Structure and kinetic studies of U(VI)-benzamidoxime complex in non-aqueous solutions by H- and C-NMR

The structural and kinetic studies of U(VI) complex with benzamidoxime(Hba) as ligand in CD₃COCD₃ have been studied by means of ¹H and ¹³C NMR. The Hba molecule was found to coordinate to UO₂²⁺ in the form of anionic benzamidoximate (ba), and the number of ba coordinated to UO₂²⁺ was determined to be 3 by analyzing the chemical shift of ¹³C NMR signal for Hba in the presence of UO₂²⁺. The exchange rate constants(k_ex) of ba in [UO₂(ba)₃] were determined by the NMR line-broadening method. The kinetic parameters were obtained as follows: k_ex(25°C) = 3.1 × 10³s⁻¹, ΔH^≠ = 35.8 ± 3.5 KJ mol⁻¹, and ΔS^≠ = −65 ± 13.7 J K⁻¹ mol⁻¹. The UV-visible absorption spectra of solutions containing UO₂²⁺ and Hba were also measured. The molar extinction coefficient of the complex was found to be extremely large compared with those of UO₂(L)₅²⁺ (L = unidentate oxygen donor ligands) complexes. This is due to the strong electron withdrawing of UO₂²⁺ from Hba and suggests that an interaction between UO₂²⁺ and Hba is very strong. Such a high affinity of monomeric amidoxime to UO₂²⁺ reasonably explains the high adsorptibility of amidoxime resin to U(VI) species, and is considered to result in the high recovery of U(VI) species from sea water using amidoxime resin.     

Chemokines and inflammatory diseases

Intoxication after ingestion of toad is rare, but it results in severe morbidity and high mortality. Recently, we encountered 2 children, one a 15-month-old boy and one a 20-month-old girl, who were fed cooked toad (Bufo melanostictus) soup. The boy expired of ventricular fibrillation. The girl presented with varying degrees of A-V block with congestive heart failure which, however, was completely resolved after intensive treatment. In our experience, early identification and intervention are necessary to decrease absorption of toxins; to correct hyperkalemia. Dysrhythmia should be treated with atropine, antiarrhythmic agents, and a temporary pacemaker, in order to avoid lethal results.     

Remarkable effect of ordered mesoporous carbon support in tantalum oxide-catalyzed selective epoxidation of cyclooctene

The olefin epoxidation is one of the most important reactions in chemical industry. Metal oxide supports often cause drawbacks in catalytic activity and selectivity, which has been overcome by introducing hydrophobic organic groups onto the oxide supports. The present study utilizes ordered mesoporous carbon (CMK-3 and CMK-1) as structurally defined hydrophobic catalyst support. Well-dispersed tantalum oxides supported on the ordered mesoporous carbon were prepared. Their application in catalytic epoxidation of cyclooctene demonstrates that the tantalum oxide catalysts on the ordered mesoporous carbon supports show higher performances than those of the catalysts supported on activated carbon and ordered mesoporous silica SBA-15.     

The pharmacokinetics of water-in-oil-in-water-type multiple emulsion of a new tacrolimus formulation

We developed a water-in-oil-in-water (W/O/W)-type multiple emulsion of a new tacrolimus formulation. A potential approach to avoid the complications of systemic immunosuppression and simultaneously enhance immunosuppressive efficacy is to deliver immunosuppressive agents locally to the site of the target organs. The W/O/W emulsion is dispersed oil drops containing smaller water droplets that allow the delivery of drugs preferentially to the reticuloendothelial system (RES). Since the liver and the spleen are primary components of the RES, and the brain and the kidney have a poor RES, we hypothesized that a W/O/W emulsion of tacrolimus would prossess the pharmacokinetic benefits of local immunosuppression. We evaluated this hypothesis in a rat model. The tacrolimus levels of whole blood, the liver, spleen, brain, and kidney in rats given intravenous emulsions of tacrolimus (W/O/W group) were compared with a group administered tacrolimus alone (T group). There were no significant differences between the pharmacokinetic parameters of W/O/W group and T group based on whole blood data. However, the W/O/W group had significantly decreased tacrolimus levels in the brain and kidney, and significantly increased levels in the liver and spleen compared with the T group. These data suggest that the W/O/W emulsion is applicable as an intravenous drug carrier for local immunosuppression.     

The effect of salinity on nitrite accumulation in a down‐flow hanging sponge reactor

BACKGROUND: In this study, the inductive effect of salinity on nitrite accumulation in a down‐flow hanging sponge (DHS) reactor, developed as a novel and cost‐effective wastewater treatment process, was evaluated by conducting a long‐term continuous experiment lasting more than 1400 days. RESULTS: The influent salinity was controlled by adding NaCl at concentrations ranging from 0 to 25 g Cl^? L^?1. The effluent nitrite increased with increases in salinity, i.e. the fraction of nitrite to total nitrogen in the effluent increased from 1.6% at 0 g Cl^? L^?1 to 87.6% at 25 g Cl^? L^?1. Fluorescence in situ hybridization (FISH) analysis revealed that as salinity increased, the nitrifying bacterial community in the DHS changed markedly at the species level. In particular, the dominant nitrite‐oxidizing bacteria changed from Nitrospira‐sublineage I at 0 g Cl^? L^?1 to Nitrobacter spp. at 15 g Cl^? L^?1. At 25 g Cl^? L^?1, no nitrite‐oxidizing bacteria were detected. CONCLUSION: Our findings suggest that the DHS reactor is suitable for cost‐effective nitrite production processes and that salinity control using NaCl is an effective method for inducing nitrite accumulation. Copyright © 2012 Society of Chemical Industry     

Growth of High-Quality Pb((Zn1/3Nb2/3)0.91Ti0.09)O3 Single Crystals by Excess ZnO Addition

A high-quality single crystal of Pb((Zn_1/3Nb_2/3)_0.91Ti_0.09)O₃ (PZNT 91/9), 40 mm in diameter and 20 mm in length, was successfully grown using the solution Bridgman method with a slight excess amount of ZnO. High-quality wafers were sliced from the light-brown single crystal. No PbO inclusions or opaque areas were observed in the transparent wafers. An array probe for echocardiography was constructed with the single-crystal wafer, and its superior performance was demonstrated.     

Neuroprotection,Growth Factors and BDNF-TrkB Signalling in Retinal Degeneration

Neurotrophic factors play key roles in the development and survival of neurons. The potent neuroprotective effects of neurotrophic factors, including brain-derived neurotrophic factor (BDNF), ciliary neurotrophic factor (CNTF), glial cell-line derived neurotrophic factor (GDNF) and nerve growth factor (NGF), suggest that they are good therapeutic candidates for neurodegenerative diseases. Glaucoma is a neurodegenerative disease of the eye that causes irreversible blindness. It is characterized by damage to the optic nerve, usually due to high intraocular pressure (IOP), and progressive degeneration of retinal neurons called retinal ganglion cells (RGCs). Current therapy for glaucoma focuses on reduction of IOP, but neuroprotection may also be beneficial. BDNF is a powerful neuroprotective agent especially for RGCs. Exogenous application of BDNF to the retina and increased BDNF expression in retinal neurons using viral vector systems are both effective in protecting RGCs from damage. Furthermore, induction of BDNF expression by agents such as valproic acid has also been beneficial in promoting RGC survival. In this review, we discuss the therapeutic potential of neurotrophic factors in retinal diseases and focus on the differential roles of glial and neuronal TrkB in neuroprotection. We also discuss the role of neurotrophic factors in neuroregeneration.     

Enantioselective addition Of diketene to aldehydes promoted by chiral schiff base—titanium alkoxide complex. Application to asymmetric synthesis of potential inhibitors of HMG coenzyme reductase

Highly enantioselective addition of diketene to aldehydes was achieved by using novel Schiff base—titanium alkoxide complexes. Up to 92% ee of 5-hydroxy-3-oxoesters was obtained. This procedure provides an efficient method for the asymmetric synthesis of potential inhibitors of HMG coenzyme reductase.     

Enantio-differentiating hydrogenation of prochiral ketones over modified nickel

This article reviews the enantio-differentiating hydrogenation of prochiral ketones over a asymmetrically modified catalyst, focusing on the hydrogenation of simple prochiral alkanones. The parameters affecting catalytic activity and enantiodifferentiating ability are considerable in number, and each parameter should be optimized in order to attain a highperformance enantio-differentiating catalyst. Optimization of the parameters and the mode of enantio-differentiation are discussed and compared with the enantio-differentiating hydrogenation of β-ketoesters.