南極ドームふじ基地における第2期氷床深層コア掘削

南極ドームふじ基地において，第2 期氷床深層コア掘削が行われた．2001 年のパイロット孔掘削に引き続き2003/2004 シーズンから4 か年にわたり本格的な深層コア掘削を実施し，2007 年1 月に3035.22 m 深に達した．夏期間のみの掘削としたので，効率よく掘削できるように第1 期深層コア掘削システムの問題点を解決しながら多くの改良を施した．特に1 回の掘削で採取可能なコア長を2.3 m から3.84 m にしたことと切削チップ収納効率を高めたことが大きい．本報告では，現地で使用した掘削システムの概要とともに，掘削の方法，掘削の経過を述べるとともに，掘削中に生じた様々なトラブルについても報告し，併せて今後の課題を示した． The second deep ice coring project was carried out at Dome Fuji, Antarctica. Following the pilot hole drilling in 2001, deep ice core drilling was conducted for four years from the 2003/2004 austral summer season, reaching a depth of 3035.22 m in January 2007. The drilling was performed only in the summer season. Therefore, many improvements were made to the problems of the first deep ice core drilling system to enable efficient drilling. In particular, the core length that can be obtained at one time was increased from 2.3m to 3.84 m, and the chip storage efficiency was enhanced. In this report, the outline of the drilling system, the method of drilling, the progress of drilling operation, and various troubles were reported. Also, future issues are indicated

氧化钆纳米粒子对A549肺癌细胞的辐射增敏效应研究

采用氧化钆纳米粒子(GON),研究钆基纳米粒子对X射线和碳离子束的辐射增敏效应。首先,通过透射电镜观察材料粒径,使用DLS检测材料的水合半径及Zeta电位,并用紫外吸收谱证实GON在培养基中稳定性较好;研究发现钆(Gd)浓度为10.0μg/mL的GON对30 keV/μm碳离子束辐照水溶液产生的羟自由基的增强系数为1.13;GON对A549肺癌细胞和正常MRC-5肺细胞没有明显的毒性,且在人肺癌A549细胞中的摄取量随共培养浓度的增加而增加,在10.0μg/mL共培养浓度下,细胞摄入Gd的量为0.73 pg/cell;进一步采用克隆存活实验证明,GON的加入对X射线和碳离子辐照A549细胞所产生的损伤具有明显的增强,在10%的细胞存活水平下,GON对A549细胞在X射线及碳离子辐照下的辐射增敏分别达15.5%和10.1%。鉴于钆材料常被用于磁共振成像(MRI),所获得的GON有望作为X射线和碳离子的诊疗一体化材料

マウス５系統を用いた空腸腺窩細胞、骨髄幹細胞における線量・反応関係の差異

第４１回学術大

Water Confined in Hydrophobic Cup-Stacked Carbon Nanotubes beyond Surface-Tension Dominance

Water confined in carbon nanotubes (CNTs) can exhibit distinctly different behaviors from the bulk. We report transmission electron microscopy (TEM) observation of water phases inside hydrophobic cup-stacked CNTs exposed to high vacuum. Unexpectedly, we observed stable water morphologies beyond surface-tension dominance, including nanometer thin free water films, complex water-bubble structures, and zigzag-shaped liquid−gas interface. The menisci of the water phases are complex and inflected, where we measured the contact angles on the CNT inner wall to be 68−104°. The superstability of the suspended ultrathin water films is attributed to the strong hydrogen-bonded network among water molecules and adsorption of water molecules on the cup-structured inner wall. The complex water-bubble structure is a result of the stability of free water films and interfacial nanobubbles, and the zigzag edge of the liquid−gas interface is explained by the pinning effect. These experimental findings provide valuable knowledge for the research on fluids under nanoscale confinement

酶法醇解合成2-花生四烯酸单甘酯Enzymatic synthesis of 2-arachidonoylglycerol by ethanolysis

2-花生四烯酸单甘酯（2-AG）是一种内源性大麻素，在神经、心血管和免疫等系统中具有一系列的生理活性。为实现2-AG的绿色高效制备，探究了脂肪酶催化醇解富含花生四烯酸的微生物油制备2-AG的方法。以2-单甘酯（2-MAG）含量为指标，通过单因素实验对酶法催化醇解反应条件进行了优化，并采用溶剂萃取法对产物进行纯化。结果表明：最佳反应条件为以Lipozyme 435脂肪酶为醇解脂肪酶、酶添加量4%（以油质量计）、油与无水乙醇物质的量比1∶ 40、叔丁醇为溶剂、油溶比2∶ 3、反应温度35 ℃、反应时间8 h，在最佳条件下粗产物中2-MAG含量为3363%；经溶剂萃取纯化后2-MAG的纯度达到了94.79%，其中2-AG含量为40.70%。 综上，酶法醇解富含花生四烯酸的微生物油可以获得高2-AG含量的2-MAG。2-Arachidonoylglycerol (2-AG) is an endogenous cannabinoid and exhibits a variety of biological activities in the central nervous, cardiovascular, and immune systems. To prepare 2-AG in a greener and efficient way, a lipase-catalyzed alcoholysis of microbial oil rich in arachidonic acid was used to synthesize 2-AG. With the 2-monoacylglycerol (2-MAG) content as an index, the reaction conditions of lipase-catalyzed alcoholysis were optimized by single factor experiment, and a solvent extraction method was employed to purify the product. The results showed that the optimal reaction conditions of lipase-catalyzed alcoholysis were as follows: Lipozyme 435 as alcoholysis enzyme, lipase dosage 4% (relative to oil mass), molar ratio of oil to anhydrous ethanol 1∶ 40, tert-butanol as solvent, ratio of oil to solvent 2∶ 3, reaction temperature 35 ℃ and reaction time 8 h. Under the optimal conditions, 2-MAG content in the crude product was up to 33.63%. The purity of 2-MAG after purification was up to 9479%, and the content of 2-AG was 40.70%. In conclusion, enzymatic alcoholysis of microbial oil rich in arachidonic acid can obtain 2-MAG with high 2-AG content

Nanoscale Bubble Dynamics Induced by Damage of Graphene Liquid Cells

Graphene liquid cells provide the highest possible spatial resolution for liquid-phase transmission electron microscopy. Here, in graphene liquid cells (GLCs), we studied the nanoscale dynamics of bubbles induced by controllable damage in graphene. The extent of damage depended on the electron dose rate and the presence of bubbles in the cell. After graphene was damaged, air leaked from the bubbles into the water. We also observed the unexpected directional nucleation of new bubbles, which is beyond the explanation of conventional diffusion theory. We attributed this to the effect of nanoscale confinement. These findings provide new insights into complex fluid phenomena under nanoscale confinement

Enhanced Thermoelectric Performance of As-Grown Suspended Graphene Nanoribbons

Conventionally, graphene is a poor thermoelectric material with a low figure of merit (ZT) of 10^− 10^. Although nanostructuring was proposed to improve the thermoelectric performance of graphene, little experimental progress has been accomplished. Here, we carefully fabricated as-grown suspended graphene nanoribbons with quartermicron length and ∼40 nm width. The ratio of electrical to thermal conductivity was enhanced by 1−2 orders of magnitude, and the Seebeck coefficient was several times larger than bulk graphene, which yielded record-high ZT values up to ∼0.1. Moreover, we observed a record-high electronic contribution of ∼20% to the total thermal conductivity in the nanoribbon. Concurrent phonon Boltzmann transport simulations reveal that the reduction of lattice thermal conductivity is mainly attributed to quasi-ballistic phonon transport. The record-high ratio of electrical to thermal conductivity was enabled by the disparate electron and phonon mean free paths as well as the clean samples, and the enhanced Seebeck coefficient was attributed to the band gap opening. Our work not only demonstrates that electron and phonon transport can be fundamentally tuned and decoupled in graphene but also indicates that graphene with appropriate nanostructures can be very promising thermoelectric materials