Soil wettability as determined from using low-field nuclear magnetic resonance

The molarity of ethanol droplet and water drop penetration time methods are commonly used to determine soil wettability because these tests are quick and easy to perform. However, these tests do not provide reproducible results on the same sample. Low-field nuclear magnetic resonance (NMR) is shown as an alternative tool to determine soil wettability. Addition of small amounts of water in dry wettable porous media produces predominant amplitude peaks at transverse relaxation times (T2) of 100 ms or less while addition of water in dry water-repellent porous media with the same pore structure produce predominant amplitude peaks at T2 values near 1000 ms. The geometric mean of T2 (T(2gm)) from water-repellent samples immediately after the addition of water is greater than 1000 ms, which is close to that of bulk water, while T(2gm) from wettable samples immediately after the addition of water is significantly less than 1000 ms. Measurements over time show that water-repellent samples eventually reach the same equilibrium end point as its corresponding wettable sample when continually exposed to water. This paper will show that NMR can be used to formulate a screening criterion for quickly determining wettability. The advantage of using NMR is that the results are reproducible provided the sample is prepared and analyzed in a systematic manner.     

Surface coverages of bonded-phase ligands on silica: a computational study

A computational study of the packing of various bonded-phase ligands bound to chromatographic silica is presented. This is done with the intention of examing the type of surface structures that are typically found in real chromatographic systems. Utilizing the surface structure of the (111) face of the beta-cristobalite crystal, it is shown that the maximum surface coverages of dimethyloctylsilane, dimethyloctadecylsilane, triisopropylsilane, diisopropyloctylsilane, and diisopropyloctadecylsilane can be calculated that are in good agreement with experiment. The maximum surface coverages are also calculated for the (100) face of the beta-cristobalite crystal and for a set of random silica surfaces. The coverages for the latter two surfaces types are found to be significantly lower than the experimental values for chromatographic silica surfaces. These results further suggest that chromatographic silica surfaces may resemble crystalline surface sites similar to the (111) face of beta-cristobalite, as has been previously suggested in the literature. Hence, these structures can be reliably utilized in molecular simulations of bonded-phase chromatography where the atomic-level detail of the silica surface has been previously lacking.     

Color tracking with contextual switching: real-time implementation on CPU

Journal of Real-Time Image Processing - The paper proposes contributions for mean-shift (MS) and covariance tracking (CT), and makes these two complementary methods cooperate. While MS runs fast...     

Establishing linkages through international psychology: Dealing with universalities and uniquenesses.

This article chronicles one change to an individual's personal odyssey toward becoming an international psychologist—and hopefully a citizen of a professional world that has no geographic borders. It is written as a narrative that is divided into chronological stages and several domains of professional activities. From each period, the main observations and lessons learned are extrapolated. It is hoped that readers who are interested in teaching, conducting workshops, and doing clinical work or research in other countries will find some of the personal reflections and professional ideas presented to be thought provoking and useful in the development of guiding principles in international psychology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Isolation and characterization of inositol sphingophospholipids from Phytophthora parasitica Dastur

Several inositol sphingophospholipids (ISPL) were isolated from mycelia of Phytophthora parasitica Dastur, a phytopathogenic fungus of carnation. The ISPL structures were determined by fast atom bombardment. All ISPL consisted of ceramides linked to inositol phosphate. We investigated the effect of growth conditions on the ISPL produced in four different media that are commonly used for fungal cultures. We showed that P. parasitica Dastur synthesized four major classes of compounds with molecular weights of M_r=751, 807, 835, and 849 containing the 16:1 base and the 16:0 or 20:0 or 22:0 or 22h:1 N-acyl group. The relative abundance of the different ISPL is dependent on growth conditions. This work is dedicated to the memory of Professor G. Michel.     

Conductometric biosensor based on glucose oxidase and beta-galactosidase for specific lactose determination in milk

This paper investigates the development of a biosensor associating two distinct enzymatic activities, that of the beta-galactosidase and that of the glucose oxidase, in order to apply it for the quantitative detection of lactose in milk. To eliminate interferences with glucose, a differential mode of measurement was used. Results show a linear calibration curve for lactose concentration between 60 and 800 μM (0.03 to 0.3 g/L). Tests with real commercial milk samples were carried out to validate the conductometric biosensor.     

Three characterization techniques coupled with adsorption for studying the nanoporosity of supported films and membranes

Three characterization techniques are described for studying the open nanoporosity, i.e. the open free volume, the microporosity, the mesoporosity and the thickness variation of thin deposited films during gas adsorption and condensation. They are all based on the coupling of the sorption of a probe gaseous molecule at room temperature and a physical characterization tool of thin deposited films: the quartz crystal microbalance, ellipsometry and X-ray reflectometry, giving the mass uptake, the refractive index variation and the electronic density variation, respectively, of the film due to the adsorbate intrusion inside the open free volume and pores. The film thickness evolution during the sorption can also be followed by the two last techniques. These techniques are complementary because each one can bring specific properties and can validate the results of another one. Both static and dynamic measurements can be carried out to characterize the porosity, the contraction or the swelling of the film and the penetration rate of the gas.     

Determination of platinum in blood by adsorptive voltammetry

This work describes a sensitive method for the determination of platinum in blood, which can be used for determining the natural levels of platinum in human blood, for monitoring patients treated with platinum cytotoxic drugs, and for monitoring occupational exposure to these drugs and other platinum compounds. The method involves dry ashing of blood samples in a muffle furnace and determination of platinum by adsorptive voltammetric (AV) measurement of the catalytic reduction of protons by the platinum-formazone complex. The detection limit for a 100-microL sample of blood is 0.017 micrograms/L, with a recovery of 94% and a relative standard deviation of 7% at a platinum level of 1 microgram/L. By using this method, the natural levels of platinum in human blood were found to be in the range 0.1-2.8 micrograms/L (median = 0.6 micrograms/L). These results were verified by inductively coupled plasma mass spectrometry (ICP-MS) with blood prepared by wet ashing and using gold as an internal standard.     

Metabolomics to Decipher the Chemical Defense of Cereals against Fusarium graminearum and Deoxynivalenol Accumulation

Fusarium graminearum is the causal agent of Fusarium head blight (FHB) and Gibberella ear rot (GER), two devastating diseases of wheat, barley, and maize. Furthermore, F. graminearum species can produce type B trichothecene mycotoxins that accumulate in grains. Use of FHB and GER resistant cultivars is one of the most promising strategies to reduce damage induced by F. graminearum. Combined with genetic approaches, metabolomic ones can provide powerful opportunities for plant breeding through the identification of resistant biomarker metabolites which have the advantage of integrating the genetic background and the influence of the environment. In the past decade, several metabolomics attempts have been made to decipher the chemical defense that cereals employ to counteract F. graminearum. By covering the major classes of metabolites that have been highlighted and addressing their potential role, this review demonstrates the complex and integrated network of events that cereals can orchestrate to resist to F. graminearum.     

SiOC Ceramic Monoliths with Hierarchical Porosity

SiOC glass monoliths possessing hierarchical porosity were produced by a one-pot processing method. Periodic mesoporous organosilica (PMO) particles were embedded into a foamed siloxane preceramic polymer. After pyrolysis at 1000°C in inert atmosphere, open celled, permeable SiOC ceramic monoliths with a high amount of pores, ranging in size from hundred of micrometers to a few nanometers, were obtained. The components possessed a specific surface area of 137 m²/g, indicating the retention of most of the mesopores after the pyrolytic conversion of the PMO precursor particles. These fillers converted to truncated rhombic dodecahedral SiOC mesoporous micron-sized grains, homogeneously distributed throughout the SiOC cellular matrix. The produced porous ceramics possessed compression strength of about 1.7 MPa, which is adequate for their use in several engineering applications.