233 research outputs found

    No stump city : the contestation and politics of urban street-trees – a case study of Sheffield

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    Issues of sustainable development, liveable cities, green infrastructure, and urban ecosystem services currently receive attention from researchers and decision-makers. Furthermore, the benefits to public wellbeing and health of high quality open spaces and green areas are now undisputed (e.g. Simson, 2008; Booth, 2005, 2006). However, with increasing pressure on urban landscapes for competing uses like housing-development green-spaces are under threat. Furthermore, austerity-driven cuts to local authority budgets mean loss of core services and skills relating to open-space management and planning. Some local authorities such as Newcastle City Council are withdrawing all expenditure on parks and community spaces. With major challenges in providing good quality urban green-spaces, the loss of most local authority countryside management services from 2008 onwards, reflects bigger problems (see Rotherham, 2014, 2015 for example). Within this wider scenario has been the growing importance of Public Private Partnerships (PPP) to deliver core environmental and green-space services in many urban areas. These have been seen as possible fixes for the current waves of austerity cuts and many local authorities such as Sheffield City Council have gone down this route. Nevertheless, real costs (financial and otherwise) of Private Finance Initiatives (PFIs) are now emerging (Syal, 2018). There are also issues of public access to information once contracts become ‘commercially sensitive’ and of profit-driven delivery of core ‘public benefit’ services. These changes threaten ‘local environmental democracy’ as part of a wider shift in democratic processes (Flinders, 2012, 2017). This paper examines wider issues of austerity-driven cuts to green-space services, of PFI projects, and of local environmental democracy. It takes the Sheffield street-trees initiative as an exemplar case-study to interrogate the broad concerns

    La cantidad de madera muerta y sus tasas de descomposición asociadas en reservas forestales y bosques manejados en el noroeste de Turquía

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    This study describes the state of coarse dead wood (CDW) in the Forest Reserve and the Managed Forest zones of northern conifer-broadleaved mixed forest. The results showed mean total CDW volumes in the ranges 30,05±11,06 m3/ha in the Forest Reserve (6,33±2,98% of the LW volume), and 9,31±2,84 m3/ha in the Managed Forest (1,96±0,84% of the LW volume). The total CDW volume was 3,22 times higher in the Forest Reserve than in the Managed Forest. The CDWlog1 and CDWsnag1 were the most abundant CDW decay classes, whilst CDWlog2 and CDWsnag2 were the lowest. Comparisons of ratios between the Managed Forest and the Forest Reserve with abundant decay classes CDWlog1 and CDWsnag1 indicated large differences. The CDWlog1 volume was 4,09 times higher, and the CDWsnag1 volume was 3,68 times greater in the Forest Reserve than in the Managed Forest. The ratio of different CWD classes in the Managed Forest to CWD classes in the Reserve Forest confirms the pattern. In both Managed and Reserve Forest zones there is balance between total CDWlogs and total CDWsnags, but the differences between total CDWlogs and total CDWsnags was not statistically significant. The total CDW volume was significantly dependent on the forest management system. The system influenced amount and diversity of CDW. In commercially managed forest the abundance and structure of CDW retained is a compromise between the needs of timber production and nature conservation.Este estudio describe el estado de la madera muerta en la zona de reserva forestal y zonas de bosques manejados de coníferas del norte de bosques mixtos de frondosas. Los resultados mostraron que la media total de los volúmenes de madera muerta es igual a 30,05 ± 11,06 m3 / ha en la Reserva Forestal (6,33 ± 2,98% del volumen de madera en pie), y 9,31 ± 2,84 m3 / ha en los bosques manejados (1,96 ± 0,84% del volumen de LW). El volumen total de madera muerta fue de 3,22 veces mayor en la Reserva Forestal de que en el bosque administrado. Las clases de decaimiento de madera muerta más abundantes eran CDWlog1 y CDWsnag1, mientras que CDWlog2 y CDWsnag2 fueron los menos abundantes. Las comparaciones de las proporciones entre el bosque manejado y la Reserva Forestal con las clases de decaimiento más abundantes (CDWlog1 y CDWsnag1) indican grandes diferencias ente las dos zonas. El volumen CDWlog1 fue 4,09 veces mayor, y el volumen CDWsnag1 fue 3,68 veces mayor en la Reserva Forestal de que en el bosque manejado. La relación de las diferentes clases de decaimiento entre los bosques manejados y la Reserva Forestal confirma el patrón. En ambos casos, bosque manejado y zonas de reserva forestal, existe un equilibrio entre CDWlogs total y CDWsnags total, pero las diferencias entre CDWlogs total y CDWsnags total no fue estadísticamente significativa. El volumen total de madera muerta depende significativamente del sistema de gestión forestal. El sistema de manejo influye sobre la cantidad y diversidad de madera muerta. En una gestión comercial de los bosques, la abundancia y estructura de madera muerta presente es un compromiso entre las necesidades de la producción de madera y la conservación de la naturaleza

    Magnetic Mechanoactivation of Wnt Signaling Augments Dopaminergic Differentiation of Neuronal Cells

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    Wnt signaling is a key developmental pathway that regulates dopaminergic progenitor cell proliferation and differentiation during neuronal development. This makes Wnt signaling an important therapeutic target for neurodegenerative conditions such as Parkinson’s disease. Wnt signaling can be modulated using peptides such as UM206, which bind to the Wnt receptor Frizzled. Previous work has demonstrated remote activation of the Wnt pathway through Frizzled using peptide-functionalized magnetic nanoparticles (MNPs) with magnetic field stimulation. Using this technology, Wnt signaling is remotely activated in the neuronal cell line SH-SY5Y, and the phenotypic response to stimulation is assessed. Results indicate β-catenin translocalization and activation of TCF/LEF responsive transcription in response to MNP and magnetic fields, which result in dopaminergic marker expression when synergistically combined with differentiation factors retinoic acid and the phorbol ester phorbol 12-myristate 13-acetate. This approach is translated into ex vivo postnatal rat brain slices modeling the developing nigrostriatal pathway. Dopaminergic marker expression is maintained in MNP-labeled SH-SY5Y cells after injection and magnetic stimulation. These results demonstrate the translational value of remote control of signal transduction for controlling neuronal precursor cell behavior and highlight the potential applications for controlled cell differentiation as part of cell therapies for neurodegenerative disease

    Remote magnetic actuation of cell signalling for tissue engineering

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    Magnetic nanoparticles (MNP) are extremely versatile tools in bioengineering and medicine with diverse uses ranging from magnetic resonance contrast agents to drug delivery vehicles. Recently, MNP have been adapted to target and regulate cell signalling pathways for control of cell behaviour. This approach has been applied to stem and progenitor cells to orchestrate tissue development in tissue engineering. This review introduces the bio-functionalisation mechanisms for MNP and highlights the recent advances in MNP-mediated cell signalling activation. We also explore how the application of this technology has novel uses for stem cell control in the context of tissue engineering and regenerative medicine

    Immobilization of Wnt Fragment Peptides on Magnetic Nanoparticles or Synthetic Surfaces Regulate Wnt Signaling Kinetics.

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    Wnt signaling plays an important role in embryogenesis and adult stem cell homeostasis. Its diminished activation is implicated in osteoporosis and degenerative neural diseases. However, systematic administration of Wnt-signaling agonists carries risk, as aberrantly activated Wnt/β-catenin signaling is linked to cancer. Therefore, technologies for local modulation and control of Wnt signaling targeted to specific sites of disease or degeneration have potential therapeutic value in the treatment of degenerative diseases. We reported a facile approach to locally activate the canonical Wnt signaling cascade using nanomagnetic actuation or ligand immobilized platforms. Using a human embryonic kidney (HEK293) Luc-TCF/LEF reporter cell line, we demonstrated that targeting the cell membrane Wnt receptor, Frizzled 2, with peptide-tagged magnetic nanoparticles (MNPs) triggered canonical Wnt signaling transduction when exposed to a high-gradient, time-varying magnetic field, and the induced TCF/LEF signal transduction was shown to be avidity-dependent. We also demonstrated that the peptide retained signaling activity after functionalization onto glass surfaces, providing a versatile platform for drug discovery or recreation of the cell niche. In conclusion, these results showed that peptide-mediated Wnt signaling kinetics depended not only on ligand concentration but also on the presentation method of the ligand, which may be further modulated by magnetic actuation. This has important implications when designing future therapeutic platforms involving Wnt mimetics

    Deploying aptameric sensing technology for rapid pandemic monitoring

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    The genome of virulent strains may possess the ability to mutate by means of antigenic shift and/or antigenic drift as well as being resistant to antibiotics with time. The outbreak and spread of these virulent diseases including avian influenza (H1N1), severe acute respiratory syndrome (SARS-Corona virus), cholera (Vibrio cholera), tuberculosis (Mycobacterium tuberculosis), Ebola hemorrhagic fever (Ebola Virus) and AIDS (HIV-1) necessitate urgent attention to develop diagnostic protocols and assays for rapid detection and screening. Rapid and accurate detection of first cases with certainty will contribute significantly in preventing disease transmission and escalation to pandemic levels. As a result, there is a need to develop technologies that can meet the heavy demand of an all-embedded, inexpensive, specific and fast biosensing for the detection and screening of pathogens in active or latent forms to offer quick diagnosis and early treatments in order to avoid disease aggravation and unnecessary late treatment costs. Nucleic acid aptamers are short, single-stranded RNA or DNA sequences that can selectively bind to specific cellular and biomolecular targets. Aptamers, as new-age bioaffinity probes, have the necessary biophysical characteristics for improved pathogen detection. This article seeks to review global pandemic situations in relation to advances in pathogen detection systems. It particularly discusses aptameric biosensing and establishes application opportunities for effective pandemic monitoring. Insights into the application of continuous polymeric supports as the synthetic base for aptamer coupling to provide the needed convective mass transport for rapid screening is also presented
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