Implementation of periodic boundary conditions for loading of mechanical metamaterials and other complex geometric microstructures using finite element analysis

The implementation of periodic boundary conditions (PBCs) is one of the most important and difficult steps in the computational analysis of structures and materials. This is especially true in cases such as mechanical metamaterials which typically possess intricate geometries and designs which makes finding and implementing the correct PBCs a difficult challenge. In this work, we analyze one of the most common PBCs implementation technique, as well as implement and validate an alternative generic method which is suitable to simulate any possible 2D microstructural geometry with a quadrilateral unit cell regardless of symmetry and mode of deformation. A detailed schematic of how both these methods can be employed to study 3D systems is also presented.

     

Trans-Splicing Improvement by the Combined Application of Antisense Strategies

Spliceosome-mediated RNA trans-splicing has become an emergent tool for the repair of mutated pre-mRNAs in the treatment of genetic diseases. RNA trans-splicing molecules (RTMs) are designed to induce a specific trans-splicing reaction via a binding domain for a respective target pre-mRNA region. A previously established reporter-based screening system allows us to analyze the impact of various factors on the RTM trans-splicing efficiency in vitro. Using this system, we are further able to investigate the potential of antisense RNAs (AS RNAs), presuming to improve the trans-splicing efficiency of a selected RTM, specific for intron 102 of COL7A1. Mutations in the COL7A1 gene underlie the dystrophic subtype of the skin blistering disease epidermolysis bullosa (DEB). We have shown that co-transfections of the RTM and a selected AS RNA, interfering with competitive splicing elements on a COL7A1-minigene (COL7A1-MG), lead to a significant increase of the RNA trans-splicing efficiency. Thereby, accurate trans-splicing between the RTM and the COL7A1-MG is represented by the restoration of full-length green fluorescent protein GFP on mRNA and protein level. This mechanism can be crucial for the improvement of an RTM-mediated correction, especially in cases where a high trans-splicing efficiency is required.     

Element contents in leaves of four plant species (birch, mountain ash, fern and spruce) along anthropogenic and geogenic concentration gradients

Forty samples each of leaves of birch (Betula pubescens Ehrh.), European mountain ash (Sorbus aucuparia (L.)) and bracken fern (Pteridium aquilinum (L.) Kuhn) as well as spruce needles (Picea abies (L.) Karsten) were collected along a 120 km south-north transect running through Norway's largest city, Oslo. Concentrations of 25 chemical elements (Ag, Au, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, La, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Sr, Ti, and Zn) as well as loss on ignition for the 4 sample materials are reported. The decline of input of sea spray with distance from the coast, geology, pH and anthropogenic contamination all played a role for the observed element concentrations in the leaves. Although growing under exactly the same natural conditions each plant species displayed quite unique uptake characteristics. Plant-species dependency and individual differences in the reaction of the plant leaves to different element sources make the investigated species of very limited value as bioindicators of anthropogenic activities. Anthropogenic contamination influences plant-leaf element content within a limited distance ( approximately 20 km) from the source.     

Redemptive Places,Charitable Choice,and Welfare Reform

The faces of the two girls featured in Danuta Rothschild's image Women's Shelter express both despair and hope. Part of a series of works on urban homelessness, the painting depicts them seated on the steps of a shelter for battered women. Such “redemptive places” and the hope they offer to desperate lives are the subject of Daphne Spain's Longer View. Spain recounts the inception of these places in the U.S. early in the last century and describes their latest incarnations in “Charitable Choice” initiatives.

Danuta Rothschild emigrated from Poland in 1971 and works daily in her studio in Venice, California. The subject matter of her paintings has included the Holocaust, Native Americans, threats of chemical war in the Middle East, and the natural world. Her work can be viewed on her Web site at <http://www.danutastudio.com> and she can be contacted at <danuta@danutastudio.com>.

A century ago, millions of Europeans, African Americans, and single women in search of work arrived in American cities. Religiously motivated volunteers met these newcomers with settlement houses, vocational schools, and boardinghouses that served as temporary respite from harsh urban conditions. Such “redemptive places” saved cities from demographic chaos by delivering social services to the poor well before the emergence of New Deal programs. Today, the federal government is actively promoting religious solutions to urban poverty. The “Charitable Choice” provision included in the 1996 welfare reform legislation makes faith-based organizations eligible to provide services to the poor. Redemptive places, therefore, are as important now as they were in the past. Planners can facilitate the creation of redemptive places by communicating the details of Charitable Choice to state and local agencies that outsource social services, identifying eligible properties, and reducing legal barriers to their existence.     

Strategies of the Bulgarian vernacular: continuity in Bulgarian house design from National Revival times to the present day

The starting point of the article is the Bulgarian ‘National Revival House’ as it represents the most noteworthy product of Bulgarian vernacular architecture. It also demonstrates the meeting of European and West Asian building traditions: based on the Ottoman dwelling, the Bulgarian house shows an adaptation of the former to Christian Balkan living as well as the impact of various outside influences from the Ottoman Baroque to Central European models.

The examples date from the late eighteenth century to the present day, with an emphasis on the second half of the nineteenth century. They are encountered in rural, small-town and urban environments and exhibit a remarkable degree of basic uniformity of design: assemblage, lightness, cleanness of form and increasing monumentality are the most abiding characteristics of the Bulgarian ‘National Revival house’.

The thrust of this study is not so much towards a theoretical definition of the Bulgarian vernacular but more the analysis of the dominant architectural strategies in the design of domestic structures. After identifying the principal formal characteristics of the Bulgarian vernacular house, the aim is to demonstrate the continuity of those strategies into the modern period and to the present day. For this purpose, not only well-documented landmark buildings of the inter-War and Communist periods but also little-known examples will be considered. This will serve to establish the idea of a continuous Bulgarian vernacular as the common architecture of the people of Bulgaria.     

Housing policy in remote Indigenous communities: how politics obstructs good policy

Abstract

When it comes to issues of housing policy, remote Indigenous housing often presents the extreme case. The failures of housing policy are most acute in remote Indigenous Australia, but despite the need to learn from the policy mistakes of the past, there has been little detailed analysis of the policy history. Through documentary and empirical analysis, we show that policies have either failed to be adapted to cultural and geographic contexts or, when they have been culturally responsive, they have lacked attention to the complexities of service delivery. Despite differences in policy settings, the long view is one of the normalization of Indigenous communities, although research points to the need for culturally appropriate arrangements. We argue that rather than politically motivated short-termism, governments need to develop a medium- to long-term approach that approaches policy solutions incrementally, builds capacity within the state and Indigenous communities, and is based on the evidence.     

Video game training to improve selective visual attention in older adults

The current study investigated the effect of video game training on older adult’s useful field of view performance (the UFOV® test). Fifty-eight older adult participants were randomized to receive practice with the target action game (Medal of Honor), a placebo control arcade game (Tetris), a clinically validated UFOV training program, or into a no contact control group. Examining pretest–posttest change in selective visual attention, the UFOV improved significantly more than the game groups; all three intervention groups improved significantly more than no-contact controls. There was a lack of difference between the two game conditions, differing from findings with younger adults. Discussion considers whether games posing less challenge might still be effective interventions for elders, and whether optimal training dosages should be higher.     

Viral diffusion of technology products: a comprehensive stage framework

Information Systems and e-Business Management - The level of viral diffusion expected after a technology product or service is launched is important for determining the marketing budget,...     

The pathway to intelligent implants: osteoblast response to nano silicon-doped hydroxyapatite patterning

Bioactive hydroxyapatite (HA) with addition of silicon (Si) in the crystal structure (silicon-doped hydroxyapatite (SiHA)) has become a highly attractive alternative to conventional HA in bone replacement owing to the significant improvement in the in vivo bioactivity and osteoconductivity. Nanometre-scaled SiHA (nanoSiHA), which closely resembles the size of bone mineral, has been synthesized in this study. Thus, the silicon addition provides an extra chemical cue to stimulate and enhance bone formation for new generation coatings, and the next stage in metallic implantation design is to further improve cellular adhesion and proliferation by control of cell alignment. Topography has been found to provide a powerful set of signals for cells and form contact guidance. Using the recently developed novel technique of template-assisted electrohydrodynamic atomization (TAEA), patterns of pillars and tracks of various dimensions of nanoSiHA were achieved. Modifying the parameters of TAEA, the resolution of pattern structures was controlled, enabling the topography of a substrate to be modified accordingly. Spray time, flow rate and distance between the needle and substrate were varied to improve the pattern formation of pillars and tracks. The 15 min deposition time provided the most consistent patterned topography with a distance of 50 mm and flow rate of 4 µl min⁻¹. A titanium substrate was patterned with pillars and tracks of varying widths, line lengths and distances under the optimized TAEA processing condition. A fast bone-like apatite formation rate was found on nanoSiHA after immersion in simulated body fluid, thus demonstrating its high in vitro bioactivity. Primary human osteoblast (HOB) cells responded to SiHA patterns by stretching of the filopodia between track and pillar, attaching to the apex of the pillar pattern and stretching between two. HOB cells responded to the track pattern by elongating along and between the track, and the length of HOB cells was proportional to the gaps between track patterns, but this relationship was not observed on the pillar patterns. The study has therefore provided an insight for future design of next generation implant surfaces to control and guide cellular responses, while TAEA patterning provides a controllable technique to provide topography to medical implants.