142 research outputs found
Multiply Folded Graphene
The folding of paper, hide, and woven fabric has been used for millennia to
achieve enhanced articulation, curvature, and visual appeal for intrinsically
flat, two-dimensional materials. For graphene, an ideal two-dimensional
material, folding may transform it to complex shapes with new and distinct
properties. Here, we present experimental results that folded structures in
graphene, termed grafold, exist, and their formations can be controlled by
introducing anisotropic surface curvature during graphene synthesis or transfer
processes. Using pseudopotential-density functional theory calculations, we
also show that double folding modifies the electronic band structure of
graphene. Furthermore, we demonstrate the intercalation of C60 into the
grafolds. Intercalation or functionalization of the chemically reactive folds
further expands grafold's mechanical, chemical, optical, and electronic
diversity.Comment: 29 pages, 10 figures (accepted in Phys. Rev. B
Development of Healthy Eating and Physical Activity Quality Standards for Out-of-School Time Programs
Abstract Background: Out-of-school time (Ost) programs serve over 8 million children per year and have ample opportunity to promote health through menu and physical activity choices. Until recently, however, the field has lacked a comprehensive set of operationalizable standards for healthy eating and physical activity. the National Afterschool Association adopted voluntary healthy eating and physical activity quality standards (HePAQs) in April, 2011. Methods: We describe the development of HePAQs. this work reflects a social ecological model for changing children's eating and activity behaviors through program-level interventions. the standards were developed using a national, mixed-methods needs assessment, review of existing standards and expert recommendations, and a participatory process of discussion, review, and consensus engaging 19 influential service and policy organizations and agencies in the Healthy Out-of-school time (HOst) coalition, which we convened in 2009. Results: the HOst coalition approved a final version of the HePAQs in January, 2011. the 11 standards address content, curriculum selection, staff training, program support, and environmental support for healthy eating and physical activity. in April, 2011, the HePAQs were adopted by the National Afterschool Association, and have subsequently been widely disseminated. extensive adoption and implementation efforts are underway. Conclusions: the availability of a comprehensive set of standards for healthy eating and physical activity in Ost provides practical information to help community-based youth-serving organizations participate in obesity and chronic disease prevention. A working awareness of their content will be useful to scientists undertaking health promotion studies in the out-of-school time setting
Selection of Single-Stranded DNA Molecular Recognition Elements against Exotoxin A Using a Novel Decoy-SELEX Method and Sensitive Detection of Exotoxin A in Human Serum
Exotoxin A is one of the virulence factors of Pseudomonas aeruginosa, a bacterium that can cause infections resulting in adverse health outcomes and increased burden to health care systems. Current methods of diagnosing P. aeruginosa infections are time consuming and can require significant preparation of patient samples. This study utilized a novel variation of the Systematic Evolution of Ligand by Exponential Enrichment, Decoy-SELEX, to identify an Exotoxin A specific single-stranded DNA (ssDNA) molecular recognition element (MRE). Its emphasis is on increasing stringency in directing binding toward free target of interest and at the same time decreasing binding toward negative targets. A ssDNA MRE with specificity and affinity was identified after fourteen rounds of Decoy-SELEX. Utilizing surface plasmon resonance measurements, the determined equilibrium dissociation constant of the MRE is between 4.2â”M and 4.5â”M, and is highly selective for Exotoxin A over negative targets. A ssDNA MRE modified sandwich enzyme-linked immunosorbent assay (ELISA) has been developed and achieved sensitive detection of Exotoxin A at nanomolar concentrations in human serum. This study has demonstrated the proof-of-principle of using a ssDNA MRE as a clinical diagnostic tool
Selection of Single-Stranded DNA Molecular Recognition Elements against Exotoxin A Using a Novel Decoy-SELEX Method and Sensitive Detection of Exotoxin A in Human Serum
Exotoxin A is one of the virulence factors of Pseudomonas aeruginosa, a bacterium that can cause infections resulting in adverse health outcomes and increased burden to health care systems. Current methods of diagnosing P. aeruginosa infections are time consuming and can require significant preparation of patient samples. This study utilized a novel variation of the Systematic Evolution of Ligand by Exponential Enrichment, Decoy-SELEX, to identify an Exotoxin A specific single-stranded DNA (ssDNA) molecular recognition element (MRE). Its emphasis is on increasing stringency in directing binding toward free target of interest and at the same time decreasing binding toward negative targets. A ssDNA MRE with specificity and affinity was identified after fourteen rounds of Decoy-SELEX. Utilizing surface plasmon resonance measurements, the determined equilibrium dissociation constant of the MRE is between 4.2â”M and 4.5â”M, and is highly selective for Exotoxin A over negative targets. A ssDNA MRE modified sandwich enzyme-linked immunosorbent assay (ELISA) has been developed and achieved sensitive detection of Exotoxin A at nanomolar concentrations in human serum. This study has demonstrated the proof-of-principle of using a ssDNA MRE as a clinical diagnostic tool
Application of Hanschâs Model to Capsaicinoids and Capsinoids: A Study Using the Quantitative StructureâActivity Relationship. A Novel Method for the Synthesis of Capsinoids
We describe a synthetic approach for two families of compounds, the capsaicinoids and capsinoids,
as part of a study of the quantitative relationship between structure and activity
Have we seen the geneticisation of society? Expectations and evidence
Abby Lippmanâs geneticization thesis, of the early 1990s, argued and anticipated that with
the rise of genetics, increasing areas of social and health related activities would come to be
understood and defined in genetic terms leading to major changes in society, medicine and
health care. We review the considerable literature on geneticization and consider how the
concept stands both theoretically and empirically across scientific, clinical, popular and lay
discourse and practice. Social science scholarship indicates that relatively little of the original
claim of the geneticization thesis has been realised, highlighting the development of more
complex and dynamic accounts of disease in scientific discourse and the complexity of
relationships between bioscientific, clinical and lay understandings. This scholarship
represents a shift in social science understandings of the processes of sociotechnical change,
which have moved from rather simplistic linear models to an appreciation of disease
categories as multiply understood. Despite these shifts, we argue that a genetic imaginary
persists, which plays a performative role in driving investments in new gene-based
developments. Understanding the enduring power of this genetic imaginary and its
consequences remains a key task for the social sciences, one which treats ongoing genetic
expectations and predictions in a sceptical yet open way
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