ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMechanism of formation of Grignard reagents. Corrosion of metallic magnesium by alkyl halides in ethersCraig L. Hill, John B. Vander Sande, and George M. WhitesidesCite this: J. Org. Chem. 1980, 45, 6, 1020–1028Publication Date (Print):March 1, 1980Publication History Published online1 May 2002Published inissue 1 March 1980https://pubs.acs.org/doi/10.1021/jo01294a021https://doi.org/10.1021/jo01294a021research-articleACS PublicationsRequest reuse permissionsArticle Views624Altmetric-Citations47LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
Hu, Frank B.; Manson, JoAnn E.; Stampfer, Meir J.; Colditz, Graham; Liu, Simin; Solomon, Caren G.; Willett, Walter C.
OBJECTIVE—The purpose of this study was to examine the association between the use of different classes of antihypertensive medications and the risk of incident type 2 diabetes. RESEARCH DESIGN AND METHODS—We conducted a prospective study of three cohorts: the Nurses’ Health Study (NHS) I and II and the Health Professionals Follow-up Study (HPFS). Antihypertensive medication use was ascertained by biennial questionnaires. After excluding participants who reported a history of diabetes at baseline, 41,193 older women (NHS I), 14,151 younger women (NHS II), and 19,472 men (HPFS), all with hypertension, were followed for 8, 10, and 16 years, respectively. RESULTS—We documented 3,589 incident cases of diabetes. After adjustment for age, BMI, physical activity, the use of other antihypertensive medications, and other risk factors, the multivariate relative risk (RR) of incident diabetes in participants taking a thiazide diuretic compared with those not taking a thiazide was 1.20 (95% CI 1.08–1.33) in older women, 1.45 (1.17–1.79) in younger women, and 1.36 (1.17–1.58) in men. The multivariate RR in participants taking a β-blocker compared with those not taking a β-blocker was 1.32 (1.20–1.46) in older women and 1.20 (1.05–1.38) in men. ACE inhibitors and calcium channel blockers were not associated with risk. CONCLUSIONS—Thiazide diuretic and β-blocker use were independently associated with a higher risk of incident diabetes. Increased surveillance for diabetes in patients treated with these medications may be warranted.
The topology of the telephone cord buckling of compressed diamond-like carbon films (DLC) on glass substrates has been characterized with atomic force microscopy (AFM) and with the focused ion beam (FIB) imaging system. The profiles of the several buckles have been measured by AFM to establish the symmetry of each repeat unit, revealing similarity with a circular buckle pinned at its center. By making parallel cuts through the buckle in small, defined locations, straight-sided buckles have been created on the identical films, enabling the residual stress in the film to be determined from the profile. It has been shown that the telephone cord topology can be effectively modeled as a series of pinned circular buckles along its length, with an unpinned circular buckle at its front. The unit segment comprises a section of a full circular buckle, pinned to the substrate at its center. The model is validated by comparing radial profiles measured for the telephone cord with those calculated for the pinned buckle, upon using the residual stress in the film, determined as above. Once validated, the model has been used to determine the energy release rate and mode mixity, G(ψ). The results for G(ψ) indicate that the telephone cord configuration is preferred when the residual stress in the DLC is large, consistent with observations that straight-sided buckles are rarely observed, and, when they occur, are generally narrower than telephone cords. Telephone cords are observed in many systems, and can be regarded as the generic morphology. Nevertheless, they exist subject to a limited set of conditions, residing within the margin between complete adherence and complete delamination, provided that the interface has a mode II toughness low enough to ensure that the buckle crack does not kink into the substrate.
The Eshelby tensor E has vanishing divergence in a homogeneous elastic material, whereas the invariance of the crack tip J integral suggests, in accord wit
It is often found that tangent-stiffness finite element solutions for elastic-plastic materials exhibit much too stiff a response in the fully plastic range. This is most striking for the perfectly plastic material idealization, in which case a limit load exists within conventional small displacement gradient assumptions. However, finite element solutions often exceed the limit load by substantial amounts, and in some cases have no limit load at all. It is shown that a cause of this inaccuracy is that incremental deformation fields of typical two and three-dimensional finite elements are highly constrained at or near the limit load. This is shown to enforce unreasonable kinematic constraints on the modes of deformation which assemblages of elements are capable of exhibiting. A general criterion for testing a mesh with topologically similar repeat units is given, and the analysis shows that only a few conventional element types and arrangements are, or can be made, suitable for computations in the fully plastic range. Further, a new variational principle, which can easily and simply be incorporated into an existing finite element program, is presented. This allows accurate computations to be made even for element designs that would not normally be suitable. Numerical results are given for three plane strain problems, namely pure bending of a beam, a thick-walled tube under pressure, and a deep double edge cracked tensile specimen. These illustrate the effects of various element designs and of the new variational procedure. An appendix extends the discussion to elastic-plastic computation at finite strain.
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The interface between nanoscale electronic devices and biological systems enables interactions at length scales natural to biology, and thus should maximize communication between these two diverse yet complementary systems. Moreover, nanostructures and nanostructured substrates show enhanced coupling to artificial membranes, cells, and tissue. Such nano–bio interfaces offer better sensitivity and spatial resolution as compared to conventional planar structures. In this work, we will report the electrical properties of silicon nanowires (SiNWs) interfaced with embryonic chicken hearts and cultured cardiomyocytes. We developed a scheme that allowed us to manipulate the nanoelectronic to tissue/cell interfaces while monitoring their electrical activity. In addition, by utilizing the bottom-up approach, we extended our work to the subcellular regime, and interfaced cells with the smallest reported device ever and thus exceeded the spatial and temporal resolution limits of other electrical recording techniques. The exceptional synthetic control and flexible assembly of nanowires (NWs) provides powerful tools for fundamental studies and applications in life science, and opens up the potential of merging active transistors with cells such that the distinction between nonliving and living systems is blurred.
