Search results for "ICAD"

Biostable Scaffolds of Polyacrylate Polymers Implanted in the Articular Cartilage Induce Hyaline-Like Cartilage Regeneration in Rabbits

2017

[EN] Purpose: To study the influence of scaffold properties on the organization of ¿in vivo¿ cartilage regeneration. Our hypothesis is that stress transmission to the cells seeded inside the scaffold pores or surrounding it, which is highly dependent on the scaffold properties, determine differentiation of both mesenchymal cells and dedifferentiated autologous chondrocytes. Methods: Four series of porous scaffolds made of different polyacrylate polymers, previously seeded with cultured rabbit chondrocytes or without cells preseeded, were implanted in cartilage defects in rabbits. Subchondral bone was always injured during the surgery in order to allow blood to reach the implantation site an…

Implantation of a polycaprolactone scaffold with subchondral bone anchoring ameliorates nodules formation and other tissue alterations

2015

Purpose: Articular cartilage has limited repair capacity. Two different implant devices for articular cartilage regeneration were tested in vivo in a sheep model to evaluate the effect of subchondral bone anchoring for tissue repair. Methods: The implants were placed with press-fit technique in a cartilage defect after microfracture surgery in the femoral condyle of the knee joint of the sheep and histologic and mechanical evaluation was done 4.5 months later. The first group consisted of a biodegradable polycaprolactone (PCL) scaffold with double porosity. The second test group consisted of a PCL scaffold attached to a poly(L-lactic acid) (PLLA) pin anchored to the subchondral bone. Result…

Chemistry and reactivity of dinuclear manganese oxamate complexes: Aerobic catechol oxidation catalyzed by high-valent bis(oxo)-bridged dimanganese(I…

2006

[EN] The high-valent bis(oxo)-bridged dimanganese(IV) complexes with the series of binucleating 4.5-X-2-o-phenylenebis(oxamate) ligands (opbaX(2); X = H, Cl, Me) (1a-c) have been synthesized and characterized structurally, spectroscopically and magnetically. Complexes la-c possess unique Mn-2(mu-O)(2) core structures with two o-phenylenediamidate type additional bridges which lead to exceptionally short Mn-Mn distances (2.63-2.65 angstrom) and fairly bent Mn-O-Mn angles (94.1 degrees-94.6 degrees). The cyclovoltammograms of la-c in acetonitrile (25 degrees C, 0.1 M Bu4NPF6) show an irreversible one-electron oxidation peak at moderately high anodic potentials (E-ap = 0.50-0.85 V versus SCE),…

El héroe mediático

2005

Generalized centro-invertible matrices with applications

2014

Centro-invertible matrices are introduced by R.S. Wikramaratna in 2008. For an involutory matrix R, we define the generalized centro-invertible matrices with respect to R to be those matrices A such that RAR = A^−1. We apply these matrices to a problem in modular arithmetic. Specifically, algorithms for image blurring/deblurring are designed by means of generalized centro-invertible matrices. In addition, if R1 and R2 are n × n involutory matrices, then there is a simple bijection between the set of all centro-invertible matrices with respect to R1 and the set with respect to R2.

Structural, magnetic and calorimetric studies of a crystalline phase of the spin crossover compound [Fe(tzpy)2(NCSe)2]

2013

The compound [Fe(tzpy)2(NCSe)2] (tzpy = 3-(2-pyridyl)-[1,2,3]triazolo[1,5-a]pyridine)) has been synthesized and its crystal structure, magnetic behavior and calorimetric properties investigated. Samples constituted of single crystals of [Fe(tzpy)2(NCSe) 2] display a relatively cooperative spin-state change centered at T1/2 ¿ 251.7 K with a hysteresis loop 3.5 K wide. The average enthalpy (¿H) and entropy (¿S) changes upon the spin crossover behavior (SCO) obtained from DSC measurements are 11.1 ± 0.4 kJ mol -1 and 44.5 ± 3 J K-1 mol-1, respectively. The magnetic and calorimetric data have been satisfactorily simulated using the mean-field regular solution model (Slichter-Drickamer) and the …

{[Hg(SCN)3]2(n-L)}2-: An Efficient Secondary Building Unit for the Synthesis of 2D Iron(II) Spin-Crossover Coordination Polymers

2018

[EN] We report an unprecedented series of two-dimensional (2D) spin-crossover (SCO) heterobimetallic coordination polymers generically formulated as {Fe-II[(He(SCN)(3))(2)](L)(x))}center dot Solv, where x = 2 for L = tvp (trans-(4,4'-vinylenedipyridine)) (1tvp), bpmh ((1E,2E)-1,2-bis(pyridin-4-ylmethylene)hydrazine) (1bpmh center dot nCH(3)OH; n = 0, 1), by eh ( (1E,2E)-1,2-bis (1-(pyridin-4-yl) ethyliden e) hydrazine) (Ibpeh center dot nH(2)O; n = 0, 1) and x = 2.33 for L = 0 0 bpbz (1,4-bis(pyridin-4-yl)benzene) (1bpbz center dot nH(2)O; n = 0, 2/ 3). The results confirm that self-assembly of Fell, [Hg-II(SCN)(4)](2-), and ditopic rodlike bridging ligands L containing 4-pyridyl moieties f…

Spin crossover in iron(II) complexes with ferrocene-bearing triazole-pyridine ligands.

2015

In the search for new multifunctional spin crossover molecular materials, here we describe the synthesis, crystal structures and magnetic and photomagnetic properties of the complexes trans-[Fe(Fctzpy)2(NCX)2]·CHCl3 where Fc-tzpy is the ferrocene-appended ligand 4-(2-pyridyl)-1H-1,2,3-triazol- 1-ylferrocene, X = S (1) and X = Se (2). Both complexes display thermal- and light-induced (LIESST) spin crossover properties characterised by T1/2 = 85 and 168 K, ΔS = 55 and 66 J K−1 mol−1 , ΔH = 4.7 and 11.1 kJ mol−1 and TLIESST = 47 K and 39 K for 1 and 2 respectively. The crystal structure of 1 and 2 measured at 275 K is consistent with the iron(II) ion in the high-spin state while the crystal st…

Organocatalytic asymmetric addition of naphthols and electron-rich phenols to isatin-derived ketimines: highly enantioselective construction of tetra…

2015

A quinine-derived thiourea organocatalyst promoted the highly enantioselective addition of naphthols and activated phenols to ketimines derived from isatins. The reaction afforded chiral 3-amino-2-oxindoles with a quaternary stereocenter in high yields (up to 99%) with excellent enantioselectivity (up to 99% ee). To the best of our knowledge, this transformation is the first highly enantioselective addition of naphthols to ketimines

Diastereoselective Michael addition of (S)-mandelic acid enolate to 2-arylidene-1,3-diketones: enantioselective diversity-oriented synthesis of dense…

2006

[EN] A diversity-oriented approach to enantiomerically pure densely substituted pyrazoles, ¿-aryl-¿-pyrazolylatrolactic acid and ¿-aryl-¿-pyrazolylacetophenones has been developed. The approach utilises the conjugated addition of the lithium enolate of the (2S,5S)-cis-1,3-dioxolan-4-one derived from optically active (S)-mandelic acid and pivalaldehyde to several 2-arylidene-1,3-diketones, which proceeds readily to give the corresponding Michael adducts in good yields and diastereoselectivities. The cyclocondensation of the 1,3-diketone moieties present in Michael adducts with several hydrazines leads to enantiomerically pure densely substituted pyrazoles. Subsequent basic hydrolysis of the …