Wound drainage after proximal femoral nail antirotation (PFNA) fixation may negatively affect the patients with intertrochanteric fractures: A prospective randomized controlled trial.

INTRODUCTION: The effect of using closed suction drainage system with the proximal femoral nail antirotation (PFNA) system fixation on outcomes in treating intertrochanteric fractures (ITFs) is still unknown. This prospective randomized controlled trial aimed to examine whether routine drainage is useful for PFNA fixation in ITFs. METHODS: A total of 80 patients with acute ITFs were treated with closed or mini-open reduction with PFNA fixation at the National Cheng Kung University Hospital and 60 eligible patients were randomized for whether to receive suction drainage. In clinical outcomes, the visual analog scale (VAS), morphine equivalent dosage, injured thigh width, body temperature, wound condition and wound infection were measured on postoperative day 1, 2, 4, 10, and 90. In laboratory outcomes, we evaluated hemoglobin and hematocrit levels postoperatively at different time points. Blood transfusion and total blood loss (TBL) were measured by Mercuriali's formula in millimeter. RESULTS: The results revealed that the amount of blood transfusion received by the drained group (543.3 mL) was more than that by the undrained group (367.8 mL; p = 0.0074), and similarly, TBL in the drained group (750.1 mL) was more than that in the undrained group (537.4 mL; p = 0.0067). Regarding clinical and laboratory outcomes, compared with the undrained group, the drained group had a higher VAS score on postoperative day 2 (p = 0.0216). No difference was observed between the 2 groups for morphine equivalent dosage, thigh swelling, wound infection and hematoma, hospitalization period, or total number of complications at every time point after index procedure. CONCLUSIONS: Blood transfusion requirement and TBL were higher in the drained group than in the undrained group of PFNA fixation for ITFs. In addition, the closed drainage system may have manifested no short-term benefit for wound condition postoperatively.

Synthesis and Characterization of N,N,O-Tridentate Aminophenolate Zinc Complexes and Their Catalysis in the Ring-Opening Polymerization of Lactides.

A series of aminophenolate ligands with various pendant groups and associated ethyl Zn complexes were synthesized and studied as catalysts for the ring-opening polymerization (ROP) of lactides (LAs). The thiophenylmethyl group (L 4 ZnEt) increased the catalytic activity more than the benzyl group (L 1 ZnEt) did, and 2-fluorobenzyl (L 3 ZnEt) and 2-methoxybenzyl (L 2 ZnEt) groups had the opposite effect. In addition, the LA polymerization mechanism proved by Nuclear Magnetic Resonance and Density Function Theory was that LA was attracted by H···O bond of an α-hydrogen of the LA molecule and the phenoxyl oxygen of the catalyst. After the dissociation of amino group from the Zn atom, the benzyl alcohol initiated LA without replacing the ethyl group of Zn complex. It is the first case where the ethyl group is regarded as a ligand and cannot be replaced by benzyl alcohol, and this information is very important for the mechanism study of ROP.

Enhanced Catalytic Activity of Aluminum Complexes for the Ring-Opening Polymerization of ε-Caprolactone.

A series of dinuclear aluminum (Al2Pyr2) complexes bridged by two pyrazole ligands were synthesized, and their catalytic activity toward ring-opening polymerization of ε-caprolactone (CL) was investigated. Different types of the Al-N-N-Al-N-N skeletal ring were found among these Al2Pyr2 complexes. The butterfly form, LThio2Al2Me4, exerted the highest catalytic activity for CL polymerization. κ2-CL coordination with both Al centers within the butterfly form LThio2Al2Me4 facilitates the initiation process. Generally speaking, the Al2Pyr2 complexes exhibited substantially higher catalytic activity for CL polymerization than literature examples such as ß-diketiminate- or traiaza-bearing aluminum complexes. In fact, the Al2Pyr2 complexes can even carry out CL polymerization at room temperature.

Synthesis of Sodium Complexes Supported with NNO-Tridentate Schiff Base Ligands and Their Applications in the Ring-Opening Polymerization of L-Lactide.

A series of sodium complexes bearing NNO-tridentate Schiff base ligands with an N-pendant arm were synthesized and used as catalysts for the ring-opening polymerization of L-lactide (L-LA). Electronic effects of ancillary ligands coordinated by sodium complexes substantially influence the catalysis, and ligands with electron-donating groups increase the catalytic activity of the sodium complexes for catalyzing L-LA polymerization. In particular, a sodium complex bearing a 4-methoxy group has the highest activity with conversion up to 95% within 30 s at 0 °C and a low polydispersity index of 1.13, whereas the 4-bromo group showed the poorest performance with regard to the catalytic rate of L-LA polymerization in the presence of benzyl alcohol (BnOH). (1)H NMR pulsed-gradient spin-echo diffusion experiments and single-crystal X-ray analyses showed that sodium complexes [L(H)Na(THF)]2 and [L(4-Cl)Na(THF)]2 were dinuclear species in both solution and the solid state. The kinetic results indicated a first-order dependence on each of [[L(4-Cl)Na]2], [l-LA], and [BnOH].

Improvement in Titanium Complexes Bearing Schiff Base Ligands in the Ring-Opening Polymerization of L-Lactide: A Dinuclear System with Hydrazine-Bridging Schiff Base Ligands.

A series of titanium (Ti) complexes bearing hydrazine-bridging Schiff base ligands were synthesized and investigated as catalysts for the ring-opening polymerization (ROP) of L-lactide (LA). Complexes with electron withdrawing or steric bulky groups reduced the catalytic activity. In addition, the steric bulky substituent on the imine groups reduced the space around the Ti atom and then reduced LA coordination with Ti atom, thereby reducing catalytic activity. All the dinuclear Ti complexes exhibited higher catalytic activity (approximately 10-60-fold) than mononuclear L(Cl-H)-TiOPr2 did. The strategy of bridging dinuclear Ti complexes with isopropoxide groups in the ROP of LA was successful, and adjusting the crowded heptacoordinated transition state by the bridging isopropoxide groups may be the key to our successful strategy.

Comparative Study of Aluminum Complexes Bearing N,O- and N,S-Schiff Base in Ring-Opening Polymerization of ε-Caprolactone and L-Lactide.

A series of Al complexes bearing Schiff base and thio-Schiff base ligands were synthesized, and their application for the ring-opening polymerization of ε-caprolactone (CL) and l-lactide (LA) was studied. It was found that steric effects of the ligands caused higher polymerization rate and most importantly the Al complexes with N,S-Schiff base showed significantly higher polymerization rate than Al complexes with N,O-Schiff base (5-12-fold for CL polymerization and 2-7-fold for LA polymerization). The reaction mechanism of CL polymerization was investigated by density functional theory (DFT). The calculations predicted a lower activation energy for a process involved with an Al complex bearing an N,S-Schiff base ligand (17.6 kcal/mol) than for that of an Al complex bearing an N,O-Schiff base ligand (19.0 kcal/mol), and this magnitude of activation energy reduction is comparable to the magnitude of rate enhancement observed in the experiment. The reduction of activation energy was attributed to the catalyst-substrate destabilization effect. Using a sulfur-containing ligand to decrease the activation energy in the ring-opening polymerization process may be a new strategy to design a new Al complex with high catalytic activity.

A closer look at ε-caprolactone polymerization catalyzed by alkyl aluminum complexes: the effect of induction period on overall catalytic activity.

Previous studies on the ring-opening polymerization of ε-caprolactone using structurally related aluminum complexes as pre-catalysts showed inconsistent trends in the total conversion time. We propose that an induction period for Al complexes for conversion to real catalytic species, Al alkoxide, should be considered because the total conversion time consists of both an induction period and polymer propagation time. Herein, the polymerization rate of a series of Al complexes bearing ketimine ligands was investigated. The catalytic results indicated complexes with more steric hindrance with an electron-withdrawing group on the ligands, or the fact that less chelating ligands demonstrated greater propagation activity. The opposite trend for these structural effects was observed on the measurement of induction periods. These features on ligands of aluminum complexes are responsible for facilitating the conversion process to Al alkoxides. The overall catalytic performance should consider both the induction period and the propagation time.

Synthesis, characterization and catalytic activity of lithium and sodium iminophenoxide complexes towards ring-opening polymerization of L-lactide.

A series of lithium and sodium iminophenoxide complexes have been successfully synthesized and characterized by X-ray crystallography and investigated as catalysts for the ring opening polymerization of L-lactide. The nature and steric bulk of the ligands coordinated to the central metal ions greatly influence the catalytic properties. Complexes with bidenate ligands exhibit higher catalytic activity than tridentate counterparts because the third coordination atom contends with L-lactide, which decreases activity. Oxygen is the third atom in the tridentate ligand, providing stronger chelation ability with Li and Na than nitrogen or sulfur and occupies the space with which L-lactide is coordinated.

Tris(1,2-dimeth-oxy-ethane-κO,O')iodidocalcium iodide.

In the title complex, [CaI(C(4)H(10)O(2))(3)]I, the Ca(II) atom is seven-coordinated by six O atoms from three 1,2-dimeth-oxy-ethane (DME) ligands and one iodide anion in a distorted penta-gonal-bipyramidal geometry. The I atom and one of the O atoms from a DME ligand lie in the axial positions while the other O atoms lie in the basal plane. The other iodide anion is outside the complex cation.

Control of foodborne pathogens on ready-to-eat roast beef slurry by epsilon-polylysine.

This study evaluates the antimicrobial effectiveness of epsilon-polylysine against Escherichia coli O157:H7, Salmonella typhimurium and Listeria monocytogenes in laboratory media and roast beef slurry. epsilon-Polylysine supplemented laboratory media and roast beef slurry were inoculated with three-strain cocktails of each pathogen and survival was periodically monitored using conventional spread plating. Inoculated laboratory media was stored at room temperature (22 degrees C) for 48 h, and inoculated roast beef slurry was stored at 4 degrees C for up to 7 days. Maximum log reductions in laboratory media/roast beef slurry were 6.01+/-1.43/3.81+/-0.37, >7.82+/-0.05/5.23+/-0.08, and 4.58+/-0.86/5.83+/-0.48 for E. coli O157:H7, S. typhimurium, and L. monocytogenes, respectively. Injured cells were produced as a result of exposure to polylysine. This study confirms the effectiveness of polylysine against pathogens in laboratory media, and demonstrates its potential as a novel antimicrobial agent in complex food matrix such as roast beef.