A novel photoreactive amphiphile of nitrophenylazide for immobilization of bioactive proteins

Monolayers of an amphiphilic nitrophenylazide (ANPA) derivative were prepared and their ability to immobilize a protein molecule by a photochemical binding reaction was demonstrated as a novel means to constitute a biofunctional membrane. Molecular orientations and photoreactions in the ANPA monolayers were investigated by Fourier transform IR spectroscopy. Rapid photolysis of ANPA was observed which reflects decomposition of the azide group to a reactive nitrene radical intermediate. As an enzyme, glucose oxidase (GOD) was immobilized on a monomolecular film of ANPA, coated on a substrate, by means of enzyme adsorption at the solid-solution interface and subsequent photolysis of ANPA. Radioisotope labelling experiments revealed that the enzyme was immobilized at a high surface concentration which corresponds to a closely packed monolayer of GOD. The specific activity of the immobilized enzyme was estimated to be high compared with those of other systems involving the adsorption of this enzyme. The usefulness of the present technique for fabricating biofunctional monolayer assemblies is discussed.     

A new recovery process of carbon dioxide from alkaline carbonate solution via electrodialysis

Bipolar membrane electrodialysis is applied to CO₂ recovery from alkaline carbonate solution. CO₂ in flue gas is captured by an alkaline hydroxide absorbing solution to form an alkaline carbonate solution. The captured CO₂ is recovered from the alkaline carbonate solution via bipolar membrane electrodialysis, and the alkaline solution is regenerated simultaneously. To reduce the power requirement for CO₂ recovery, this study considers optimal design and operation. Three membrane arrangements were compared, and the results indicate the membrane arrangement comprising a bipolar membrane and cation exchange membrane is the most energy saving. With further optimization of operation conditions, the minimum power requirement for CO₂ recovery was reduced to 2.1 MJ/kg‐CO₂ (or 2.1 GJ/t‐CO₂). © 2009 American Institute of Chemical Engineers AIChE J, 2009     

Study on environmental effect on fatigue and creep-fatigue strength of 316FR stainless steel in sodium at elevated temperature

Low-carbon 316 stainless steel with medium-nitrogen (316FR) is considered as the principal structural material for next generation fast breeder reactor (FBR) plants in Japan. The material strength standard and the creep-fatigue life evaluation method for 316FR have been developed. However, they are based on the results of material tests in air, while actual structural material will be used mainly in liquid sodium environment in the plants. In order to clarify the environmental effect, cyclic bending tests were carried out with and without hold time in sodium. Tested materials were 316FR and conventional 304 and 316 stainless steels. Weld metal of 316FR was also tested. As a result, it was found that fatigue and creep-fatigue lives of 316FR in sodium were larger than those in air and no explicit consideration of the environmental effect is necessary in design. It was also found that the life evaluation method based on the ductility exhaustion concept is applicable to creep-fatigue life assessment in sodium.     

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.     

Severe myoclonic epilepsy in infancy: evolution of seizures

Demonstration of the full extent of abnormality in patients with the Struge-Weber syndrome (SWS) is important for prognosis and in planning surgery to remove the seizure focus. We compared single-photon emission computed tomography (SPECT), MRI and CT in nine children under the age of 4 years with seizures as part of SWS, in an attempt to determine the optimal method of imaging in different clinical settings. Seven unilateral and two bilateral cases were studied by interictal 99mtechnetium hexamethylpropyleneamineoxime (HMPAO) SPECT, and contrast-enhanced CT and MRI, giving information on 11 abnormal hemispheres. All imaging modalities showed abnormalities in every child. Perfusion imaging showed focal regions of decreased uptake in 9 of 11 (82%) abnormal hemispheres and demonstrated a widespread decrease but no focal defect in 2; it also revealed crossed cerebellar diaschisis in 2 cases. CT demonstrated typical gyriform calcification in 9 of 11 (82%) affected hemispheres. Contrast-enhanced MRI showed more extensive involvement than contrast-enhanced CT in 5 of 11 (45%) cases. The area of hypoperfusion shown by SPECT was smaller than the area of contrast enhancement on MRI in 6 of 11 cases (55%), comparable in 3 (27%) and larger in 2 cases (18%). CT is sufficient to confirm the clinical diagnosis of SWS, but MRI frequently shows more extensive abnormal areas. 99mTc HMPAO imaging is a useful addition when it is important to know the full extent of the disease, for example prior to surgery. It is likely to detect areas of hypoperfusion, representing ischaemic regions, which may act as an epileptogenic focus and may not be shown by CT or MRI.     

Surface pressure and wind load characteristics on prisms immersed in a simulated transient gust front flow field

Thunderstorm generated gust fronts are responsible for various degrees of structural damage in many areas of the world. However, the resulting impact of gust front winds is not fully understood to such a level that their flow kinematics, dynamics and impact on structures can be quantified with some certainty. Gust front winds are transient in nature and have a flow profile which differs significantly from a typical boundary layer flow field. This study focuses on investigating the effects of this flow profile and its transient nature on the aerodynamics of bluff, prismatic bodies. A gust front type flow field is generated using a multiple fan wind tunnel and the resulting surface pressures are captured on a suite of prismatic models, which vary in size in relationship to the oncoming wind profile. The temporal variations in surface pressures are analyzed using traditional time, frequency and time-frequency domain schemes. Results indicate the changing nature of the surface pressure field in time, highlighting both qualitative and quantitative differences between local and area-averaged pressures under a host of flow profiles.     

Evaluation of hexabromocyclododecane in fish and marine mammal oil supplements

We analyzed the dietary fish and marine mammal oil supplements purchased from Japanese markets for hexabromocyclododecane (HBCD); 20 brands were analyzed by liquid chromatography–tandem mass spectrometry (LC/MS/MS). HBCD was detected in 15 of 22 samples, and the concentrations of all the HBCD isomers (α, β, and γ) ranged from <0.9 to 67 ng/g lipid weight. α-HBCD was the dominant residue among the HBCD isomers. However, the composition of HBCD isomers varied according to the sample type. We found that 1 sardine oil brand and 2 shark liver oil brands extracted from fish captured in seawater around Japan contained relatively high levels of HBCD, indicating that both the surface and deep seawaters around Japan may have been contaminated with HBCD.