Hybridization Networks of mRNA and Branched RNA Hybrids

Messenger RNA (mRNA) is emerging as an attractive biopolymer for therapy and vaccination. To become suitable for vaccination, mRNA is usually converted to a biomaterial, using cationic peptides, polymers or lipids. An alternative form of converting mRNA into a material is demonstrated that uses branched oligoribonucleotide hybrids with the ability to hybridize with one or more regions of the mRNA sequence. Two such hybrids with hexamer arms and adamantane tetraol as branching element were prepared by solution-phase synthesis. When a rabies mRNA was treated with the branched hybrids at 1 M NaCl concentration, biomaterials formed that contained both of the nucleic acids. These results show that branched oligoribonucleotides are an alternative to the often toxic reagents commonly used to formulate mRNA for medical applications.     

Effect of Ti,Nb, and Ti + Nb Coatings on the Bond Strength-Structure Relationship in Al/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> Joints

There is a growing interest in metal-ceramic bonding for wide range of applications in electronic devices and high technology industry for fabrication of metal matrix composites and bonding of ceramic components to metals. The object of the work was to study the effect of Ti, Nb, and Ti + Nb thin films deposited by PVD method on alumina substrates on structure and bond strength properties of Al/Al₂O₃ joints. The joints were fabricated using the results of a wetting experiment and the sessile drop method at a temperature of 1223 K in a vacuum of 0.2 MPa for 30 min of contact. The structure of the metal/ceramic interface was investigated using scanning electron microscopy. The elemental distribution at the metal-ceramic interface was analyzed using energy dispersive x-ray spectroscopy. Transmission electron microscopy was also used to investigate some aspects of the metal/ceramic interface. The bond strength properties of joints were measured using shear test. The shear strength results demonstrated significant improvement of shear strength of Al/Al₂O₃ joints due to the application of Ti + Nb thin film on alumina substrate. Microstructural investigations of the interface indicated that Al/coating/Al₂O₃ couples have diffusion transition interface which influences the strengthening of these joints. A conclusion could be drawn that the presence of thin film layers changes the character of interaction and leads to the formation of new reaction products in the bonding layer.     

Knowledge-based hand tool selection in concurrent design of mechanical systems

Selection of hand tools for cost-effective assembly and maintenance of a mechanical system has a significant impact on its life-cycle cost. A knowledge-based automated procedure for the selection of hand tools needed to efficiently carry out fastening operations in a mechanical assembly is presented. The objective is to select a tool that is applicable to a particular fastening operation, minimizes time and cost of the fastening operation, and satisfies accessibility requirements, and to provide design assistance to the design engineer. The role of the tool selection procedure in the concurrent design of mechanical systems is described.     

Children's understanding of the knowledge prerequisites of drawing and pretending.

Many young children will claim that someone is pretending to be something even when the person does not know what that something is. To examine whether children's failure to take knowledge prerequisites into account is part of a more fundamental problem in recognizing how mental representations constrain external ones, the authors asked children whether an artist who did not know what something was, yet whose drawing bore resemblance to it, was drawing it. The same questions were asked regarding pretending. Children performed similarly on pretending and drawing questions, and performance on both questions improved when the protagonists' point of view was emphasized. Performance for drawing improved somewhat when alternative goals were stated. Further, cross-sectional data indicated that understanding how knowledge relates to producing external representations increases gradually from age 4 to age 8, suggesting that experiential factors may be crucial to this understanding. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Master's-level training and employment in community mental health.

The training and employment of master's-level psychologists have long been controversial issues. We describe a master's-level program for training community mental health practitioners, and we present information on the placement of program graduates. The information suggests that there continues to be a demand for well-trained, master's-level practitioners. (PsycINFO Database Record (c) 2010 APA, all rights reserved)