| 1. |
- Homanen, Pertti, et al.
(författare)
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A Cluster-based Catalytic Hydrogenation System with High Conversion and Reversible Enantioselectivity
- 2000
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Ingår i: Organometallics. - : American Chemical Society (ACS). - 1520-6041 .- 0276-7333. ; 19:26, s. 5568-5568
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Tidskriftsartikel (refereegranskat)abstract
- Four tetranuclear ruthenium carbonyl hydrido clusters consisting of the enantiomeric pairs [H4Ru4(CO)10{-1,2-(R/S,R/S)-bdpp}] and [H4Ru4(CO)10{1,1-(R/S,R/S)-bdpp}] containing chiral (R,R)- or (S,S)-bdpp [bdpp = (2R/S,4R/S)-2,4-bis(diphenylphosphino)pentane] have been prepared and fully characterized. These clusters catalyze asymmetric hydrogenation of tiglic acid [trans-2-methyl-2-butenoic acid] with high conversion rates (75-100%) under relatively mild reaction conditions. Enantiomeric excesses of 40-46% were observed; the predominating enantiomeric form of the hydrogenated product is dependent on the configuration of the diphosphine ligand, indicating strong chiral induction.
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| 2. |
- Järvinen, Kristiina, et al.
(författare)
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Nanoteknologia biomateriaalien ja lääkkeiden kantaja-aineiden pintojen räätälöinnissä [Nanoscale tailoring of the surface properties of biomaterials and drug carriers]
- 2012
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Ingår i: Duodecim. - 0012-7183 .- 2242-3281. ; 128:20, s. 2085-2092
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Forskningsöversikt (refereegranskat)abstract
- Functionalities of biomaterials and drug delivery systems are improved by tailoring their surface properties using modern nanotechnology. Orthopedic implants and invasive electrodes are examples of implantable biomaterials. Biological interactions of orthopedic implants can be optimized by the synergetic effect of surface micro- and nanotexturing with a chemical composition of coating. Further, mechanical flexibility and electrochemical characteristics of invasive electrodes are improved by using micro- and nanotechnology. In nano-size drug delivery systems, surface properties of nanocarriers strongly affect their safety and efficacy. Mesoporous silicon nanoparticles are example of nanocarriers those properties can be tailored for drug delivery applications.
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| 3. |
- Kiriakidou-Kazemifar, Nitsa, et al.
(författare)
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Formation of Rhodium Carbonyl Cluster Thiolates with Concomitant H2 evolution
- 2001
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Ingår i: Journal of Organometallic Chemistry. - 0022-328X. ; 623:1-2, s. 65-73
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Tidskriftsartikel (refereegranskat)abstract
- Reaction of [Rh6(CO)15(NCMe)] with p-thiocresol [(4-Me)C6H4SH] leads to the formation of [Rh2(CO)4(μ-SC6H4CH3)2] as the main product along with a small amount of [Rh6(CO)16]. An approximately 30-fold excess of the thiol is required in order to obtain a good yield of the thiolate-bridged dimer while reaction of [Rh4(CO)12] with an excess of p-thiocresol leads to an apparently clean conversion to the dimeric Rh(I) complex. Mass spectrometric measurements show that the latter reaction involves evolution of H2, and CO evolution is indicated by the retardation of the reaction in CO saturated solution; these results suggest the following reaction stoichiometry: [Rh4(CO)12]+4RSH→2[Rh2(CO)4(μ-SR)2]+2H2+4CO. Kinetic measurements show that the reaction proceeds in three stages which are proposed to involve two rapid pre-equilibria and a final irreversible and relatively slow conversion to the products. The crystal and molecular structure of [Rh2(CO)4(μ2-SC6H4CH3)2] is reported.
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| 4. |
- Myllymaa, Katja, et al.
(författare)
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Improved adherence and spreading of Saos-2 cells on polypropylene surfaces achieved by surface texturing and carbon nitride coating.
- 2009
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Ingår i: Journal of materials science. Materials in medicine. - : Springer. - 0957-4530 .- 1573-4838. ; 20:11, s. 2337-2347
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Tidskriftsartikel (refereegranskat)abstract
- The adhesion and contact guidance of human primary osteogenic sarcoma cells (Saos-2) were characterized on smooth, microstructured (MST) and micro- and nano-structured (MNST) polypropylene (PP) and on the same samples with a silicon-doped carbon nitride (C(3)N(4)-Si) coating. Injection molding was used to pattern the PP surfaces and the coating was obtained by using ultra-short pulsed laser deposition (USPLD). Surfaces were characterized using atomic force microscopy and surface energy components were calculated according to the Owens-Wendt model. The results showed C(3)N(4)-Si coated surfaces to be significantly more hydrophilic than uncoated ones. In addition, there were 86% more cells in the smooth C(3)N(4)-Si coated PP compared to smooth uncoated PP and 551%/476% more cells with MST/MNST C(3)N(4)-Si coated PP than could be obtained with MST/MNST uncoated PP. Thus the adhesion, spreading and contact guidance of osteoblast-like cells was effectively improved by combining surface texturing and deposition of osteocompatible C(3)N(4)-Si coating.
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| 5. |
- Prittinen, Juha, 1989-, et al.
(författare)
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Chondrocyte behavior on nanostructured micropillar polypropylene and polystyrene surfaces
- 2014
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Ingår i: Materials Science and Engineering. C, Materials for Biological Applications. - : Elsevier. - 0928-4931. ; 43, s. 424-431
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Tidskriftsartikel (refereegranskat)abstract
- This study was aimed to investigate whether patterned polypropylene (PP) or polystyrene (PS) could enhance the chondrocytes' extracellular matrix (ECM) production and phenotype maintenance. Bovine primary chondrocytes were cultured on smooth PP and PS, as well as on nanostructured micropillar PP (patterned PP) and PS (patterned PS) for 2 weeks. Subsequently, the samples were collected for fluorescein diacetate-based cell viability tests, for immunocytochemical assays of types I and II collagen, actin and vinculin, for scanning electronic microscopic analysis of cell morphology and distribution, and for gene expression assays of Sox9, aggrecan, procollagen α1(II), procollagen α1(X), and procollagen α2(I) using quantitative RT-PCR assays. After two weeks of culture, the bovine primary chondrocytes had attached on both patterned PP and PS, while practically no adhesion was observed on smooth PP. However, the best adhesion of the cells was on smooth PS. The cells, which attached on patterned PP and PS surfaces synthesized types I and II collagen. The chondrocytes' morphology was extended, and an abundant ECM network formed around the attached chondrocytes on both patterned PP and PS. Upon passaging, no significant differences on the chondrocyte-specific gene expression were observed, although the highest expression level of aggrecan was observed on the patterned PS in passage 1 chondrocytes, and the expression level of procollagen α1(II) appeared to decrease in passaged chondrocytes. However, the expressions of procollagen α2(I) were increased in all passaged cell cultures. In conclusion, the bovine primary chondrocytes could be grown on patterned PS and PP surfaces, and they produced extracellular matrix network around the adhered cells. However, neither the patterned PS nor PP could prevent the dedifferentiation of chondrocytes.
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| 6. |
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| 7. |
- Tunik, Sergey, et al.
(författare)
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Reactions of Diacetylene Ligands with Trinuclear Clusters; Cyclization of Diynes with beta-amino moieties on the surface of H2Os3(CO)10
- 2001
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Ingår i: Organometallics. - : American Chemical Society (ACS). - 1520-6041 .- 0276-7333. ; 20:18, s. 3854-3863
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Tidskriftsartikel (refereegranskat)abstract
- Reactions of [H2Os3(CO)10] with the substituted diynes R-C2-C2-R' (1, R = Ph, R' = CH2NHPh; 2, R = Ph, R' = CH2NHCH2Ph; 3, R = R' = CH2NHPh) afford the clusters [HOs3(CO)10(L)] (L = {-1:2-PhCH2C(H)=C-C(H)=C-NPh} (4), {-1:2-PhCH2C(H)=C-C(H)=C-NCH2Ph} (5), and {-1:1-CH3CC=C-C(H)=C(H)-NPh} (6), which have been characterized by single-crystal X-ray diffraction analyses as well as by various spectroscopic methods. In clusters 4-6, the starting diynes 1-3 have been rearranged to form substituted pyrrolyl rings which bridge two osmium atoms in 1:2- (4, 5) or 1:1- (6) coordination modes depending on the nature of substituents in 1-3. A possible reaction pathway for the diyne cyclization reactions that yield 4-6 involves initial transfer of a hydride onto a coordinated diyne followed by a series of 1,3-shifts and subsequent nucleophilic attack of the nitrogen on the third carbon atom of the diyne system to afford the five-membered pyrrolyl ring. Cluster 6 and its previously characterized furanyl analogue [HOs3(CO)10{-1:1-(OCHCHCC)-C-CH3)}] (7) undergo facile thermal transformation accompanied by the loss of a CO ligand to give the clusters [HOs3(CO)9{3,3-CH3CC=C-C(H)=C(H)-NPh}] (8) and [HOs3(CO)9{3,3-(OCH=CHC=CCCH3)}] (9). In both 8 and 9, single-crystal X-ray analysis revealed the presence of pentagonal pyramid cluster cores containing three osmium and three carbon atoms.
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