404 research outputs found

    Design of a High-Throughput Flow Perfusion Bioreactor System for Tissue Engineering

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    Flow perfusion culture is used in many areas of tissue engineering and offers several key advantages. However, one challenge to these cultures is the relatively low-throughput nature of perfusion bioreactors. Here, a flow perfusion bioreactor with increased throughput was designed and built for tissue engineering. This design uses an integrated medium reservoir and flow chamber in order to increase the throughput, limit the volume of medium required to operate the system, and simplify the assembly and operation

    Acid functionalized conjugated microporous polymers as a reusable catalyst for biodiesel production

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    A series of conjugated microporous polymers (CMPs) based on bromophenol blue (BB) and bromocresol green (BG) have been synthesized via Sonogashira-Hagihara cross coupling reaction with surface areas up to 747 m2/g. The CMPs can be post functionalized with chlorosulfonic acid to yield corresponding sulfonated polymers with high acidity up to 7.67 mmol/g. The sulfonated CMPs showed excellent catalytic activity for the esterification of free fatty acids and transesterification of various vegetable oils and waste cooking oil as well as excellent reusability up to 4 consecutive runs without significant activity loss. These sulfonated CMPs have potential applications as recyclable acid catalysts for environmentally friendly biodiesel production from waste cooking oil

    Tempo and mode of performance evolution across multiple independent origins of adhesive toe pads in lizards

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    Understanding macroevolutionary dynamics of trait evolution is an important endeavor in evolutionary biology. Ecological opportunity can liberate a trait as it diversifies through trait space, while genetic and selective constraints can limit diversification. While many studies have examined the dynamics of morphological traits, diverse morphological traits may yield the same or similar performance and as performance is often more proximately the target of selection, examining only morphology may give an incomplete understanding of evolutionary dynamics. Here, we ask whether convergent evolution of pad‐bearing lizards has followed similar evolutionary dynamics, or whether independent origins are accompanied by unique constraints and selective pressures over macroevolutionary time. We hypothesized that geckos and anoles each have unique evolutionary tempos and modes. Using performance data from 59 species, we modified Brownian motion (BM) and Ornstein–Uhlenbeck (OU) models to account for repeated origins estimated using Bayesian ancestral state reconstructions. We discovered that adhesive performance in geckos evolved in a fashion consistent with Brownian motion with a trend, whereas anoles evolved in bounded performance space consistent with more constrained evolution (an Ornstein–Uhlenbeck model). Our results suggest that convergent phenotypes can have quite distinctive evolutionary patterns, likely as a result of idiosyncratic constraints or ecological opportunities

    Behaviour and Climate Change: Consumer Perceptions of Responsibility

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    This paper explores the under-researched notion of consumer responsibility, a potentially significant influence on consumer behaviour that marketers and policymakers may be able to harness as they attempt to respond to environmental challenges such as climate change. The paper uses data derived from a commercially motivated survey (n = 1513) to explore domestic consumption behaviours most closely associated with the issue of disruptive climate change. A measure of 'General Environmental Responsiveness' (GER) is used to test: (1) the effects of consumers both taking responsibility for their actions and placing responsibility on others for the consequences of their consumption behaviour; and (2) whether sociodemographic variables can aid the targeting of consumers by the level and type of responsibility and pro-environmental behavioural intentions expressed. The study's findings demonstrate clear, if not strong, relationships between consumer conceptions of responsibilities for causing and tackling climate change and environment-related consumer behaviour. The study's implications both challenge accepted wisdom about environment-related consumer behaviour and suggest avenues for future research

    Green consumer segmentation: managerial and environmental implications from the perspective of business strategies and practices

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    With the new millennium, environmental concern entered a new phase, with stricter governmental regulations and incentives. Currently, within environmental issues, there is a broader challenge to commitment with economic and social goals. This is motivating companies and organizations to participate in transformation processes with the aim of minimizing the negative impacts of their activities. Within this context, new business philosophies, emerged empowering organizations to consider sustainability issues that have come to be viewed as an innovative and differentiating factor, providing competitive advantages (Fraj-Andres, MartinezSalinas, & Matute-Vallejo. Journal of Business Ethics, 88,263-286, 2009; Leipziger. The corporate responsibility code book. Greenleaf Publishing Limited, 2016; Leipziger. The corporate responsibility code book. Greenleaf Publishing Limited, 2016). Therefore, organizations have begun incorporating these concerns in their processes, adopting green management policies, and including green marketing strategies in order to remain competitive (Straughan & Roberts. Journal of Consumer Marketing, 16(6), 558-575, 1999; Rivera-Camino. European Journal of Marketing, 41, 1328-1358, 2007). From the marketing perspective, the importance of understanding green consumer behaviour in order to develop better segmentation and targeting strategies is highlighted. Green consumers are changing significantly. Consumers, although with some reluctance, are moving to greener products. The Mintel organization reported that the number of consumers buying green has tripled in recent years. Furthermore, it found that the number of consumers that never bought green products have decreased. These results show that widespread environmental awareness had an important role in purchasing behaviour, with more consumers considering the environmental impact of their buying decisions and looking for a greener alternative to their conventional purchasing options. The existing literature suggests that previous research regarding the green consumer profile has different perspectives. The first group of researchers attempted to characterize green consumer profile using sociodemographic variables such as age, gender, education, income and occupation. In tum, the second group of researchers used psychographic variables instead of sociodemographic ones (Mainieri, Barnett, Valdero, Unipan, & Oskamp. Journal of Social Psychology, 137(2), 189-204, 1997). This chapter aims to better explore the importance of green consumer segmentation and its implications from a management point of view. More specifically, the aim is to analyze which variables better characterize green consumers (sociodemographic and psychographic). At the end, a theoretical framework is proposed to enable and support organizations to better understand green consumer profile. It also enables managers and marketers to target and develop better marketing strategies for these segments.info:eu-repo/semantics/publishedVersio

    Whole-brain modelling identifies distinct but convergent paths to unconsciousness in anaesthesia and disorders of consciousness

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    The human brain entertains rich spatiotemporal dynamics, which are drastically reconfigured when consciousness is lost due to anaesthesia or disorders of consciousness (DOC). Here, we sought to identify the neurobiological mechanisms that explain how transient pharmacological intervention and chronic neuroanatomical injury can lead to common reconfigurations of neural activity. We developed and systematically perturbed a neurobiologically realistic model of whole-brain haemodynamic signals. By incorporating PET data about the cortical distribution of GABA receptors, our computational model reveals a key role of spatially-specific local inhibition for reproducing the functional MRI activity observed during anaesthesia with the GABA-ergic agent propofol. Additionally, incorporating diffusion MRI data obtained from DOC patients reveals that the dynamics that characterise loss of consciousness can also emerge from randomised neuroanatomical connectivity. Our results generalise between anaesthesia and DOC datasets, demonstrating how increased inhibition and connectome perturbation represent distinct neurobiological paths towards the characteristic activity of the unconscious brain

    The human FK506-binding proteins: characterization of human FKBP19

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    Analysis of the human repertoire of the FK506-binding protein (FKBP) family of peptidyl-prolyl cis/trans isomerases has identified an expansion of genes that code for human FKBPs in the secretory pathway. There are distinct differences in tissue distribution and expression levels of each variant. In this article we describe the characterization of human FKBP19 (Entrez Gene ID: FKBP11), an FK506-binding protein predominantly expressed in vertebrate secretory tissues. The FKBP19 sequence comprises a cleavable N-terminal signal sequence followed by a putative peptidyl-prolyl cis/trans isomerase domain with homology to FKBP12. This domain binds FK506 weakly in vitro. FKBP19 mRNA is abundant in human pancreas and other secretory tissues and high levels of FKBP19 protein are detected in the acinar cells of mouse pancreas

    Novel Structural Components of the Ventral Disc and Lateral Crest in Giardia intestinalis

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    Giardia intestinalis is a ubiquitous parasitic protist that is the causative agent of giardiasis, one of the most common protozoan diarrheal diseases in the world. Giardia trophozoites attach to the intestinal epithelium using a specialized and elaborate microtubule structure, the ventral disc. Surrounding the ventral disc is a less characterized putatively contractile structure, the lateral crest, which forms a continuous perimeter seal with the substrate. A better understanding of ventral disc and lateral crest structure, conformational dynamics, and biogenesis is critical for understanding the mechanism of giardial attachment to the host. To determine the components comprising the ventral disc and lateral crest, we used shotgun proteomics to identify proteins in a preparation of isolated ventral discs. Candidate disc-associated proteins, or DAPs, were GFP-tagged using a ligation-independent high-throughput cloning method. Based on disc localization, we identified eighteen novel DAPs, which more than doubles the number of known disc-associated proteins. Ten of the novel DAPs are associated with the lateral crest or outer edge of the disc, and are the first confirmed components of this structure. Using Fluorescence Recovery After Photobleaching (FRAP) with representative novel DAP::GFP strains we found that the newly identified DAPs tested did not recover after photobleaching and are therefore structural components of the ventral disc or lateral crest. Functional analyses of the novel DAPs will be central toward understanding the mechanism of ventral disc-mediated attachment and the mechanism of disc biogenesis during cell division. Since attachment of Giardia to the intestine via the ventral disc is essential for pathogenesis, it is possible that some proteins comprising the disc could be potential drug targets if their loss or disruption interfered with disc biogenesis or function, preventing attachment
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