Congratulatory Message

Kobayashi,Kompenhans 한국가시화정보학회 2003 한국가시화정보학회지 Vol.1 No.1

Abatement of Methane Production from Ruminants: Trends in the Manipulation of Rumen Fermentation

Kobayashi, Yasuo Asian Australasian Association of Animal Productio 2010 Animal Bioscience Vol.23 No.3

Methane emitted from ruminant livestock is regarded as a loss of feed energy and also a contributor to global warming. Methane is synthesized in the rumen as one of the hydrogen sink products that are unavoidable for efficient succession of anaerobic microbial fermentation. Various attempts have been made to reduce methane emission, mainly through rumen microbial manipulation, by the use of agents including chemicals, antibiotics and natural products such as oils, fatty acids and plant extracts. A newer approach is the development of vaccines against methanogenic bacteria. While ionophore antibiotics have been widely used due to their efficacy and affordable prices, the use of alternative natural materials is becoming more attractive due to health concerns regarding antibiotics. An important feature of a natural material that constitutes a possible alternative methane inhibitor is that the material does not reduce feed intake or digestibility but does enhance propionate that is the major hydrogen sink alternative to methane. Some implications of these approaches, as well as an introduction to antibiotic-alternative natural materials and novel approaches, are provided.

Synthesis, crystal structure, solution and spectroscopic properties, and hydrogen-evolving activity of [K(18-crown-6)][Pt(II)(2-phenylpyridinato)$Cl_2$]

Kobayashi, Masayuki,Masaoka, Shigeyuki,Sakai, Ken Korean Society of Photoscience 2009 Photochemical & photobiological sciences Vol.8 No.2

A water-soluble ortho-metalated platinum(II) complex $[K(18-crown-6)][Pt(ppy)Cl_2]{\cdot}5H_2O$ (1) (ppy = phenylpyridinate, 18-crown-6 = 1,4,7,10,13,16-hexaoxacyclooctadecane) was prepared from a 1 : 1 reaction of $[K(18-crown-6)]_2[PtCl_4]$ and 2-phenylpyridine in methanol. The compound crystallizes in the triclinic system, space group $P{\bar{1}$ (No. 2). A solvolysis product of 1, Pt(ppy)Cl(DMF) (DMF = N,N-dimethylformamide) (10), was also isolated and structurally characterized by X-ray diffraction (monoclinic system, space group $P2_1$/n (No. 14)), revealing the lability of the coordination bond trans to the C(ppy) donor. Ligand substitution reactions of 1 in water were investigated by means of UV-visible absorption spectroscopy and time-dependent DFT calculations. The initial hydrolysis product in aqueous media was suggested to be Pt(ppy)Cl($OH_2$), in which the chloride ion trans to the C(ppy) donor in $[Pt(ppy)Cl_2]^-$ is replaced with an aqua ligand due to the stronger trans effect originated by the C(ppy) donor. It was found that the ligand substitution reactions of $[Pt(ppy)Cl_2]^-$ is extremely complicated. Leaving the complex in solution for a prolonged time resulted in deposition of a yellowish green chloride-bridged dimer $Pt_2(ppy)_2({\mu}-Cl)_2$. Moreover, an unidentified blue species, ascribable to a Pt(II)/Pt(III) mixed-valence species, started to form while the initial hydrolysis reactions proceeded. Photochemical hydrogen production from water catalyzed by $[Pt(ppy)Cl_2]^-$ was examined using a photosystem made up of ${Ru(bpy)3}^{2+}$ (bpy = 2,2'-bipyridine), methylviologen, and a sacrificial electron donor (EDTA) in an acetate buffer (pH 5). It is shown that the $H_2$-evolving activity of $[Pt(ppy)Cl_2]^-$ is higher that those of the hydrolysis products of $[Pt(ppy)Cl_2]^-$, but are comparable to those of other common Pt(II) complexes having a cis-Pt(II)$Cl_2$ unit, such as cis-$PtCl_2(NH_3)_2$, $PtCl_2$(4,4'-dicarboxybpy), and $PtCl_2$(2,2'-bipyrimidine).

中上級日本語クラスにおける Problem-based Learningの試み : 学習者の動機づけに着目して

Kobayashi, Akiko,Fukuda, Michiko 한국일어교육학회 2020 일본어교육연구 Vol.0 No.51

The purpose of this study was to investigate the effectiveness and issues in the practice of Problem-based Learning (PBL) in Japanese language instruction as regards learner motivation. A questionnaire survey was conducted on 22 international students learning Japanese, and 4 learners who exhibited characteristic changes in motivation were interviewed. No change in motivation was found as a result of PBL in the class taken as a whole, but individual differences were indicated. Learners who fulfilled the three psychological needs of autonomy, competence, and relatedness showed improved motivation. In contrast, learners who did not meet the three psychological needs presented no change or decrease in motivation. For example, learners who perceived group activities as meaningful fulfilled the need of relatedness and displayed increased motivation. On the other hand, learners who recognized that they deepened their opinions had lower motivation. This suggests that it was necessary to spend additional time on individual activities before group activities to support more active exchange of opinions. Some issues of PBL were indicated from the viewpoint of motivation, and the overall progress of the class was considered. 本研究の目的は、Problem-based Learning(PBL)を取り入れた日本語授業を実施し、学習者の動機づけ という観点からPBLの有効性と課題を探ることであった。日本国内の大学で中上級日本語クラスを履 修する留学生22名を対象に、PBL実施前後の動機づけの変化と影響要因を探った。質問紙調査を実施 したうえで、特徴的な動機づけの変化を示した学習者4名に対してインタビューを行い、動機づけに影 響を与えた要因を考察した。結果として、クラス全体としてはPBL実施前後に動機づけの変動は見ら れなかったが、学習者による個人差が見られた。PBLを通して自律性、有能性、関係性の3つの心理的欲 求が満たされていた学習者では、内発的動機づけの上昇が見られたが、3つの心理的欲求が満たされな かった学習者では、変化が見られないか、または下降がみられた。例えば、PBLのなかで実施したグ ループ討論や分担読解を有意義だと認識した学習者では、関係性の欲求が満たされ内発的動機づけが 高まっていた。一方、それらの活動において相手の発言がよく理解できない、話し合っても考えが深 まらないと認識した学習者は、内発的動機づけが下降していた。このことから、情報収集や資料の読 解といった個人活動により多くの時間を割き、その後のグループ活動における情報共有や意見交換が 活発になるよう支援することが必要であることが示唆された。その他にも動機づけの観点からPBL実 施上の課題が示され、それらをもとに授業改善案を検討した。

Behavior of pyriftalid in soil and its phytotoxic activity on Echinochloa oryzoides seedlings emerging from various soil depths

Kobayashi, Katsuichiro,Tsunekawa, Yuko The Korean Society of Weed Science and The Turfgra 2010 Weed Biology and Management Vol.10 No.4

The phytotoxic activity of pyriftalid ([RS]-7-[4,6-dimethoxypyrimidin-2-ylthio]-3-methyl-2-benzofuran-1[3H]-one) on barnyard grass (Echinochloa oryzoides) seedlings emerging from various depths in the soil was investigated in relation to its behavior in the soil. The growth of the barnyard grass seedlings in the soil mixed with pyriftalid was inhibited, depending on the concentration of the herbicide in the soil water but not on the amount in the total soil. A topmost pyriftalid-treated layer was formed by applying the herbicide to the soil surface under water-leakage conditions. The concentration of pyriftalid in the soil water and the amount that was adsorbed on the soil solid decreased with time, but the decrease was more marked in the pyriftalid concentration in the soil water than in the amount that was adsorbed on the soil solid. The emergence time of barnyard grass in the soil was faster in the seeds that were located in the shallower soil layer, compared to the deeper soil layer. The growth inhibition of the barnyard grass seedlings emerging from the shallower soil layer was greater than that of the barnyard grass seedlings emerging from the deeper soil layer after the soil surface application of pyriftalid. It is suggested that the emergence timing from the different soil depths is an important factor affecting the herbicidal activity of pyriftalid when it is applied to the soil surface under paddy field conditions.

Preparation of silica-coated gadolinium compound particle colloid solution and its application in imaging

Kobayashi, Yoshio,Morimoto, Hikaru,Nakagawa, Tomohiko,Gonda, Kohsuke,Ohuchi, Noriaki Techno-Press 2013 Advances in nano research Vol.1 No.3

A preparation method for gadolinium compound (GdC) nanoparticles coated with silica ($GdC/SiO_2$) is proposed. GdC nanoparticles were prepared with a homogeneous precipitation method at $80^{\circ}C$ using $1.0{\times}10^{-3}$ M $Gd(NO_3)_3$, 0.5 M urea and $0-3.0{\times}10^{-4}$ M ethylenediarinnetetraacetic acid disodium salt dihydrate (ETDA) in water. As a result of preparation at various EDTA concentrations, GdC nanoparticles with a size as small as $40.5{\pm}6.2$ nm, which were colloidally stable, were prepared at an EDTA concentration of $2.0{\times}10^{-4}$ M. Silica-coating of the GdC nanoparticles was performed by a St$\ddot{o}$ber method at $35^{\circ}C$ using $1.0-10.0{\times}10^{-3}$ M tetraethylorthosilicate (TEOS), 11 M $H_2O$ and $1.5{\times}10^{-3}$ M NaOH in ethanol in the presence of $1.0{\times}10^{-3}$ M GdC nanoparticles. Performance of preparation at various TEOS concentrations resulted in production of $GdC/SiO_2$ particles with an average size of $106.1{\pm}11.2$ nm at a TEOS concentration of $5.0{\times}10^{-3}$ M. The gadolinium (Gd) concentration of $1.0{\times}10^{-3}$ M in the as-prepared $GdC/SiO_2$ particle colloid solution was increased up to a Gd concentration of 0.2 M by concentrating with centrifugation. The core-shell structure of $GdC/SiO_2$ particles was undamaged, and the colloid solution was still colloidally stable, even after the concentrating process. The concentrated $GdC/SiO_2$ colloid solution showed images of X-ray and magnetic resonance with contrast as high as commercial Gd complex contrast agents.

How to Apply Tricky Biological Mechanisms to Agricultural and Industrial Production

Kobayashi, Akio 한국응용생명화학회 2000 Journal of Applied Biological Chemistry (J. Appl. Vol.43 No.4

By the end of the $21^st$ century, the world population will surely far exceed the current 6.6 billion, threatening the essential requirements for life due to environmental deterioration and shortened food supply. To overcome this looming threat, we must develop new biotechnologies. There are so many known natural phenomena that we may have neglected, not perceiving them as blessings of nature. Many more remain unknown. We must examine each of them carefully since the many tricky and complicated mechanisms behind simple natural workings could provide us with attractive research targets. How then do we apply these complicated natural mechanisms to agricultural/ industrial production?.

INHIBITORY EFFECT OF THE IONOPHORE SALINOMYCIN ON DEAMINATION BY MIXED RUMEN BACTERIA

Kobayashi, Y.,Suda, K.,Wakita, M.,Baran, M.,Hoshino, S. Asian Australasian Association of Animal Productio 1996 Animal Bioscience Vol.9 No.1

A series of in vitro experiments was conducted to investigate response of rumen bacterial deamination to the ionophore salinomycin. Addition of salinomycin to the inoculum, strained rumen fluid, depressed ammonia production from casein, while increased accumulation of ${\alpha}$-amino acids. This suggests an inhibitory effect of salinomycin on ruminal deamination. When the effect in washed bacterial suspension was monitored with individual amino acid, aspartic acid degradation was markedly inhibited by salinomycin. This inhibition was not observed when the mixed rumen bacteria were ultrasonically disrupted and used as the enzyme source. Extent of the inhibition tended to be higher in the bacteria source from sheep on a high roughage diet. From these results it was speculated that the inhibition of deamination with salinomycin is caused by a decreased transport of amino acid into the bacterial cells as well as a decreased proportion of deaminating bacteria in the rumen.

Laser methane detector-based quantification of methane emissions from indoor-fed Fogera dairy cows

Kobayashi, Nobuyuki,Hou, Fujiang,Tsunekawa, Atsushi,Yan, Tianhai,Tegegne, Firew,Tassew, Asaminew,Mekuriaw, Yeshambel,Mekuriaw, Shigdaf,Hunegnaw, Beyadglign,Mekonnen, Wondimeneh,Ichinohe, Toshiyoshi Asian Australasian Association of Animal Productio 2021 Animal Bioscience Vol.34 No.8

Objective: Portable laser methane detectors (LMDs) may be an economical means of estimating CH₄ emissions from ruminants. We validated an LMD-based approach and then used that approach to evaluate CH₄ emissions from indigenous dairy cows in a dryland area of Ethiopia. Methods: First, we validated our LMD-based approach in Simmental crossbred beef cattle (n = 2) housed in respiration chambers and fed either a high- or low-concentrate diet. From the results of the validation, we constructed an estimation equation to determine CH₄ emissions from LMD CH₄ concentrations. Next, we used our validated LMD approach to examine CH₄ emissions in Fogera dairy cows grazed for 8 h/d (GG, n = 4), fed indoors on natural-grassland hay (CG1, n = 4), or fed indoors on Napier-grass (Pennisetum purpureum) hay (CG2, n = 4). All the cows were supplemented with concentrate feed. Results: The exhaled CH₄ concentrations measured by LMD were linearly correlated with the CH₄ emissions determined by infrared-absorption-based gas analyzer (r² = 0.55). The estimation equation used to determine CH₄ emissions (y, mg/min) from LMD CH₄ concentrations (x, ppm m) was y = 0.4259x+38.61. Daily CH₄ emissions of Fogera cows estimated by using the equation did not differ among the three groups; however, a numerically greater milk yield was obtained from the CG2 cows than from the GG cows, suggesting that Napier-grass hay might be better than natural-grassland hay for indoor feeding. The CG1 cows had higher CH₄ emissions per feed intake than the other groups, without significant increases in milk yield and body-weight gain, suggesting that natural-grassland hay cannot be recommended for indoor-fed cows. Conclusion: These findings demonstrate the potential of using LMDs to valuate feeding regimens rapidly and economically for dairy cows in areas under financial constraint, while taking CH₄ emissions into consideration.

Atmospheric Bioaerosol, Bacillus sp., at an Altitude of 3,500 m over the Noto Peninsula: Direct Sampling via Aircraft

Kobayashi, Fumihisa,Morosawa, Shinji,Maki, Teruya,Kakikawa, Makiko,Yamada, Maromu,Tobo, Yutaka,Hon, Chun-Sang,Matsuki, Atsushi,Iwasaka, Yasunobu Korean Society for Atmospheric Environment 2011 Asian Journal of Atmospheric Environment (AJAE) Vol.5 No.3

This work focuses on the analysis of bioaerosols in the atmosphere at higher altitudes over Noto Peninsula, Japan. We carried out direct sampling via aircraft, separated cultures, and identified present isolates. Atmospheric bioaerosols at higher altitudes were collected using a Cessna 404 aircraft for an hour at an altitude of 3,500 m over the Noto Peninsula. The aircraft-based direct sampling system was devised to improve upon the system of balloon-based sampling. In order to examine pre-existing microorganism contamination on the surface of the aircraft body, bioaerosol sampling was carried out just before takeoff using the same method as atmospheric sampling. Identification was carried out by a homology search for 16S or 18S rDNA isolate sequences in DNA databases (GenBank). Isolate sampling just before takeoff revealed Stretpomyces sp., Micrococcus sp., and Cladosporium sp. One additional strain, Bacillus sp., was isolated from the sample after bioaerosol collection at high altitude. As the microorganism contamination on the aircraft body before takeoff differed from that while in the air, the presence of additional, higher atmosphere-based microorganisms was confirmed. It was found that Bacillus sp. was floating at an altitude of 3,500 m over Noto Peninsula.