Photoresponsive liquid membrane transport of alkali metal ions using crowned spirobenzopyrans

Several azacrown ether derivatives, which are monoaza-12-crown-4, -15-crown-5, and -18-crown-6 and diaza-12-crown-4 and -18-crown-6, bearing one or two spirobenzopyran(s), which we call crowned spirobenzopyran or crowned bis(spirobenzopyran), were synthesized and were used as carriers for liquid membrane transport of alkali metal ions. The passive alkali metal transports through liquid membranes containing crowned spirobenzopyrans were carried out under dark, and UV- and visible-light irradiation conditions. The metal ion transport was accelerated and retarded by UV- and visible-light irradiation, respectively. On the other hand, the photoresponse of the metal ion selectivity in membrane transport by crowned spirobenzopyrans was different, depending on the kind of crown ether units. Especially, diaza-12-crown-4-bis(spirobenzopyran) exhibited an excellently selective and effective transporting ability for Li(+). The uphill transports of Li(+) through a liquid membrane containing monoaza-12-crown-4-spirobenzopyran or diaza-12-crown-4-bis(spirobenzopyran) were realized under the conditions where the same aqueous solution was used as the source and receiving phases with UV and visible lights being irradiated onto the boundary phases between the source and membrane phases and between the receiving and membrane phases, respectively. The uphill transport of Li(+) from the source to receiving phases through a liquid membrane containing a crowned spirobenzopyran was also attained by the proton-concentration gradient between the source and receiving phases under dark conditions, and the transporting ability was remarkably increased by photoirradiation.     

Extraction of a plasma time-activity curve from dynamic brain PET images based on independent component analysis

A compartment model has been used for kinetic analysis of dynamic positron emission tomography (PET) data [e.g., 2-deoxy-2-18F-fluoro-D-glucose (FDG)]. The input function of the model [the plasma time-activity curve (pTAC)] was obtained by serial arterial blood sampling. It is of clinical interest to develop a method for PET studies that estimates the pTAC without needing serial arterial blood sampling. For this purpose, we propose a new method to extract the pTAC from the dynamic brain PET images using a modified independent component analysis [extraction of the pTAC using independent component analysis (EPICA). Source codes of EPICA are freely available at http://www5f.biglobe.ne.jp/?kimura/Software/top.html]. EPICA performs the appropriate preprocessing and independent component analysis (ICA) using an objective function that takes the various properties of the pTAC into account. After validation of EPICA by computer simulation, EPICA was applied to human brain FDG-PET studies. The results imply that the EPICA-estimated pTAC was similar to the actual measured pTAC, and that the estimated blood volume image was highly correlated with the blood volume image measured using 15O-CO inhalation. These results demonstrated that EPICA is useful for extracting the pTAC from dynamic PET images without the necessity of serial arterial blood sampling.     

Digital copy milling—autonomous milling process control without an NC program

Conventional NC machine tools do not generally allow the change of cutting conditions such as depth of cut and stepover during machining operations, once they are given machining commands as NC programs. For that reason, the NC programs must be prepared adequately and verified in advance, which requires extensive time and effort. It is therefore necessary to develop functions to generate the cutter path autonomously and control the cutting conditions adaptively during machining to optimize the cutting process, maintain stable cutting, and avoid cutting trouble. This paper proposes a new architecture to realize autonomous control of the cutting process without using NC programs. A technique called digital copy milling is developed to control the NC machine tool in real time. The digital copy milling system can generate tool paths in real time, based on the principle of copy milling. In addition, a new control strategy is developed to control the cutting conditions adaptively. A prototype of an autonomous controller was implemented in a three-axis control machining center. Thereafter, experimental milling tests were carried out to verify the effectiveness of the proposed system. The cutter paths were generated autonomously by the digital copy milling system. Results show that the cutting depth and stepover can be changed during milling tests. Cutting conditions were controlled adaptively.     

In situ observation of freeze-fractured and deep-etched red blood cells with a high-vacuum low-temperature atomic force microscope

A high-vacuum low-temperature atomic force microscope (AFM) for the direct observation of freeze-fracture samples has been developed. This AFM has a freeze-fracture mechanism inside the vacuum chamber. With this AFM it is possible to observe the fractured surface directly without both fabricating a replica and exposure to the ambient atmosphere. Both sandwich and knife fracture methods have been achieved to obtain freeze-fracture surfaces and after deep etching. A fine structure of the fractured red blood cell membrane has been observed using both methods. These are relatively quick and easy methods for the observation of freeze-fracture surfaces without introducing replica artifacts.     

Nitric Oxide and Reactive Oxygen Species in the Pathogenesis of Preeclampsia

Preeclampsia (PE) is characterized by disturbed extravillous trophoblast migration toward uterine spiral arteries leading to increased uteroplacental vascular resistance and by vascular dysfunction resulting in reduced systemic vasodilatory properties. Its pathogenesis is mediated by an altered bioavailability of nitric oxide (NO) and tissue damage caused by increased levels of reactive oxygen species (ROS). Furthermore, superoxide (O₂⁻) rapidly inactivates NO and forms peroxynitrite (ONOO⁻). It is known that ONOO⁻ accumulates in the placental tissues and injures the placental function in PE. In addition, ROS could stimulate platelet adhesion and aggregation leading to intravascular coagulopathy. ROS-induced coagulopathy causes placental infarction and impairs the uteroplacental blood flow in PE. The disorders could lead to the reduction of oxygen and nutrients required for normal fetal development resulting in fetal growth restriction. On the other hand, several antioxidants scavenge ROS and protect tissues against oxidative damage. Placental antioxidants including catalase, superoxide dismutase (SOD), and glutathione peroxidase (GPx) protect the vasculature from ROS and maintain the vascular function. However, placental ischemia in PE decreases the antioxidant activity resulting in further elevated oxidative stress, which leads to the appearance of the pathological conditions of PE including hypertension and proteinuria. Oxidative stress is defined as an imbalance between ROS and antioxidant activity. This review provides new insights about roles of oxidative stress in the pathophysiology of PE.     

Effect of carbon fibres on the static and fatigue mechanical properties of fibre metal laminates

It is crucial to understand the characteristic fatigue crack initiation and its growth mechanisms, as well as the relationship between the mechanical properties and the fatigue damage evolution in fibre metal laminates (FMLs). Two types of FML were studied in this work: a polyacrylonitrile‐based carbon fibre epoxy matrix composite sandwiched by Ti‐6Al‐4V (Ti‐alloy) sheets (IMS60‐Ti) and a pitch‐based carbon fibre epoxy matrix composite sandwiched by Ti‐alloy sheets (K13D‐Ti). The static and fatigue mechanical properties of IMS60‐Ti and K13D‐Ti were investigated. The increased failure strain of the FML was greater than that of carbon fibre‐reinforced polymer (CFRP) matrix composites. The fatigue life of IMS60‐Ti was much longer than that of K13D‐Ti. The fatigue damage process in IMS60‐Ti was related to the fatigue creep behaviour of the Ti‐alloy face sheet and mode II cracking at the CFRP/Ti‐alloy interface, and the damage in K13D‐Ti was related to the K13D CFRP laminate.     

Promoting Effect of Pt on Self-activation over NiO–MgO Solid Solution in Oxidative Steam Reforming of Methane

The addition of Pt on NiO–MgO solid solution enhanced the performance of oxidative steam reforming of methane, especially, the catalyst can be activated during the oxidative reforming of methane at low reaction temperature like 823 K. 0.1% Pt/Ni_0.2Mg_0.8O exhibited much higher performance than 0.1% Pt/MgO and Ni_0.2Mg_0.8O. From the comparisons, the additive effect of Pt to Ni_0.2Mg_0.8O is to promote both the activity of combustion and reforming of methane. This additive effect can be explained by the high combustion activity caused by the synergy of Pt with NiO–MgO solid solution and the high catalyst reducibility.     

Natural denitrification in the Kakamigahara groundwater basin,Gifu prefecture,central Japan

Although nitrate is recognized as the most common groundwater contaminant due to growing anthropogenic sources, such as agriculture in particular, its adverse effects on human and animal health are debatable. The current issue, however, is to control and reduce nitrate contamination with regards to the long residence time of groundwater within aquifers. Denitrification has recently been recognized for its ability to reduce high nitrate concentrations in groundwater. The Kakamigahara groundwater basin, Gifu prefecture, Japan, witnessed rising levels of nitrate (>12 mg/l NO(3)-N) originating from agricultural sources. Chemical analyses for the determination of major constituents of groundwater and delta(15)N of residual nitrate were performed on representative groundwater samples in order to fulfill two main objectives. One is to investigate the current situation of nitrate groundwater pollution. The second objective is to determine whether the denitrification is a potential natural mechanism, which eliminates nitrate pollution in the Kakamigahara aquifer. Agricultural nitrate contamination of groundwater was obvious from characteristically high concentrations of Ca(2+), Mg(2+), NO(3)(-) and SO(4)(2-). High nitrate concentrations were found on the eastern side of the basin in association with vegetable cultivation fields, and decreased gradually towards the west of the basin along the direction of groundwater flow. The decrease of nitrate concentration was conveniently coupled with increase of HCO(3)(-) (the heterotrophic denitrification product), pH and delta(15)N of residual nitrate (due to isotopic fractionation) from east to west. Therefore, denitrification in situ is continuously removing nitrate from the Kakamigahara groundwater system.