| 1. |
- Agmo Hernández, Víctor, 1980-, et al.
(författare)
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The electrochemistry of liposomes
- 2008
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Ingår i: Israel Journal of Chemistry. - 0021-2148. ; 48, s. 169-184
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Recension (refereegranskat)
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| 2. |
- Andreasson, Joakim, 1973, et al.
(författare)
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Storage and Processing of Information Using Molecules: The All-Photonic Approach with Simple and Multi-Photochromic Switches
- 2013
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Ingår i: Israel Journal of Chemistry. - : Wiley. - 0021-2148. ; 53:5, s. 236-246
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Forskningsöversikt (refereegranskat)abstract
- The use of photochromes for the implementation of molecular logic operations is a very promising approach toward molecular computing. This statement is based on a) the possibility of operating such molecular devices exclusively with photonic signals and b) spatiotemporally and remotely controlled switching, which is characteristic for photochromes. Herein, a brief overview of the application of simple photochromes and multi-photochromic conjugates for the small-scale functional integration of complicated logic circuits is given. This complements and extends efforts to design molecular photochromic memories for data storage described by many research groups worldwide.
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| 3. |
- Azuri, Ido, et al.
(författare)
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Fe-porphyrin on Co(001) and Cu(001) : A Comparative Dispersion-augmented Density Functional Theory Study
- 2020
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Ingår i: Israel Journal of Chemistry. - : Wiley. - 0021-2148 .- 1869-5868. ; 60:8-9, s. 870-875
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Tidskriftsartikel (refereegranskat)abstract
- We present a comparative density functional theory (DFT) investigation of the interaction of the iron porphyrin (FeP) molecule with the metallic Co(001) and Cu(001) surfaces, with the aim of elucidating the effect of different choices for the treatment of dispersion. We compare a GGA+U approach, several flavors of dispersion-augmented terms, and two variants of the vdW-DF approach, which treats long-range correlation explicitly. For the Co surface, we find that all approaches predict chemisorption and a high-spin state, although vdW-DF functionals generally predict weaker bonds and weaker chemisorption. For the Cu surface, we find that the functionals augmented by pair-wise dispersion once again predict chemisorption and a preferred HS state, but the vdW-DF functionals predict physisorption and a LS state. These results demonstrate the importance of careful assessment of the level of theory at which dispersion is treated, as this may have significant quantitative and even qualitative effects on the predictions made. The results also call for additional experimental data for these systems.
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| 4. |
- Becconi, Olga, et al.
(författare)
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Protein-ion Interactions : Simulations of Bovine Serum Albumin in Physiological Solutions of NaCl, KCl and LiCl
- 2017
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Ingår i: Israel Journal of Chemistry. - : Wiley-Blackwell. - 0021-2148. ; 57:5, s. 403-412
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Tidskriftsartikel (refereegranskat)abstract
- Specific interactions that depend on the nature of electrolytes are observed when proteins and other molecules are studied by potentiometric, spectroscopic and theoretical methods at high salt concentrations. More recently, it became clear that such interactions may also be observed in solutions that can be described by the Debye-Hückel theory, i.e., at physiological (0.1 mol dm−3) and lower concentrations. We carried out molecular dynamics simulations of bovine serum albumin in physiological solutions at T=300 and 350 K. Analysis of the simulations revealed some differences between LiCl solutions and those of NaCl and KCl. The binding of Li+ ions to the protein was associated with a negative free energy of interaction whereas much fewer Na+ and K+ ions were associated with the protein surface. Interestingly, unlike other proteins BSA does not show a preference to Na+ over K+. Quantum chemical calculations identified a significant contribution from polarisation to the hydration of Li+ and (to a lesser degree) Na+, which may indicate that polarisable force-fields will provide more accurate results for such systems.
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| 5. |
- Berg, Johan, et al.
(författare)
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Single Proteoliposomes with E.coli Quinol Oxidase : Proton Pumping without Transmembrane Leaks
- 2017
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Ingår i: Israel Journal of Chemistry. - : Wiley. - 0021-2148. ; 57:5, s. 437-445
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Tidskriftsartikel (refereegranskat)abstract
- Respiratory oxidases are transmembrane enzymes that catalyze the reduction of dioxygen to water in the final step of aerobic respiration. This process is linked to proton pumping across the membrane. Here, we developed a method to study the catalytic turnover of the quinol oxidase, cytochromebo(3) from E.coli at single-molecule level. Liposomes with reconstituted cytochromebo(3) were loaded with a pH-sensitive dye and changes in the dye fluorescence, associated with proton transfer and pumping, were monitored as a function of time. The single-molecule approach allowed us to determine the orientation of cytochromebo(3) in the membrane; in approximate to 70% of the protein-containing liposomes protons were released to the outside. Upon addition of substrate we observed the buildup of a pH (in the presence of the K+ ionophore valinomycin), which was stable over at least approximate to 800s. No rapid changes in pH (proton leaks) were observed during steady state proton pumping, which indicates that the free energy stored in the electrochemical gradient in E.coli is not dissipated or regulated through stochastic transmembrane proton leaks, as suggested from an earlier study (Li etal. J. Am. Chem. Soc. (2015) 137, 16055-16063).
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| 6. |
- Bernholt, Sascha, et al.
(författare)
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Digitising teaching and learning : additional perspectives for chemistry education
- 2019
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Ingår i: Israel Journal of Chemistry. - : Wiley-VCH Verlagsgesellschaft. - 0021-2148 .- 1869-5868. ; 59, s. 554-564
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Tidskriftsartikel (refereegranskat)abstract
- Chemistry requires and combines both observable and mental representations. Still we know that learners often struggle in combining these perspectives successfully, especially when experimental observations contradict the model-based explanations, e.g. in interpreting the chemical equilibrium as dynamic processes while observing a static system without any visible changes. Digital media offer potentials that might not have been accessible to this degree until now. However, we do not know enough with regard to the degree and effects these media tools have in supporting learning processes but perhaps also in hindering them. This article presents four approaches on how to potentially make use of digital media in learning processes based on theoretical considerations and empirical investigations. The projects will explore applications of media as visualization, learning and investigation tools in chemistry education, embracing techniques from virtual realities to eye-tracking.
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| 7. |
- Edlund, Ulrica, et al.
(författare)
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Nano Patterened Covalent Surface Modification of Poly(ε-caprolactone)
- 2005
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Ingår i: Israel Journal of Chemistry. - 0021-2148. ; 45:4, s. 429-435
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Tidskriftsartikel (refereegranskat)abstract
- Using our new vapor-phase grafting technique, we have simultaneously chemically and physically modified the surface of poly(e-caprolactone) (PCL) films. The substrates were covered with nano patterned silicone rubber stamps and subjected to UV irradiation in the presence of the solvent-free vapor phase of either N-vinyl pyrrolidone or maleic anhydride, and a photoinitiator, under reduced pressure. The treated films display a surface pattern of grafted channels of 450-nm width, as confirmed by AFM and SEM. The grafting was further verified with ATR-FTIR, and contact angle measurements show an increased wettability of the surfaces.
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| 8. |
- Fransson, Jonas, 1970-
(författare)
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The Chiral Induced Spin Selectivity Effect What It Is, What It Is Not, And Why It Matters
- 2022
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Ingår i: Israel Journal of Chemistry. - : Wiley-VCH Verlagsgesellschaft. - 0021-2148 .- 1869-5868. ; 62:11-12
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Tidskriftsartikel (refereegranskat)abstract
- The chiral induced spin selectivity effect is an excited states phenomenon, which can be probed using photo-spectroscopy as well as transport measurements. On the one hand such measurements represent averaged quantities, on the other hand nearly all theoretical descriptions, with only a few exceptions, have been concerned with energy dependent properties of the pertinent structures. While those properties may or may not be relevant for the chiral induced spin selectivity effect, many of those properties have been attributed as being the, or part of the, origins of the effect. Here, it is demonstrated that, for instance, the spin-resolved transmission provides little, if any, information about the chiral induced spin selectivity effect. Moreover, although effective single-electron theory can be used in this context, reasons are given for why such descriptions are not viable.
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| 9. |
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| 10. |
- Friedman, Ran
(författare)
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Proton Transfer on the Molecular Surface of Proteins and Model Systems
- 2009
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Ingår i: Israel Journal of Chemistry. - 0021-2148. ; 49:2, s. 149-153
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Tidskriftsartikel (refereegranskat)abstract
- Proton transfer (PT) reactions take place oil the molecular Surface of proteins, membranes, ionic polymers, and other molecules. The rates of the reactions can be followed experimentally, while the atomistic details can be elucidated by molecular modeling. This manuscript gives a brief overview of the use of computer simulations and molecular modeling, in conjuction with experiments, to study PT reactions oil the surface of solvated molecules. An integrative approach is discussed, where molecular dynamics simulations are performed with a protein, and quantum-mechanics-based calculations are performed oil a small molecule. The simulation results allow the identification of the necessary conditions that yield PT reactions oil the molecular surface. The reactions are efficient when they involve a donor and acceptor located a few A apart and under the influence of a negative electrostatic field. In proton-pumping proteins, it is possible to identify such conditions a priori and locate proton-attracting antenna domains without the need to mutate each potential donor and acceptor. Based on density functional theory calculations, the arrangement of water molecules that interconnect the donor and acceptor moieties is suggested as the rate-limiting step for proton transfer on the molecular surface.
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