Publications

Electric field modulation of visible and ultraviolet nanoscale lasers consisting of single CdS or GaN nanowires has been achieved using integrated, microfabricated electrodes. Modulation of laser emission intensity is achieved with no detectable change in the laser wavelength. The devices can also be operated below the lasing threshold to modulate the intensity of light propagating within the nanowire waveguide. Studies of the electric field dependence in devices of varied geometry indicate that modulation is due to an electroabsorption mechanism. These findings expand opportunities for multicolor, nanowire-based photonic devices and circuits.

'PFOB Nanoparticles' published in 'Encyclopedia of Nanotechnology'

Alles im Kasten: Ein preisgünstiger, tragbarer Proteindetektor, der unter Feldbedingungen wie direktem Sonnenlicht arbeitet, wurde entwickelt. Der "POCKET-Immunoassay" (siehe Bild) besteht aus kommerziellen Bauteilen und hat eine analytische Performance ähnlich der von herkömmlichen Laborgeräten. Er könnte z. B. für die Diagnose von HIV-Infektionen in Entwicklungsländern eingesetzt werden. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2001/2004/z53016_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Abstract Background and Aims Moderate wine consumption has been associated with lower cardiovascular disease (CVD) risk in older populations. However, wine consumption information through self-reports is prone to measurement errors inherent to subjective assessments. The aim of this study was to evaluate the association between urinary tartaric acid, an objective biomarker of wine consumption, and the rate of a composite clinical CVD event. Methods A case-cohort nested study was designed within the PREDIMED trial with 1232 participants: 685 incident cases of CVD and a random subcohort of 625 participants (including 78 overlapping cases). Wine consumption was registered using validated food frequency questionnaires. Liquid chromatography-tandem mass spectrometry was used to measure urinary tartaric acid at baseline and after one year of intervention. Weighted Cox regression models were used to estimate hazard ratios (HRs) of CVD. Results Tartaric acid was correlated with self-reported wine consumption at baseline [r = 0.46 (95% CI 0.41; 0.50)]. Five categories of post hoc urinary tartaric acid excretion were used for better representation of risk patterns. Concentrations of 3–12 and 12–35 μg/mL, which reflect ∼3–12 and 12–35 glasses/month of wine, were associated with lower CVD risk [HR 0.62 (95% CI 0.38; 1.00), P = .050 and HR 0.50 (95% CI 0.27; 0.95), P = .035, respectively]. Less significant associations between self-reported wine consumption and CVD risk were observed. Conclusions Light-to-moderate wine consumption, measured through an objective biomarker (tartaric acid), was prospectively associated with lower CVD rate in a Mediterranean population at high cardiovascular risk.

Electronic and optoelectronic devices impact many areas of society, from simple household appliances and multimedia systems to communications, computing, and medical instruments. Given the demand for ever more compact and powerful systems, there is growing interest in the development of nanoscale devices that could enable new functions and/or greatly enhanced performance. Semiconductor nanowires are emerging as a powerful class of materials that, through controlled growth and organization, are opening up substantial opportunities for novel nanoscale photonic and electronic devices. We review the broad array of nanowire building blocks available to researchers and discuss a range of electronic and optoelectronic nanodevices, as well as integrated device arrays, that could enable diverse and exciting applications in the future.

This paper describes a method for fabricating three-dimensional (3D) microfluidic channel systems in poly(dimethylsiloxane) (PDMS) with complex topologies and geometries that include a knot, a spiral channel, a "basketweave" of channels, a chaotic advective mixer, a system with "braided" channels, and a 3D grid of channels. Pseudo-3D channels, which are topologically equivalent to planar channels, are generated by bending corresponding planar channels in PDMS out of the plane into 3D shapes. True 3D channel systems are formed on the basis of the strategy of decomposing these complex networks into substructures that are planar or pseudo-3D. A methodology is developed that connects these planar and/or pseudo-3D structures to generate PDMS channel systems with the original 3D geometry. This technique of joining separate channel structures can also be used to create channel systems in PDMS over large areas by connecting features on different substrates. The channels can be used as templates to form 3D structures in other materials.

A mid-infrared (mid-IR) label-free chemical sensor was developed using opto-nanofluidics consisting of a Si-liquid-Si slot-structure. A broadband mid-IR lightwave can be strongly confined within a nanofluidic capillary by utilizing the large refractive index contrast (Δn ~ 2) between the liquid core waveguide and the Si cladding. Through an optical-field enhancement together with a direct interaction between the probe light and the analyte, the sensitivity for chemical detection is increased by 50 times when compared to evanescent-wave sensing. This spectral characterization distinguished several common organic liquids (e.g., n-bromohexane, toluene, isopropanol) accurately, and could determine the ratio of chemical species (e.g., acetonitrile and ethanol) at low concentration (< 5 μL/mL) in a mixture through spectral scanning over their characteristic mid-IR absorption peaks. The combination of CMOS-compatible planar mid-IR microphotonics, and a high-throughput nanofluidic sensor system, provides a unique platform for chemical detection.

Introduction: The 2010 Dietary Guidelines for Americans concludes that there is currently not enough evidence to support a specific recommendation for behaviors such as snacking and frequency of eating, but does recommend eating breakfast daily to prevent obesity, especially for children and adolescents. Among adults, skipping meals has been shown to be positively associated with excess weight, dyslipidemia, hyperglycemia, and total mortality. However, the influence of eating frequency on risk of coronary heart disease (CHD) remains unclear. Objective and Hypothesis: The objective of this study was to test the hypothesis that abnormal eating habits are related to an increased risk of fatal CHD and non-fatal myocardial infarction. Methods: Eating frequency (meals and/or snacks per day), breakfast consumption (yes or no) and eating after going to bed at night (yes or no) were assessed in 1992 in 35,221 men from the prospective Health Professionals Follow-up Study. Between 1992 and 2008, 2761 incident CHD cases were diagnosed. Multivariate Cox proportional hazards regression models were used to estimate relative risks (RR) and 95% confidence intervals (CI) for these eating habits. Results: Men who ate &lt;3 times/day, compared to the men who ate 3 times/day, had a 22% higher risk of CHD ( table ). Men who skipped breakfast had a significant 18% higher risk of CHD compared to men who ate breakfast. Those who reported eating after going to bed had a 34% higher risk of CHD compared to the men who did not. Conclusions: Even when controlling for known CHD risk factors including diet quality, general infrequent eating was associated with increased CHD risk, as were skipping breakfast and eating after bedtime. Table Multivariate * RR and 95% CI of CHD by categories of eating habit Cases (n) Person Years Age-RR (95% CI) MV-RR (95% CI) p (trend) Eating Frequency &lt; 3 times/day 503 85,920 1.26 (1.14-1.40) 1.22 (1.08-1.37) 0.01 3 times/day 1222 217,400 1.00 (Ref) 1.00 (Ref) &gt; 3 times/day 1036 191,974 1.08 (0.99-1.17) 0.98 (0.90-1.07) Breakfast Eating Yes 2164 380,491 1.00 (Ref) 1.00 (Ref) 0.005 No 597 114,802 1.28 (1.16-1.40) 1.18 (1.06-1.31) Eating After Bedtime Yes 49 5,515 1.64 (1.23-2.17) 1.34 (1.00-1.79) 0.0009 No 2712 489,531 1.00 (Ref) 1.00 (Ref) * Adjusted for: smoking status, race, diabetes, parental MI before 60 years of age, hypercholesterolemia, hypertension, aspirin use, multivitamin use, alternative Healthy Eating Index score, alcohol intake, total energy intake, BMI, and physical activity.