Variations in diffusion coefficient of disperse dyes in single PET fibres: monitored and interpreted by confocal laser scanning microscopy

A novel method is proposed for determining the diffusion coefficient (D) of disperse dyes in PET fibres. Concentration-distance profiles are recorded on optical sections of single fibres by confocal laser scanning microscopy. This allows for an accurate value of the true diffusion coefficient in the fibres as well as for a founded insight in the dye diffusion process and its interrelation with the glass transition, which is not possible by the commonly used methods. At 130 °C, the common industrial dyeing temperature, the diffusion coefficient showed to be constant for the dyes tested, with D being about five times larger for the anthraquinone dye than for the benzodifuranone dye. At 100-110 °C, near to the start of the glass transition region of the fibres, D could no longer be regarded as a constant for the anthraquinone dye but was concentration dependent. This was explained by the plasticising effect of the anthraquinone dye.     

Effect of polypropylene morphology on thermal cis-trans isomerization and photofading of some azo dyes: A kinetic study

Five polypropylene films were prepared having different crystallinity and morphology, the latter having been modified by stretching. They were colored with azo dyes XC₆H₄N?NC₆H₄N(C₂H₅)₂ (where X?H, OCH₃, CN, and NO₂). The kinetics of the thermal cis-trans isomerization of these dyes has been studied in the range 21–41°C, much above the glass transition temperature of the polymer. The isomerization process was found to be strictly first-order; the kinetic parameter values have been correlated with the free volume extent in the amorphous regions of the matrix. Lightfastness of the dyes in the polymer matrices has been also investigated: It appeared to be more important for the unoriented samples with respect to the stretched ones and substantially independent on the crystalinity degree.     

Stable transfection of human β‐1,4N‐acetylgalactosaminyltransferase and α‐2,8‐sialyltransferase cDNAs in C6 rat glioma cells induces modifications in ganglioside metabolism

Ganglioside distribution in cells undergoes deep modifications during physiological and pathological events, possibly depending on the activity of glycosyltransferases involved in their biosynthesis. To understand how the ganglioside pattern can be altered by the selective expression of specific glycosyltransferases, C6 rat glioma cell line was stably transfected with two human glycosyltransferase cDNAs: β ‐1,4N‐acetylgalactosaminyltransferase (GalNAcT) and α ‐2,8‐sialyltransferase (ST‐II). GalNAcT and ST‐II are key enzymes in ganglioside biosynthesis; whereas ST‐II synthesizes GD₃, precursor of the “b” pathway, GalNAcT produces GM₂, GD₂ and asialo‐GM₂ and it is, therefore, involved in “a”, “b” and “asialo” pathways. C6 cells were subjected to three independent transfections: one with a construct containing GalNAcT cDNA, one with a construct containing the ST‐II cDNA, and one with both constructs simultaneously. Whereas control cells present mainly N‐acetyl‐ and N‐glycolyl‐GM₃, selected transfected clones show more complex ganglioside profiles: GalNAcT‐expressing cells are enriched in the “a” series gangliosides, ST‐II‐expressing cells synthesize the “b” series species, cells expressing contemporarily the two glycosyltransferases produce gangliosides of both series. Furthermore, among the selected clones, expression of GalNAcT and ST‐II correlates with changes in the ST‐I and ST‐IV activities, indicating that the switching on of the biosynthetic enzymes we investigated influences the activity of endogenous glycosyltransferases, possibly through the modification of the amount of their substrates or products.     

Diphenylamino-substituted derivatives of 9-phenylcarbazole as glass-forming hole-transporting materials for solid state dye sensitized solar cells

The synthesis and properties of glass-forming diphenylamino-substituted derivatives of 9-phenylcarbazole with methoxy groups in the different position of diphenylamino moieties are reported. A comparative study on their thermal, optical, photoelectrical and electrochemical properties is presented. The synthesized compounds exhibit high thermal stability with 5% weight loss temperatures ranging from 344 to 475 °C. The derivatives absorb electromagnetic irradiation in the range of 225–425 nm with the band gaps of 2.94–3.08 eV. The ionization energies of the synthesized compounds range from 5.04 to 5.56 eV. The lowest ionization energies and band gaps are observed for compounds containing para methoxy-substituted phenyl rings of diphenylamino moieties and for disubstituted carbazole derivatives. Charge-transporting properties of the selected compounds were tested by time-of-flight technique. Hole drift mobilities in the amorphous layers of the materials reach 10⁻³ cm²/V s at high electric fields. The derivatives were tested as hole transport materials in solid-state dye sensitized solar cells and showed conversion efficiency up to 0.54%.     

Modeling granular segregation in flow from quasi-three-dimensional, wedge-shaped hoppers

Granular materials may segregate upon processing and handling based on differences in particle properties such as size, density, or shape. In most instances, this segregation is problematic in that product quality is usually dependent on maintaining homogeneity of the blend. The present work investigates the causes and extent of segregation of granular materials during discharge from a hopper using the discrete element method. A quasi-three-dimensional, wedge-shaped hopper is modeled using two parallel periodic boundary conditions. The effects of various particle properties, such as diameter ratio, mean size, and mass fraction of each species, as well as hopper geometries, such as the height, width, outlet width, and wall angle, on the segregation results are examined. Additionally, the effects of friction coefficient and hopper fill methods are investigated. Results show that many factors affect the extent of segregation during hopper discharge, but some of the key factors include the particle diameter ratio, mass fraction, and ratio of hopper outlet to mean particle diameter as well as the hopper wall angle and wall roughness. Additionally, the method used to fill the hopper is shown to play a significant role in determining the segregation upon discharge. Visualization of the internal hopper flow patterns gives insight into the causes of segregation, which then aids in the proposal of various recommendations for reducing the extent of segregation during hopper discharge.     

Does creatine supplementation improve the plasma lipid profile in healthy male subjects undergoing aerobic training?

   

We aimed to investigate the effects of creatine (Cr) supplementation on the plasma lipid profile in sedentary male subjects undergoing aerobic training.     

Determination of viability of Aeromonas hydrophila in increasing concentrations of sodium chloride at different temperatures by flow cytometry and plate count technique

Aeromonads in waters and foods can represent a risk to human health. Factors such as sodium chloride concentration and temperature can affect growth and viability of several food and water-borne pathogens. The behaviour of an Aeromonas hydrophila strain in the presence of 1.7%, 3.4% and 6% NaCl concentrations at 24 degrees C and 4 degrees C was studied over a 188 day period. Viability and membrane potential were assessed by flow cytometry; growth was evaluated by plate count technique. Flow cytometry evidenced that A. hydrophila retained viability over the period although varying according to temperature and salt concentrations. Colony Forming Units were generally lower in number than viable cells especially in the presence of 6% NaCl, indicating the occurrence of stressed cells which maintain metabolic activity yet are not able to grow on agar plates. In conclusion, A. hydrophila showed a long-term halotolerance even at elevated (6%) NaCl concentrations and a lesser sensitivity to salt at low temperature; therefore, low temperature and salt, which are two important factors limiting bacterial growth, do not assure safety in the case of high initial contamination. Finally, cytometry appears a valid tool for the rapid detection of the viability of pathogenic bacteria in food and environmental matrices to control and prevent health risks.     

Exposure of several Belgian consumer groups to pesticide residues through fresh fruit and vegetable consumption

The output of a pesticide surveillance program (detection frequency and number of exceeding measures) can lead to unnecessary concern among consumers since they lack information concerning the actual exposure. In this study, the exposure to pesticide residues through fruit and vegetable consumption is evaluated based on the 2008 surveillance data of the Belgian Federal Agency for the Safety of the Food Chain (FASFC).Results (deterministic and probabilistic approach) demonstrate that the chronic exposure of the adult population (>15 years) is generally under control, even at high or frequent consumption of fruit and vegetables. For most of the pesticide residues studied, the exposure is one hundred times lower than the ‘acceptable daily intake’ or ADI. With regard to children (2–5 years) who consume regularly or large amounts of fruit and vegetables, there are however, indications that for some pesticides the ADI can be exceeded. Nevertheless, due to the large uncertainty in these calculations, a more detailed study is required for this vulnerable group of consumers. In addition, it was demonstrated that washing and peeling of fruit and vegetables result in an exposure that is probably five to six times lower.     

Towards Using Scientific Publications to Automatically Extract Information on Rare Diseases

A small percentage of the population is afflicted by what is called an orphan or a rare disease. All over the world, there are about several thousand of these diseases. When adding up together all the individuals who are affected, it amounts for up to 10% of the US population. Scientific works on these diseases are often poorly financed due to the lack of potential markets for a treatment, which means for patients and clinicians a very limited and scattered access to vital information. To contribute addressing this issue, we present in this paper a new software tool for automating the extraction of information related to rare diseases from scientific publications. More precisely, our contribution consists in a new method of extracting automatically symptoms of these diseases from research papers exploiting a Named Entity Recognition (NER) algorithm based on the numerical statistic Term Frequency - Inverse Document Frequency (TF-IDF). The proposed tool has been tested using PubMed Central (PMC) database.