Quick recovery and no arthrofibrosis in acute anterior cruciate ligament reconstruction. A prospective trial of early versus delayed reconstruction

Background. Anterior cruciate ligaments tears is one of the most frequent orthopae- dics and sports medicine injuries in the athletically active population and timing of reconstruction represents a debated topic. The aim of the study is to compare range of motion (ROM) recovery and clinical outcomes between patients operated for acute reconstruction (maximum 2 weeks injury-surgery interval) and delayed reconstruction (minimum 3 weeks injury-surgery interval). Methods. A total of 52 patients were prospectively involved in the study. 26 patients underwent acute reconstruction and 26 delayed reconstruction. A standard physical examination with Lachman and Pivot shift test and a passive ROM measurement with a goniometer were performed at each follow-up (2, 4, 8, 12 and 24 weeks postoper- atively). Clinical outcomes were measured at final follow-up using Knee Injury and Osteoarthritis outcome score (KOOS), Tegner Lysholm Score and International Knee Documentation Committe (IKDC 2000) and KT-1000 evaluation. Single-leg hop test and thigh circumference measurement were performed at final follow-up. Results. Both groups showed no statistically significant differences regarding the ROM. Full ROM was achieved 12 weeks after surgery in both groups. The mean IKDC was 98.7 and 95.2; the mean Tegner Lysholm was 100 and 93.8 and the mean KOOS was 99 and 95.5 in the acute group and delayed ACLR group respectively. Conclusions. There were no differences between acute and delayed anterior cruci- ate ligament reconstruction regarding the risk of arthrofibrosis and clinical outcomes. Acute reconstruction can be performed safely with no increased risk of arthrofibrosis

p-Carborane: a New Cage Spacer for Photoactive Metal Polypyridine Dyads

The first example of a binuclear ruthenium complex involving the p-carborane framework in the bridging ligand is reported. The bridging ligand is a symmetric linear array comprising a central p-carborane unit, two p-phenylene spacers, and two 5-yl-2,2¢- bipyridine coordinating units. A homobinuclear RuII complex, with 2,2¢-bipyridine as peripheral ligands, was synthesized and characterized. The RuII-RuIII mixed-valence species, obtained by partial oxidation, has been investigated with steady-state and time-resolved techniques in CH3CN. The rate of photoinduced electron transfer is 2.3 ´ 108 s-1

Photoinduced Processes in Self-Assembled Porphyrin/Perylene Bisimide Metallosupramolecular Boxes

Two new supramolecular boxes, (ZnMC)2(rPBI)2 and (ZnMC)2(gPBI)2, have been obtained by axial coordination of N,N′-dipyridyl-functionalized perylene bisimide (PBI) dyes to the zinc ion centers of two 2+2 porphyrin metallacycles (ZnMC ) [trans,cis,cis-RuCl2(CO)2(Zn · 4′-cis-DPyP)]2). The two molecular boxes involve PBI pillars with different substituents at the bay area: the “red” PBI (rPBI ) N,N′-di(4-pyridyl)- 1,6,7,12-tetra(4-tert-butylphenoxy)perylene-3,4:9,10-tetracarboxylic acid bisimide) containing tert-butylphenoxy substituents and the “green” PBI (gPBI ) N,N′-di(4-pyridyl)-1,7-bis(pyrrolidin-1-yl)perylene-3,4:9,10- tetracarboxylic acid bisimide) bearing pyrrolidinyl substituents. Due to the rigidity of the modules and the simultaneous formation of four pyridine-zinc bonds, these discrete adducts self-assemble quantitatively and are remarkably stable in dichloromethane solution. The photophysical behavior of the new supramolecular boxes has been studied in dichloromethane by emission spectroscopy and ultrafast absorption techniques. A different photophysical behavior is observed for the two systems. In (ZnMC)2(rPBI)2, efficient electron transfer quenching of both perylene bisimide and zinc porphyrin chromophores is observed, leading to a charge separated state, PBI--Zn+, in which a perylene bisimide unit is reduced and zinc porphyrin is oxidized. In the deactivation of the perylene bisimide localized excited state, an intermediate zwitterionic charge transfer state of type PBI--PBI+ seems to play a relevant role. In (ZnMC)2(gPBI)2, singlet energy transfer from the Zn porphyrin chromophores to the perylene bisimide units occurs with an efficiency of 0.7. This lower than unity value is due to a competing electron transfer quenching, leading to the charge separated state PBI--Zn+. The distinct photophysical behavior of these two supramolecular boxes is interpreted in terms of energy changes occurring upon replacement of the “red” rPBI by “green” gPBI

Photoinduced Electron and Energy Transfer in Rigidly bridged Ru(II)-Rh(III) binuclear complexes

A series of binuclear Ru(II)-Rh(III) complexes of general formula (ttpy)Ru-tpy-(ph)n-tpy-Rh(ttpy)5+ (n ) 0-2) have been synthesized, where ttpy ) 4¢-p-tolyl-2,2¢:6,2¢¢-terpyridine and tpy-(ph)n-tpy represents a bridging ligand where two 2,2¢:6¢,2¢¢-terpyridine units are either directly linked together (n ) 0) or connected through one (n ) 1) or two (n ) 2) phenyl spacers in the 4¢-position. This series of complexes is characterized by (i) rigid bridge structures and (ii) variable metal-metal distances (11 Å for n ) 0, 15.5 Å for n ) 1, 20 Å for n ) 2). The photophysics of these binuclear complexes has been investigated in 4:1 methanol/ethanol at 77 K (rigid glass) and 150 K (fluid solution) and compared with that of mononuclear [Ru(ttpy)2 2+ and Rh(ttpy)2 3+] or binuclear [(ttpy)Ru-tpy-tpy-Ru(ttpy)4+] model compounds. At 77 K, no quenching of the Ru(II)-based excited state is observed, whereas energy transfer from excited Rh(III) to Ru(II) is observed for all complexes. At 150 K, energy transfer from excited Rh(III) to Ru(II) is again observed for all complexes, while quenching of excited Ru(II) by electron transfer to Rh(III) is observed, but only in the complex with n ) 0. The reasons for the observed behavior can be qualitatively understood in terms of standard electron and energy transfer theory. The different behavior between n ) 0 and n ) 1, 2 can be rationalized in terms of better electronic factors and smaller reorganizational energies for the former species. The freezing of electron transfer quenching but not of energy transfer, in rigid glasses reflects the different reorganizational energies involved in the two processes. Unusual results arising from multiphotonic and conformational effects have also been observed with these systems

Photoinduced Electron Transfer in Ru(II)-Rh(III) Terpyridine Dyads

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