Publications

Abstract This paper compares rates of charge transport by tunneling across junctions with the structures Ag TS X(CH 2 ) 2 n CH 3 //Ga 2 O 3 /EGaIn ( n =1–8 and X= SCH 2  and O 2 C); here Ag TS is template‐stripped silver, and EGaIn is the eutectic alloy of gallium and indium. Its objective was to compare the tunneling decay coefficient ( β , Å −1 ) and the injection current ( J 0 , A cm −2 ) of the junctions comprising SAMs of n ‐alkanethiolates and n ‐alkanoates. Replacing Ag TS SCH 2 ‐R with Ag TS O 2 C‐R (R=alkyl chains) had no significant influence on J 0 (ca. 3×10 3 A cm −2 ) or β (0.75–0.79 Å −1 )—an indication that such changes (both structural and electronic) in the Ag TS XR interface do not influence the rate of charge transport. A comparison of junctions comprising oligo(phenylene)carboxylates and n ‐alkanoates showed, as expected, that β for aliphatic (0.79 Å −1 ) and aromatic (0.60 Å −1 ) SAMs differed significantly.

This paper describes a method and a sensor that use magnetic levitation (MagLev) to characterize samples of food and water on the basis of measurements of density. The sensor comprises two permanent NdFeB magnets positioned on top of each other in a configuration with like poles facing and a container filled with a solution of paramagnetic ions. Measurements of density are obtained by suspending a diamagnetic object in the container filled with the paramagnetic fluid, placing the container between the magnets, and measuring the vertical position of the suspended object. MagLev was used to estimate the salinity of water, to compare a variety of vegetable oils on the basis of the ratio of polyunsaturated fat to monounsaturated fat, to compare the contents of fat in milk, cheese, and peanut butter, and to determine the density of grains.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSelf-Assembled Monolayers of Long-Chain Hydroxamic Acids on the Native Oxide of MetalsJohn P. Folkers, Christopher B. Gorman, Paul E. Laibinis, Stefan Buchholz, George M. Whitesides, and Ralph G. NuzzoCite this: Langmuir 1995, 11, 3, 813–824Publication Date (Print):March 1, 1995Publication History Published online1 May 2002Published inissue 1 March 1995https://pubs.acs.org/doi/10.1021/la00003a024https://doi.org/10.1021/la00003a024research-articleACS PublicationsRequest reuse permissionsArticle Views2677Altmetric-Citations308LEARN 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

This paper describes a simple technique for fabricating uniform arrays of metal and metal oxide nanotubes with controlled heights and diameters. The technique involves depositing material onto an anodized aluminum oxide (AAO) membrane template using a collimated electron beam evaporation source. The evaporating material enters the porous openings of the AAO membrane and deposits onto the walls of the pores. The membrane is tilted with respect to the column of evaporating material, so the shadows cast by the openings of the pores onto the inside walls of the pores define the geometry of the tubes. Rotation of the membrane during evaporation ensures uniform deposition inside the pores. After evaporation, dissolution of the AAO in base easily removes the template to yield an array of nanotubes connected by a thin backing of the same metal or metal oxide. The diameter of the pores dictates the diameter of the tubes, and the incident angle of evaporation determines the height of the tubes. Tubes up to approximately 1.5 mum in height and 20-200 nm in diameter were fabricated. This method is adaptable to any material that can be vapor-deposited, including indium-tin oxide (ITO), a conductive, transparent material that is useful for many opto-electronic applications. An array of gold nanotubes produced by this technique served as a substrate for surface-enhanced Raman spectroscopy: the Raman signal (per molecule) from a monolayer of benzenethiolate was a factor of approximately 5 x 10(5) greater than that obtained using bulk liquid benzenethiol.

This prospective study indicates a significant association between carotid IMT and incidence of CHD and stroke in Chinese adults. These measurements may be useful for cardiovascular risk assessment and stratification in Chinese.

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.

'Polymer–Metal Oxide Solar Cells' published in 'Encyclopedia of Nanotechnology'

Prospective evidence of the associations of smoking cessation with chronic obstructive pulmonary disease (COPD) and other causes of death in Asia is scarce. Previous studies, which were mostly based on baseline smoking behavior only, were subject to sick-quitter bias and misclassification resulting from changes in smoking behavior during follow-up. We followed up a cohort for 18 years (1976-1994) to assess changes in smoking behavior and then for an additional 17 years (1994-2011) to examine the relationships of continuing to smoke and new quitting with mortality risk in 1,494 Chinese people (961 men, 533 women). Of the baseline current smokers, 38.7% quit between 1976 and 1994. From 1994 to 2011, a total of 488 persons (359 men, 129 women) died. Ever smokers had increased risks of lung cancer, coronary heart disease, thrombotic stroke, and COPD, with dose-response relationships. For all tobacco-related mortality, the relative risk for new quitters compared with continuing smokers was 0.68 (95% confidence interval: 0.46, 0.99) for those who had quit 2-7 years previously and 0.56 (95% confidence interval: 0.37, 0.85) for those who had quit 8 years or more previously. The corresponding relative risks were 0.69 and 0.45 for lung cancer, 0.78 and 0.51 for coronary heart disease, 0.76 and 0.84 for thrombotic stroke, and 0.89 and 0.61 for COPD, respectively. Smoking increased tobacco-related deaths, and particularly deaths from COPD, in China, whereas quitting at middle age (at approximately 50 years of age) substantially reduced the risks of death from these causes. The benefits of smoking cessation were underestimated in previous studies that did not use repeated measures.

Optical loss of a chemically-synthesized light-emitting nanowire can be reduced by embedding the nanowire in an optical microcavity. Design of nanowire/photonic crystal platform as well as characterization of nanowire embedded in race-track microresonator are presented.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSelective functionalization of gold microstructures with ferrocenyl derivatives via reaction with thiols or disulfides: characterization by electrochemistry and Auger electron spectroscopyJames J. Hickman, David Ofer, Chaofeng Zou, Mark S. Wrighton, Paul E. Laibinis, and George M. WhitesidesCite this: J. Am. Chem. Soc. 1991, 113, 4, 1128–1132Publication Date (Print):February 1, 1991Publication History Published online1 May 2002Published inissue 1 February 1991https://pubs.acs.org/doi/10.1021/ja00004a010https://doi.org/10.1021/ja00004a010research-articleACS PublicationsRequest reuse permissionsArticle Views639Altmetric-Citations96LEARN 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

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.