Optimized gold nanoshell ensembles for biomedical applications

We theoretically study the properties of the optimal size distribution in the ensemble of hollow gold nanoshells (HGNs) that exhibits the best performance at in vivo biomedical applications. For the first time, to the best of our knowledge, we analyze the dependence of the optimal geometric means of the nanoshells’ thicknesses and core radii on the excitation wavelength and the type of human tissue, while assuming lognormal fit to the size distribution in a real HGN ensemble. Regardless of the tissue type, short-wavelength, near-infrared lasers are found to be the most effective in both absorption- and scattering-based applications. We derive approximate analytical expressions enabling one to readily estimate the parameters of optimal distribution for which an HGN ensemble exhibits the maximum efficiency of absorption or scattering inside a human tissue irradiated by a near-infrared laser.     

Identification of the Sex Pheromone of the Swede Midge, <Emphasis Type="Italic">Contarinia nasturtii</Emphasis>

Coupled gas chromatographic–electroantennographic detection analyses of ovipositor extracts of calling Contarinia nasturtii females revealed two compounds that elicited responses from antennae of male midges. Using synthetic reference samples, these components were identified by gas chromatography–mass spectrometry and enantioselective GC as (2S,9S)-diacetoxyundecane and (2S,10S)-diacetoxyundecane. In addition, trace amounts of 2-acetoxyundecane were found in ovipositor extracts, and the (S)-enantiomer was synthesized. When tested in the wind tunnel, a blend of 5ng (2S,9S)-diacetoxyundecane and 10 ng (2S,10S)-diacetoxyundecane (mimicking the ratio found in the extracts) did not attract any of the males tested, but when 0.1 ng (S)-2-acetoxyundecane was added to the blend, 86.8% of the males were attracted to the bait. Three-component blends with lower or higher relative concentrations than 1% of (S)-2-acetoxyundecane [relative to (2S,10S)-diacetoxyundecane] were less attractive. In a field trapping experiment with released laboratory-reared C. nasturtii adults, traps baited with 500:1000:10 ng of (2S,9S)-diacetoxyundecane/(2S,10S)-diacetoxyundecane/(S)-2-acetoxyundecane applied to rubber septa or dental cotton rolls were tested. Traps without dispensers were used as controls. All three treatments were tested at 20 and 50 cm above ground. The estimated recapture rate was 30–50%, and 81.9% of the recaptured males were caught in traps positioned at 20 cm above ground, and 88.4% in traps with dental cotton rolls as dispensers.     

Biodegradable lactone copolymers. II. Hydrolytic study of ε-caprolactone and lactide copolymers

Copolymers of ε-CL/L-LA and ε-CL/DL-LA were allowed to age in a buffer solution of pH 7 at 23 and 37°C. The effects of time and temperature on the rate of hydrolysis were examined by various techniques including weighing (water absorption and weight loss), SEC (molecular weight and polydispersity), and DSC (thermal properties). For comparison, the hydrolytic behavior of PLLA, PDLLA, and commercial PCL homopolymers was investigated by the same methods. SEC measurements showed that molecular weights of the copolymers and PLA homopolymers started to decrease during the first week of hydrolysis, but significant mass losses occurred only much later. As expected, there was no change in either molecular weight or mass of PCL during the hydrolysis study. The kinetic results for copolymers and homopolymers were calculated to study the degradation mechanism. During hydrolysis, the crystallinity of the initially semicrystalline copolymers increased and some crystallinity appeared in the initially amorphous L-LA-containing copolymers. © 1996 John Wiley & Sons, Inc.     

Generation of low‐contrast sinusoidal test patterns on a high‐brightness display

Abstract— By using a technique of addressing individual subpixels, low‐contrast sinusoidal test patterns were generated on a high‐brightness color LCD. Detection tasks were performed using 2AFC experiments, and the value obtained for the contrast threshold was found to agree well with previously published data. As long as the shape of the pattern was close to sinusoidal, a good correlation was found between pattern contrast and detection rate. The influence of the eye‐adaptation luminance level was studied and compared to the f‐factor published by Barten. Luminance non‐uniformities in the background did not cause any significant change in the detection threshold.     

An algorithm for fast adaptive image binarization with applications in radiotherapy imaging

Locally adaptive image binarization with a sliding-window threshold can be an effective tool for various image processing tasks. We have used the method for the detection of bone ridges in radiotherapy portal images. However, a straight-forward implementation of sliding-window processing is too time consuming for routine use. Therefore, we have developed a new thresholding criterion suitable for incremental update within the sliding window, and we show that our algorithm gives better results on difficult portal images than various publicly available adaptive thresholding routines. For small windows, the routine is also faster than an adaptive implementation of the Otsu algorithm that uses interpolation between fixed tiles, and the resulting images are equally good.     

Towards integrated catchment management: increasing the dialogue between scientists,policy‐makers and stakeholders

The aim of the Hydrology for the Environment, Life and Policy (HELP) project is to strengthen the role and inputs of the scientific community in the integrated catchment management process. Water resources management in the 21st century requires a radical reorientation and an effective dialogue between decision‐makers, stakeholders and the scientific water community. This paper offers a skeleton worldview as a starting point for that dialogue by bringing together key issues as identified by water resource experts from different disciplines. Experiences from all over the world demonstrate the need for multistakeholder advocacy and the importance of compromise‐building mechanisms. Water law defines the rules of the game and provides a necessary framework for policy and its execution. However, there must be adequate social acceptance and active compliance, otherwise the formal rules and administrative regulation will not be perceived as legitimate and ultimately could prove ineffective. The challenge now is to create management systems where the formal decision‐makers interact with relevant members of the scientific community, users and other stakeholders for a coordinated approach that successfully orchestrates water uses towards internal compatibility. Integrated water resources management is essential for securing a proper overview of all the activities that depend on the same resource—the precipitation over the basin—and which are internally linked by the mobility of water from the water divide to the river mouth.     

Conjugate mixed convection heat transfer from a vertical rectangular fin

A numerical investigation of the heat transfer from a rectangular fin by combined forced and natural convection is presented. Results are given for buoyancy parameters in the range of $\text{0 ?}\text{Gr/Re}{}^2\text{? 2}$ and convection - conduction parameters in the range of $\text{0 ? √}\text{Re k}{}_{\mathrm{f}}\text{L/k}{}_{\mathrm{s}}\text{b}\text{? 10}$. The results are compared with the conventional fin theory and it is found that concerning the fin efficiency, the latter produces acceptable results although it is not strictly correct.