Lithium, sodium, potassium and calcium amine-bis(phenolate) complexes in the ring-opening polymerization of rac-lactide.

Compounds of Li, Na, K and Ca of a tetradentate amino-bis(phenolato) ligand were prepared. Bimetallic compounds formulated as M[L](THF) (where M = Na, n = 1 (1·THF) or Li, n = 1 (2·THF)) were synthesized via the reaction of H[L] (where [L] = 2-pyridylmethylamino-N,N-bis(2-methylene-4-methoxy-6-tert-butylphenolato) with sodium hydride or n-butyllithium, respectively, in THF. Monometallic complexes MH[L](THF) (where M = Na, n = 1 (3·THF), Li, n = 0 (4) and K, n = 0 (5)) were obtained by reaction of H[L] with MN(SiMe) where M = Na, Li, or K.

Accelerated Stress Test Method for the Assessment of Membrane Lifetime in Vanadium Redox Flow Batteries.

An accelerated stress test (AST) method was developed to estimate the lifetime of ion-exchange membranes in a vanadium redox flow battery. The oxidative VO ions present in the charged positive electrolyte are the predominant stressor causing loss of functional groups and membrane conductivity. Membrane aging was accelerated in ex situ tests by exploiting elevated temperatures and the increased oxidative strength of Ce.

Tackling Capacity Fading in Vanadium Redox Flow Batteries with Amphoteric Polybenzimidazole/Nafion Bilayer Membranes.

Vanadium flow batteries are among the most promising technologies for stationary energy storage applications if their cost of storage can be further decreased. Capacity fading resulting from imbalanced vanadium crossover is a key operating cost component. Herein, a new approach is reported to avoid this cost by balancing electrolyte transport with amphoteric bilayer Nafion/meta-polybenzimidazole membranes.

Revealing the role of phosphoric acid in all-vanadium redox flow batteries with DFT calculations and in situ analysis.

The present work suggests the use of a mixed water-based electrolyte containing sulfuric and phosphoric acid for both negative and positive electrolytes of a vanadium redox flow battery. Computational and experimental investigations reveal insights on the possible interactions between the vanadium ions in all oxidation states and sulphate, bisulphate, dihydrogen phosphate ions and phosphoric acid. In situ cycling experiments and ion-specific electrochemical impedance measurements confirmed a significant lowering of the charge-transfer resistance for the reduction of V(iii) ions and, consequently, an increase of the voltaic efficiency associated with the negative side of the battery.

Reaction of a polydentate cysteine-based ligand and its nickel(ii) complex with electrophilic and nucleophilic methyl-transfer reagents - from S-methylation to acetyl coenzyme A synthase reactivity.

The L-cysteine derived N2S2 ligand precursor H2L and its nickel(ii) complex L2Ni2 were investigated with respect to their behaviour in contact with electrophilic and nucleophilic methylation reagents (H2L = (N,N'-dimethyl-(2R,5R)-bis-(sulfanylmethyl)-piperazine). Treatment of deprotonated L(2-) with MeI led to the selective methylation of the thiolate groups thus generating a novel potential ligand, Me2L, which is neutral and contains two thioether donors. The coordinating properties of Me2L were demonstrated by the synthesis of a first nickel(ii) complex: reaction with NiBr2 led to a mononuclear complex 2 where all donor atoms coordinate to the nickel ion, which completes its octahedral coordination sphere by the two bromide ligands.

A structural and functional model for the 1-aminocyclopropane-1-carboxylic acid oxidase.

The hitherto most realistic low-molecular-weight analogue for the 1-aminocyclopropane-1-carboxylic acid oxidase (ACCO) is reported. The ACCOs 2-His-1-carboxylate iron(II) active site was mimicked by a TpFe moiety, to which the natural substrate ACC could be bound. The resulting complex [Tp(Me,Ph) FeACC] (1), according to X-ray diffraction analysis performed for the nickel analogue, represents an excellent structural model, featuring ACC coordinated in a bidentate fashion-as proposed for the enzymatic substrate complex-as well as a vacant coordination site that forms the basis for the first successful replication also of the ACCO function: 1 is the first known ACC complex that reacts with O2 to produce ethylene.

Simultaneous ipsilateral avulsion of the anterior superior and anterior inferior iliac spines in an adolescent.

Background: Only one case of simultaneous avulsion fractures of the anterior superior and anterior inferior iliac spines has been previously reported. This was associated with a hip dislocation.

Methods: A 16-year-old male adolescent sustained ipsilateral avulsion fractures of his superior and inferior iliac spines from a hyperextension injury of his right hip in a skiing accident.

A bridging demineralized bone implant facilitates posterolateral lumbar fusion in New Zealand white rabbits.

Study Design: Randomized controlled animal study.

Objective: Test the effectiveness of a single-strip demineralized bone matrix with hyaluronan and gelatin.

Summary Of Background Data: Demineralized bone matrix is widely used to augment spinal fusion, however, the effect of changing the physical characteristic and carrier is not known.

Treatment of patients hospitalized for exacerbations of chronic obstructive pulmonary disease: comparison of an oral/metered-dose inhaler regimen and an intravenous/nebulizer regimen.

Objective: Compare the therapeutic efficacy of an oral/metered-dose inhaler (oral/MDI) regimen to an intravenous/nebulizer (I.V./neb) regimen of methylprednisolone, cefuroxime, and inhaled albuterol and ipratropium bromide in patients hospitalized for exacerbations of chronic obstructive pulmonary disease (COPD).

Efficacy of a vibratory stimulus for the relief of HIV-associated neuropathic pain.

Pain related to HIV disease is frequently debilitating. Of the many pain syndromes that occur in persons with HIV, distal symmetrical polyneuropathy (DSPN) is particularly devastating. Because DSPN often responds, at best, only partially to available pharmacologic interventions, non-pharmacologic interventions need to be investigated.

Respiratory failure and cor pulmonale associated with tracheal mucoid accumulation from a SCOOP transtracheal oxygen catheter.

Transtracheal oxygen (TTO) delivery for patients with chronic hypoxemia has been used increasingly since its introduction in 1982. Most complications have been relatively minor and usually occur in conjunction with catheter placement. This report describes two patients with long-term catheter use who developed increasing respiratory failure and cor pulmonale, at least in part, due to a large tracheal mucus plug.

Transbronchial needle aspiration in clinical practice. A five-year experience.

We conducted a five-year review of our use of TBNA during bronchoscopy in our clinical practice. Out of 1,630 bronchoscopic procedures, 633 patients (39 percent) had TBNA performed as part of the initial examination. Mediastinal nodes were sampled in 86 percent of the patients who had TBNA performed, and 127 (23 percent) of 547 of these aspirates were positive.

Transbronchial needle aspiration in clinical practice.

Transbronchial needle aspiration has recently been adapted for use with the flexible bronchoscope. We studied 108 patients, who had a total of 110 aspirations performed, and diagnosed thoracic cancer in 70 cases. Transbronchial needle aspiration revealed malignant disease in 32 (46%) of these 70 patients.

The preferential deposition of inhaled isoproterenol and propranolol in asthmatic patients.

This study describes the use of central and diffuse airway deposition patterns of isoproterenol and radiotracer aerosol alone, and in the presence of centrally deposited propranolol and radiotracer aerosol, to investigate the distribution of beta 2 adrenoreceptors in six asthmatic patients. The central deposition technique was only partially successful. No definite beta 2 receptor distribution pattern could be interpreted from the airway function responses.

Effects of postural drainage, exercise, and cough on mucus clearance in chronic bronchitis.

The effects of postural drainage, exercise, and cough on mucus clearance were compared in 8 patients with chronic bronchitis. A bolus of 99mTc albumin aerosol was inhaled at a high inspiratory flow rate to enhance proximal deposition. Retention of deposited aerosol in the lung, as a function of time, was quantified using a gamma camera and subsequent computer analysis.

A comparison of exercise responses in stairclimbing and cycling.

A free-paced 14.8-m stairclimb was compared to cycle ergometry at equivalent power outputs in six normal subjects. Heart rate (HR), inspiratory flow (VI) andd oxygen saturation in arterial blood (Sao2) were analyzed continuously, carbon dioxide output (Vco2) and oxygen consumption (Vo2) for the duration of exercise, and rebreathing mixed venous carbon dioxide pressure (Pvco2), capillary blood gases, and lactates at the completion of exercise.

Thoracoscopy. A safe, accurate diagnostic procedure using the rigid thoracoscope and local anesthesia.

A thoracoscopic examination was performed in 41 patients under local anesthesia in the lateral decubitus position. Prior thoracocentesis (38 patients) and blind biopsy with an Abrams' needle (32 patients) had been nondiagnostic. The initial nine patients were examined with the flexible fiberoptic bronchoscope, yielding a diagnostic accuracy of 56 percent (five cases).

Cerebral dye embolus: a complication of selective bronchography following transbronchial biopsy.

Cerebral embolization of an aqueous solution of propyliodone (Dionosil) occurred during selective bronchographic studies following a fiberoptic bronchoscopic procedure with transbronchial biopsy in a patient undergoing investigation of a pulmonary lesion. The embolization resulted in a grand mal seizure and transient neurologic deficits. This potential complication has not been previously reported.