A New Transient Two-Wire Method for Measuring the Thermal Diffusivity of Electrically Conducting and Highly Corrosive Liquids Using Small Samples

The transient hot-wire (THW) technique is widely used for measurements of the thermal conductivity of most fluids, and some attempts have also been carried out for simultaneous measurements of the thermal diffusivity with the same hot wire. However, for some particular liquids like concentrated nitric acid solutions or similar nitric mixtures, for which the thermal properties are important for industrial or security applications, this technique may be difficult to use, because of possible technological incompatibilities between measurement probe materials and highly electrically conducting and corrosive liquids. Moreover, the possible highly energetic (explosive) character of these liquids requires minimum volume liquid samples and safety measurement devices and processes. It is the purpose of this paper to report on a modified THW technique (previously used for thermal-diffusivity measurements in soils), which is associated with a specific patented double-wire probe and is shown to be valid for direct thermal-diffusivity measurements in liquids. This method responds to the previous requirements and allows automatic and quasi-simultaneous thermal-conductivity and thermal-diffusivity measurements to be made safely on liquids compatible with the tantalum technology, with liquid sample volumes < 2 cm³. Low uncertainties are found for the thermal-diffusivity data when relative measurements are carried out with reference liquids like water or toluene.     

Denitrification of Coal Tar Diesel Fraction by Phosphate Imidazolium Based Polymeric Ionic Liquids

A series of highly cross-linked polymeric ionic liquids P[Ci(Vim)_2][Cl]_2(i = 2,3,4,5,6) were synthesized by quaternization reaction and polymerization,and used to remove nitrogen compounds from oils.The polymeric ionic liquids P[Ci(Vim)_2][H_2PO_4]_2(i = 2,3,4,5,6) were then obtained via ion exchange.The structures of P[C_4(Vim)_2][Cl]_2 and P[C_4(Vim)_2][H_2PO_4]_2 were characterized by Fourier transform infrared(FT-IR) spectroscopy,energy dispersive spectrometry(EDS),N2 adsorption-desorption isotherm measurements,scanning electron microscopy(SEM),thermogravimetric analysis and differential scanning calorimetry(TG/DSC).The removal of nitrogen compounds was characterized by pyridineFTIR spectrometry.The results indicated that P[C_4(Vim)_2][H_2PO_4]_2 with an average pore size of 19.23 nm and a specific surface area of 11.78 m~2/g was efficient for the removal of nitrogen compounds,and exhibited good thermal stability.The adsorption rate in the simulated oil reached 93.8% when using a polymeric ionic liquid P[C_4(Vim)_2][H_2PO_4]_2 to oil ratio of 0.04 and a temperature of 313 K.The nitrogen removal rate from the coal-tar diesel fraction achieved by P[C_4(Vim)_2][H_2PO_4]_2 was 90.3%.     

Comparison of the phagocytosis of two types of cyclosporin (SDZ OXL 400 and SDZ IMM 125) by alveolar macrophages from hamsters

The aim of this study was to compare two types of cyclosporin (Cs) particles, SDZ OXL 400 and SDZ IMM 125, the latter being more hydrophilic, to understand their uptake by airway macrophages. Alveolar macrophages (AM), harvested by bronchoalveolar lavage (BAL) of hamster lungs, were cultured with two different doses (0.1 mg and 0.5 mg) for 1 h, 6 h, and 24 h. Control incubations without Cs particles or with latex particles were carried out simultaneously. Cell viability, cell activation (i.e., respiratory burst, interleukin-6 (IL-6) synthesis) and mean volume of particles phagocytosed per macrophage were measured. Both types of Cs particles did not modify the AM viability, and failed to induce IL-6 synthesis during phagocytosis but slightly decreased the cell oxidative respiratory burst. The comparison between SDZ OXL 400 and SDZ IMM 125 showed that for the lower dose the mean volume of both Cs types phagocytosed was similar at 1 h and 6 h. At 24 h an increase of the mean volume phagocytosed was seen for SDZ IMM 125 but not for SDZ OXL 400. For the higher dose the mean volume of SDZ IMM 125 phagocytosed was higher than SDZ OXL 400 at 1 h and 6 h and comparable for both types at 24 h. SDZ IMM 125 particles were phagocytosed more rapidly than SDZ OXL 400. The mean volume of phagocytosed latex particles increased with time and dose and was higher than for both Cs particle types. In conclusion, AM were seen to phagocytose particles of different physical properties (i.e., form, size, and shape), chemical properties (i.e., inert or peptidic) and degrees of hydrophilicity in a different manner.     

Imparting biomimetic ion-gating recognition properties to electrodes with a hydrogen-bonding structured core-shell nanoparticle network

This paper presents findings of the creation of biomimetic ion-gating properties with core-shell nanoparticle network architectures. The architectures were formed by hydrogen-bonding linkages via an exchange-cross-linking-precipitation reaction pathway using gold nanoparticles capped with thiolate shell and alkylthiols terminated with carboxylic groups as model building blocks. Such network assemblies have open frameworks in which void space is in the form of a channel or chamber with the nanometer-sized cores defining its size, the geometric arrangement defining its shape, and the shell structures defining its chemical specificity. The formation of the network linkages via head-to-head hydrogen-bonded carboxylic terminals and the reversible pH-tuned structural properties between neutral and ionic states were characterized using infrared reflectance spectroscopic technique. The biomimetic ion-gating properties were demonstrated by measuring the pH-tuned network "open-close" responses to charged redox probes. Such redox responses were shown to depend on the degree of protonation-deprotonation of carboxylic groups at the interparticle linkages, core sizes of the nanoparticles, and charges of the redox probes. Differences in structural networking, pH-tuning, and electrochemical gating properties were identified between the network films derived from nanoparticles of two different core sizes (2 and 5 nm). The mechanistic correlation of these structural properties was discussed. These findings have added a new pathway to the current approaches to biomimetic molecular recognition via design of core-shell nanoparticle architectures at both nanocrystal and molecular scales.     

Using EC and ES cell culture to study early development: recent observations on Indian hedgehog and Bmps

Despite great technological advances in the study of mammalian development in the past two decades, certain problems in early development, such as how the extraembryonic lineages are established, have remained intractable. We suggest that teratocarcinoma (EC) and embryonic stem cells (ES) remain useful in vitro tools for studying some of these problems. We present a continuation of our studies on the role of IHH-based signaling in early development and demonstrate that the IHH N-peptide is expressed in the outer visceral endoderm cells of both the EC and ES-derived embryoid body. We also show that Bmp2 is upregulated and Bmp4 downregulated during the differentiation of F9 EC cells into embryoid bodies, whereas both genes are upregulated when J7 ES cells differentiate into embryoid bodies. We also examine the spatial localization of Ihh, Bmp2, and Bmp4 in day 6.5-7.0 and 7.5-8.0 embryos by in situ hybridization analysis. These data support the EC temporal expression data in that all 3 genes are expressed in visceral endoderm. Bmp4 expression appears to be limited to extraembryonic regions, where mesoderm as well as visceral endoderm are stained. Ihh and Bmp2 are expressed in extraembryonic tissues and the embryo proper. Functional roles for the observed expression patterns are discussed.     

Core-shell nanostructured nanoparticle films as chemically sensitive interfaces

This paper reports the results of an investigation of vapor molecule sorption at different types of nanostructured nanoparticle films. Core-shell nanoparticles of two different core sizes, AU2-nm and Au5-nm, and molecular linkers of two different binding properties, 1,9-nonanedithiol and 11-mercaptoundecanoic acid, are utilized as building blocks for constructing chemically sensitive interfaces. The work couples measurements of two different transducers, interdigitated microelectrodes and quartz crystal microbalance, to determine the correlation of the electronic resistance change and the mass loading with vapor sorption. The responses to vapor sorption at these nanostructured interfaces are demonstrated to be dependent on the core size of nanoparticles and the chemical nature of linking molecules. The difference of molecular interactions of vapor molecules at the nanostructured interface is shown to have a significant impact on the response profile and sensitivity. For the tested vapor molecules, while there are small differences for the sorption of nonpolar and hydrophobic vapor molecules, there are striking differences for the sorption of polar and hydrophilic vapor molecules at these nanostructured interfacial materials. The implication of the findings to the delineation of design parameters for constructing core-shell nanoparticle assemblies as chemically sensitive interfacial materials is also discussed.     

Comparisons of results of publication counting using different methods

Using a database for publications established at CEST and covering the period from 1981 to 2002 the differences in national scores obtained by different counting methods have been measured. The results are supported by analysing data from the literature. Special attention has been paid to the comparison between the EU and the USA. There are big differences between scores obtained by different methods. In one instance the reduction in scores going from whole to complete-normalized (fractional) counting is 72 per cent. In the literature there is often not enough information given about methods used, and no sign of a clear and consistent terminology and of agreement on properties of and results from different methods. As a matter of fact, whole counting is favourable to certain countries, especially countries with a high level of international cooperation. The problems are increasing with time because of the ever-increasing national and international cooperation in research and the increasing average number of authors per publication. The need for a common understanding and a joint effort to rectify the situation is stressed. The author sequence is alphabetic and does not reflect relative contributions to the work.