Catalyst Development of Microbial Fuel Cells for Renewable-Energy Production

In this chapter, we focus on microbial fuel cells (MFCs) that convert the energy from organic matters into electrical energy using microorganisms. MFCs are greatly expected to be used as a relatively low-cost and safe device for generating renewable energy using waste biomass as a raw material. At present, however, it has not reached the desired practical application because of the low-power generation; hence, improvements on fuel cell efficiency, such as electrode materials, are still being examined. Here, we focus on the microorganisms that can be used as catalysts and play a central role in improving the efficiency of the fuel cells. Several kinds of microbial catalysts are used in MFCs. For example, Shewanella oneidensis has been well studied, and as known, since S. oneidensis transports the electrons generated within the cell to the surface layer, it does not require a mediator to pass the electrons from the cells to the electrode. Furthermore, Escherichia coli and Saccharomyces cerevisiae, a model organism for MFCs, are also used. The improvements of such microbial catalysts have also been proceeding actively. Here, we elaborated on the principle of MFCs as well as the current situation and latest research on the catalyst development

Tolerogenic effect of non-inherited maternal antigens in hematopoietic stem cell transplantation

Major histocompatibility complex antigens that provoke severe transplant reactions are referred to as the human leukocyte antigen (HLA) in human and as the H-2 in mice. Even if the donor and recipient are HLA-identical siblings, graft-versus-host reactions have been linked to differences in the minor histocompatibility antigen. As the chance of finding an HLA-identical sibling donor is only 25%, attention has been focused on using alternative donors. An HLA-mismatched donor with non-inherited maternal antigens (NIMA) is less immunogenic than that with non-inherited paternal antigens, because the contact between the immune systems of the mother and child during pregnancy affects the immune response of the child against NIMA. However, the immunologic effects of developmental exposure to NIMA are heterogeneous, and can be either tolerogenic or immunogenic. We recently have devised a novel method for predicting the tolerogenic effect of NIMA. In this review, we overview the evidence for the existence of the NIMA tolerogenic effect, the possible cellular and molecular basis of the phenomenon, and its utilization in hematopoietic stem cell transplantation. We suggest a future direction for the safe clinical use of this phenomenon, fetomaternal tolerance, in the transplantation field

Biomineralization in Magnetospirillum magnetotacticum

金沢大学Scedule:17-18 March 2003, Vemue: Kanazawa, Japan, Kanazawa Citymonde Hotel, Project Leader : Hayakawa, Kazuichi, Symposium Secretariat: XO kamata, Naoto, Edited by:Kamata, Naoto

Identification of iron transporters expressed in the magnetotactic bacterium magnetospirillum magnetotacticum

金沢大学理工研究域自然システム学系The magnetotactic bacterium Magnetospirillum magnetotacticum MS-1 mineralizes the magnetite (Fe3O4) crystal and organizes a highly ordered intracellular structure, called the magnetosome. However, the iron transport system, which supports the biogenesis of magnetite, is not fully understood. In this study, we first identified the expressions of both the ferric and the ferrous iron transporter proteins in M. magnetotacticum. The cellular protein compositions of ferric and ferrous iron-rich cultures were examined using two-dimensional electrophoresis. According to the gel patterns, two outer-membrane ferric-siderophore receptor homologues were identified as proteins strongly induced in the ferrous iron-rich condition. Also, we identified for the first time that the ferrous iron transport protein, FeoB, is expressed in the M. magnetotacticum cytoplasmic membrane using immunoblotting.

スクリーン／フィルム乳房撮影法における乳房線量測定システム

The average glandular dose to glandular tissue m mammography is generally assumed to be a function of beam quality (HVL), x-ray tube target material, tube voltage, breast thickness, breast composition and, to a lesser extent, x-ray tube voltage waveform. The average glandular dose is generally determined from published tables with knowledge of the above function. Tables for a high frequency x-ray generator are not yet published. In our study, the lookup tables for the average glandular dose were made at 28 kV (high frequency x-ray generator), employing a breast simulating tissue (0-100% adipose tissue, 0-100% glandular tissue) phantom for an Mo target - Mo filter source assembly. We tried to estimate breast composition from x-ray mammograms by digital image processing techniques, also using the simulating tissue phantom. Then the system that automatically calculates the average glandular dose from digitized clinical x-ray mammograms was built. It is considered that this system can contribute to objective evaluation of the average glandular dose.乳房X線撮影法において乳腺組織に対する平均放射線吸収線量，すなわち平均乳腺線量は放射線のリスクの最も有用な測定法であり，現在，乳房に対する線量の評価に用いられている指標である。一般に，平均乳腺線量は線質（HVL），X線管球ターゲット材料，管電圧，圧迫乳房厚さ，乳房構成および（ある程度）X線管電圧波形の関数であるとされている。平均乳腺線量は，上記の関数についての情報を備えた表が公表されており，一般にその表を使って決定されている。近年，インバータ式といわれる高周波X線発生装置が普及してきた。しかし，その装置用の表は，まだ公表されていない。我々の研究では，乳房組織をシュミレートするファントム（0～100％乳腺組織，0～100％脂肪組織）を使用して，28kVでMoターゲット―Moフィルタソースアセンブリーを備えた高周波X線発生装置のために，平均乳腺線量用のルックアップテーブルを作成した。同様に，乳房組織をシュミレートするファントムを使用して，乳房X線写真から，ディジタル・イメージプロセシング技術によって，乳房構成の評価を試みた。そして，ディジタイズされた臨床乳房X線写真から，平均乳腺線量を自動的に計算するシステムを構築した。サンプル数が少ないため断定はできないが，日本女性は，基準構成（50％の脂肪および50％の乳腺組織）と比較すると，脂肪が少ない傾向を分析結果は示唆していた。また，平均乳腺吸収線量の限度は，明確に規定されていないが，American College of Radiology（ACR）は4 mGyなどを推奨している。また日本では，3 mGyが推奨されているが，我々の撮影システムはこれらを十分満足していた。このように本システムは，平均乳腺線量の客観的な評価に寄与するとともに，DR（digital radiography）などに応用すると，すなわちルックアップテーブルをDRのコンピュータに保存しておけば，撮影後すぐに乳房構成および平均乳腺線量を算出できる可能性をもつ

Measurements and Evaluation of Proximal Femoral Bone Mineral Density with Dual Energy X-ray Absorptiometry

Proximal femoral bone mineral density (BMD) can be measured by dual energy X-ray absorptiometry method in the neck, trochanter, intertrochanter, total and Ward's triangle area. Ward's triangle area of the proximal femur is a smaller area to measure than the others, and the position varies, depending on the status of inner rotation of the target leg. In this study, the measurements of the proximal femoral BMD in women were carried out on the neck, trochanter, intertrochanter, total and Ward's triangle area with the, subjects' legs turned 15 degrees toward the inside. The Ward's BMD were measured using Ward's cognitive method, in which the measured BMD were compared among age groups of 50-59, 60-69, 70-79 and 80-89 to determine whether this process could reveal decreased femoral BMD in elderly women. The correlation between BMD and age was tested using the Pearson correlation coefficient. In all measured parts, the BMD of women age 50-59 were significantly higher than those of women age 80-89. The correlations between BMD and age were negative in all measured parts, and the most negative correlation was between age and Ward's BMD. The study using Ward's cognitive method showed an inverse correlation between Ward's BMD and age in women

Nitrate reductase from the magnetotactic bacterium Magnetospirillum magnetotacticum MS-1: purification and sequence analyses

金沢大学理学部金沢大学大学院自然科学研究科We purified the nitrate reductase from the soluble fraction of Magnetospirillum magnetotacticum MS-1. The enzyme was composed of 86- and 17-kDa subunits and contained molybdenum, non-heme iron, and heme c. These properties are very similar to those of the periplasmic nitrate reductase found in Paracoccus pantotrophus. The M. magnetotacticum nap locus was clustered in seven open reading frames, napFDAGHBC. The phylogenetic analyses of NapA, NapB, and NapC suggested a close relationship between M. magnetotacticum nap genes and Escherichia coli nap genes, which is not consistent with the 16S rDNA data. This is the first finding that the α subclass of Proteobacteria possesses a napFDAGHBC-type nap gene cluster. The nap gene cluster had putative fumarate and nitrate reduction regulatory protein (Fnr) and NarL protein binding sites. Furthermore, we investigated the effect of molybdate deficiency in medium on the total iron content of the magnetosome fraction and discussed the physiological function of nitrate reductase in relation to the magnetite synthesis in M. magnetotacticum

Extended-cycle processによる乳房撮影用増感紙／フィルムシステムの画質改善

Extended-cycle process is the term used for a processor in which the processing time has been prolonged usually to approximate 210 seconds. It has been known that the extended-cycle process of some single-emulsion films as used for mammography may enhance film contrast and increase film speed. So the speed was increased in lower speed and higher resolution system than conventional systems by means of using the extended-cycle process in this paper. We investigated how much the resolution of the system was kept. A single screen-single emulsion combination, Konica M-100/CM-H was employed as a low speed and high resolution system. This film after exposure was processed in the different combinations of developing temperatures, 30, 32 and 34℃, and processing time of 210 seconds. On the other hand, Konica M-200/CM-H was employed as a high speed system. This film was processed in the standard-cycle processing (34℃, 90 seconds). Those systems were compared on contrast, speed, screen-film blur and noise by a characteristic curve, MTF (modulation transfer function) and WS (wiener spectrum). Furthermore, the RMI 165 phantom was used to evaluate visibility of mammographic details of these systems. As a result, in the extended-cycle process at the developing temperatures of 32 or 34°C and processing time of 210 seconds for M-100/CM-H, it was possible to increase the speed as much as the higher speed system, M-200/CM-H. Then the contrast, the MTF and the visibility were also improved as compared to the higher speed system. Furthermore patient dose could be reduced at the developing temperature of 34℃ and processing time of 210 seconds in M-100/CM-H.通常,extended-cycle processは処理時間が約210秒に延ばされた現像機のために使われる用語である｡乳房撮影に使われるような片面乳剤フィルムにおけるextended-cycle processは,フィルムコントラストを増し,感度をあげることが良く知られている｡そこで,本論文ではextended-cycle processにより低感度,高解像度システムの感度を上げ,どの程度解像度が維持されるかを調べた｡片面増感紙／片面フィルムの組合わせであるKonica M-100/CM-Hを低感度,高解像度システムとして用いた｡露光後のフィルムは現像温度30,32, 34度,処理時間210秒の異なる組合わせで現像処理した。一方,高感度システムとしてKonica M-200/CM-Hを用い,このフィルムは標準現像(34℃,90秒)された｡感度,増感紙／フイルムのぼけ,雑音に関して,特性曲線,MTF(modulation transfer function), WS(wiener spectrum)によってこれらのシステムを比較した｡さらにこれらのシステムにおける乳房写真の細部視覚評価のためにRM165ファントムを使用した｡その結果,M-100/CM-Hに対するextended-cycle process現像温度32, 34℃,処理時間210秒のextended-cycle processにおいて,高感度システムM-200/CM-Hと同等の感度を上げることが可能であった｡そのとき,コントラスト,MTF,視覚的検出能も高感度システムより向上した｡さらに,現像温度34℃,処理時間210秒では,被曝線量の低減が可能であった

Method to Develop Pseudo Three-dimensional Dental Image from Dental Panoramic Radiograph

Although three-dimensional imaging can be a powerful tool for dentists to explain treatments to patients, obtaining of three-dimensional image of teeth in general dental clinics is difficult. This paper proposed a method to develop pseudo three-dimensional dental image from conventional dental panoramic radiograph and dental impression. The method estimates imaging parameters of given panoramic radiograph through comparison with dental cast, and re-projects the radiograph into three-dimensional space. The developed pseudo three-dimensional image gives clear impression of the patient’s dental condition