| 1. |
- Nicholls, Ian A., et al.
(författare)
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Rational design of biomimetic molecularly imprinted materials : theoretical and computational strategies for guiding nanoscale structured polymer development
- 2011
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Ingår i: Analytical and Bioanalytical Chemistry. - : Springer Science and Business Media LLC. - 1618-2642 .- 1618-2650. ; 400:6, s. 1771-1786
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Forskningsöversikt (refereegranskat)abstract
- In principle, molecularly imprinted polymer science and technology provides a means for ready access to nano-structured polymeric materials of predetermined selectivity. The versatility of the technique has brought it to the attention of many working with the development of nanomaterials with biological or biomimetic properties for use as therapeutics or in medical devices. Nonetheless, the further evolution of the field necessitates the development of robust predictive tools capable of handling the complexity of molecular imprinting systems. The rapid growth in computer power and software over the past decade has opened new possibilities for simulating aspects of the complex molecular imprinting process. We present here a survey of the current status of the use of in silico-based approaches to aspects of molecular imprinting. Finally, we highlight areas where ongoing and future efforts should yield information critical to our understanding of the underlying mechanisms sufficient to permit the rational design of molecularly imprinted polymers.
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| 2. |
- Öhrström, Lars, 1963
(författare)
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Now you see me too Attaching chiral molecules to a chiral framework allows their molecular structures to be determined
- 2016
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 353:6301, s. 754-755
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Forskningsöversikt (refereegranskat)abstract
- Knowledge of three-dimensional (3D) molecular structures is crucial for scientific advances in fields ranging from materials chemistry to medicine. For solar cell materials, human proteins, or new drugs, the revelation of the exact arrangement of atoms and bonds vastly advances understanding of their properties. On page 808 of this issue, Lee et al. (1) report an approach that allows better structural data to be obtained for large, complex organic molecules that are difficult to crystallize on their own.
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| 3. |
- Tehrani, Ali, 1976, et al.
(författare)
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Solubilization of hydrophobic dyes in surfactant solutions
- 2013
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Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 6:2, s. 580-608
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Forskningsöversikt (refereegranskat)abstract
- In this paper, the use of surfactants for solubilization of hydrophobic organic dyes (mainly solvent and disperse dyes) has been reviewed. The effect of parameters such as the chemical structures of the surfactant and the dye, addition of salt and of polyelectrolytes, pH, and temperature on dye solubilization has been discussed. Surfactant self-assemble into micelles in aqueous solution and below the concentration where this occurs-the critical micelle concentration (CMC)-there is no solubilization. Above the CMC, the amount of solubilized dye increases linearly with the increase in surfactant concentration. It is demonstrated that different surfactants work best for different dyes. In general, nonionic surfactants have higher solubilization power than anionic and cationic surfactants. It is likely that the reason for the good performance of nonionic surfactants is that they allow dyes to be accommodated not only in the inner, hydrocarbon part of the micelle but also in the headgroup shell. It is demonstrated that the location of a dye in a surfactant micelle can be assessed from the absorption spectrum of the dye-containing micellar solution.
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| 4. |
- Eklund, Per, et al.
(författare)
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The Mn + 1AXn phases : Materials science and thin-film processing
- 2010
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 518:8, s. 1851-1878
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Forskningsöversikt (refereegranskat)abstract
- This article is a Critical review of the M(n + 1)AX(n) phases ("MAX phases", where n = 1, 2, or 3) from a materials science perspective. MAX phases are a class of hexagonal-structure ternary carbides and nitrides ("X") of a transition metal ("M") and an A-group element. The most well known are Ti2AlC, Ti3SiC2, and Ti4AlN3. There are similar to 60 MAX phases with at least 9 discovered in the last five years alone. What makes the MAX phases fascinating and potentially useful is their remarkable combination of chemical, physical, electrical, and mechanical properties, which in many ways combine the characteristics of metals and ceramics. For example, MAX phases are typically resistant to oxidation and corrosion, elastically stiff, but at the same time they exhibit high thermal and electrical conductivities and are machinable. These properties stem from an inherently nanolaminated crystal structure, with M1 + nXn slabs intercalated with pure A-element layers. The research on MAX phases has been accelerated by the introduction of thin-film processing methods. Magnetron sputtering and arc deposition have been employed to synthesize single-crystal material by epitaxial growth, which enables studies of fundamental material properties. However, the surface-initiated decomposition of M(n + 1)AX(n) thin films into MX compounds at temperatures of 1000-1100 degrees C is much lower than the decomposition temperatures typically reported for the corresponding bulk material. We also review the prospects for low-temperature synthesis, which is essential for deposition of MAX phases onto technologically important substrates. While deposition of MAX phases from the archetypical Ti-Si-C and Ti-Al-N systems typically requires synthesis temperatures of similar to 800 degrees C, recent results have demonstrated that V2GeC and Cr2AlC can be deposited at similar to 450 degrees C. Also, thermal spray of Ti2AlC powder has been used to produce thick coatings. We further treat progress in the use of first-principle calculations for predicting hypothetical MAX phases and their properties. Together with advances in processing and materials analysis, this progress has led to recent discoveries of numerous new MAX phases such as Ti4SiC3, Ta4AlC3. and Ti3SnC2. Finally, important future research directions are discussed. These include charting the unknown regions in phase diagrams to discover new equilibrium and metastable phases, as well as research challenges in understanding their physical properties, such as the effects of anisotropy, impurities, and vacancies on the electrical properties, and unexplored properties such as Superconductivity, magnetism, and optics.
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| 5. |
- An, Rong, et al.
(författare)
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Atomic force microscopy probing interactions and microstructures of ionic liquids at solid surfaces
- 2022
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Ingår i: Nanoscale. - : Royal Society of Chemistry. - 2040-3364 .- 2040-3372. ; 14:31, s. 11098-11128
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Forskningsöversikt (refereegranskat)abstract
- Ionic liquids (ILs) are room temperature molten salts that possess preeminent physicochemical properties and have shown great potential in many applications. However, the use of ILs in surface-dependent processes, e.g. energy storage, is hindered by the lack of a systematic understanding of the IL interfacial microstructure. ILs on the solid surface display rich ordering, arising from coulombic, van der Waals, solvophobic interactions, etc., all giving near-surface ILs distinct microstructures. Therefore, it is highly important to clarify the interactions of ILs with solid surfaces at the nanoscale to understand the microstructure and mechanism, providing quantitative structure–property relationships. Atomic force microscopy (AFM) opens a surface-sensitive way to probe the interaction force of ILs with solid surfaces in the layers from sub-nanometers to micrometers. Herein, this review showcases the recent progress of AFM in probing interactions and microstructures of ILs at solid interfaces, and the influence of IL characteristics, surface properties and external stimuli is thereafter discussed. Finally, a summary and perspectives are established, in which, the necessities of the quantification of IL–solid interactions at the molecular level, the development of in situ techniques closely coupled with AFM for probing IL–solid interfaces, and the combination of experiments and simulations are argued.
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| 6. |
- Lindholm-Sethson, Britta, et al.
(författare)
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Electrochemical impedance spectroscopy in label-free biosensor applications : multivariate data analysis for an objective interpretation
- 2010
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Ingår i: Analytical and Bioanalytical Chemistry. - : Springer Science and Business Media LLC. - 1618-2642 .- 1618-2650. ; 398:6, s. 2341-2349
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Forskningsöversikt (refereegranskat)abstract
- Electrochemical impedance spectroscopy plays an important role in biosensor science thanks to the possibility of finding specific information from processes with different kinetics at a chosen electrode potential in one experiment. In this paper we briefly discuss label-free impedimetric biosensors described in the literature. A novel method for neutral interpretation of impedance data is presented that includes complex number chemometrics. Three examples are given based on impedance measurements on synthetic biomembranes, in this case a lipid monolayer deposited on a mercury electrode. The interaction of various compounds with the monomolecular lipid layer is illustrated with the following: (1) different concentrations of magainin (Geladi et al. in Proc. Int. Fed. Med. Biomed. Eng. 9:219-220, 2005); (2) different derivatives of gramicidin A (Lindholm-Sethson et al. in Langmuir 24:5029-5032, 2007), and (3) an antimicrobial peptide (Ringstad et al. in Langmuir 24:208-216, 2008).
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| 7. |
- Ahrens, Lutz, et al.
(författare)
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Fate and effects of poly- and perfluoroalkyl substances in the aquatic environment: A review
- 2014
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Ingår i: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268 .- 1552-8618. ; 33, s. 1921-1929
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Forskningsöversikt (refereegranskat)abstract
- Polyfluoroalkyl and perfluoroalkyl substances (PFASs) are distributed ubiquitously in the aquatic environment, which raises concern for the flora and fauna in hydrosystems. The present critical review focuses on the fate and adverse effects of PFASs in the aquatic environment. The PFASs are continuously emitted into the environment from point and nonpoint sources such as sewage treatment plants and atmospheric deposition, respectively. Although concentrations of single substances may be too low to cause adverse effects, their mixtures can be of significant environmental concern. The production of C-8-based PFASs (i.e., perfluorooctane sulfonate [PFOS] and perfluorooctanoate [PFOA]) is largely phased out; however, the emissions of other PFASs, in particular short-chain PFASs and PFAS precursors, are increasing. The PFAS precursors can finally degrade to persistent degradation products, which are, in particular, perfluoroalkane sulfonates (PFSAs) and perfluoroalkyl carboxylates (PFCAs). In the environment, PFSAs and PFCAs are subject to partitioning processes, whereby short-chain PFSAs and PFCAs are mainly distributed in the water phase, whereas long-chain PFSAs and PFCAs tend to bind to particles and have a substantial bioaccumulation potential. However, there are fundamental knowledge gaps about the interactive toxicity of PFAS precursors and their persistent degradation products but also interactions with other natural and anthropogenic stressors. Moreover, because of the continuous emission of PFASs, further information about their ecotoxicological potential among multiple generations, species interactions, and mixture toxicity seems fundamental to reliably assess the risks for PFASs to affect ecosystem structure and function in the aquatic environment. (c) 2014 SETAC
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| 8. |
- Busch, Michael, 1983
(författare)
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Water oxidation: From mechanisms to limitations
- 2018
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Ingår i: Current Opinion in Electrochemistry. - : Elsevier BV. - 2451-9111 .- 2451-9103. ; 9, s. 278-284
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Forskningsöversikt (refereegranskat)abstract
- Water oxidation is a central reaction for energy conversion and storage. On the basis of the detailed analysis of different reaction mechanisms the limitations associated with the O2evolution reaction is analysed. We find that overpotentials lower than the 0.4 eV, which have been observed for a mono-nuclear mechanism, are possible if the problematic *-OOH intermediate is avoided. This is the case for the bi-nuclear and bi-functional reaction paths. 3-dimensional volcano plots are constructed and used to explore the performance of these reaction mechanisms. Our results suggest, that in contrast to previous analysis of the mono-nuclear mechanism, the true top of the water oxidation volcano is placed at slightly lower *=O binding energies of only 2.46 eV if combined with a suitable co-catalyst. On the basis of this new analysis, design criteria for improved catalysts are developed.
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| 9. |
- Grommet, Angela Beth, 1991, et al.
(författare)
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Molecular Photoswitching in Confined Spaces
- 2020
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Ingår i: Accounts of Chemical Research. - : American Chemical Society (ACS). - 0001-4842 .- 1520-4898. ; 53:11, s. 2600-2610
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Forskningsöversikt (refereegranskat)
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| 10. |
- Janssens, Ton, et al.
(författare)
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The [(NH 3 ) 4 Cu 2 O 2 ] 2+ -Peroxo Complex as the Key Intermediate for NH 3 -SCR Activity and Deactivation of Cu-CHA Catalysts.
- 2024
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Ingår i: ChemCatChem. - 1867-3899 .- 1867-3880. ; In Press
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Forskningsöversikt (refereegranskat)abstract
- In NH3-SCR over Cu-CHA catalysts in the low-temperature range 150–300 °C, the activation of oxygen occurs via oxidation of a pair of mobile (NH3)2CuI-complexes located in the cages of the zeolite. In this step, a reactive [(NH3)4Cu2O2]2+-peroxo complex (μ-η2,η2-peroxo diamino dicopper(II)-complex) is formed. The chemistry of this complex determines several catalytic properties of the Cu-CHA catalyst. The reaction of NO with the [(NH3)4Cu2O2]2+-peroxo complex governs the NH3-SCR activity. A reaction of the [(NH3)4Cu2O2]2+-peroxo complex with ammonia hinders the reaction of NO with the complex, thus leading to an inhibition of the NH3-SCR reaction. Finally, the deactivation in presence of SO2 is due to a reaction of SO2 with the [(NH3)4Cu2O2]2+-peroxo complex, leading to the formation of Cu−S compounds in the catalyst. In this review, the characterization and the reactions of the [(NH3)4Cu2O2]2+-peroxo complex with NO, NH3, and SO2, and mean-field kinetic models based on first principles calculations for NH3-SCR activity and SO2 poisoning are discussed.
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