A general approach to high-yield biosynthesis of chimeric RNAs bearing various types of functional small RNAs for broad applications.

RNA research and therapy relies primarily on synthetic RNAs. We employed recombinant RNA technology toward large-scale production of pre-miRNA agents in bacteria, but found the majority of target RNAs were not or negligibly expressed. We thus developed a novel strategy to achieve consistent high-yield biosynthesis of chimeric RNAs carrying various small RNAs (e.g. miRNAs, siRNAs and RNA aptamers), which was based upon an optimal noncoding RNA scaffold (OnRS) derived from tRNA fusion pre-miR-34a (tRNA/mir-34a). Multi-milligrams of chimeric RNAs (e.g. OnRS/miR-124, OnRS/GFP-siRNA, OnRS/Neg (scrambled RNA) and OnRS/MGA (malachite green aptamer)) were readily obtained from 1 l bacterial culture. Deep sequencing analyses revealed that mature miR-124 and target GFP-siRNA were selectively released from chimeric RNAs in human cells. Consequently, OnRS/miR-124 was active in suppressing miR-124 target gene expression and controlling cellular processes, and OnRS/GFP-siRNA was effective in knocking down GFP mRNA levels and fluorescent intensity in ES-2/GFP cells and GFP-transgenic mice. Furthermore, the OnRS/MGA sensor offered a specific strong fluorescence upon binding MG, which was utilized as label-free substrate to accurately determine serum RNase activities in pancreatic cancer patients. These results demonstrate that OnRS-based bioengineering is a common, robust and versatile strategy to assemble various types of small RNAs for broad applications

2-Ethyl-8-methoxy­methyl-4-oxo-4H-chromen-7-yl (1S,4R)-4,7,7-trimethyl-3-oxo-2-oxabicyclo­[2.2.1]heptane-1-carboxyl­ate

The title compound C23H26O7, was prepared by esterification of 2-ethyl-7-hydr­oxy-8-methoxy­methyl-4H-chromen-4-one with (S)-(−)-camphanic chloride. The two rings of the chromone system are coplanar, making a dihedral angle of 1.99 (19)°, and the camphanoyl unit substituted at 7-O retains the original bicyclo­[2.2.1]heptane conformation of the starting reagent

11β,17aα-Dihydr­oxy-17aβ-methyl-d-homoandrosta-1,4-diene-3,17-dione monohydrate

In the title compound, C21H28O4·H2O, the cyclo­hexa­dienone ring is planar (r.m.s. deviation 0.0186 Å), whereas the two cyclo­hexane rings and the cyclo­hexa­none ring adopt chair conformations. The crystal structure is stabilized by O—H⋯O and C—H⋯O hydrogen bonds

Two Energy Release Processes for CMEs: MHD Catastrophe and Magnetic Reconnection

It remains an open question how magnetic energy is rapidly released in the solar corona so as to create solar explosions such as solar flares and coronal mass ejections (CMEs). Recent studies have confirmed that a system consisting of a flux rope embedded in a background field exhibits a catastrophic behavior, and the energy threshold at the catastrophic point may exceed the associated open field energy. The accumulated free energy in the corona is abruptly released when the catastrophe takes place, and it probably serves as the main means of energy release for CMEs at least in the initial phase. Such a release proceeds via an ideal MHD process in contrast with nonideal ones such as magnetic reconnection. The catastrophe results in a sudden formation of electric current sheets, which naturally provide proper sites for fast magnetic reconnection. The reconnection may be identified with a solar flare associated with the CME on one hand, and produces a further acceleration of the CME on the other. On this basis, several preliminary suggestions are made for future observational investigations, especially with the proposed KuaFu satellites, on the roles of the MHD catastrophe and magnetic reconnection in the magnetic energy release associated with CMEs and flares.Comment: 7 pages, 4 figures, Adv. Spa. Res., in press

High-efficiency segmented thermoelectric power generation modules constructed from all skutterudites

Development of thermoelectric conversion technology for power generation can alleviate the demand for fossil energy and increase the efficiency of energy utilization. To achieve more efficient heat-to-electric conversion, it is desirable to maximize the figure of merit (zT) over a wide temperature range. Constructing a segmented thermoelectric device by serially connecting materials with high zT at different operating temperatures has been proven feasible. However, the issue of compatibility of different thermoelectric materials and the method of connecting different segments to ensure high interfacial stability remain unsolved. Herein, we demonstrate a full skutterudite-based segmented thermoelectric power generation module. The use of thermoelectric materials from the same parent avoids the difference in thermal expansion coefficients and compatibility factors and allows the preparation of thermoelectric junctions by a one-step sintering process. As a result, a high module efficiency of 10.4% is obtained owing to the rational design of the materials, device geometry, and interfaces and is the highest value among skutterudite-based modules reported so far

2-(4-Bromo-1H-indol-3-yl)acetonitrile

In the title compound, C10H7BrN2, the non-H atoms, except the N atom of the acetonitrile group and the C atom bonded to it, lie in the least-squares plane defined by the atoms of the indole ring system (r.m.s deviation = 0.019 Å), with the N and C atom of the cyano group displaced by 2.278 (1) and 1.289 (1) Å, respectively, out of that plane. In the crystal, N—H⋯N hydrogen bonds link the mol­ecules into a C(7) chain along [100]