited. - 1751-8253 .- 1751-7192. ; 15:1, s. 151-159
-
Tidskriftsartikel (refereegranskat)abstract
- Research towards the production of renewable chemicals for fuel and energy industries has found lignin valorization as key. With a high carbon content and aromaticity, a fine-tuning of the depolymerization process is required to convert lignin into valuable chemicals. In context, model compounds have been used to understand the electrocatalyzed depolymerization for mimicking the typical linkages of lignin. In this investigation, 2-phenoxyacetophenone, a model compound for lignin beta-O-4 linkage, was electro-catalytically hydrogenated (ECH) in distinct three-electrode setups: an open and a membrane cell. A deep eutectic solvent based on ethylene-glycol and choline chloride was used to pursue sustainable routes to dissolve lignin. Copper was used as electrocatalyst due to the economic feasibility and low activity towards hydrogen evolution reaction (HER), a side reaction of ECH. By varying the cell type, we demonstrate a simple ECH route for the generation of different monomers and oligomers from lignin. Gas chromatography of the products revealed a higher content of carbonyl groups in those using the membrane cell, whereas the open cell produced mostly hydroxyl-end chemicals. Aiming at high value-added products, our results disclose the cell type influence on electrochemical reductive depolymerization of lignin. This approach encompasses cheap transition metal electrodes and sustainable solvents.
|
|
| 7. |
- A. da Cruz, Márcia G., et al.
(författare)
-
Solvent-free synthesis of photoluminescent carbon nanoparticles from lignin-derived monomers as feedstock
- 2023
-
Ingår i: Green Chemistry Letters and Reviews. - 1751-8253 .- 1751-7192. ; 16:1
-
Tidskriftsartikel (refereegranskat)abstract
- Photoluminescent carbon nanoparticles (CNPs), such as carbon dots (CDs), have attracted much attention owing to a unique set of properties, like high and tunable fluorescence. In this way, the use of carbon-rich lignin has been demonstrated to be a sustainable approach to producing a broad range of photoluminescent CNPs. However, the valorization of this complex polyphenol is limited when it comes to green and efficient ways of conversion. In addition, the existing solvothermal approaches using lignin often result in CDs with low photoluminescence, while flammable and/or toxic solvents are employed. Here, we depolymerized technical lignins, i.e. kraft and soda, through electroreductive cleavage in two different sustainable media: deep eutectic solvent and levulinic acid. After depolymerization, lignin-derived monomers were generated, with a predominance of aryl ether and phenolic groups, which were further combined with 1,2-Phenylenediamine to produce N-doped CNPs in a solvent-free approach. Photoluminescent CNPs with varied sizes were generated (5–50 nm), which presented a wide photoluminescence emission, from blue to red, depending on solvent polarity. These results demonstrate a feasible and sustainable route for the solvent-free synthesis of photoluminescent CNPs using lignin-derived monomers as carbon source, which may find applications in a wide range of fields.
|
|
| 8. |
- A, Lavanya, et al.
(författare)
-
Smart energy monitoring and power quality performance based evaluation of 100-kW grid tied PV system
- 2023
-
Ingår i: Heliyon. - 2405-8440. ; 9:6
-
Tidskriftsartikel (refereegranskat)abstract
- Globally, the demand for energy from renewable sources is growing due to the increasing electricity consumption and the pollution of fossil fuels. The government has framed various policies to facilitate green energy generation, encouraging renewable energy source usage through PV installations in multiple sectors, including educational institutions. The primary objective of this paper is to propose a methodological approach for analysing the performance of the installed PV system on the rooftop of a university building in Tamil Nadu, India. The site selected is favourable for electricity generation from PV systems with an average global solar radiation of 5.82 kWh/m2day. Solar energy changes periodically with annual and daily variations and is not steady due to seasonal changes. The step-by-step performance assessment and the annual performance of the 100-kW solar PV system, which was instituted in 2019, with the forecasted parameters, are presented in this paper. Therefore, the assessment analysis is carried out in four phases: feasibility assessment, Energy yield assessment, Life cycle assessment, and Power quality assessment. To improve the solar PV output and efficiency, considering the solar irradiation, temperature, wind velocity, etc., PV yield is measured to evaluate the PV system's energy metrics. This paper also considers the carbon credits earned, solar power generated in the location, and the payback period. The power quality assessment is carried out in this paper to test the PV plant's compliance with effective grid integration.
|
|
| 9. |
- A. Mouris, Boules, et al.
(författare)
-
Multi-tone Signal Optimization for Wireless Power Transfer in the Presence of Wireless Communication Links
- 2020
-
Ingår i: IEEE Transactions on Wireless Communications. - : Institute of Electrical and Electronics Engineers (IEEE). - 1536-1276 .- 1558-2248. ; 19:5, s. 3575-3590
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, we study optimization of multi-tone signals for wireless power transfer (WPT) systems. We investigate different non-linear energy harvesting models. Two of them are adopted to optimize the multi-tone signal according to the channel state information available at the transmitter. We show that a second-order polynomial curve-fitting model can be utilized to optimize the multi-tone signal for any RF energy harvester design. We consider both single-antenna and multi-antenna WPT systems. In-band co-existing communication links are also considered in this work by imposing a constraint on the received power at the nearby information receiver to prevent its RF front end from saturation. We emphasize the importance of imposing such constraint by explaining how inter-modulation products, due to saturation, can cause high interference at the information receiver in the case of multi-tone signals. The multi-tone optimization problem is formulated as a non-convex linearly constrained quadratic program. Two globally optimal solution approaches using mixed-integer linear programming and finite branch-and-bound techniques are proposed to solve the problem. The achieved improvement resulting from applying both solution methods to the multi-tone optimization problem is highlighted through simulations and comparisons with other solutions existing in the literature.
|
|
| 10. |
|
|
