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Ohmic contacts on (Bi, Pb)-Sr-Ca-Cu-O (BSCCO) superconductor ceramics have been studied. When the electrodes were formed on the as-sintered surface of a BSCCO pellet, nonohmic characteristics were observed. Analysis by X-ray photoelectron spectroscopy suggests that the surface layer of the BSCCO pellet is degraded. When the fractured section of a BSCCO pellet was used, both Cu and Ag electrodes were found to be ohmic without thermal annealing.

ZnS: MnF2 phosphors and their references were investigated with X-ray photoelectron spectroscopy. The atomic ratio of F to Mn in ZnS: MnF2 was found to be remarkably lower than that in MnF2 film. The binding energy of Mn2p3/2 in ZnS: MnF2 is near that in β-MnS and ZnS doped with Mn atoms by heat-treatment. It is concluded that most Mn atoms in ZnS: MnF2 are not in the MnF2 molecules, but replace Zn atoms. This fact is also discussed on the basis of self lattice potential energy.

A modified calculation of the semi-quantitative method assuming local thermal equilibrium has been proposed. This method is applied to the quantitative analysis of dopant in ZnS thin film. Agreement between the calculated concentration and those determined with X-ray fluorescence and atomic absorption spectrometry is found to be satisfactory.

The rotary type beater, such as the saw toothed beater of a cotton opener and picker, performs good opening action, but for effective cleaning action a special mechanism is needed. Model D Opener of our designing is intended for effective cleaning and has given good results. In this report we describe the mechanical feature of our new opener and report the results of tests by some mills. This opener is also good for the short-cut system of opening and picking process for cotton and for the opening process for rayon.

As one approach to the mechanism of nutrient uptake by fruit tree roots, the authors reported on the cation exchange capacity of fruit tree roots and on the adsorption of calcium and potassium from solutions containing these cations (13).

In this report, the mechanism of automatic level control system for product sliver is described. The variation of product sliver's thickness is measured by air-micrometer.The appearance of this air-micro-nozzle is same as that of the conventional trumpet and this nozzle is set on the front side of the delivery roller. The transmitting loop of signal is as follows: air-micro nozzle (measuring the variation of thickness of product sliver)→bellows→Record pet→electric switch (with limit of adress)→relay→pilot motor→speed regulater→draft change gear train→feed roller (or delivery roller).The conculusion of this analysis is as follows;(1) Transfer function of this control loop G(s) is where, kn=2B√4a2-Δ2/πa2, Y0: average thickness of feed sliver, V1: surface speed of delivery roller, L=τ1+τ2, τ1: dead time in draft zone, τ2: dead time between front nip point and airmicro nozzle (trumpet), kn: transfer function of electric circuit which has the non-linear characteristics with limit of adress (range Δ), a sin ωt: input of electric circuit, k1: gain constant of air micro nozzle, km: gain constant of speed regulator and gear train of draft change, K; gain conctant of sensing device, B; voltage of pilot motor, Tm; time constant of speed regulater and gear train of draft change, T; time constant of sensing device.(2) This control system meets with the stability criterion of NYQUIST in the conventional and so-called high speed of delivery roller.(3) By using Toka's definition of residual variation of thickness of product sliver, the effect of automatic control is discussed.Definition of residual variation of thickness of product sliver E % is as follows;where, X0 is average thickness of product sliver., X(s) and Y(s) notation of laplace transformation for x(t) (variation of thickness of product sliver) and y(t) (variation of thickness of feed sliver). In this control system, E is caluculated by the following equation.The theoretical conclusion of this analysis, shows close resemblance with actual data and good effect of control is expected for domain of long term variation (more than 3 meter) of product sliver's thickness.(4) By the theoretical analysis of frequency response by Bode diagram, the effect of delivery roller's surface-speed is discussed, and author shows the close resemblance on frequency response betwen conventinal speed and so-called high speed of the delivery roller.

The application of our automatic draft control system by Ever Even which has the decided neutral zone in controller was performed for our cotton spinning process. This application is classified into two types, one is for double and more deliveries, and the other for single delivery.*One kind of the former type is the application for automatic draft control of the variation of average sliver thickness produced from drawing frame. This automatic control means the control of long term variation of average sliver thickness produced control means the control of long term variation of average sliver thickness produced and our conventional control method is performed by so-called X-R control chart system.Form the test by Ever Even, the following are observed:(1) The variation of average sliver thickness produced from drawing frame #2 is controlled in the range ±0.5% for standard value.(2) Average counts of yarn is controlled in the same range of drawing sliver the coefficient of variation of yarn counts is about 1.2_??_1.4%. The variation of lea strength for 40S is also decreased and the percentage of lea strength under 50 lbs in controlled lot is about 9% and that of conventional lot is 19%.(3) The variation of cake weight of control lot is about 1/2 of that of conventional lot.(4) It is proved by Nyquist criterion that the stability of this control system is maintained.The short cut of the spinning process by the automatic draft control system for single delivery is proven beneficial by our mill test.It may be expected that if the draft control system is applied for draft element with single delivery to which some card slivers are fed as the same feed method of comber draw-box. excellent uniform sliver may be produced.*Draw-box with Ever Even for some sets of card (i.e., 6 sets)…Drawing frame super high draft spinning frame.*Draw-box with Ever Even for some sets of card (i.e., 6 sets)…Drawing frame…Roving frame high draft spinning frame.

京都府下胡麻開拓地の黒土に対する微量要素施用効果について小麦を用いて圃場試験を行なつた。その結果, 生育調査においては微量要素区が標準区より草丈では若干劣る様であつたが, 穂長および分けつ数では勝れていた。収量調査においては明らかに微量要素の施用効果が認められ, 10a当りklを標準区100とした場合, 無肥料区84,銅区117,マンガン区110,銅+マンガン区103,FTE区111であつた。また収穫後の穀粒および藁稈について銅およびマンガンを, 跡地土壌については全銅, 置換態銅, 全マンガン, 置換態および還元態のマンガンを定量した。その結果, 微量要素施用区の吸収量は穀粒部分では差異が認められず, 藁稈部分で銅およびマンガン施用区はともに明らかにこれらの吸収量が高かつた。土壌については微量要素施用区はこれら要素が多く検出され, マンガン施用区では特に置換態と還元態のマンガン量が多かつた。, A field experiment was carried out on the effect of minor elements on wheat. The field is located at GOMA Reclamation Land in KYOTO Prefectnre. The soil is classified as Kuroboku soil (black soil, ando soil). No distinct effect was found on the growth, however, clear effect was observed on the yield. The yield index of each plot which is calculated on the basis of yield of the plot without minor elements is : no fertilizer 84,copper 117,manganese 110,copper plus manganese 103,and FTE 111. FTE refers to fritted trace elements. Minor element analysis was conducted on the grains and straws, and also on the soils. The elements analyzed were copper and manganese on the crops, and total copper and manganese, exchangeable copper and manganese, and reducible manganese on the soils. No difference was found on the grain, however, a distinct difference was found on the straw. A large amount of exchangeable and reducible manganese were found on the soil of manganese plot.

粗糸の牽伸によつて伸ばされる機構を明きらかにし, 又現在唯一の粗糸の試験機であるロービング, テスターの原理を調べる爲, 筆者等は粗糸の匍匐現象を研究した。又, ロービング・テスターの性能を力学的に解明した。然して, 粗糸の匍匐現象がλ=α.tβで示されることを説き, dλ/dt=∞の点を以て, 粗糸の破壊点を定義した。

柑橘葉中の亜鉛, 鉄および土壌中の全マンガンを螢光X線分析法による定量法の検討を行ない次の結果をえた。柑橘葉中の亜鉛含量の定量の場合, Dithizon法で行なった結果とは必ずしもよい一致を示さなかったが, 内部標準法, 標準曲線法ともに亜鉛欠乏症の発現と濃度を関係づけるに足る精度での分析は可能であった。しかし葉中の鉄の定量結果は化学分析値に対しよい一致を示さず半定量の程度の精度しかえられなかった。土壌中のマンガンの定量の場合は, 標準曲線の変異はかなり大きいが, 化学分析結果との対応においてはCV8%とかなりよい精度で分析が可能であった。, The methods of quantitative determinations of zinc and and iron contents in citrus leaves and manganese contents in soils by X-ray fluorescent analysis were examined and the following results were obtained. In the case of determination of zinc, the zinc contents in the citrus leaves could be estimated by both the internal standard and standard curve methods in X-ray fluorescent analysis to establish the relationship between the appearance of symptom of zinc defficiency and the contents of zinc in leaves, though the data determined by chemical method did not show good agreement with the ones estimated by X-ray fluorescent analysis. For the determination of iron contents in leaves, the X-ray fluorescent analysis can not adapt, because the variance was large in the repetition of determination and in the comparison with the data estimated by chemical method. The coefficient of variance of manganese contents in soils determined by X-ray fluorescent analysis to the data estimated by chemical method was about 8 per cent and considerably low. From this result, the manganese contents in soils may be determined by X-ray fluorescent analysis.

殺線虫剤としてVapam (natrium methyldithiocarbamate)およびNemafume (1,2-dibromethan)を用いて土壌処理を行ない, これが土壌および植生に与える影響について栽培および室内実験を行なつた。その結果, 生育および収量においては, 対照区よりVapam処理が有効であつたがジイナ数が多いため稔実歩合が悪く稔実重において変化がなかつた。土壌のEhの変化においてはVapam処理が他の区に比べて, 初期にEhの低下が見られ, 最低電位を示す時期が1週間早かつた。根のカチオン置換容量は僅かであるがVapam区およびNemafume区が対照区より大となつた。水田および畑状態におけるアンモニアおよび硝酸態窒素の消長については水田状態の場合, 各試験区ともアンモニア態窒素が増加し硝酸態窒素が減少するという消長経過を示したが, 量的にはVapam区が最もすぐれていた。畑状態の場合はNemafume区および対照区はアンモニア態窒素が減少し, 硝酸態窒素が増加する消長経過を示したにもかかわらず, Vapam区が他の2区と逆の消長を示し, かなりアンモニア態窒素の増加が認められた。従つて部分殺菌の効果としてはVapamがすぐれていることがわかつた。, Effect of nematocides on some soil properties and rice growth was studied. The nematocides used were Vapam (Na-methyl dithiocarbamate) and Nemafume (ethylene dibromide). The results are summarized as follows : 1. The yield of rice grown on the soil treated with vapam was higher than the yield on untreated soil. However, no distinct effect was found on the weight of seed. 2. Cation exchange capacity of the root increased by the application of nematocides. 3. Oxidation reduction potential of the vapam treated soil showed lower value than the potential of the untreated soil. 4. Laboratory experiment was conducted on ammonification and nitrification in the soil. Soils were incubated under paddy field and upland field conditions. Determination of ammonium and nitrate nitrogen was run after 3,7,14 and 21 days the experiment started. The amount of both nitrogen was higher in the treated soil than in the untreated soil. The soil treated with vapam showed a degree of high amount of ammonium nitrogen compared to the untreated soil.

京都府下丹後地方のカンキツ園において開園時期を異にする園を供試し, 土壌の化学的性質および葉成分について時期的変化を調べた。その結果, 土壌の反応は新しい園(高石)が古い園(石浦)にくらべると酸性が強い傾向を示したが, マンガンについては両園とも水溶性および置換性マンガンが少なかった。葉成分については石浦でマンガン欠乏, 高石でマンガンおよび亜鉛欠乏の可能性が推定された。また, 結果枝は無結枝にくらべるとカルシウムマンガンおよび亜鉛を多く含み, 窒素および加里は逆に少ない傾向を示した。, Studies were carried out on the seasonal change of chemical properties of soils and inorganic compositions of leaves at the two citrus groves (variety UNSHU)-old ones (the age of tree : 60 years) and young ones (the age of tree : 10 years)-in northern part of Kyoto Prefecture and the following results overe obtained : The soil of young grove (TAKAISHI) showed more acidic properties than the soil of old grove (ISHIURA). A small amount of water soluble and exchang-able manganese were found on the both soils. The seasonal change of inorganic compositions of leaves showed no distinct differences between the two kinds of groves. However, from the compositions of leaves, a manganese defficiency found at the old grove, and also manganese and zink defficiency at the young groves were expected. Calcium, manganese and zink contents in the leaves were higher in the bearing shoots than in the non bearing shoots, Nitrogen and potassium contents showed a reverse relation to these three elements.

Wakayama Prefecture is one of the important districts of citrus production in Japan. The citrus groves are located in the northern districts of the prefecture along the watershed of the Kii, and Arita rivers. Geologically, the rocks in these districts are classified into crystalline schist, Palaeozoic Upper Chichibu and Mesozoic Cretaceous systems. The associated soils are chiefly members of the Red Yellow Podzolic and Lithosol group.7)

The soils of the apple orchards in Aomori Prefecture may be classified into three kinds; that is, ando soils, brown podzolic soils and alluvial soils. They have been studied with regard to both physical and chemical properties respectively. The soils show various mechanical compositions. Alluvial soils are rather clayey, ando soils and brown podzolic soils being loamy. The reaction is mostly acidic or weakly acidic. The contents of the main nutrients of the surface soils are as followings: highest lowest average Humus 22.75% 3.13% 10.26% N 0.806% 0.112% 0.457% P2O5 (soluble in 1/5 N HCl) 0.0672% 0.0064% 0.0244% K2O (ditto) 0.2557% 0.0319% 0.0861% These contents generally decrease with depth. From the data obtained it may be concluded that the orchard soils of Aomori Prefecture have rather desirable properties for apple growings, both chemically and physically.

カンキツの異常落葉園土壌を供試して無肥料で大豆を栽培, その幼植物の生育と養分吸収におよぼす殺菌剤およびEDTAの影響を調べた。その結果, 乾物重においては殺菌剤処理で増加したが, EDTA処理は減少の傾向を示し, 有害的であった。地上部成分の吸収量については殺菌剤処理で各成分とも増加の傾向を示すのに対し, EDTA処理では結合金属によって若干傾向を異にするようで, 共通して増加したのは地上部でリン, アルミニウム, 鉄, 減少したのはカルシウムおよびマンガンであった。しかし根部ではいずれの成分も減少を示した。, Studies were carried out on the effect of application of soil fungicide and EDTA (Ethylenediamine-tetraacetic acid) on the growth and nutrient absorption by soy bean plant. The soils used in this experiment were taken from the citrus orchard with abnormal defoliation. The results are summarized as follow : 1) The dry whight of young plant on the soil treated with fungicide was heavier than the plant whight on untreated soil. However, an application of EDTA resulted in a decrease of weight. 2) The difference was found between the nutyients absorption from the treated and untreated soils. That is the amount of absorbed nutrient increased by fungicide treatment. Phosohorus, aluminum and iron absorption increased, and calcium and manganese absorotion decreased by EDTA treatment. 3) The amount of nutrients absorbed by roots showed the tendency of decrease by the application of fungigide and EDTA.

京都府下丹後地方の柑橘園土壌の一般理化学的性質および葉成分について分析し, 今後の当地方の柑橘栽培における土壌, 肥培管理の基礎資料をえた。すなわち丹後地方の柑橘園土壌は植物栄養的に母材をほぼ同じくする近畿, 中国地方の主産地土壌にくらべてせき薄な土壌地帯であり, 葉分析より診断される柑橘の栄養状態も良好とはいえず, とくに微量要素の欠乏に注意すべきことを明らかにした。, The chemical and physical properties of soils and the inorganic compositions of leaves in the citrus gardens in Tango District, Kyoto Prefecture, were studied and the following results were obtained. The citrus garden soils in Tango District, which were formed on granite and palezoic shale, showed lower fertility level than the soils which were formed on the same parent materials in the citrus growing parts of Wakayama, Mie, Hiroshima and Yamaguchi Prefecture. The nutritional status of citrus were not so good and especially the trace element status in both soils and plants were very bad, for example, the manganese and zinc defficiency had appeared.

螢光X線分析装置(島津FX402型)を用いて柑橘葉中の微量要素の定性およびマンガン濃度の定量の可能性を検討した。タングステンX線管球から銅のX線が強く発生し, 銅の定性は不能であったが, 粉砕試料, 押葉試料ともに鉄, マンガン, 亜鉛の定性は可能であった。マンガンの定量は粉末試料をプレスすることなしに, 化学分析値に対し15%前後のCVで定量可能であり, 柑橘の異常落葉現象と葉中マンガン濃度との関係を検討するには十分な精度と思われた。, The possibility of qualititative determination of minor nutritional elements and quantitative determination of manganese contents in citrus leaves were investigated using the apparatus of X-ray fluorescent analysis (Shimazu FX 402) and the following results were obtained. Manganese, Iron and Zinc in the powdered and pressed citrus leaves could be determined qualitatively but cupper couldn't be detected because the X-ray of cupper had been radiated from the tungsten X-ray tube using is this research. Manganese contents in citrus leaves could be estimated quantitatively at the accuracy of coefficient of variance of about 15 percent against the values chemically analyzed.

国府地区開拓地の現地踏査を行い, 又1町歩に就き1点の割合で採取した土壌試料に就き物理的及び化学的分析を行つた。その結果本地区土壌をA, B, Cの3土壌型に分ける事が出来る。各土壌型は更に2乃至4の亜型に細分する事が出来る。これ等各型土壌の共通的欠陥は礫盤層に基く物理的性質の不良, 有機質の不足, 強酸性, 可吸態燐酸の欠乏である。以上の3型土壌の中, B型土壌は他に比してこれ等の欠点は比較的少く, 或は改良されている。要するに本開拓地不振の主な原因は, 今指摘した様な土壌の欠陥に因る事が明かになつた。, Soil survey was made at the Koofu reclamation land in Miye Prefecture. Physical and chemical analyses were carried out on the soil samples taken from the upper and lower layers of soil profiles. From these results the soils of this reclamation land are classified into three types, namely A-, B- and C-type. Each soil type is further classified into a few subtypes. In general the soils have a large amount of gravel near surface horizon, and show storng acidity and low content of humus anb available phosphorus. The B-type soils surpass the A- and C-type soils in these properties and the fields are well reclaimed. In conclusion the main reason of poor development of this reclamation land could be attributed to the poor soil properties.

無機質の埴質土壌に調整剤A-22及び石灰を添加して団粒形成量とその分布状態, 透水性, 置換容量及び燐酸吸収力について実験を行つた。調整剤は土壌に対して0.03%及び0.05%, 石灰はカチオン置換容量に相当する量を加えた。本実験の結果を要約すると次の如くである。(1)団粒形成量については調整剤及び石灰添加の効果が明らかに見られた。(2)透水性は調整剤添加によつて早くなるが, 0.05%区では0.03%区よりも遅く, 石灰の併用は多少阻害する様である。(3)置換容量及び燐酸吸収力については調整剤の添加量と共に増大した。, A soil conditioner, A-22,was applied to an inorganic clayey soil. Lime was applied combined with the soil conditioner. The amount of lime was just equal to the cation exchange capacity of the soil, and the amounts of soil conditioners were 0.05 and 0.03 per cent of the soil weight. Experiment was carried out on the effect of the soil conditioner on aggregate formation, water permeability, cation exchange capacity and phosphorus adsorption. The results are summarized as follows : 1) Formation of soil aggregate was remarkably affected by the application of soil conditioner and lime. 2) Water permeability was increased by soil conditioner. The increase by 0.03 per cent application was larger than the increase by 0.05 per cent application. Slight decrease of permeability was observed by the addition of lime. 3) Cation exchange capacity and phosphorus absorption of the soil increased by the application of soil conditioner.

Ion exchange is thought to be one of the mechanisms of nutrient uptake by plant. The plant root has cation exchange capacity and this is considered to be attributed to pectin, pectic acid, cellulose, and some organic compounds with similar structure to these compounds. Cation held by exchange adsorption does not diffuse out into water but is released by other cation.

Endemics are peculiar diseases prevalent in certain limited areas. The causes of endemics are generally complicated. Amyotrophic lateral sclerosis (ALS) is found on some Islands in the Pacific Ocean. ALS patients have been reported from New Guinea, Guam Island, and the South Muro district of Kii Peninsula in Japan. The cause of ALS has not yet been made clear. Many hypotheses have been proposed as to the causes, and the soil seems to be concerned with this disease. The authors studied the soils of this district in a joint project with Wakayama Medical College.

チューリツプについて生育過程において吸収され[figure]たPの収穫物中に於ける分布の模様をP^を用いて研究した。その結果, 各施用期および各部位ごとにP^の吸収量に差が見られ, 根に於ける集積が大であると同時に生育後期に施用したもの程, 多量集積する傾向を示した。これは生育段階に於けるP吸収量の差と, 吸収される時の生理的特異性によるものと考えられる。, It is the purpose of this study to investigate the distribution of absorbed phosphorus in tulip at different stages of growth. The experiment was carried out by sand culture using p^. The measurement of radioactivity and determination of phosphorus were run on stems, leaves, petals, roots and bulbs. Each portion showed different absorption of phosphorus. A large amount of applied phosphorus accumulated in roots and bulbs, and this tendency increased with growth. Proportion of absorbed phosphorus to total phosphorus also increased with growth. This shows that phosphorus applied at later stage of growth accumulated in these portions.

水稲種子にγ線を照射した場合, 無照射種子との間に生育および養分吸収に差異が生じるのではないかと考えられるので栽培試験を行ない, 各生育時期別に三要素の吸収状態を調べた。その結果γ線照射種子は無照射種子に比べ, 生育は初期にはすぐれていたが後期において劣つた。しかし茎数においては生育各期を通じてすぐれていた。収量調査においては対照区より照射区の方が劣つた。生育各期における地上部の三要素含有率については, 窒素および加里では照射区が7月に最大の含有率を示したのに対し, 対照区では8月に最大含有率を示した。燐酸では, 照射区が生育の進むに従つて減少したのに対し, 対照区は8月に最大含有率を示しのち減少した。1株当りの各要素の吸収量の変化は照射区, 対照区ともに同様の傾向を示し, 9月に最大吸収量が認められ, 各時期とも照射区の方が対照区より吸収量が大であつた。根のカチオン置換容量については, 一定の傾向および差異が認められなかつた。, Effect of γ-ray radiation on seed was studied on rice plant. Experiment was conducted on nutrient uptake and plant growth. The results are summarized as follows : 1. Distinct positive effect of γ-ray radiation was found on the growth at early stage However, no effect was observed on the yield. 2. The rice plant whose seed was radiated by γ-ray showed the highest percentage of nitrogen and potassium on July 24,However, the percentage of phosphorus decreased with growth. The rice from untreated seed showed the highest percentage of nitrogen, phosphorus and potassium on August 4. The amount of nitrogen, phosphorus and potassium absorbed by the treated and untreated rice showed the maximum value on September 5. The amount of these elements in the treated rice was higher than the amount of the untreated rice through all stages of growth. 3. No distinct difference and also no tendency of increase or decrease was found between the cation exchange capacities of roots of γ-ray radiated and check plants.

Continuous cell cultivation was tried on the surgical biopsy specimens from 40 clinical brain tumor cases and only one long-termed culture was obtained from a case of astrocytoma. The culture has so far been maintained 39 passages for 297 days and showed a pseudo-diploid character which consistently had three marker chromosomes. As a reference experiment, normal diploid cells were isolated from the cerebellar cortex of a human embryo and maintained in vitro. By comparison with this reference experiment in culture history, growth characteristics and chromosome constitution, it was strongly suggested that the long-termed culture has established a cell line. As to the drug sensitivity, the cells in the long-termed culture were more sensitive to Vinblastine than the normal cells in vitro, while both the cells had a similar sensitivity to Japanese encephalitis virus.

Background Oral care is important for oral and systemic health, especially for elderly institutionalized individuals and compromised patients. However, conventional mechanical plaque control is often difficult for these patients because of the pain or the risk of aspiration. Although antimicrobial photodynamic therapy (aPDT), which is considered an alternative or adjunct to mechanical approaches, has potential application as a less stressful method of daily plaque control, no clinical application of this technique has been reported. Methods We investigated the inhibitory effect of a combination of toluidine blue O (TBO), and a red light-emitting diode (LED) on dental plaque formation in healthy volunteers. The optimal concentration of TBO was determined in preliminary in vitro experiments to evaluate the bactericidal effect of aPDT on Streptococcus oralis and to clarify its safety in fibroblast cells. To survey the mechanism of TBO-mediated aPDT, the quality and quantity of reactive oxygen species (ROS) generated during aPDT were also examined using electron spin resonance (ESR) spectroscopy. Subsequently, the inhibitory effect of aPDT on dental plaque formation was investigated in eleven subjects as a clinical pilot study. The right or left mandibular premolars were randomly assigned to the treatment (with aPDT) or control (without aPDT) groups. In total, aPDT was applied six times (twice per day) to the teeth in the test group over a period of four days. On the fourth day, the study concluded and the analyses were performed. Results A combination of 500 or 1000 μg/ml TBO and LED irradiation for 20 s significantly decreased the number of colony forming units of Streptococcus oralis. The cytotoxicity of aPDT was comparable to that of standard antiseptics used in the oral cavity. Hydroxyl radicals were detected by ESR analysis, but singlet oxygen was not. A randomized controlled trial demonstrated that aPDT with 1000 μg/ml TBO and red LED irradiation significantly suppressed dental plaque formation without harming teeth or the surrounding tissues. Conclusions aPDT has the potential to be a promising novel technical modality for dental plaque control. Trial registration This trial was registered with University Hospital Medical Information Network Clinical Trials Registry (number UMIN000012504). Electronic supplementary material The online version of this article (doi:10.1186/1472-6831-14-152) contains supplementary material, which is available to authorized users.

The electrical properties and X-ray photoelectron spectroscopy (XPS) of Y1Ba2Cu3O7-δ (YBCO) contacts formed by Ag, Au, Sn, Zn, In and Al metal films have been studied. The Cu, In, Zn and Sn film contacts show high resistivities with semiconductive temperature dependence. The Au, Ag, and Pt film contacts have low resistivities with metallic temperature dependence. The XPS analyses show that Sn and Al react with the oxygen on the YBCO surface. However, little change in copper and oxygen states can be observed in Ag/YBCO and Au/YBCO systems. It is assumed that the oxygen-deficient layer at the interfaces of Sn/YBCO and Al/YBCO systems makes the contact resistance high, while the semiconductive layer is insignificant at the Ag/YBCO and Au/YBCO interfaces, and their resistance is low. Analyses indicate that Ag/YBCO and Au/YBCO systems provide very effective ohmic contacts.