| 1. |
- Bartholeyns, J, et al.
(författare)
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Cellular vaccines
- 1998
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Ingår i: Research in Immunology. - 0923-2494 .- 1879-1425. ; 149, s. 647-649
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Tidskriftsartikel (refereegranskat)abstract
- This project is devoted to the development of novel cellular vaccines designed to treat cancer patients. These cellular vaccines present and enhance immunogens, which will elicit a potent immune response. The goal is to achieve safe and effective immune reaction against the patient's own tumour. (1) Autologous cellular vaccines are prepared by processing circulating brood mononuclear cells outside of the patient's body (ex vivo) to differentiate them into antigen-presenting cells (APCs). Monocyte-derived APCs (MD-APCs) are then grown in the presence of exogenous target antigens (tumour cell debris, or apoptotic bodies) to become fully mature APCs. (2) Functionality for antigen presentation to T cells of ex vivo MD-APCs is evaluated in vivo. (3) Cellular vaccines are tested in selected rodent animal models. Efficiency and immune response are monitored in pertinent experimental systems for cancer. Pharmacological data are generated for clinical investigation. Tolerance and biologic effects are documented in primates. (4) The first clinical trials on cancer patients are taking place in 1998 on melanoma and prostate cancer to validate the concept. Specialized eel processors with dedicated software and standardized controls are being developed and used for the preparation of cellular vaccines. (5) The evaluation of new non-viral vectors and the validation of new non-viral transfection methods of mononuclear cells with marker genes is in progress and will lead to the ex vivo transfection of genes coding for immunostimulating cytokines or for tumour antigens in MD-APCs. Efficiency will be validated in vitro and in animal models. The ex vivo and animal model studies validate the clinical relevance of this new cellular immunotechnology. Clinical validation of individual autologous cellular vaccines in specific indications for which no treatment is presently available will allow the development of cellular and gene immunotherapy for other types of cancers.
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| 2. |
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| 3. |
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| 4. |
- Malmsten, M, et al.
(författare)
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Adsorption of apolipoprotein B at phospholipid model surfaces
- 1995
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Ingår i: Journal of Colloid and Interface Science. - 0021-9797 .- 1095-7103. ; 172, s. 485-493
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Tidskriftsartikel (refereegranskat)abstract
- The adsorption of apolipoprotein B (Apo B) at a series of surfaces was investigated with in situ ellipsometry. For silica and methylated silica, the adsorbed amount (G), the adsorbed layer thickness (del) and the mean adsorbed layer refractive index (nf) were obtained by a procedure involving studies of the bare substrate at two different ambient refractive indices, as well as four-zone averaging. The adsorbed amount of Apo B is much higher at silica than at methylated silica. Despite this, the adsorbed layer thickness is the same at the two surfaces, and the adsorbed layer formation proceeds similarly. In both cases, the adsorbed layer formation occurs through the adsorption of Apo B molecules in an essentially random orientation, the difference between silica and methylated silica being the number of molecules adsorbed per unit area. Furthermore, the adsorption of Apo B at phospholipid surfaces was investigated. It was found that the adsorption at phosphatidylcholine (PC) was quite limited, whereas that at phosphatidic acid (PA) was substantial. Studies with mixed PA/PC layers showed that the Apo B adsorption depends on the mixed phospholipid layer composition in an essentially linear fashion. Finally, mixed phospholipid layers of PC and ganglioside GM1, as well as phosphatidylinositol (PI) layers, showed a dramatic preferential adsorption of Apo B over, e. g. human serum albumin (HSA), IgG, fibronectin and fibrinogen.
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| 5. |
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| 6. |
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| 7. |
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| 8. |
- Jing, Xiaona, et al.
(författare)
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Delivery of siRNA Complexed with Palmitoylated alpha-Peptide/beta-Peptoid Cell-Penetrating Peptidomimetics : Membrane Interaction and Structural Characterization of a Lipid-Based Nanocarrier System
- 2016
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Ingår i: Molecular Pharmaceutics. - : American Chemical Society (ACS). - 1543-8384 .- 1543-8392. ; 13:6, s. 1739-1749
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Tidskriftsartikel (refereegranskat)abstract
- Proteolytically stable alpha-peptide/beta-peptoid peptidomimetics constitute promising cell-penetrating carrier candidates exhibiting superior cellular uptake as compared to commonly used cell-penetrating peptides (CPPs). The aim of the present study was to explore the potential of these peptidomimetics for delivery of small interfering RNA (siRNA) to the cytosol by incorporation of a palmitoylated peptidomimetic construct into a cationic lipid-based nanocarrier system. The optimal construct was selected on the basis of the effect of palmitoylation and the influence of the length of the peptidomimetic on the interaction with model membranes and the cellular uptake. Palmitoylation enhanced the peptidomimetic adsorption to supported lipid bilayers as studied by ellipsometry. However, both palmitoylation and increased peptidomimetic chain length were found to be beneficial in the cellular uptake studies using fluorophore-labeled analogues. Thus, the longer palmitoylated peptidomimetic was chosen for further formulation of siRNA in a dioleoylphosphatidylethanolamine/cholesteryl hemisuccinate (DOPE/CHEMS) nanocarrier system, and the resulting nanoparticles were found to mediate efficient gene silencing in vitro. Cryo-transmission electron microscopy (cryo-TEM) revealed multilamellar, onion-like spherical vesicles, and small-angle X-ray scattering (SAXS) analysis confirmed that the majority of the lipids in the nanocarriers were organized in lamellar structures, yet coexisted with a hexagonal phase, which is important for efficient nanocarrier-mediated endosomal escape of siRNA ensuring cytosolic delivery. The present work is a proof-of-concept for the use of alpha-peptides/beta-peptoid peptidomimetics in an efficient delivery system that may be more generally exploited for the intracellular delivery of biomacromolecular drugs.
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| 9. |
- Malekkhaiat Häffner, S., et al.
(författare)
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Composition effects on photooxidative membrane destabilization by TiO2 nanoparticles
- 2021
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Ingår i: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797. ; 584, s. 19-33
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Tidskriftsartikel (refereegranskat)abstract
- Membrane interactions and photooxidative membrane destabilization of titanium dioxide (TiO2) nanoparticles were investigated, focusing on the effects of membrane composition, notably phospholipid headgroup charge and presence of cholesterol. For this, we employed a battery of state-of-the-art methods for studies of bilayers formed by zwitterionic palmitoyloleoylphosphatidylcholine (POPC) containing also polyunsaturated palmitoylarachidonoylphosphocholine (PAPC), as well as its mixtures with anionic palmitoyloleoylphosphatidylglycerol (POPG) and cholesterol. It was found that the TiO2 nanoparticles display close to zero charge at pH 7.4, resulting in aggregation. At pH 3.4, in contrast, the 6 nm TiO2 nanoparticles are well dispersed due to a strongly positive ζ-potential. Mirroring this pH dependence, TiO2 nanoparticles were observed to bind to negatively charged lipid bilayers at pH 3.4, but much less so at pH 7.4. While nanoparticle binding has some destabilizing effect alone, illumination with ultraviolet (UV) light accentuates membrane destabilization, a result of oxidative stress caused by generated reactive oxygen species (ROS). Neutron reflectivity (NR), quartz crystal microbalance (QCM), and small-angle X-ray scattering (SAXS) results all demonstrate that membrane composition strongly influences membrane interactions and photooxidative destabilization of lipid bilayers. In particular, the presence of anionic POPG makes the bilayers more sensitive to oxidative destabilization, whereas a stabilizing effect was observed in the presence of cholesterol. Also, structural aspects of peroxidation were found to depend strongly on membrane composition, notably the presence of anionic phospholipids. The results show that membrane interactions and UV-induced ROS generation act in concert and need to be considered together to understand effects of lipid membrane composition on UV-triggered oxidative destabilization by TiO2 nanoparticles, e.g., in the context of oxidative damage of bacteria and cells.
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| 10. |
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| 11. |
- Scherlund, M, et al.
(författare)
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Local anaesthetic block copolymer system undergoing phase transition on dilution with water
- 2001
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Ingår i: European Journal of Pharmaceutical Sciences. - 0928-0987 .- 1879-0720. ; 14, s. 53-61
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Tidskriftsartikel (refereegranskat)abstract
- The possibility of formulating a local anaesthetic system displaying in situ gelation on dilution with water, as well as its dependence on concentration of active ingredients and pH was investigated. For this purpose Lutrol F68, water, a eutectic mixture of lidocaine and prilocaine and Akoline MCM were mixed in different ratios and investigated using crossed polarisers, small-angle X-ray diffraction, rheology, conductivity and NMR self-diffusion measurements. In particular, an isotropic phase of low viscosity turning into a high viscous hexagonal phase upon dilution with water was found. The increase in viscosity is only weakly dependent on temperature in the temperature range of 20-37 degrees C. The rheology and in vitro drug release of these systems were studied and the elastic modulus was found to be fairly independent of concentration of active ingredients and pH in the investigated region. The in vitro release of lidocaine and prilocaine was found to increase with increasing concentration of the active ingredients and with decreasing pH, the latter as a consequence of the pH-dependent ionisation of these substances. The behaviour of the system is promising from a pharmaceutical point of view, since the isotropic low-viscous phase can be injected into, e.g. a periodontal pocket where the presence of saliva will cause a temporal transition into a rigid hexagonal phase thus making the formulation stay at the application site. At even higher water content, either as a result of longer application time or rinsing with water, the hexagonal phase is effectively dissolved through transformation to a water-rich micellar phase
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| 12. |
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| 13. |
- Scherlund, M, et al.
(författare)
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Micellization and gelation in block copolymer systems containing local anesthetics
- 2000
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Ingår i: International Journal of Pharmaceutics. - 0378-5173 .- 1873-3476. ; 211, s. 37-49
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Tidskriftsartikel (refereegranskat)abstract
- A formulation consisting of a eutectic mixture of lidocaine and prilocaine, Lutrol(R) F68 and Lutrol(R) F127, suitable for anesthetizing the periodontal pocket has previously been developed. This consists of discrete micelles with a diameter of 20-30 nm and has a suitable gelation temperature, a good release profile and excellent long-term stability. In this study, the unimer/micelle transition and gel formation of the formulation, in its concentrated state, are investigated using differential scanning calorimetry (DSC), dye solubilization, rheology, and nuclear magnetic resonance (NMR) self-diffusion. The critical micellization temperature (cmt) and gelation temperature are found to be interconnected and influenced by cosolutes, such as electrolytes and hydrophobic substances, the latter as found particularly for the eutectic mixture of the local anesthetic agents lidocaine and prilocaine. Both cmt and the gelation temperature decrease with increasing pH of the system, i.e. at reduced solubility of the active ingredients. Moreover, both cmt and the gelation temperature increase upon diluting the system with water. The ratio between the two block copolymers present in the system also has an impact on both cmt and the gelation temperature, resulting in a decrease in onset tt temperature of both processes with an increase of Lutrol(R) F127, The amount of the active ingredients present in the micelle phase depends on the pH of thc system bring approximately 0% w/w at pH 5, 50-60% w/w at pH 7.8 and 80% w/w at pH 9.
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| 14. |
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| 15. |
- Scherlund, M, et al.
(författare)
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Nonionic cellulose ethers as potential drug delivery systems for periodontal anesthesia
- 2000
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Ingår i: Journal of Colloid and Interface Science. - 0021-9797 .- 1095-7103. ; 229, s. 365-374
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Tidskriftsartikel (refereegranskat)abstract
- Nonionic cellulose ethers displaying a lower consolute temperature, or cloud-point, close to body temperature were investigated as potential carrier systems for the delivery of local anesthetic agents to the periodontal pocket. The interaction between the polymers, i.e., ethyl(hydroxyethyl)cellulose (EHEC) and hydrophobically modified EHEC (HM-EHEC), and ionic surfactants was determined in the absence and in the presence of the local anesthetic agents lidocaine and prilocaine. The cloud-point and rheology data indicate interactions between the polymer and both anionic and cationic surfactants. More precisely, a number of ionic surfactants were found to result in an increase in cloud-point at higher surfactant concentrations, a surfactant-concentration-dependent thickening, and a temperature-induced gelation upon heating. Upon addition of the local anesthetic agents lidocaine and prilocaine in their uncharged form to EHEC and HM-EHEC, in the absence of surfactants, only minor interaction with the polymer could be inferred. However, these substances were found to affect the polymer-surfactant interaction. In particular, the drug release rate in vitro as well as the stability and temperature-dependent viscosity were followed for an EHEC/SDS system and EHEC/myristoylcholine bromide system upon addition of lidocaine and prilocaine. The data indicate a possibility of formulating a local anesthetic drug delivery system suitable for administration into the periodontal pocket where at least small amounts of active ingredients can be incorporated into the system without severely affecting the gelation behavior. The results found for the cationic myristoylcholine bromide system are particularly interesting for the application in focus here since this surfactant is antibacterial and readily biodegradable.
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| 16. |
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| 17. |
- Scherlund, M, et al.
(författare)
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Stabilization of a thermosetting emulsion system using ionic and nonionic surfactants
- 1998
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Ingår i: International Journal of Pharmaceutics. - 0378-5173 .- 1873-3476. ; 173, s. 103-116
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Tidskriftsartikel (refereegranskat)abstract
- Ways of achieving a suitable local anesthetic formulation for use in the periodontal cavity were investigated in this study. By choosing poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymers as excipients, formulations which are low viscosity fluids at room temperature and rigid elastic gels at body temperature are obtained. Despite the solubilizing capacity of these polymers, formulations containing Lutrol(R) F127 (EO99PO65EO99) and the active ingredients lidocaine and prilocaine at the desired concentrations, i.e. approximately 25 mg g(-1) of each component, are unstable. In order to achieve a more stable formulation a second surfactant can be added to the system since it could help both to solubilize the hydrophobic active ingredients and to stabilize the droplets of lidocaine and prilocaine from flocculation and coalescence. Thus, formulations containing local anesthetic compounds comprising the oil phase, a block copolymer giving the system unique rheological properties, and a suitable second surfactant were evaluated with regard to rheological behavior, drug release properties and stability. The system needs to be balanced regarding the concentration of polymer, active ingredients and surfactant in order to achieve a formulation with suitable properties. Stable formulations with appropriate characteristics for the application in focus here were obtained with anionic, cationic and nonionic surfactants.
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| 18. |
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| 19. |
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| 20. |
- Schillén, Karin, et al.
(författare)
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Properties of poly(ethylene oxide)-poly(butylene oxide) diblock copolymers at the interface between hydrophobic surfaces and water
- 1997
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 101, s. 4238-4252
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Tidskriftsartikel (refereegranskat)abstract
- The interaction between molecules of a low molecular weight diblock copolymer of poly(ethylene oxide) (E) and poly(butylene oxide) (B), B8E41, at hydrophobic surfaces were investigated experimentally by using two surface force techniques and ellipsometry. Extended mean-field theory was employed to describe the adsorption of EB diblock copolymers at planar surfaces as well as the forces between surfaces with adsorbed diblock copolymers. It is the hydrophobic poly(butylene oxide) block that anchors the diblock copolymer at the hydrophobic surface with the water-soluble poly(ethylene oxide) block protruding in the aqueous solution in a "brushlike" or at least streched structure. The adsorption kinetics demonstrate that two adsorption regimes exist, one which is transport-limited and the other at higher adsorption where a slower branch due to crowding effects at the surface exists. Only monotonic repulsuve steric forces between the diblock copolymer-coated surfaces were observed in the surface force measurements. The range of the steric repulsion increased with increasing bulk copolymer concentration, whereas the concentration of an inert salt (KBr, up to 0.1 M) did not influence the measured steric interaction. Upon dilution the block copolymer slowly dissolved, which resulted in a less long-range steric force, and under a high force the layers were squeezed out from between the surfaces. The adsorbed layer thickness obtained in the experiments varied with solution volume-to-surface area ratio. This is interpreted as being caused by the polydispersity of the diblock copolymer. The interaction parameters entering the mean-field model were fitted to reproduce adsorption isotherms of the diblock copolymer and of two triblock copolymers of different architectures. Calculations were performed for mondisperse and polydisperse diblock copolymers. The agreement between theory and experiment was improved when the molecular polydispersity (Mm/Mn = 1.1) of the sample was taken into account. In particular, polydispersity led to predicted adsorption isotherms that are more of the high affinity type and more sensitive to low volume-to-surface area ratio and to the interaction between surfaces starting at a longer separation. Among the polymer components, it is those with the largest B block that adsorb preferentially, which leads to an increased amount adsorbed and forces the E chains to adopt more extended conformations.
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| 21. |
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| 22. |
- Siegel, G, et al.
(författare)
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Anionic biopolymers as blood flow sensors
- 1996
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Ingår i: Biosensors & bioelectronics. - 0956-5663 .- 1873-4235. ; 11, s. 281-294
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Tidskriftsartikel (refereegranskat)abstract
- The finding of flow-dependent vasodilatation rests on the basic observation that with an increase in blood flow the vessels become wider, with a decrease the vascular smooth muscle cells contract. Proteoheparan sulphate could be the sensor macromolecule at the endothelial cell membrane-blood interface, that reacts on the shear stress generated by the flowing blood, and that informs and regulates the vascular smooth muscle cells via a signal transduction chain. This anionic biopolyelectrolyte possesses viscoelastic and specific ion binding properties which allow a change of its configuration in dependence on shear stress and electrostatic charge density. The blood flow sensor undergoes a conformational transition from a random coil to an extended filamentous state with increasing flow, whereby Na+ ions from the blood are bound. Owing to the intramolecular elastic recoil forces of proteoheparan sulphate the slowing of a flow rate causes an entropic coiling the expulsion of Na+ ions and thus an interruption of the signal chain. Under physiological conditions, the conformation and Na+ binding proved to be extremely Ca2+-sensitive while K+ and Mg2+ ions play a minor role for the susceptibility of the sensor. Via counterion migration of the bound Na+ ions along the sensor glycosaminoglycan side chains and following Na+ passage through an unspecific ion channel in the endothelial cell membrane, the signal transduction chain leads to a membrane depolarization with Ca2+ influx into the cells. This stimulates the EDRF/NO production and release from the endothelial cells. The consequence is vasodilatation.
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| 23. |
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| 24. |
- Siegel, G., et al.
(författare)
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Nanotechnologic biosensor ellipsometry and biomarker pattern analysis in the evaluation of atherosclerotic risk profile.
- 2009
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Ingår i: Biosensors & bioelectronics. - : Elsevier BV. - 1873-4235 .- 0956-5663. ; 24:5, s. 1512-1517
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Tidskriftsartikel (refereegranskat)abstract
- A proteoheparan sulfate coated, hydrophobic silica surface serves as lipoprotein receptor at which the Ca(2+)-driven arteriosclerotic nanoplaque formation can be pursued by laser-based ellipsometry. Any lipoprotein from human blood can be very sensitively tested for its atherogenic properties. From the same blood sample, it is possible to determine the concentration and activity of a series of interacting biomarker molecules which, through a pattern analysis, allow to assess the state of health with respect to cardiovascular diseases. These two interlinked and complementary biosensors make a prospective cardio-cerebro-vascular risk stratification feasible, especially the sequelae of an underlying arteriosclerotic disease. Based on these diagnostic tools, an optimized therapy decision for the patient can be taken and the necessary preventive measures for the still healthy person.
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| 25. |
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