Publications

Using Self-Assembled Monolayers That Present Oligo(ethylene glycol) Groups To Control the Interactions of Proteins with Surfaces

This chapter reviews the use of self-assembled monolayers of alkanethiolates on gold to control the interactions of proteins and cells with man-made materials. The work is based on the ability of monolayers that present oligo(ethylene glycol) groups to resist the non-specific adsorption of protein. The chapter describes the use of functionalized monolayers for the bio- and chemo-specific adsorption of proteins. The chapter concludes with a discussion of techniques that can pattern the formation of monolayers and that can prepare tailored substrates for the control of cell attachment.

Bifurcation analysis of the onset of necking in an elastic/plastic cylinder under uniaxial tension

The Bifurcation problem governing the onset of axisymmetric necking in a circular cylindrical specimen in uniaxial tension is analysed. The specimen is made of an incompressible elastic/plastic material. One end is subject to a prescribed uniform axial displacement relative to the other and both ends are shear free. The true stress at bifurcation is greater than the stress at which the maximum load is attained by an amount which depends on (i) the radius to length ratio of the specimen, (ii) the ratio of the elastic shear modulus to the tangent modulus, and (iii) the derivative of the tangent modulus with respect to the stress. Bifurcation takes place immediately following attainment of the maximum load when the specimen is sufficiently slender.

THE INITIATION AND GROWTH OF SHEAR BANDS

No abstract is provided for this article.

Epidemiology of Diabetes

Mechanics of quasi-static crack growth

No abstract is provided for this article.

Heating and Weakening of Major Faults During Seismic Rupture

No abstract is provided for this article.

Broadly Available Imaging Devices Enable High-Quality Low-Cost Photometry

This paper demonstrates that, for applications in resource-limited environments, expensive microplate spectrophotometers that are used in many central laboratories for parallel measurement of absorbance of samples can be replaced by photometers based on inexpensive and ubiquitous, consumer electronic devices (e.g., scanners and cell-phone cameras). Two devices, (i) a flatbed scanner operating in transmittance mode and (ii) a camera-based photometer (constructed from a cell phone camera, a planar light source, and a cardboard box), demonstrate the concept. These devices illuminate samples in microtiter plates from one side and use the RGB-based imaging sensors of the scanner/camera to measure the light transmitted to the other side. The broadband absorbance of samples (RGB-resolved absorbance) can be calculated using the RGB color values of only three pixels per microwell. Rigorous theoretical analysis establishes a well-defined relationship between the absorbance spectrum of a sample and its corresponding RGB-resolved absorbance. The linearity and precision of measurements performed with these low-cost photometers on different dyes, which absorb across the range of the visible spectrum, and chromogenic products of assays (e.g., enzymatic, ELISA) demonstrate that these low-cost photometers can be used reliably in a broad range of chemical and biochemical analyses. The ability to perform accurate measurements of absorbance on liquid samples, in parallel and at low cost, would enable testing, typically reserved for well-equipped clinics and laboratories, to be performed in circumstances where resources and expertise are limited.

Preparation of phosphoenolpyruvate from D-(-)-3-phosphoglyceric acid for use in regeneration of ATP

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPreparation of phosphoenolpyruvate from D-(-)-3-phosphoglyceric acid for use in regeneration of ATPEthan S. Simon, Sven Grabowski, and George M. WhitesidesCite this: J. Am. Chem. Soc. 1989, 111, 24, 8920–8921Publication Date (Print):November 1, 1989Publication History Published online1 May 2002Published inissue 1 November 1989https://pubs.acs.org/doi/10.1021/ja00206a026https://doi.org/10.1021/ja00206a026research-articleACS PublicationsRequest reuse permissionsArticle Views267Altmetric-Citations34LEARN 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

Intake of whole grain foods and risk of coronary heart disease in US men and women

Insulin resistance and systemic metabolic changes in oral glucose tolerance test in 5340 individuals: an interventional study

Insulin resistance (IR) is predictive for type 2 diabetes and associated with various metabolic abnormalities in fasting conditions. However, limited data are available on how IR affects metabolic responses in a non-fasting setting, yet this is the state people are mostly exposed to during waking hours in the modern society. Here, we aim to comprehensively characterise the metabolic changes in response to an oral glucose test (OGTT) and assess the associations of these changes with IR. Blood samples were obtained at 0 (fasting baseline, right before glucose ingestion), 30, 60, and 120 min during the OGTT. Seventy-eight metabolic measures were analysed at each time point for a discovery cohort of 4745 middle-aged Finnish individuals and a replication cohort of 595 senior Finnish participants. We assessed the metabolic changes in response to glucose ingestion (percentage change in relative to fasting baseline) across the four time points and further compared the response profile between five groups with different levels of IR and glucose intolerance. Further, the differences were tested for covariate adjustment, including gender, body mass index, systolic blood pressure, fasting, and 2-h glucose levels. The groups were defined as insulin sensitive with normal glucose (IS-NGT), insulin resistant with normal glucose (IR-NGT), impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and new diabetes (NDM). IS-NGT and IR-NGT were defined as the first and fourth quartile of fasting insulin in NGT individuals. Glucose ingestion induced multiple metabolic responses, including increased glycolysis intermediates and decreased branched-chain amino acids, ketone bodies, glycerol, and triglycerides. The IR-NGT subgroup showed smaller responses for these measures (mean + 23%, interquartile 9–34% at 120 min) compared to IS-NGT (34%, 23–44%, P < 0.0006 for difference, corrected for multiple testing). Notably, the three groups with glucose abnormality (IFG, IGT, and NDM) showed similar metabolic dysregulations as those of IR-NGT. The difference between the IS-NGT and the other subgroups was largely explained by fasting insulin, but not fasting or 2 h glucose. The findings were consistent after covariate adjustment and between the discovery and replication cohort. Insulin-resistant non-diabetic individuals are exposed to a similar adverse postprandial metabolic milieu, and analogous cardiometabolic risk, as those with type 2 diabetes. The wide range of metabolic abnormalities associated with IR highlights the necessity of diabetes diagnostics and clinical care beyond glucose management.

The role of iron in type 2 diabetes in humans

Abstract MP27: Weight Change, BMI, and Mortality Among Survivors of Myocardial Infarction: Analysis of Two Prospective US Cohort Studies

Background: The relation between BMI, weight change and mortality among survivors of Myocardial Infarction (MI) remains controversial, with some studies reporting favorable survival outcomes among overweight and obese patients, as compared to those with normal weight. We aim to examine the relationship between BMI reported shortly before and after MI diagnosis in addition to weight change with all-cause and cardiovascular disease (CVD) mortality among MI survivors. Methods: Using the data from Nurses’ Health Study (NHS) and Health Professionals Follow up Study (HPFS) cohorts, we studied 4278 participants who were free of CVD and cancer before their MI. Weight change (in BMI units) was categorized as loss of (&gt; 4, 2-4, &lt;2-0 (reference)), or gain of (0.1-2, or &gt;2) units. Multivariable Cox models were used to estimate hazard ratios and 95 % confidence interval for mortality across BMI/weight change categories. Results: During up to 36 (NHS) and 28 (HPFS) years of follow-up post-MI, there were 2071 all-cause and 835 CVD deaths. Overweight patients with BMI before or after MI of 25-27.49 kg/m 2 had decreased mortality as compared to normal weight patients (22.5-24.9 kg/m 2 ). All-cause mortality increased progressively with higher BMI. Obese patients (BMI≥30) had the highest risk of CVD mortality (HR=1.35; 95% CI, 1.06-1.73). Among MI patients who had never smoked (N=1484) or were younger than 65 years of age at the time of diagnosis (N=1873), no survival advantage was observed for overweight/obese patients. Compared to stable weight (a BMI reduction of 0-1.99 units) from before to after MI, a reduction of 2-4 or &gt;4 BMI units was associated with increased mortality (HR=1.12; 95% CI, 0.96-1.29 and 1.42; 95% CI, 1.17-1.71 respectively, Figure). Conclusions: We observed a J-shaped association between BMI and mortality among all MI patients, but not among those who had never smoked or were younger than 65 years of age. Weight loss associated with acute MI, potentially related to disease severity, is an important predictor of higher mortality.

Detection, Stimulation, and Inhibition of Neuronal Signals with High-Density Nanowire Transistor Arrays

We report electrical properties of hybrid structures consisting of arrays of nanowire field-effect transistors integrated with the individual axons and dendrites of live mammalian neurons, where each nanoscale junction can be used for spatially resolved, highly sensitive detection, stimulation, and/or inhibition of neuronal signal propagation. Arrays of nanowire-neuron junctions enable simultaneous measurement of the rate, amplitude, and shape of signals propagating along individual axons and dendrites. The configuration of nanowire-axon junctions in arrays, as both inputs and outputs, makes possible controlled studies of partial to complete inhibition of signal propagation by both local electrical and chemical stimuli. In addition, nanowire-axon junction arrays were integrated and tested at a level of at least 50 "artificial synapses" per neuron.

The force exerted by a moving ice sheet on an offshore structure

A uniform ice sheet moves steadily against a flat-sided fixed offshore structure. The ice deforms in creep: the problem is to determine the relation between the force on the structure and the velocity of the ice. The problem cannot be solved analytically, but a conventient approximate solution can be found by the reference stress method of creep structural analysis, which makes systematic use of a small number of numerical and analytic solutions to related problems, including solutions to the corresponding problem for a perfectly-plastic material. The method is applicable to any observed relation between stress and strain rate. It is tested by comparison with additional numerical solutions, and with published data on indentation experiments.

Depression mediates the relationship between alexithymia and obesity in the Northern Finland Birth Cohort 1966 (NFBC1966)

41st Annual Frequency Control Symposium - 1987 SURFACE INTERACTION OF ATOMIC HYDROGEN WITH TEFLON

Summary We studied the process of deterioration of a hydrogen maser’s Teflon storage bulb coating, and examined the coating’s physical and chemical characteristics. The deterioration, which accompanied exposure to the maser’s atomic hydrogen beam, was marked by decreasing maser line Q and microwave output power. The likelihood of Teflon degradation by ultraviolet radiation from the beam source was eliminated. Teflon from the bulb, and Teflon from the same original batch, were compared with Teflon from

Microcontact printing of self-assembled monolayers: applications in microfabrication

This paper describes applications in microfabrication using patterned self-assembled monolayers (SAMs) formed by microcontact printing. Microcontact printing is a flexible new technique that forms patterned SAMs with regions terminated by different chemical functionalities (and thus different physical and chemical properties), in patterns with dimensions. Patterns of SAM are formed using an alkanethiol as an `ink', and printing the alkanethiol on a metal support with elastomeric `stamp'. We fabricate the stamp by moulding a silicone elastomer using a master prepared by optical or x-ray microlithography or by other techniques. SAMs of long-chain alkanethiolates on gold and other metals can act as nanometer resists by protecting the supporting metal from corrosion by appropriately formulated etchants: the fabrication of microstructures of gold and silicon demonstrates the utility of patterned SAMs (formed by ) as nm resists. Patterned SAMs formed by can also control the wettability of a surface on the scale. The organization of liquids in patterned arrays with dimensions, and the patterned deposition of microcrystals and microcrystal arrays illustrate the use of controlled wettability for microfabrication.

PLANE STRAIN DEFORMATION NEAR A CRACK TIP IN A POWER LAW HARDENING MATERIAL