Atomic emission spectrometric analysis of airborne particulate matter by direct nebulization of suspensions into the inductively-coupled plasma

A method is described for the rapid, direct emission spectrometric determination of iron in airborne particulate matter collected on polystyrene fiber filters using a conventional high-volume sampler and a Japanese low-volume sampler. The suspension prepared by dissolving the filter material in xylene was directly nebulized into the inductivelycoupled plasma excitation source. An ultrasonic immersion device was used for stirring purposes. Particles within the size range 0.1–100 μm in diameter are collected on the high-volume filters, while the largest particles on low-volume filters do not exceed 10 μm in diameter. The difference in the particle size composition entailed the use of a separate set of standard suspensions for each sample type. Standard suspensions for calibration were prepared from NBS SRM-1648 (urban particulates) as originally received and from its ground powder for high-volume and low-volume samples, respectively. The relative standard deviation was usually below 5%, which is acceptable for large-scale air pollution survey work. The possibility of determining other major and minor elements in airborne particulate matter was also examined.     

High-pass filters for spectral background suppression in airborne passive Fourier transform infrared spectrometry

High-pass (HP) digital filtering and second-derivative (SD) filtering are evaluated as methods of removing background contributions from spectra collected by passive Fourier transform infrared spectrometry. In measurements performed with a downward-looking spectrometer mounted on an aircraft platform, the effects of non-constant background radiance from the ground make it challenging to build automated classifiers for detecting an analyte of interest. Applying HP digital filtering to the spectra to remove background contributions is evaluated as a strategy to help improve classifier performance. This methodology is tested by building classifiers for detecting heated ethanol plumes released from a portable emission stack. The classifiers are trained with data collected on the ground with the spectrometer viewing the plumes against a synthetic backdrop designed to simulate a terrestrial radiance source. The resulting classifiers are tested with data collected by the same spectrometer mounted on an aircraft flying over the emission stack. Support vector machines are employed as a classification algorithm with HP filtered spectra used as input patterns. Butterworth filters are used to implement HP digital filtering, while Savitzky-Golay filters are used to implement SD filtering. Significant improvement in classification performance is achieved by use of the HP filters. Because of variation in backgrounds between the training and prediction data, the best classifier obtained with unfiltered spectra is unable to detect ethanol in 37% of the test cases. HP filtering of spectra with an optimized Butterworth filter (order 8, cutoff frequency 0.060) improves the prediction results, resulting in no missed ethanol detections and false positive rates of less than 0.4%.     

New methods and reagents in organic synthesis. 49. A highly efficient stereoselective synthesis of L-daunosamine through direct C-acylation using diphenyl phosphorazidate (DPPA)

L-Daunosamine, the carbohydrate component of a group of important anticancer anthracycline antibiotics, has been efficiently prepared from L-lactic acid in a completely stereoselective manner through direct C-acylation using diphenyl phosphorazidate (DPPA).     

Spray Pyrolysis Preparation of Apatite-Composite Particles for Biological Application

Apatite derived by sol-gel routes through an amorphous state or derived biomimetically is likely to provide chemically and biologically active surfaces. Thus apatite or apatite-composite particles were prepared by spray-pyrolysis of several solutions as they were applicable to medical treatment. Calcium lactate and ammonium dihydrogen phosphate aqueous solutions stabilized with ethylenediaminetetraacetic acid were sprayed ultrasonically and pyrolysed at 600°C to yield amorphous particles of apatite while apatite-ferric oxide composite powders were prepared from the solutions of calcium lactate and ferric nitrate. Solutions of calcium nitrate and titanium ethoxide in 0.5 N HNO₃ were also spray-pyrolysed at 600°C to prepare calcium titanate and titanium oxide particles trapped on a Ti substrate. Apatite could biomimetically be developed on the calcium titanate particles when they were soaked in an acellular simulated body fluid.     

Nanogel engineering for new nanobiomaterials: from chaperoning engineering to biomedical applications

Nanosize hydrogels (nanogels) are polymer nanoparticles with three‐dimensional networks, formed by chemical and/or physical cross‐linking of polymer chains. Recently, various nanogels have been designed, with a particular focus on biomedical applications. In this review, we describe recent progress in the synthesis of nanogels and nanogel‐integrated hydrogels (nanogel cross‐linked gels) for drug‐delivery systems (DDS), regenerative medicine, and bioimaging. We also discuss chaperone‐like functions of physical cross‐linking nanogel (chaperoning engineering) and organic‐inorganic hybrid nanogels. © 2010 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Published online in Wiley InterScience ( www.interscience.wiley.com ) DOI 10.1002/tcr.201000008     

Nano‐Encapsulation of Lipase by Self‐Assembled Nanogels: Induction of High Enzyme Activity and Thermal Stabilization

The effects of self‐assembled polysaccharide nanogels on colloidal and thermal stability of lipase from Pseudomonas cepacia were investigated. The enzyme activity, especially k_cat, drastically increased in the presence of nanogels of cholesterol‐bearing pullulan (CHP). The thermostability of lipase complex increased because the denaturation temperature of lipase increased by more than 20 °C by complexation with CHP nanogels. Lipase denaturation and aggregation upon heating was effectively prevented by complexation with CHP nanogels. Moreover, complexation with CHP nanogels protected lipase from lyophilization‐induced aggregation. Nano‐encapsulation with CHP nanogel is a useful method for colloidal and thermal stabilization of unstable enzyme.

     

Study on thermal stability of tertiary pyridine resin

The fundamental properties of tertiary pyridine resin (TPR) and its mixtures with methanol/HCl and HNO₃ were investigated in order to evaluate the thermal stability of TPR and to determine the conditions necessary to avoid runaway reactions. Based on experimental DSC results, it was found that TPR with HCl was thermally stable, but strong decomposition was possible with TPR in the presence of HNO₃. From the results of heating tests on the gram scale, TPR with HNO₃ reacted violently under high temperature regardless of HNO₃ concentration and presence or absence of methanol. However, it was considered that the violent exothermic reaction could be controlled by heating temperature.