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81.
Using water-soluble, fluorescent, flexible polymers, we have devised a novel methodology for identification and differentiation of prostate cancer cells. Using a stepwise linear discriminant analysis, we demonstrate that the differential modulations of the polymer emission intensities in the presence of conditioned cell culture media can be used to distinguish between prostate cancer subtypes and between cancerous and noncancer cells. The differences in the compositions of the conditioned cell culture media are likely contributing to different fluorescence spectral patterns of the polymers. This in vitro approach may provide a novel platform for the development of an alternative prostate cancer diagnostic and subtyping technique.  相似文献   
82.
Adequately preparing for and responding to terrestrial (land-based) chemical spills are critical to the protection of human health and the environment. To facilitate analysis and support decision-making for such events, the authors have developed an environmental risk management system that characterizes the ability of a spilled chemical to immediately impact human health, groundwater, surface water, and soil resources, and incorporates these four risk areas into an overall measure of terrestrial chemical risk. This system incorporates a risk index model, leverages geographic information systems (GIS) technology, and contains a comprehensive chemical and environmental database to assess and delineate the immediate threat posed by a terrestrial chemical spill. It is designed to serve a variety of stakeholders, including managers and policy-makers, who would benefit from generating screening-level environmental risk assessments without requiring a technical background or collection of detailed environmental and chemical data. Areas of potential application include transportation routing, industrial zoning, environmental regulatory compliance and enforcement, spill response, and security planning.  相似文献   
83.
The suitability of mathematical models used to extract kinetic information from correlated data constitutes a significant issue in fluorescence correlation spectroscopy (FCS). Standard FCS equations are derived from a simple Gaussian approximation of the optical detection volume, but some investigations have suggested this traditional practice can lead to inaccurate and misleading conclusions under many experimental circumstances, particularly those encountered in one-photon confocal measurements. Furthermore, analytical models cannot be derived for all measurement scenarios. We describe a novel numerical approach to FCS that circumvents conventional analytical models, enabling meaningful analyses even under extraordinarily unusual measurement conditions. Numerical fluorescence correlation spectroscopy (NFCS) involves quantitatively matching experimental correlation curves with synthetic curves generated via diffusion simulation or direct calculation based on an experimentally determined 3D map of the detection volume. Model parameters are adjusted iteratively to minimize the residual differences between synthetic and experimental correlation curves. In order to reduce analysis time, we distribute calculations across a network of processors. As an example of this new approach, we demonstrate that synthetic autocorrelation curves correspond well with experimental data and that NFCS diffusion measurements of Rhodamine B remain constant, regardless of the distortion present in a confocal detection volume.  相似文献   
84.
The spectral signatures of nitro attack of the aromatic portion of thermoplastic urethanes (TPU) were determined. Eight fragment molecules were synthesized that represent the nitrated and pristine methylenediphenyl section common to many TPUs. Infrared (IR) and Raman (785 nm illumination) spectra were collected and modeled using the B3LYP/6-31G(d)//B3LYP/6-31G(d) model chemistry. Normal mode animations were used to fully assign the vibrational spectra of each fragment. The vibrational assignment was used to develop a diagnostic method for aromatic nitro attack in thermoplastic urethanes. The symmetric NO(2) stretch coupled out of phase with the C-NO(2) stretch (1330 cm(-1)) was found to be free from spectral interferences. Spectral reference regions that enable correction for physical differences between samples were determined. The carbonyl stretch at 1700 cm(-1) was the best IR reference region, yielding a limit of quantitation (LOQ) of 0.66 +/- 0.02 g N/100 g Estane. Secondary IR reference regions were the N-H stretch at 3330 cm(-1) or the urethane nitrogen deformation at 1065 cm(-1). The reference region in the Raman was a ring stretching mode at 1590 cm(-1), giving an LOQ of 0.69 +/- 0.02 g N/100 g Estane. Raman spectroscopy displayed a larger calibration sensitivity (slope = 0.110 +/- 0.004) than IR spectroscopy (slope = 0.043 +/- 0.001) for nitration determination due to the large nitro Raman cross-section. The full spectral assignment of all eight molecules in the infrared and Raman is presented as supplemental material.  相似文献   
85.
Purification of arc-discharge grown multiwalled boron nitride nanotubes (BN MWNTs) was possible using a simple solubilization and filtration method. Using the common method of arc-discharge with h-BN/Ni/B packed molybdenum tube and a water cooled copper cathode, results in a mixture of hexagonal boron nitride, metal catalyst and boron nitride nanotubes. We show that a simple purification based on the use of surfactants that provide sufficient solubilization for solution filtering of the other materials results in highly purified BN MWNTs. The purified samples were characterized by transmission electron microscopy and scanning tunneling spectroscopy and microscopy. We observed in the purified BN MWNTs square and triangular tube ends, characteristic for this type of nanotube with no metal observed at the tips. Tunneling spectroscopy measurements showed an averaged band gap of approximately 5 eV with the band gap values independent of tube chirality and diameters.  相似文献   
86.
Flam.  DL 莫铭 《微电子学》1991,21(4):55-59
由美国真空协会组织,在加州大学伯克利分校召开的“集成电路(IC)制造中的高密度等离子技术及其工艺”专题讨论会(AVS/Berkely会议),于去年(1990)9月结束。这次会议的各小组会集中讨论了新等离子源,主要的美国工艺设备制造厂家都  相似文献   
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有关国内专家在对英国、德国、挪威、瑞典、荷兰等欧洲国家进行学习考察后发现,单在多、高层住宅的形体高度、外观造型和立面色彩方面,国内与欧洲国家已看不出有多大的区别,国内许多著名小区的住宅放到欧洲去也称得上是上乘之作。但在节能等内在品质上,差距非常之大。[编者按]  相似文献   
90.
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