Application of the simultaneous iteration method to undamped vibration problems

The simultaneous iteration method of obtaining eigenvalues and eigenvectors is employed for the solution of undamped vibration problems. This method is of significance when a few of the dominant eigenvalues and eigenvectors are required from a large matrix, and hence is particularly suitable for vibration problems involving a large number of degrees of freedom. It is shown that advantage may be taken of both the symmetry and the band form of the mass and stiffness matrices, thus making it feasible to process on a computer larger order vibration problems than can be processed using transformation methods. A method of allowing for body freedom is given and some numerical tests are discussed.     

Studies on the toxicity of ammonia, nitrate and their mixtures to guppy fry

Using guppy fry as the test fish the individual and joint toxicities of ammonia and nitrate were estimated in static tests at constant pH and temperature. The 72-h lc₅₀ values were 199 and 1.26 mg 1⁻¹ −N for potassium nitrate and free ammonia, respectively. The toxicities of mixtures of the two were additive except at very low ammonia to nitrate ratios. Watson's equation, a disinfection law relating toxicant concentration to survival, was applicable to both toxicants. The applicability of Chick's law and other kinetic models to fish toxicity was also evaluated.     

Rapidly prototyped three-dimensional nanofluidic channel networks in glass substrates

Microfluidic and nanofluidic technologies have long sought a fast, reliable method to overcome the creative limitations of planar fabrication methods, the resolution limits of lithography, and the materials limitations for fast prototyping. In the present work, we demonstrate direct 3D machining of submicrometer diameter, subsurface fluidic channels in glass, via optical breakdown near critical intensity, using a femtosecond pulsed laser. No postexposure etching or bonding is required; the channel network (or almost any arbitrary-shaped cavity below the surface) is produced directly from "art-to-part". The key to this approach is to use very low energy, highly focused, pulses in the presence of liquid. Microbubbles that result from laser energy deposition gently expand and extrude machining debris from the channels. These bubbles are in a highly damped, low Reynolds number regime, implying that surface spalling due to bubble collapse is unimportant. We demonstrate rapid prototyping of three-dimensional "jumpers", mixers, and other key components of complex 3D microscale analysis systems in glass substrates.     

Nanoprobe-based affinity mass spectrometry for selected protein profiling in human plasma

In recent decades, magnetic nanoparticles have emerged as a promising new platform in biomedical applications, particularly bioseparations. We have developed an immunoassay using antibody-conjugated magnetic nanoparticles as an efficient affinity probe to simultaneously preconcentrate and isolate targeted antigens from biological media. We combined this probe with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI MS) to profile proteins in diluted human plasma. The nanoparticles were designed to detect several disease-associated proteins and could be used directly in MALDI MS without an elution step, thereby facilitating multiple antigen screening and the characterization of antigen variants. Plasma antigens bound rapidly (approximately 10 min) to the antibody-conjugated nanoparticles, allowing the assay to be performed within 20 min. With sensitivity of detection in the femtomole range, the nanoscale immunoassay is superior to assays using microscale particles. We applied our method to comparative protein profiling of patients with gastric cancer and healthy individuals and found differential protein expression levels associated with the disease as well as individuals. Given the flexibility of manipulating functional groups on the nanoprobes, their low cost, robustness, and simplicity of the assay, our approach shows promise for targeted proteome profiling in clinical settings.     

Pore size analysis of fallow deer (<Emphasis Type="Italic">Dama dama</Emphasis>) antler bone

Deer antler is of interest to material scientists because it represents bone which can withstand applied stresses of over 300 MPa. In this work we demonstrate the presence of nanopores in this material by nuclear magnetic resonance (NMR) spectroscopy, and gas adsorption and mercury intrusion experiments. It is also shown that organic material in the antler influences observed pore sizes. Different modal groups of pores were observed when organic lipid material was removed from the sample and the sample saturated with water. The dominant organic phase associated with the small pores is protein.     

A step-by-step procedure to aid the assessment of intake and doses from measurement data

The interpretation of bioassay data to assess intakes and doses depends not only on the biokinetic model used but also on the choice of parameter values made by the assessor. Therefore, it is understandable that different assessors will draw different conclusions from the same datasets even if the same models are used. A systematic step-by-step procedure is proposed for the assessment of cases with comprehensive data in which the time of intake is known. The aims are to promote harmonisation of dose assessments and to assist in obtaining the best available assessment of intake and dose from the monitoring data. The procedure is illustrated by means of an example reported recently in the literature. The case which involves a 6 y follow-up of a subject who inhaled (241)Am, is somewhat unusual in that there are comprehensive in vivo measurements, but few excretion data. The rate at which activity is absorbed from lungs to blood can be one of the largest sources of uncertainty in any inhalation assessment, and significantly improved fits to the measurement data were obtained by choosing appropriate values for the relevant parameters. 'The best estimate' of the resulting effective dose in this case was higher by a factor of approximately 2 or 3, respectively, than those obtained assuming ICRP default values for Type M or Type S.     

Speciation of chromium(III) and cobalt(III) (amino)carboxylate complexes using capillary electrophoresis

Capillary electrophoresis (CE) can very efficiently resolve different dissolved metal ion species as long as rates of ligand exchange are slow relative to time scales required for electromigration. Here, we detail the separation of several Cr(III) and Co(III) complexes with the multidentate chelating agents iminodiacetic acid, nitrilotriacetic acid, trans-1,2-cyclohexanediaminetetracetic acid, N-(2-hydroxyethyl)ethylenediaminetriacetic acid, trimethylenediaminetetraacetic acid, and ethylenediaminetetraacetic acid. Successes in speciating some Ni(II) and Co(II) complexes are also reported. For Cr(III) and Co(III), subtle differences in metal ion-chelating agent stereochemistry, chelating agent denticity, and number of bridging ligands are discernible due to the high resolving power of CE. New peaks and heightened baselines were encountered when a pH buffer with strong complexing properties (orthophosphate) was employed in the background electrolyte. For this reason, we recommend using pH buffers with very weak or negligible complex properties (e.g., MES and MOPS).     

An information fidelity criterion for image quality assessment using natural scene statistics.

Measurement of visual quality is of fundamental importance to numerous image and video processing applications. The goal of quality assessment (QA) research is to design algorithms that can automatically assess the quality of images or videos in a perceptually consistent manner. Traditionally, image QA algorithms interpret image quality as fidelity or similarity with a "reference" or "perfecft" image in some perceptual space. Such "full-referenc" QA methods attempt to achieve consistency in quality prediction by modeling salient physiological and psychovisual features of the human visual system (HVS), or by arbitrary signal fidelity criteria. In this paper, we approach the problem of image QA by proposing a novel information fidelity criterion that is based on natural scene statistics. QA systems are invariably involved with judging the visual quality of images and videos that are meant for "human consumption." Researchers have developed sophisticated models to capture the statistics of natural signals, that is, pictures and videos of the visual environment. Using these statistical models in an information-theoretic setting, we derive a novel QA algorithm that provides clear advantages over the traditional approaches. In particular, it is parameterless and outperforms current methods in our testing. We validate the performance of our algorithm with an extensive subjective study involving 779 images. We also show that, although our approach distinctly departs from traditional HVS-based methods, it is functionally similar to them under certain conditions, yet it outperforms them due to improved modeling. The code and the data from the subjective study are available at.