Controlling DNA Bundle Size and Spatial Arrangement in Self-assembled Arrays on Superhydrophobic Surface

Nano-Micro Letters - The use of superhydrophobic surfaces (SHSs) is now emerging as an attractive platform for the realization of one-dimensional (1D) nanostructures with potential applications in...     

Polymerization of cysteine functionalized thiophenes

Different synthetic pathways leading to polythiophenes (PTs) containing units derived from methyl N-(tert-butoxycarbonyl)-S-3-thienyl-l-cysteinate (1) and methyl N-(tert-butoxycarbonyl)-S-(2-thien-3-ylethyl)-l-cysteinate (2) were investigated. The oxidative coupling with FeCl₃ applied to N-deprotected monomer 1 generates a chemically fleeting PT, whereas when applied to N-deprotected monomer 2 generates a mixture of oligomers. Two co-polymers bearing cysteine moieties, poly{[methyl N-(tert-butoxycarbonyl)-S-3-thienyl-l-cysteinate]-co-thiophene} (co-PT1) and poly{[methyl N-(tert-butoxycarbonyl)-S-(2-thien-3-ylethyl)-l-cysteinate]-co-thiophene} (co-PT2), were eventually synthesized through Stille coupling of 2,5-bis(trimethylstannyl)thiophene and 2,5-dibromo derivative of compound 1 and through the post-functionalization with protected cysteine of a tosylate co-polymer, poly{[2-(3-thienyl)ethyl 4-methylbenzenesulfonate]-co-thiophene} (co-PTTs). UV-vis, CD, NMR and GPC analyses evidenced that these polymers are able to form chiral self-assembling structures, due to the formation of a hydrogen bond network and to π-stacks, not only in the solid state but also in solution.     

Structural and mechanical investigations of magnetron sputtering TiO<Subscript>2</Subscript>/Ti/TiN multilayer films on Si(100) substrate

TiO₂/Ti/TiN multicompositional coating was prepared by DC reactive magnetron sputtering (MS) at a temperature of 150°C using a combination of a Ti metal target and a pure Ar, an Ar–O₂ mixture, or an Ar–N₂ mixture discharge gas, onto a Silicon(100) substrate. This system represents nano-structured multilayer substrate model for biomedical application as well as substrate models to reproduce the bulk titanium surface. This substrate model (Ti/TiN/Si(100)) makes possible and easy mechanical and microscopic characterization in particular for transmission electron microscopy after biocompatible test. The model multilayer TiO₂/Ti/TiN/(100) was obtained after preparation of two intermediate samples: TiN/Si(100) and Ti/TiN/Si(100). Structural (X-ray diffraction), morphological (scanning electron and atomic force microscopy) as well as mechanical (hardness and elastic modulus) studies of the MS films were performed.     

Compositional analysis of the styrene–isobutylene copolymer

Analysis for composition of the styrene–isobutylene copolymer has been accomplished by independent techniques which include carbon-hydrogen analysis and infrared and NMR spectroscopy. The use of blends of homopolymers presents difficulties in establishing true absorptivities for the solution of two-component systems, and appropriate corrections were applied to enable use of IR as an analytical technique. Carbonhydrogen elemental analysis and NMR spectroscopy were used to verify the IR results.     

Role of parental motivational practices in children's academic intrinsic motivation and achievement.

Tested the role of parental motivational practices in children's academic intrinsic motivation and achievement in a longitudinal study of children at ages 9 and 10 yrs. Two types of motivational practices were assessed: mothers' encouragement of children's task endogeny and provision of task-extrinsic consequences. Structural equations path models for general-verbal and math academic areas supported the 2 predictions that children's academic intrinsic motivation is positively related to encouragement of task endogeny and negatively related to provision of task-extrinsic consequences. Academic intrinsic motivation at age 9 yrs predicted motivation and achievement at age 10 yrs. Moreover, through motivation at 9 yrs, the motivational practices indirectly affected motivation at 10 yrs and achievement. Findings provide ecological validity for the role of parental motivational practices in children's academic intrinsic motivation and achievement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

AI Planner Assisted Test Generation

This paper describes an AI planner assisted approach to generate test cases for system testing based on high level test objectives. We use four levels of test generation: the metaprocessor, the preprocessor, the AI planner, and the postprocessor levels. Test generation is based on an extended UML model of the system under test and a mapping of high-level test objectives into initial and goal conditions of the planner. Test objectives are derived from a series of interviews with professional testers. We suggest various options for test criteria related to test objectives. The AI planner was used to generate hundreds of test cases for a robot controlled tape silo. The planner generated tests within a reasonable time. It was successful for each test objective given.     

Climbing Plant‐Inspired Micropatterned Devices for Reversible Attachment

Climbing plants have evolved over millions of years and have adapted to unpredictable scenarios in unique ways. These crucial features make plants an outstanding biological model for scientists and engineers. Inspired by the ratchet‐like attachment mechanism of the hook‐climber Galium aparine, a novel micropatterned flexible mechanical interlocker is fabricated using a 3D direct laser lithography technique. The artificial hooks are designed based on a morphometric analysis of natural hooks. They are characterized in terms of pull‐off and shear forces, both in an array and as individual hooks. The microprinted hooks array shows high values of pull‐off forces (up to F_⊥ ≈ 0.4 N cm^?2) and shear forces (up to F_// ≈ 13.8 N cm^?2) on several rough surfaces (i.e., abrasive materials, fabrics, and artificial skin tissues). The contact separation forces of individual artificial hooks are estimated when loads with different orientations are applied (up to F ≈ 0.26 N). In addition, a patterned tape with directional microhooks is integrated into a mobile platform to demonstrate its climbing ability on inclined surfaces of up to 45°. This research opens up new opportunities for prototyping the next generation of mechanical interlockers, particularly for soft‐ and microrobotics, the textile industry, and biomedical fields.     

Development of Residual Stresses and Texture in Drawn Copper Tubes

The residual stress state and the texture in Cu‐tubes, drawn without a plug under controlled laboratory conditions, are presented. Neutron stress determination confirms a stress gradient from the outer to the inner surface of the tube walls. High energy X‐rays were used to analyze the texture gradient around the perimeter of the tubes as well as over the wall thickness. Anisotropic flow during tube processing results in texture variations described by ODF‐analysis.     

Metal–polymer–metal sandwiches with local metal reinforcements: A study on formability by deep drawing and bending

The formability of metal–polymer–metal sandwich composites with embedded different solid and mesh steel inlays was investigated with the aim to gain information about their forming behaviour by shaping, especially deep drawing and bending. Therefore the geometry and the size of the local inlays have been varied. The reduction in thickness of these composites was quantified by photogrammetry. As a result the formability of sandwich composites with solid steel inlays is lower compared to non-reinforced ones. Sandwiches with mesh inlays showed a slightly increased thinning compared to sandwiches with circular solid inlays. Both variations revealed good formability. The results will be used for future tailoring of sandwich structures with particularly demanded properties.     

All or none hypothesis: A global-default mode that characterizes the brain and mind.

It is proposed that the mind and brain often work at a gross level and only with fine tuning or inhibition act in a more differentiated manner, even when one might think the domains being issued the global command should be distinct. This applies to disparate findings in cognitive science and neuroscience in both children and adults. Thus, it is easier to switch everything, or nothing, than to switch one thing (the rule one is following or which button to press) but not the other. It is easier to issue the same command to both hands than to move only one hand. If one needs to respond to the opposite (or antonym) of a stimulus, one is faster if the correct response is to the side opposite the stimulus. People tend to think of the nervous system as sending out very precise commands only to the relevant recipient, but it appears that often the command goes out more globally and then parts of the system need to be inhibited from acting on the command. (PsycINFO Database Record (c) 2010 APA, all rights reserved)