大規模密度汎関数強結合分子動力学シミュレータの開発とシリコン及びカーボン系材料の化学気相成長プロセスの理論設計

要約のみTohoku University久保百司課

“If I could have it back, all the time that we wasted I’d only waste it again” : Arcade Fire, The Suburbs ニ オケル コウガイ ノ ノスタルジー

Cultural Formation Studies(3

プロセス ライティング フィクション ノ ココロミ オートフィクション ト メタフィクション ノ リロン ニ ツイテ

Cultural Formation Studies(4

A sacrificial millipede altruistically protects its swarm using a drone blood enzyme, mandelonitrile oxidase

Soldiers of some eusocial insects exhibit an altruistic self-destructive defense behavior in emergency situations when attacked by large enemies. The swarm-forming invasive millipede, Chamberlinius hualienensis, which is not classified as eusocial animal, exudes irritant chemicals such as benzoyl cyanide as a defensive secretion. Although it has been thought that this defensive chemical was converted from mandelonitrile, identification of the biocatalyst has remained unidentified for 40 years. Here, we identify the novel blood enzyme, mandelonitrile oxidase (ChuaMOX), which stoichiometrically catalyzes oxygen consumption and synthesis of benzoyl cyanide and hydrogen peroxide from mandelonitrile. Interestingly the enzymatic activity is suppressed at a blood pH of 7, and the enzyme is segregated by membranes of defensive sacs from mandelonitrile which has a pH of 4.6, the optimum pH for ChuaMOX activity. In addition, strong body muscle contractions are necessary for de novo synthesis of benzoyl cyanide. We propose that, to protect its swarm, the sacrificial millipede also applies a self-destructive defense strategy—the endogenous rupturing of the defensive sacs to mix ChuaMOX and mandelonitrile at an optimum pH. Further study of defensive systems in primitive arthropods will pave the way to elucidate the evolution of altruistic defenses in the animal kingdom

Improvement of acid resistance of Zn-doped dentin by newly generated chemical bonds

Dental caries, the world's most prevalent infectious disease, is caused by the diffusion of hydroxyl ions into tooth structures. To prevent dental caries, the application of fluoride (F) and zinc (Zn) ions to teeth surfaces are potential effective measures. In this study, The ionic influence, especially the chemical bond of F and Zn, on the acid resistance of dentin were investigated by particle induced X-ray / gamma-ray emission, X-ray diffraction, X-ray photoelectron spectroscopy and X-ray absorption spectroscopy. The results showed Zn was distributed in the limited surface layer of dentin without altering its crystal structure. From the Zn K edge extended X-ray absorption fine structure, Zn incorporated into dentin was surrounded by oxygen and demonstrated four-fold coordination. The bond length and chemical state of Zn–O in Zn doped dentin suggested newly generated Zn–O covalent bond, which may improve acid resistance of dentin. This study showed that the atomic and molecular structures, such as the molecular distances and chemical state, influenced acid resistance of teeth, emphasizing the validity of chemical state analysis for understanding properties in biomaterials.Naito K., Kuwahara Y., Yamamoto H., et al. Improvement of acid resistance of Zn-doped dentin by newly generated chemical bonds. Materials and Design, 215, 110412. https://doi.org/10.1016/j.matdes.2022.110412

Measurements of short-lived cosmogenic nuclides in rain samples

金沢大学自然計測応用研究センター自然計測研究部門金沢大学理学部Extremely low activity levels of cosmic ray induced nuclides have been measured in freshly precipitated rainwater by quick chemical separation coupled with ultra low background gamma-spectrometry. The nuclides detected were 38S (T1/2 = 2.83 h)-38Cl (37.2 m), 39Cl (55.6 m), 24Na (14.96 h), 28Mg (20.9 h), 7Be (53.3 d) and 22Na (2.602 y). The number of atoms in rain water were evaluated to be ranging from 400-1900 l-1 for 39Cl (n = 6, mean: 1200), 30-1500 l-1 for 24Na (n = 16, mean: 520), 80-600 l-1 for 28Mg (n = 13, mean: 260), 1·106-4·107 l-17Be (n = 16, mean: 7·106) and 2·10 3-1·105 l-1 for 22Na (n = 9, mean: 2·104). Measurements of activity levels and activity ratios of short-lived cosmic-ray induced short-lived nuclides will open new method to understand atmospheric processes occurred at the altitude of rain cloud. © 2006 Akadémiai Kiadó

ジドウ ソウサホウ ニヨル ガン チリョウヨウ 125 Ｉ シード ホウシャセン キョウド ケンテイ システム ノ カイハツ

A new scanning system using a NaI(Tl) scintillation survey meter, copper slit and drive-unit has been developed for quality control of radioactive seeds. Radioactive seed implants, also called brachytherapy, are widely used modality in the treatment of early stage prostate cancers. Seeds containing the iodine-125 are most commonly used for permanent implant prostate brachytherapy. These seeds are commercially available and delivered in a sterile environment in the form of packaged cartridge. It is impractical to re-sterilize and re-load seeds after calibration. This paper describes a new method to calibrate all seeds in the seed cartridge in a sterile package

Odor Removal Characteristics of a Laminated Film-Electrode Packed-Bed Nonthermal Plasma Reactor

Odor control has gained importance for ensuring a comfortable living environment. In this paper, the authors report the experimental results of a study on the detailed characteristics of a laminated film-electrode and a laminated film-electrode packed-bed nonthermal plasma reactor, which are types of dielectric barrier discharge (DBD) reactor used for odor control. These plasma reactors can be potentially used for the decomposition of volatile organic compounds (VOCs) and reduction of NOx. The reactor is driven by a low-cost 60-Hz neon transformer. Removal efficiencies under various experimental conditions are studied. The complete decomposition of the main odor component, namely, NH3, is achieved in a dry environment. The retention times are investigated for the complete removal of NH3 in the case of the film-electrode plasma reactor and the film-electrode packed-bed plasma reactor. The removal efficiency of the former reactor is lower than that of the latter reactor. Mixing another odor component such as CH3CHO in the gas stream has no significant effect on NH3 removal efficiency