Injection molding of products with functional surfaces by micro-structured, PVD coated injection molds

Molding of micro structures by injection molding leads to special requirements for the molds e.g. regarding wear resistance and low release forces of the molded components. At the same time it is not allowed to affect the replication precision. Physical vapor deposition (PVD) is one of the promising technologies for applying coatings with adapted properties like high hardness, low roughness, low Young’s modulus and less adhesion to the melt of polymers. Physical vapor deposition technology allows the deposition of thin films on micro structures. Therefore, the influence of these PVD layers on the contour accuracy of the replicated micro structures has to be investigated. For this purpose injection mold inserts were laser structured with micro structures of different sizes and afterwards coated with two different coatings, which were deposited by a magnetron sputter ion plating PVD technology. After deposition, the coatings were analyzed by techniques regarding hardness, Young’s modulus and morphology. The geometries of the micro structures were analyzed by scanning electron microscopy before and after coating. Afterwards, the coated mold inserts were used for injection molding experiments. During the injection molding process, a conventional and a variothermal temperature control of the molds were used. The molded parts were analyzed regarding roughness, structure height and structure width by means of laser microscopy.     

Sibling relationship quality and adolescent delinquency: A latent growth curve approach.

The present study examined whether level and changes in sibling relationship quality and older sibling delinquency are related to level and changes in younger sibling delinquency, for brother, sister, older brother/younger sister and older sister/younger brother sibling pairs. Questionnaire data were collected from 249 Dutch sibling pairs (11–15 years old) over a period of three years, with annual measurements. Results showed that level and over-time changes in sibling relationship quality and older and younger sibling delinquency were significantly different for the four sibling gender combinations. Results of multivariate growth curve modeling showed that sibling relationship quality was related to delinquency of older siblings (but not younger siblings), and delinquency of older siblings was associated with younger sibling delinquency two years later. We also found differences between the four sibling gender combinations. For example, for brother and sister pairs (but not mixed-sex sibling pairs), over-time changes in older sibling delinquency were related to younger sibling delinquency two years later as well as the change pattern in younger sibling delinquency over time. Strengths, limitations and possible implications for research and intervention of adolescent delinquency are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

3D printing of bone substitute implants using calcium phosphate and bioactive glasses

Customized implants for bone replacement are a great help for a surgeon to remodel maxillofacial or craniofacial defects in an esthetical way, and to significantly reduce operation times. The hypothesis of this study was that a composite of β-tricalcium phosphate (β-TCP) and a bioactive glass similar to the 45S5 Henchglass^® is suitable to manufacture customized implants via 3D-printing process. The composite was chosen because of the bioresorption properties of the β-TCP, its capability to react as bone cement, and because of the adjustability of the bioactive glass from inert to bioresorbable. Customized implants were manufactured using the 3D-printing technique. The four point bending strength of the printed specimens was 14.9 MPa after sintering. XRD analysis revealed the occurrence of two other phases, CaNaPO₄ and CaSiO₃, both biocompatible and with the potential of biodegradation. We conclude that it is possible to print tailored bone substitute implants using a bioactive TCP/glass composite. The glass is not involved as reactive substance in the printing process. This offers the opportunity to alter the glass composition and therefore to vary the composition of the implant.     

Soft Futures: Mushrooms and Regenerative Design

Three recent projects fabricated from living mushroom bricks that create a visceral experience of mycelium biocomposites are described as a natural example of a “soft system.” The move toward soft, regenerative systems has important implications for the way we approach the production of architectural materials and environments in the Anthropocene. Collectively, the projects suggest a future in which dynamic materials that contribute to local ecosystems are grown rather than manufactured and engage with temporality in new and productive ways.     

A Burnside Approach to the Finite Substitution Problem

We introduce a new model of weighted automata: the desert automata. We show that their limitedness problem is PSPACE-complete by solving the underlying Burnside problem. As an application of this result, we give a positive solution to the so-called finite substitution problem which was open for more than 10 years: given recognizable languages K and L, decide whether there exists a finite substitution σ such that σ(K) = L.     

Multimedia displays for conceptual discovery: information seeking with strand maps

This article explores the use of a multimedia search interface for digital libraries based on strand maps developed by the American Association for the Advancement of Science. As semantic-spatial displays, strand maps provide a visual organization of relevant conceptual information that may promote the use of science content during digital library use. A study was conducted to compare users' cognitive processes during information seeking tasks when using a multimedia strand maps interface, versus the textual search interface currently implemented in the Digital Library for Earth System Education. Quantitative and qualitative data from think-aloud protocols revealed that students were more likely to engage with science content (e.g., analyzing the relevance of science concepts with regard to task needs) during search when using the strand maps interface compared to those using textual searching. In contrast, students using a textual search interface engaged more frequently with surface-level information (e.g., the type of a resource regardless of its science content) during search and retrieval. As a multimedia search interface for digital libraries, strand maps appear to be promising tools to promote conceptual discovery and learning through content-based processes that promote learner engagement with relevant science knowledge.     

Survival and movement of enterovirus in connection with land disposal of sludges

Coxsackievirus and tritiated water were added to municipal sludges which were placed on lysimeters containing sandy soil or clay soil. It took 23 weeks during a normal Danish winter to inactivate virus from an initial 10⁶tcid₅₀/g sludge to a not demonstrable level. Irrespective of sludge and soil type no virus was demonstrated in the leachate water. The rainfall during December–May was 300 mm.     

Application of the Cytosensor microphysiometer to drug discovery

The Cytosensor microphysiometer uses silicon chip technology to correlate changes in extracellular acidification rates with quantitative changes in cellular metabolism in response to ligand binding to surface receptors. This functional measure of physiology makes the Cytosensor a valuable tool in drug discovery research by allowing application of the instrument to screening of prospective pharmacologically active agents, characterizations of dose responses and structure-activity relationships, and investigation of mechanisms of action.