Small geometrical imperfections in some structures can be responsible for large reductions in their static buckling strengths. As is well known, a thin shell is often very imperfection-sensitive in this sense, with a perfect specimen sometimes having a "classical" buckling strength several times higher than that of an imperfect one. Many analytical studies have sought to correlate reductions in buckling strength with assumed initial imperfections of various sizes and shapes. Such studies may eventually provide the quantitative information needed for the establishment of a statistical theory of buckling, which would relate the probability of buckling under a given static load to the spectrum of imperfections (see [1]). But at the present time, the design of shells leans heavily on experiment, and analysis has been mainly useful in identifying imperfection-sensitive structures and in establishing, in a qualitative way, the degree of this sensitivity.
Abstract Die Reaktion des vermutlich in meridionaler Form vorliegenden Cr(III)‐ Komplexes (I) mit Butin (II) verläuft wahrscheinlich unter Einlagerung eines Butin‐Moleküls in eine Cr‐C‐Bindung und durch Cyclisierung der entstandenen Vinyl‐Cr‐Verbindung (III) unter Benzolabspaltung zum Cr‐Heterocyclen (IV), das mit einem weiteren Butin‐Molekül das Naphthalin (V) ergibt.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA practical enzymic synthesis of (Sp)-adenosine 5'-O-(1-thiotriphosphate) ((Sp)-ATP-.alpha.-S)John R. Moran and George M. WhitesidesCite this: J. Org. Chem. 1984, 49, 4, 704–706Publication Date (Print):February 1, 1984Publication History Published online1 May 2002Published inissue 1 February 1984https://pubs.acs.org/doi/10.1021/jo00178a028https://doi.org/10.1021/jo00178a028research-articleACS PublicationsRequest reuse permissionsArticle Views282Altmetric-Citations24LEARN 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
Energy dissipation chemical force microscopy has been used to analyze the dissipative properties of chemically similar regions of hydroxyl- and carboxyl-terminated SAMs on gold with a hydroxyl-terminated tip. Energy dissipation imaging quantitatively isolates dissipative interfacial interactions from topography, producing a significantly more informative image than phase imaging. Also, energy dissipation force curves probed the rheological properties of the tip-sample interaction. Viscosity of the confined water increased slightly over that of the bulk, and SAM deformation was found to have a longer retardation time than restructuring of interfacial ions and solvent during tip-sample contact.
Background— The prevailing efforts for cardiovascular disease (CVD) prevention focused on treatment of common CVD risk factors rather than primordial prevention of risk factors through health behaviors. The previously validated Healthy Heart Score effectively predicted the 20-year risk of CVD in midadulthood; however, it is unknown whether this risk score is associated with clinically relevant CVD risk factors. Methods and Results— We analyzed the association between the Healthy Heart Score and the incidence of clinical CVD risk factors, including diabetes mellitus, hypertension, and hypercholesterolemia among 69 505 US women in the Nurses’ Health Study II (NHSII; 1991–2011). The Healthy Heart Score estimates the 20-year CVD risk based on 9 lifestyle factors; thus, a higher score reflected a higher predictive CVD risk. During 20 years, we documented 3275 incident cases of diabetes mellitus, 17 420 of hypertension, and 24 385 of hypercholesterolemia. Women with higher predicted CVD risk based on the Healthy Heart Score (highest quintile versus lowest quintile) had significantly greater risk of each clinical risk factor individually (hazard ratios: 18.1 [95% confidence interval, 14.4–22.7] for diabetes mellitus, 5.10 [4.66–5.57] for hypertension, and 2.57 [2.40–2.75] for hypercholesterolemia). The hazard ratio for developing the high-CVD profile was 52.5 (33.6–82.1). These associations were most pronounced among women who were younger, were nonsmokers, or had optimal weight. Conclusions— An absolute 20-year risk of CVD, estimated by the Healthy Heart Score, was strongly associated with the development of CVD clinically relevant risk factors. This risk score may serve as the first step for CVD risk assessment in primordial prevention.
All‐metal sandwich construction holds promise for significant improvements in stiffness, strength and blast resistance for built‐up plate structures. Analysis of the performance of sandwich plates under various loads, static and dynamic, requires modelling of face sheets and core with some fidelity. While it is possible to model full geometric details of the core for a few selected problems, this is unnecessary and unrealistic for larger complex structures under general loadings. In this paper, a continuum constitutive model is proposed as an alternative means of modelling the core. The constitutive model falls within the framework of a compressible rate‐independent, anisotropic elastic–plastic solid. The general form of the model is presented, along with algorithmic aspects of its implementation in a finite element code, and selected problems are solved which benchmark the code against existing codes for limiting cases and which illustrate features specific to compressible cores. Three core geometries (pyramidal truss, folded plate, and square honeycomb) are considered in some detail. The validity of the approach is established by comparing numerical finite element simulations using the model with those obtained by a full three‐dimensional meshing of the core geometry for each of the three types of cores for a clamped sandwich plate subject to uniform pressure load. Limitations of the model are also discussed. Copyright © 2004 John Wiley & Sons, Ltd.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLimited nerve impulse blockade by "leashed" local anestheticsJohn F. Butterworth IV, John R. Moran, George M. Whitesides, and Gary R. StrichartzCite this: J. Med. Chem. 1987, 30, 8, 1295–1302Publication Date (Print):August 1, 1987Publication History Published online1 May 2002Published inissue 1 August 1987https://pubs.acs.org/doi/10.1021/jm00391a006https://doi.org/10.1021/jm00391a006research-articleACS PublicationsRequest reuse permissionsArticle Views278Altmetric-Citations9LEARN 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
The purpose of this study was to describe gender differences in children's health until the age of 7 y. The study cohort consisted of all children born in Finland in 1987 ( n = 60 254), of whom 99.9% were identified in the follow‐up. Childhood health data were received from five national registers (1987‐94), from regional registers of intellectual disabilities (1987‐96) and from education registers in the largest county (1996). Boys had a 20% higher risk for a low 5‐min Apgar score and an 11% higher risk for being preterm. After the perinatal period, boys had a 64% higher cumulative incidence of asthma, a 43% higher cumulative incidence of intellectual disability, a 22% higher incidence of mortality and a higher, but not statistically significant, incidence of epilepsy and vision disorders. No male excess was found for diabetes or hearing disorders. The healthcare‐related indicators showed poorer health for boys, who had a 37% higher mean of hospital days, a 28% higher risk for receiving social benefits due to health problems and a 13% higher risk for long‐term medication. The differences in the socially defined indicators were greatest, and boys had a two‐ to three‐fold risk of having delayed development, postponed school start or attendance in special education programmes. Gender differences in different social classes were similar. Boys' shorter gestational age at birth did not explain the gender differences in childhood health. Some of boys' poorer health seemed to be biologically based, but the social causes of health problems are amenable to change. In particular, the potential of the school system to reduce ill health among boys should be investigated.
