179 research outputs found

    Organic synthesis: march of the machines.

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    Organic synthesis is changing; in a world where budgets are constrained and the environmental impacts of practice are scrutinized, it is increasingly recognized that the efficient use of human resource is just as important as material use. New technologies and machines have found use as methods for transforming the way we work, addressing these issues encountered in research laboratories by enabling chemists to adopt a more holistic systems approach in their work. Modern developments in this area promote a multi-disciplinary approach and work is more efficient as a result. This Review focuses on the concepts, procedures and methods that have far-reaching implications in the chemistry world. Technologies have been grouped as topics of opportunity and their recent applications in innovative research laboratories are described.The authors gratefully acknowledge support from UK Engineering and Physical Sciences Research Council (SVL and RMM), Woolf Fisher Trust (DEF) and Pfizer Worldwide Research and Development (CB, RJI).This is the accepted manuscript. The final version is available at http://onlinelibrary.wiley.com/doi/10.1002/anie.201410744/abstract

    Machine-Assisted Organic Synthesis.

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    In this Review we describe how the advent of machines is impacting on organic synthesis programs, with particular emphasis on the practical issues associated with the design of chemical reactors. In the rapidly changing, multivariant environment of the research laboratory, equipment needs to be modular to accommodate high and low temperatures and pressures, enzymes, multiphase systems, slurries, gases, and organometallic compounds. Additional technologies have been developed to facilitate more specialized reaction techniques such as electrochemical and photochemical methods. All of these areas create both opportunities and challenges during adoption as enabling technologies

    Size and conformation limits to secretion of disulfide-bonded loops in autotransporter proteins

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    Autotransporters are a superfamily of virulence factors typified by a channel-forming C terminus that facilitates translocation of the functional N-terminal passenger domain across the outer membrane of Gram-negative bacteria. This final step in the secretion of autotransporters requires a translocation-competent conformation for the passenger domain that differs markedly from the structure of the fully folded secreted protein. The nature of the translocation-competent conformation remains controversial, in particular whether the passenger domain can adopt secondary structural motifs, such as disulfide- bonded segments, while maintaining a secretion-competent state. Here, we used the endogenous and closely spaced cysteine residues of the plasmid-encoded toxin (Pet) from enteroaggregative Escherichia coli to investigate the effect of disulfide bond-induced folding on translocation of an auto-transporter passenger domain. We reveal that rigid structural elements within disulfide-bonded segments are resistant to autotransporter-mediated secretion. We define the size limit of disulfide-bonded segments tolerated by the autotransporter system demonstrating that, when present, cysteine pairs are intrinsically closely spaced to prevent congestion of the translocator pore by large disulfide-bonded regions. These latter data strongly support the hairpin mode of autotransporter biogenesis

    Size and conformation limits to secretion of disulfide-bonded loops in autotransporter proteins

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    Autotransporters are a superfamily of virulence factors typified by a channel-forming C terminus that facilitates translocation of the functional N-terminal passenger domain across the outer membrane of Gram-negative bacteria. This final step in the secretion of autotransporters requires a translocation-competent conformation for the passenger domain that differs markedly from the structure of the fully folded secreted protein. The nature of the translocation-competent conformation remains controversial, in particular whether the passenger domain can adopt secondary structural motifs, such as disulfide- bonded segments, while maintaining a secretion-competent state. Here, we used the endogenous and closely spaced cysteine residues of the plasmid-encoded toxin (Pet) from enteroaggregative Escherichia coli to investigate the effect of disulfide bond-induced folding on translocation of an auto-transporter passenger domain. We reveal that rigid structural elements within disulfide-bonded segments are resistant to autotransporter-mediated secretion. We define the size limit of disulfide-bonded segments tolerated by the autotransporter system demonstrating that, when present, cysteine pairs are intrinsically closely spaced to prevent congestion of the translocator pore by large disulfide-bonded regions. These latter data strongly support the hairpin mode of autotransporter biogenesis

    Cognitive Phenotypes and the Evolution of Animal Decisions

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    Despite the clear fitness consequences of animal decisions, the science of animal decision making in evolutionary biology is underdeveloped compared with decision science in human psychology. Specifically, the field lacks a conceptual framework that defines and describes the relevant components of a decision, leading to imprecise language and concepts. The ‘judgment and decision-making’ (JDM) framework in human psychology is a powerful tool for framing and understanding human decisions, and we apply it here to components of animal decisions, which we refer to as ‘cognitive phenotypes’. We distinguish multiple cognitive phenotypes in the context of a JDM framework and highlight empirical approaches to characterize them as evolvable traits

    Cognitive Phenotypes and the Evolution of Animal Decisions

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    Despite the clear fitness consequences of animal decisions, the science of animal decision making in evolutionary biology is underdeveloped compared with decision science in human psychology. Specifically, the field lacks a conceptual framework that defines and describes the relevant components of a decision, leading to imprecise language and concepts. The ‘judgment and decision-making’ (JDM) framework in human psychology is a powerful tool for framing and understanding human decisions, and we apply it here to components of animal decisions, which we refer to as ‘cognitive phenotypes’. We distinguish multiple cognitive phenotypes in the context of a JDM framework and highlight empirical approaches to characterize them as evolvable traits

    Medical Sequencing of Candidate Genes for Nonsyndromic Cleft Lip and Palate

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    Nonsyndromic or isolated cleft lip with or without cleft palate (CL/P) occurs in wide geographic distribution with an average birth prevalence of 1/700. We used direct sequencing as an approach to study candidate genes for CL/P. We report here the results of sequencing on 20 candidate genes for clefts in 184 cases with CL/P selected with an emphasis on severity and positive family history. Genes were selected based on expression patterns, animal models, and/or role in known human clefting syndromes. For seven genes with identified coding mutations that are potentially etiologic, we performed linkage disequilibrium studies as well in 501 family triads (affected child/mother/father). The recently reported MSX1 P147Q mutation was also studied in an additional 1,098 cleft cases. Selected missense mutations were screened in 1,064 controls from unrelated individuals on the Centre d'Étude du Polymorphisme Humain (CEPH) diversity cell line panel. Our aggregate data suggest that point mutations in these candidate genes are likely to contribute to 6% of isolated clefts, particularly those with more severe phenotypes (bilateral cleft of the lip with cleft palate). Additional cases, possibly due to microdeletions or isodisomy, were also detected and may contribute to clefts as well. Sequence analysis alone suggests that point mutations in FOXE1, GLI2, JAG2, LHX8, MSX1, MSX2, SATB2, SKI, SPRY2, and TBX10 may be rare causes of isolated cleft lip with or without cleft palate, and the linkage disequilibrium data support a larger, as yet unspecified, role for variants in or near MSX2, JAG2, and SKI. This study also illustrates the need to test large numbers of controls to distinguish rare polymorphic variants and prioritize functional studies for rare point mutations

    Prospective study design and data analysis in UK Biobank

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    Population-based prospective studies, such as UK Biobank, are valuable for generating and testing hypotheses about the potential causes of human disease. We describe how UK Biobank's study design, data access policies, and approaches to statistical analysis can help to minimize error and improve the interpretability of research findings, with implications for other population-based prospective studies being established worldwide.</p

    Envisioning a World Beyond APCs/BPCs

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    This archival page includes documents and recordings related to the international symposium, “Envisioning a World Beyond APCs/BPCs,” held in Lawrence, Kansas, on Thursday and Friday, November 17-18. The presenters were a group of 18 internationally respected scholars, publishers, university librarians, and executives from foundations and organizations, who were asked to participate in a discussion about current models available for achieving an expansive, inclusive, and balanced worldwide open publishing ecosystem. The symposium was co-sponsored by the University of Kansas Libraries, Open Access Network (a project of K|N Consultants), Allen Press, SPARC, and ARL. The materials included here are the symposium schedule, recordings of Parts 1 and 2 of the Nov. 17 livestream, a transcript of the livestream, and team proposals originating from the Nov. 18 morning session.This symposium was sponsored by the University of Kansas Libraries, Open Access Network (a project of K|N Consultants), Allen Press, and SPARC
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