Palladium‐Catalyzed Hydroxymethylation of Aryl‐ and Heteroarylboronic Acids using Aqueous Formaldehyde

Cyclometallated NHC palladium complexes prepared from palladium(II) acetate [Pd(OAc)₂] and unsymmetrical 1,3‐diarylimidazolinium salts catalyzed the hydroxymethylation of (hetero)arylboronic acids using an excess amount of formalin to afford (hetero)arylmethanols in good to satisfactory yields.

     

Reflection and absorption characteristics of electromagnetic waves for PV modules

In this paper, the authors investigated the reflection and absorption characteristics of a general photovoltaic (PV) module. As a result, the electromagnetic waves could be attenuated only 6 dB in typical PV module. However, if the PV module is installed in the outer wall of buildings, electromagnetic interference is caused by the surroundings. To reduce this electromagnetic interference, the authors suggested a method to absorb electromagnetic wave using multiple PV modules that have deference impedance, and simulation was performed. As a result, it was confirmed that using a typical PV module and the PV module including electronic device, the reflection waves of those PV modules could be attenuated up to 12 dB.     

Hybridized hydrogen production system with Fe—I. Photochemical reaction in concentrated phosphoric acid

An attempt was made to carry out the following photochemical reaction, 2Fe²⁺ + I^?₃ + light → 2Fe^3? + 3I^? in concentrated phosphoric acid in order to obtain hydrogen iodide as a gaseous product. By means of the above photochemical, and two other consecutive chemical reactions, water is decomposed into hydrogen and oxygen. Compared to the water-splitting system with dilute sulfuric acid, this system has an advantage of easy separation of hydrogen iodide from the reaction mixture. Experiments are made with various conditions of phosphoric acid, temperature, light intensity and concentrations of iodine.     

Photochemical and thermoelectric utilization of solar energy in a hybrid water-splitting system

A hybrid thermochemical water-splitting cycle using solar energy is proposed and experimental results are presented. The cycle consists of a photochemical reaction conducted in a flat cell with a Fresnel lens and concentrating the remaining solar energy on a thermoelectric generator which produces electric power for the electrolysis steps. The photochemical reaction is:

$\text{2}\text{Fe}{}^{\mathrm{2+}}\text{+}\text{I}{}^{\mathrm{?}}\text{+}\text{light}\text{→2}\text{Fe}{}^{\mathrm{3+}}\text{+3}\text{I}{}^{\mathrm{?}}$

The overall efficiency is estimated to be as high as 15–25%.     

Recent progress in the development of visible light-driven powdered photocatalysts for water splitting

Many photocatalyst materials for water splitting have been developed, particularly since the second half of the 1990s. Highly efficient water splitting on tantalate photocatalysts under UV irradiation has been achieved. Moreover, band engineering by doping, valence band formation, and synthesis of solid solutions, has led to the development of a large number of visible light-driven photocatalysts for _H2${\mathrm{H}}_2$ or _O2${\mathrm{O}}_2$ evolution from aqueous solutions containing electron donors or acceptors. Z-scheme photocatalyst systems for water splitting to _H2${\mathrm{H}}_2$ and _O2${\mathrm{O}}_2$ under visible light irradiation have been developed. This progress in the development of visible light-driven photocatalysts for water splitting is reviewed.     

Risk of cancer and non-cancer diseases in the atomic bomb survivors

Late health effects of exposure to atomic bomb radiation have been evaluated in survivors. A cohort of 120 321 people has been followed since 1950 for mortality, including the cause of death using the Japanese population registry system (Life Span Study), and for cancer incidence using population-based cancer registries. Findings have included a markedly increased risk of leukaemia several years after the exposure, increased risk of various malignant tumours several decades after the exposure and, more recently, findings of increased rates of non-cancer diseases such as cardiovascular diseases.     

Effect of oxygen content on impact toughness of a fine-grained magnesium alloy

Fine-grained Mg-3Al-Zn alloys with various oxygen contents were prepared by a powder metallurgy process, and the effect of oxygen content on the impact toughness of the fine-grained magnesium alloys was quantitatively investigated. It is found that the impact toughness of magnesium alloys with mean grain size smaller than 3 μm is extremely high when the oxygen content is less than 400 pp, but it becomes very low as the oxygen content is higher than 1000 ppm. Both magnesium oxides and hydroxides are detected in the magnesium alloys. The presence of excessive magnesium oxides and hydroxides deteriorates the dynamic plastic deformation ability of the fine-grained magnesium alloys.     

Use of liposome encapsulated hemoglobin as an oxygen carrier for fetal and adult rat liver cell culture

Engineering liver tissue constructs with sufficient cell mass for transplantation implies culturing large numbers of hepatocytes in a reduced volume; however, providing sufficient oxygen to dense cell cultures is still not feasible using only conventional culture medium. Liposome-encapsulated hemoglobin (LEH), an oxygen-carrying blood substitute originally designed for short-term perfusion, may be a good candidate as an oxygen carrier to cultured liver cells. In this study, we investigated the feasibility of maintaining long term hepatocyte cultures using LEH. Primary fetal and adult rat liver cells were directly exposed to LEH for 6 to 14 days in static culture or in a perfused flat plate bioreactor. The functions and viability of adult rat hepatocytes exposed to LEH were not adversely affected in static monolayer culture and were even improved in the bioreactor. However, some cytotoxicity of LEH was observed with fetal rat liver cells after 4 days of culture. LEH, though a suitable oxygen carrier for long-term culture of mature hepatocytes, is not suitable in its present form for perfusing fetal hepatocyte cultures in direct contact with the liposomes; either the LEH will have to be made less toxic or a more sophisticated bioreactor that prevents the direct contact between hepatocytes and perfusates will have to be designed if fetal cells are to be used for liver tissue engineering.     

Enhancement of optical absorption for below 5 μm thin-film poly-Si solar cell on glass substrate

Optical confinement effect of thin-film polycrystalline-Si (poly-Si) solar cell on glass substrate fabricated at low-temperature has been investigated as a function of cell thickness of less than 5 μm. We found that it is possible to fabricate the textured Si thin film in situ on a glass substrate and that the reflectance at long-wavelength light is reduced by surface texturing. Thin-film poly-Si solar cell and a-Si:H/(0.45 μm)/poly-Si (5 μm) tandem solar cell exhibit the efficiency of 8.6% and 12.8%, respectively. The numerical study in terms of the light trapping explains the excellent high short-circuit current density (_sc above 27 mA/cm² at the 4.7 μm thin-film poly-Si solar cell.