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81.
Rantanen T Päkkilä H Jämsen L Kuningas K Ukonaho T Lövgren T Soukka T 《Analytical chemistry》2007,79(16):6312-6318
In fluorescence resonance energy transfer (FRET)-based assays, spectral separation of acceptor emission from donor emission is a common problem affecting the assay sensitivity. The challenge derives from small Stokes shifts characteristic to conventional fluorescent dyes resulting in leakage of donor emission to the measurement window intended only to collect the acceptor emission. We have studied a FRET-based homogeneous bioaffinity assay utilizing a tandem dye acceptor with a large pseudo-Stokes shift (139 nm). The tandem dye was constructed using B-phycoerythrin as an absorber and multiple Alexa Fluor 680 dyes as emitters. As a donor, we employed upconverting phosphor particles, which uniquely emit at visible wavelengths under low-energy infrared excitation enabling the fluorescence measurements free from autofluorescence even without time-resolved detection. With the tandem dye, it was possible to achieve four times higher signal from a single binding event compared to the conventional Alexa Fluor 680 dye alone. Tandem dyes are widely used in cytometry and other multiplex purposes, but their applications can be expanded to fluorescence-based homogeneous assays. Both the optimal excitation and emission wavelengths of tandem dye can be tuned to a desired region by choosing appropriate fluorophores enabling specifically designed acceptor dyes with large Stokes shift. 相似文献
82.
Lifetime distribution functions and current network age data can be combined to provide an assessment of the future replacement needs for drinking water distribution networks. Reliable lifetime predictions are limited by a lack of understanding of deterioration processes for different pipe materials under varied conditions. An alternative approach is the use of real historical data for replacement over an extended time series. In this paper, future replacement needs are predicted through historical data representing more than one hundred years of drinking water pipe replacement in Gothenburg, Sweden. The verified data fits well with commonly used lifetime distribution curves. Predictions for the future are discussed in the context of path dependence theory. 相似文献
83.
The aim of this paper is to show the special characteristics of the indoor environment related to radio propagation and furthermore
to radio network planning. The aspects of the radio network planning are highlighted especially for Wideband Code Division
Multiple Access (WCDMA) radio access technology that is used widely in the third generation mobile networks. Moreover, the
detailed planning parameters in indoor environment are studied for High Speed Downlink Packet Access (HSDPA) in order to support
high throughput data applications in Universal Mobile Telecommunications System (UMTS). The final target of the paper is to
compare pico cell, distributed antenna system (DAS), and radiating cable network configurations in indoor environment to provide
the optimal radio conditions for the data applications, and thus to serve highest number of mobile users. Several measurement
campaigns with different antenna configurations have been conducted in order to study the effect of multi path related parameters,
as delay spread of the signal. Also other capacity related parameters as received signal levels, interference, throughput,
and transmit power levels have been studied in order to find out the optimal solution for HSDPA in UMTS. The results clearly
show that pico cells and distributed antenna system have outstanding performance in indoor propagation channel compared to
radiating cable. In sense of signal quality, pico cell performance is slightly better compared to distributed antenna system.
However, measurements with HSDPA indicate that practical capacity of DAS outperforms pico cells. The measurements also show
that separation of the antennas is a key capacity related parameter when planning WCDMA based indoor systems. 相似文献
84.
Joan Vila-Comamala Konstantins Jefimovs Jörg Raabe Tero Pilvi Rainer H. Fink Mathias Senoner Andre Maaßdorf Mikko Ritala Christian David 《Ultramicroscopy》2009
Further progress in the spatial resolution of X-ray microscopes is currently impaired by fundamental limitations in the production of X-ray diffractive lenses. Here, we demonstrate how advanced thin film technologies can be applied to boost the fabrication and characterization of ultrahigh resolution X-ray optics. Specifically, Fresnel zone plates were fabricated by combining electron-beam lithography with atomic layer deposition and focused ion beam induced deposition. They were tested in a scanning transmission X-ray microscope at 1.2 keV photon energy using line pair structures of a sample prepared by metalorganic vapor phase epitaxy. For the first time in X-ray microscopy, features below 10 nm in width were resolved. 相似文献
85.
Eerik Halonen Vesa PynttäriJuha Lilja Hannu SillanpääMatti Mäntysalo Jouko HeikkinenRiku Mäkinen Tero KaijaPekka Salonen 《Microelectronic Engineering》2011,88(9):2970-2976
Electrically conductive silver nanoparticle ink patterns were fabricated using the inkjet printing method. Two different polymer films were used as the substrate materials. The patterns were exposed to humidity and salt fog and the electrical performance (sheet resistance and RF performance) as well as mechanical endurance (adhesion) were measured before and after the environmental tests. The electrical properties of the printed structures remained good in all the measurable samples. The adhesion between the ink and a substrate material appeared to be a greater challenge in harsh environments. Protection capabilities of one dip coated and one hot laminated barrier materials were evaluated during the environmental tests. The results showed that there is a need for environmental protection in printed electronics. Especially the laminated barrier films can offer a potential solution for shielding printed electronics in harsh environments as they can provide good mechanical protection, and can easily be integrated in roll-to-roll process. 相似文献
86.
Xin Yi Choo Lachlan E. McInnes Alexandra Grubman Joanna M. Wasielewska Irina Belaya Emma Burrows Hazel Quek Jorge Caas Martín Sanna Loppi Annika Sorvari Dzhessi Rait Andrew Powell Clare Duncan Jeffrey R. Liddell Heikki Tanila Jose M. Polo Tarja Malm Katja M. Kanninen Paul S. Donnelly Anthony R. White 《International journal of molecular sciences》2022,23(18)
Neuroinflammation has a major role in several brain disorders including Alzheimer’s disease (AD), yet at present there are no effective anti-neuroinflammatory therapeutics available. Copper(II) complexes of bis(thiosemicarbazones) (CuII(gtsm) and CuII(atsm)) have broad therapeutic actions in preclinical models of neurodegeneration, with CuII(atsm) demonstrating beneficial outcomes on neuroinflammatory markers in vitro and in vivo. These findings suggest that copper(II) complexes could be harnessed as a new approach to modulate immune function in neurodegenerative diseases. In this study, we examined the anti-neuroinflammatory action of several low-molecular-weight, charge-neutral and lipophilic copper(II) complexes. Our analysis revealed that one compound, a thiosemicarbazone–pyridylhydrazone copper(II) complex (CuL5), delivered copper into cells in vitro and increased the concentration of copper in the brain in vivo. In a primary murine microglia culture, CuL5 was shown to decrease secretion of pro-inflammatory cytokine macrophage chemoattractant protein 1 (MCP-1) and expression of tumor necrosis factor alpha (Tnf), increase expression of metallothionein (Mt1), and modulate expression of Alzheimer’s disease-associated risk genes, Trem2 and Cd33. CuL5 also improved the phagocytic function of microglia in vitro. In 5xFAD model AD mice, treatment with CuL5 led to an improved performance in a spatial working memory test, while, interestingly, increased accumulation of amyloid plaques in treated mice. These findings demonstrate that CuL5 can induce anti-neuroinflammatory effects in vitro and provide selective benefit in vivo. The outcomes provide further support for the development of copper-based compounds to modulate neuroinflammation in brain diseases. 相似文献
87.
88.
89.
R. M. Lum J. K. Klingert D. W. Kisker D. M. Tennant M. D. Morris D. L. Malm J. Kovalchick L. A. Heimbrook 《Journal of Electronic Materials》1988,17(2):101-104
In the metalorganic chemical vapor deposition of GaAs there is increasing interest in replacing arsine with a less toxic arsenic
source. However, GaAs films grown with metalorganic arsenic reactants usually contain significantly higher levels of carbon
than films grown with arsine. Using 50% isotopically enriched13C trimethylarsenic (TMAs), we report the first direct evidence that the methyl groups from TMAs are a major source of the
carbon observed in the GaAs films. The measured13C concentration in these films was 5 x 1016 cm.3 Conversely, incorporation of13C was not detected when 99%13C-enriched methane was added to the source gases during growth of GaAs with arsine in place of the13C-TMAs. 相似文献
90.
J. P. Franey T. E. Graedel G. J. Gualtieri G. W. Kammlot J. Kelber D. L. Malm L. H. Sharpe V. Tierney 《Journal of Materials Science》1981,16(9):2360-2368
Among the important properties of conductive silver-epoxy pastes are their relatively low internal electrical resistance and their low rate of sulphidizing relative to pure silver. To investigate these properties in more detail and to gain understanding of the physical mechanisms involved, paste and bulk silver samples have been exposed to a controlled corrosive atmosphere of hydrogen sulfide and water vapour in purified air. The exposed samples were then analysed by a variety of surface and bulk techniques. The results demonstrate that (1) although the contact resistance of the bulk silver is initially much lower than that of the conductive paste, it increases much more rapidly with long exposure to corrosive atmospheres than that of the paste; this is especially true at low contact probe forces, (2) the hydrogen sulfide permeation constant through a free-standing film of unsilvered paste is (7.0±0.3)×10–2 barrers: sufficiently low that transport of H2S into the bulk paste is strongly inhibited, (3) silver flakes projecting outward from the surface of the paste have little or no resin coating. Corrosion thus occurs on the surface of the material but is inhibited within the material. The relative softness of the material allows contact probe penetration into the uncorroded bulk matrix. As a result, little decrease in the conductivity of the paste occurs even after extended exposures to a corrosive environment. 相似文献