Heterodimerization of Group I Ribozymes Enabling Exon Recombination through Pairs of Cooperative trans‐Splicing Reactions

Group I (GI) self‐splicing ribozymes are attractive tools for biotechnology and synthetic biology. Several trans‐splicing and related reactions based on GI ribozymes have been developed for the purpose of recombining their target mRNA sequences. By combining trans‐splicing systems with rational modular engineering of GI ribozymes it was possible to achieve more complex editing of target RNA sequences. In this study we have developed a cooperative trans‐splicing system through rational modular engineering with use of dimeric GI ribozymes derived from the Tetrahymena group I intron ribozyme. The resulting pairs of ribozymes exhibited catalytic activity depending on their selective dimerization. Rational modular redesign as performed in this study would facilitate the development of sophisticated regulation of double or multiple trans‐splicing reactions in a cooperative manner.     

Thermal Decomposition of Titanium Alkoxide and Silicate Ester in Organic Solvent: A New Method for Synthesizing Large-Surface-Area, Silica-Modified Titanium(IV) Oxide of High Thermal Stability

Silica-modified titanium oxide (S-TiO₂) powders that have an anatase structure were synthesized via the thermal decomposition of mixtures of titanium(IV) isopropoxide (TIP) and tetramethyl orthosilicate (TMOS) in toluene at 300°C. These S-TiO₂ materials had high rutile-transformation temperatures and maintained large surface areas at elevated temperatures (550°–1000°C). For example, the product that was prepared from a 9:1 TIP:TMOS mixture transformed to rutile at ∼1100°C and possessed a surface area of 160 m²/g, even after calcination at 800°C for 1 h.     

Structural analysis of hydroperoxides formed by oxidation of phosphatidylcholine with singlet oxygen

Soybean phosphatidylcholine (PC) and dilinoleoyl PC (di-18∶2 PC) were oxidized with singlet molecular oxygen using methylene blue as the photosensitizer. The oxidation products, PC monohydroperoxides (PC-MHP) and PC dihydroperoxides (PC-DHP), were isolated by reverse phase liquid chromatography, and their structures were analyzed by nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GC-MS). Signals for the hydroperoxy proton appeared downfield in NMR spectra of PC-MHP and PC-DHP. Soybean PC-MHP and di-18∶2 PC-MHP were converted to trimethylsilyl (TMS) derivatives of hydrogenated diglycerides when treated with phospholipase C and hydrogenated. Thetert-butyldimethylsilyl (TBDMS) derivatives of hydrogenated diglycerides were also prepared from di-18∶2 PC-MHP. Fragmentation of the TMS and TBDMS derivatives was obtained in electron impact mass spectra. The isomeric composition of hydroperoxylinoleate component in di-18∶2 PC-MHP was determined by methanolysis of the hydrogenated diglyceride and mass chromatographic analysis of the resulting isomeric hydroxy octadecanoates.     

Team O2AS' approach for the task-board task of the World Robot Challenge 2018

ABSTRACT

In this paper, we describe the approach of Team O2AS to complete the task-board task of the World Robot Challenge 2018, held in Tokyo. We use a custom gripper and graspable tools with in-built compliance to work with various kinds of parts, increase robustness against uncertainties, and to avoid complicated control strategies. The robots are able to finish all the sub-tasks without the need to exchange grippers. The main idea is to use mechanical compliance and self-centering mechanisms to deal with uncertainty. This is achieved by aligning the objects using either the gripper and tools, or by the design of the robot motions.