Nano Research Research Articles

Miscibility Enhancement in All-Polymer Nanocomposites Composed of Weakly-Charged Flexible Chains and Polar Nanoparticles

We report the phase behavior of nanocomposites composed of weakly-charged flexible polymers and polar nanoparticles by extending a mean-field theory for all-polymer nanocomposites recently introduced (Journal of Nano Research 2 (2008) 105). Translational, nanoparticle-driven, electrostatic and enthalpic interaction effects are taken into account. Weakly-charged polymers are predicted to be miscible with polar nanoparticles about one order of magnitude larger (in radius) than conventional uncharged polymers, even in the presence of moderate unfavorable enthalpic interactions. The detrimental effect of addition of a low molecular weight monovalent 1-1 salt on nanocomposite miscibility is also evaluated.

How interdisciplinary is nanotechnology?

Facilitating cross-disciplinary research has attracted much attention in recent years, with special concerns in nanoscience and nanotechnology. Although policy discourse has emphasized that nanotechnology is substantively integrative, some analysts have countered that it is really a loose amalgam of relatively traditional pockets of physics, chemistry, and other disciplines that interrelate only weakly. We are developing empirical measures to gauge and visualize the extent and nature of interdisciplinary interchange. Such results speak to research organization, funding, and mechanisms to bolster knowledge transfer. In this study, we address the nature of cross-disciplinary linkages using “science overlay maps” of articles, and their references, that have been categorized into subject categories. We find signs that the rate of increase in nano research is slowing, and that its composition is changing (for one, increasing chemistry-related activity). Our results suggest that nanotechnology research encompasses multiple disciplines that draw knowledge from disciplinarily diverse knowledge sources. Nano research is highly, and increasingly, integrative—but so is much of science these days. Tabulating and mapping nano research activity show a dominant core in materials sciences, broadly defined. Additional analyses and maps show that nano research draws extensively upon knowledge presented in other areas; it is not constricted within narrow silos.

Detection for Spring Constant of Microcantilevers in Atomic Force Microscopy Based on Frequency Measurements

Micro cantilevers in atomic force microscopy are important force sensors in nano research, and the spring constant is one of the most important parameters of the cantilevers. Normal testing methods are not suitable for the spring constant detecting of micro cantilevers according to the strict scale of the cantilevers, and new methods are needed to the study of micro cantilevers. A method for detecting of spring constant of micro cantilevers based on combining the numerical simulation and frequency measurements is presented in this paper. The new method involves four steps, the first step is developing the vibration model of the micro cantilever studied immersed in air and determine the fluid parameters in the model during dynamic tests in atomic force microscopy presented in this paper; the second step is analyzing the vibration behavior of the corresponding cantilevers with the same geometry but different young’s modulus. The third step is measuring the natural frequencies of the micro cantilevers and comparing the experimental results with the numerical results to determine the young’s modulus of the cantilever. The last step is conducting the young’s modulus to the cantilever FEA model for determination of its spring constant. Experiments on a NSC cantilever have been done to validate the method presented in this paper.

Pitfalls in employing superparamagnetic iron oxide particles for stem cell labelling andin vivoMRI tracking

Pitfalls in employing superparamagnetic iron oxide particles for stem cell labelling and<i>in vivo</i>MRI tracking

Toward Green Nano

SummaryCommercial and research interest in nanotechnology has exploded in recent years, with nearly US$9 billion in investment from public and private sources in 2005. While the list of potential applications for nanotechnologies continues to grow, there is increasing pressure from governments and researchers alike to understand the implications of this new class of materials. The emerging field of green nano applies green chemistry and engineering principles to the synthesis of nanomaterials. Here we outline several strategies for the development of green nano and review past policy and research activities in understanding nanotechnology's environmental implications. By means of the green chemistry metric of E‐factor, an analysis is undertaken of the traditional syntheses of several specific nanomaterials, including carbon nanotubes, fullerenes, and metal nanoparticles. It was found that the E‐factors of these production processes vary over several orders of magnitude, making it difficult to comment generally about the resource use efficiencies of nanomaterials production. For gold nanoparticles specifically, E‐factors for six different production methods are found to range from 102 to 105, demonstrating that greener synthesis routes are possible and that environmental benefits can begin to be quantified. Expanding the analysis to include life‐cycle stages upstream and downstream of production and to incorporate environmental health effects is encouraged, though significant data gaps exist.

An extraordinary scientist for an extraordinary journal

Seven years ago, in an Editorial for the first issue of Lab on a Chip (LOC), Andreas Manz asked a simple question: What is so speical about micro and nano research?

Monitoring Multiwalled Carbon Nanotube Exposure in Carbon Nanotube Research Facility

With the increased production and widespread use of multiwalled carbon nanotubes (MWCNTs), human and environmental exposure to MWCNTs is inevitably increasing. Therefore, this study monitored the possible exposure to MWCNT release in a carbon nanotube research laboratory. To estimate the potential exposure of researchers and evaluate the improvement of the workplace environment after the implementation of protective control measures, personal and area monitoring were conducted in an MWCNT research facility where the researchers handled unrefined materials. The number, composition, and aspect ratio of MWCNTs were measured using scanning transmission electron microscopy with an energy-dispersive x-ray analyzer. The gravimetric concentrations of total dust before any control measures ranged from 0.21 to 0.43 mg/m3, then decreased to a nondetectable level after implementing the control measures. The number of MWCNTs in the samples obtained from the MWCNT blending laboratory ranged from 172.9 to 193.6 MWCNTs/cc before the control measures, and decreased to 0.018–0.05 MWCNTs/cc after the protective improvements. The real-time monitoring of aerosol particles provided a signature of the MWCNTs released from the blending equipment in laboratory C. In particular, the number size response of an aerodynamic particle sizer with a relatively high concentration in the range of 2 to 3 μ m in aerodynamic diameter revealed the evidence of MWCNT exposure. The black carbon mass concentration also increased significantly during the MWCNT release process. Therefore, the present study suggests that the conventional industrial hygiene measures can significantly reduce exposure to airborne MWCNTs and other particulate materials in a nano research facility.

Erratum: “Characteristics of a stick waveguide resonator in a two-dimensional photonic crystal slab” [J. Appl. Phys. 95, 411 (2004)

This work is supported by the National Research Laboratory Project, Nano Research and Development program of Korea and NICOP program of the Office of Naval Research.

Nanotechnology and the Modern University

The novelty of nanotechnology presents social scientists with an interesting dilemma. On the one hand, the scientists and engineers doing nano research have been at it for such a brief time, and are performing such a diffuse array of activities, that it is very difficult to see what social scientists should be studying, much less how they should go about it. On the other hand, social scientists who study science and engineering have (at least over the past decade) focused largely on disciplines that are relatively marginal to nano—computing-information technology, genomics-biotech, psychology-cognitive science, economics, and medicine (this gross generalization is based on looking through the program of the annual Society for Social Studies of Science meeting for the past few years). There is very little sociology or anthropology of the core fields of nano (materials science, chemistry, applied and/or condensed matter physics, electrical and mechanical engineering)—though the exceptions are some of the best representatives of social studies of science (e.g. Hugh Gusterson, Laura McNamara, Bart Simon, Harry Collins). Obviously, some lessons from ethnographies or recent histories of biotech, economics, etc. will translate well to the study of nanotechnology; but we should also accept that it will probably take as long for social scientists to develop a methodology for nanotechnology as it will take scientists and engineers to develop a practice of nanotechnology.

Introducing Standards of Care in the Commercialization of Nanotechnology

While the entire wish-list of expected benefits from nanotechnology has received little scrutiny in the U.S. with regard to issues of social justice, ethics specialists and social scientists are beginning to focus on the responsible conduct of actual nano research and development (RD another is the formulation and implementation of standards of care that are the outcome of inclusive, deliberative processes.

Images in cardiovascular medicine. Avoiding papillary muscle infarction with myocardial contrast echocardiographic guidance of nonsurgical septal reduction therapy for hypertrophic obstructive cardiomyopathy.

Intracoronary myocardial contrast echocardiography (MCE) can be used to guide the delivery of ethanol during nonsurgical septal reduction therapy for hypertrophic obstructive cardiomyopathy. The echocardiographic contrast agent is injected immediately before the injection of ethanol, down the lumen of the inflated balloon that resides in the target septal coronary artery. This is the artery that supplies the area of the septum involved with the mitral leaflet(s) in causing dynamic outflow tract obstruction. MCE provides a direct visualization of the myocardial territory that should receive ethanol and consequently undergo infarction. In rare instances, the cannulated vessel does not supply the culprit septal segment(s) but supplies instead …

Zeroing in on ethical issues in nanotechnology

Setting aside exaggerated notions of both the benefits and harms to be expected from nanotechnologies, we need to focus ethical investigation on specific initiatives at the nano scale that are already underway or planned. The aims are to anticipate ethical issues likely to arise in specific cases, to foster sensitivity to ethical issues and responsibility among nano specialists and policy makers, and to stimulate interchange between nano specialists and members of the public so that the public can become involved. After clarifying what the term nanotechnology embraces and looking at cautionary lessons from experience with the information technologies and biotechnology, the discussion turns to the importance of anticipating consequences, intended and unintended. Although specific nano options to consider are lacking, a brief survey indicates the issues to watch out for: preventable harms, conflicts about justice and fairness, respect for persons, and more specifically, safeguards for workers in new production processes, intellectual property concerns, preservation of university values in university/industry relationships, and conflicts of interest. Three main fronts of activity are needed to address ethical issues: 1) incorporating ethics research into nano research and development enterprises; 2) devising mechanisms to involve the public so that their perspectives and concerns feed back into research and development; and 3) initiating educational efforts at every level addressing both technical aspects and ethics and social implications aspects.

DTI puts $50m to micro & nano research

Expressions of interest were being sought by the DTI from organisations working in the nano and micro technology fields, deadlined September 19 for collaborative research eligible for support. These will help DTI assess whether themes should be prioritised in the subsequent two stage call for proposals. Within this initiative, DTI has allocated $50m for an Applied Research Programme that will support collaborative R&D projects and technology transfer initiatives. This is a short news story only. Visit www.three-fives.com for the latest advanced semiconductor industry news.

Brave small world

Nanotechnology resurfaces regularly in the popular and scientific press. But despite the pretty pictures of ‘nano submarines’ patrolling the body for tumour cells in popular magazines and miniature cogs on the cover of Nature , there are few applications of nanotechnology that have actually made it to the market place. So far, dirt‐repelling surface coatings and paint additives are the only commercial applications to result from nano research. Miniature machines and submarines may be some way off, but in the biomedical sector a fledgling industry is emerging that exploits nanotechniques for diagnosis and drug delivery. > It was the physicist and Nobel laureate Richard Feynman who saw the day when it would be possible to build miniature devices bottom‐up, starting with single atoms or molecules It was the physicist and Nobel laureate Richard Feynman who saw the day when it would be possible to build miniature devices bottom‐up, starting with single atoms or molecules. This differs from conventional miniaturisation techniques, which are top‐down. They start with larger substrates, and make it smaller by taking matter away—the miniature cogs in Nature are such an example. Nanoscience today is often defined as the study of systems of the order of 1 to 100 nm in size, although larger structures, for example those made by etching silicon, have been referred to as ‘nano’ as well. On one thing all agree: nanotechnology and its applications are proving a middle ground for the meeting of intellects from a wide diversity of scientific backgrounds; the life sciences, physics, chemistry, engineering, electronics and chemistry to name some. As Hermann Gaub, Chair of Applied Physics at the Ludwig Maximilian University in Munich, remarked, ‘at the nanometer scale, the differences between disciplines disappear.’ Gaub's group studies the biophysics of single molecules, in particular the folding processes of protein molecules. By …

Aircraft icing

Aircraft icing

Bubble dynamics, shock waves and sonoluminescence

Sound and light emission by bubbles is studied experimentally. Single bubbles kept in a bubble trap and single lasergenerated bubbles are investigated using ultrafast and highspeed photography in c...