Modular and Versatile Spatial Functionalization of Tissue Engineering Scaffolds through Fiber‐Initiated Controlled Radical Polymerization

Native tissues are typically heterogeneous and hierarchically organized, and generating scaffolds that can mimic these properties is critical for tissue engineering applications. By uniquely combining controlled radical polymerization (CRP), end‐functionalization of polymers, and advanced electrospinning techniques, a modular and versatile approach is introduced to generate scaffolds with spatially organized functionality. Poly‐ε‐caprolactone is end functionalized with either a polymerization‐initiating group or a cell‐binding peptide motif cyclic Arg‐Gly‐Asp‐Ser (cRGDS), and are each sequentially electrospun to produce zonally discrete bilayers within a continuous fiber scaffold. The polymerization‐initiating group is then used to graft an antifouling polymer bottlebrush based on poly(ethylene glycol) from the fiber surface using CRP exclusively within one bilayer of the scaffold. The ability to include additional multifunctionality during CRP is showcased by integrating a biotinylated monomer unit into the polymerization step allowing postmodification of the scaffold with streptavidin‐coupled moieties. These combined processing techniques result in an effective bilayered and dual‐functionality scaffold with a cell‐adhesive surface and an opposing antifouling non‐cell‐adhesive surface in zonally specific regions across the thickness of the scaffold, demonstrated through fluorescent labelling and cell adhesion studies. This modular and versatile approach combines strategies to produce scaffolds with tailorable properties for many applications in tissue engineering and regenerative medicine.     

In the Pursuit of Pleasure: The Not so Fleeting Life of the Pavilion and its Ilk

Author and architecture critic for the London Evening Standard, Robert Bevan reflects on the enduring appeal of the temporary structure, speaking ‘to a latent desire for freedom and movement’ as a hangover of our nomadic past in a sedentary ‘civilised’ society. He highlights the type's historical apex in Henry VIII's palatial pop-up on the Field of the Cloth of Gold, questioning the purpose and purposelessness of more recent examples.     

Theory and Practice and the Neutral's Persona

Editor's note: Longtime Alternatives columnist Bob Creo, a veteran Pittsburgh neutral, is revisiting his classic CPR Institute website columns of a decade ago in a Back to Basics Series that he has subtitled “Human Problems, Human Solutions.” These updated and expanded columns, in print for the first time, began late last year. He has revisited and re‐examined mediation‐room techniques and practice issues. This month, he returns to the second column he wrote at www.cpradr.org a decade ago, and brings it forward.     

Dealing with the One‐Hour SO2 NAAQS Implementation

In June 2010, the US Environmental Protection Agency (EPA) finalized a new, very stringent National Ambient Air Quality Standard (NAAQS) for sulfur dioxide¹ (SO₂).     

A portable data system for reindeer herd management

A portable computer system is described which supports timely data management for reindeer herding. An initial version has been in use for two years, supporting research on reindeer diseases. Versions are being developed which will expand the system to support commercial herd management. The hardware system is integrated from commercially available equipment. The software is currently composed of a set of ten programs, with others under development for enhancements and modifications. At field roundups, the computer allows new animals to be added to the data base plus rapid access to information on existing individual animals. Historical information can be displayed, including detailed historical records of reproductive activity, medical treatments, serological exam results, and observations of anomalies (e.g. infections, injuries, etc.). In the field, or in the lab, the data base may be accessed for information on specific animals and for summaries of herd data.     

Structural Response of World Trade Center Buildings 1, 2 and 7 to Impact and Fire Damage

The National Institute of Standards and Technology (NIST) conducted an extensive investigation of the collapse of World Trade Center towers (WTC 1 and WTC 2) and the WTC 7 building. This paper describes the component, subsystem, and global analyses performed for the reconstruction of the structural response of WTC buildings 1, 2, and 7 to impact and fire damage. To illustrate the component and subsystem analyses, the approach taken for simulating the performance of concrete slabs and shear stud connectors in composite floors subject to fire conditions are presented, as well as steel floor framing connections for beams and girders. The development of the global models from the component and subsystem analyses is briefly described, including the sets of input data used to bound the probable conditions of impact and fire damage. The final analysis results that were used to develop the probable collapse hypotheses, and a comparison of the results against observed events, are presented for each building. A review of research activities focused on improving understanding of structural system response to multi-floor fires following the WTC disaster is also provided.     

The limited role for Carbon Capture and Storage (CCS) technologies in a sustainable Australian energy future

There is considerable debate regarding the potential role of Carbon Capture and Storage (CCS) technologies in reducing Australia's greenhouse emissions. The latest climate change science suggests that major (60% or more by 2050), rapid (peaking within 20 years) cuts in global emissions may be required to avoid dangerous climate change. There are a number of existing abatement options including energy efficiency, various renewable energy technologies, nuclear power and fuel switching to natural gas; as well as emerging options including CCS. We outline a simple technology assessment framework for policymakers to evaluate these different options given the climate change imperative. This framework includes technology status, delivered energy services, present and possible future costs, potential scale of abatement, potential speed of deployment and other possible social outcomes. Application of this framework to CCS suggests that it should be considered as a promising, but still somewhat unproven, option that potentially offers very significant abatement potential and good integration into the existing energy industry. There are, however, some outstanding questions regarding its effectiveness and safety, its abatement is likely to come at significant cost, and it is unlikely to be able to make a significant contribution for well over a decade. The Australian policy implications are that while government support for R&D and Demonstration of CCS is appropriate and should in our view be expanded, the major priority should be to support greater deployment of existing abatement options including energy efficiency, efficient gas-fired generation and cogeneration and renewable energy. Such policy support is noticeably lacking at present.