Influence of ageing on viscoelastic properties of PMMA/ATH modified bitumen

This article deals with the influence of the ageing treatment on the viscoelastic behavior of PMMA/ATH modified paving bitumen. Waste composite powder (polymethyl methacrylate filled with aluminium trihydrate)—PMMA/ATH and Fischer–Tropsch wax were used as modifying agents for 70/100 paving grade bitumen. Measurements in intermediate temperature range were carried out under oscillatory shear conditions on a dynamic shear rheometer (DSR). Creep testing in low temperature range was conducted on a bending beam rheometer (BBR). The time‐dependent behavior of investigated samples was presented in a form of relaxation moduli G(t) and E(t). Dynamic moduli, i.e., G′(ω) and G″(ω), were converted to relaxation modulus G(t) using the Schwarzl method. The interconversion between tensile creep compliance D(t), and tensile relaxation modulus E(t) was performed using the Hopkins and Hamming approach. It was found that modified binders are less susceptible to the oxidation process during bitumen ageing, since the viscoelastic properties changed less than for the base bitumen. Our results indicate that the use of waste PMMA/ATH in the selected bitumen altered the time‐dependent deformation behavior of asphalt binder. The effect of ageing treatment on material functions was particularly manifested at longer times. Different stress relaxation behavior of modified binders could result in higher deformation resistance of asphalt mixture. POLYM. COMPOS., 36:1738–1747, 2015. © 2014 Society of Plastics Engineers     

Allogeneic bone marrow transplantation for acute leukaemia--IGCI experience. International Group for Chemo-Immunotherapy

1. The influence of strain and sex on the effect of enflurane and isoflurane and administration on heme metabolism was investigated to identify the animal model which could best reproduce the biochemical signs of acute intermittent porphyria. 2. Enflurane produced 35% and 80% increases in ALA-S activity only in CF1 male and female mice, respectively, whereas isoflurane induced 40% enzyme activity in CF1 male. 3. CF1 males showed around 35% decrease in blood PBGase and PBG-deaminase after administration of enflurane, whereas isoflurane provoked a striking inhibition (70%) in males of the C57 strain. 4. Enflurane produced alterations in heme synthesis, which would fit a model of acute porphyria in CF1 male mice. On the other hand, isoflurane would mimic biochemical alterations of this porphyria in C57 males.     

Bonding of densified beech wood using adhesives based on thermally modified soy proteins

The bondability/glueability of aged and sanded thermo-hydro-mechanically (THM) densified beech wood (Fagus sylvatica L.) was tested and compared with undensified sanded beech wood as a control. THM and control specimens were bonded with five different soy protein isolate (SPI) based adhesives. Commercial SPI powder was thermally modified in the vacuum chamber at 50 or 100?°C and pH adjusted (to pH 10.0) dispersions in water prepared at 24, 50 or 90?°C. Wettability was determined with measuring the sessile drop contact angles of water. Effective penetrations (EPs) and tensile shear strengths of THM and control specimens were determined. THM and control wood had similar wettability. Although THM wood had lower moisture content than control wood, it absorbed the water more slowly than control wood. THM specimens showed lower EPs than control specimens when comparing individual adhesives due to increased density of THM wood. Adhesives prepared with SPI thermally modified at 50?°C showed statistically significantly lower tensile shear strength of bonded THM specimens than that of bonded control specimens. THM densification had no significant effect on the bonding strengths of adhesives prepared with non-modified SPI and SPI thermally modified at 100?°C.     

Bacillus cereus food intoxication and toxicoinfection

Bacillus cereus is one of the leading etiological agents of toxin-induced foodborne diseases. Its omnipresence in different environments, spore formation, and its ability to adapt to varying conditions and produce harmful toxins make this pathogen a health hazard that should not be underestimated. Food poisoning by B. cereus can manifest itself as an emetic or diarrheal syndrome. The former is caused by the release of the potent peptide toxin cereulide, whereas the latter is the result of proteinaceous enterotoxins (e.g., hemolysin BL, nonhemolytic enterotoxin, and cytotoxin K). The final harmful effect is not only toxin and strain dependent, but is also affected by the stress responses, accessory virulence factors, and phenotypic properties under extrinsic, intrinsic, and explicit food conditions and host-related environment. Infamous portrait of B. cereus as a foodborne pathogen, as well as a causative agent of nongastrointestinal infections and even nosocomial complications, has inspired vast volumes of multidisciplinary research in food and clinical domains. As a result, extensive original data became available asking for a new, both broad and deep, multifaceted look into the current state-of-the art regarding the role of B. cereus in food safety. In this review, we first provide an overview of the latest knowledge on B. cereus toxins and accessory virulence factors. Second, we describe the novel taxonomy and some of the most pertinent phenotypic characteristics of B. cereus related to food safety. We link these aspects to toxin production, overall pathogenesis, and interactions with its human host. Then we reflect on the prevalence of different toxinotypes in foods opening the scene for epidemiological aspects of B. cereus foodborne diseases and methods available to prevent food poisoning including overview of the different available methods to detect B. cereus and its toxins.     

Influence of type of food on the kinetics and overall production of Bacillus cereus emetic toxin

Potato puree and penne pasta were inoculated with cereulide producing B. cereus 5964a and B. cereus NS117. Static incubation at 28 degrees C proved these two foods to be a better substrate for higher cereulide production (4,080 ng/g in puree and 3,200 ng/g in penne were produced by B. cereus 5964a during 48 h of incubation) compared with boiled rice (2,000 ng/g). This difference occurred despite B. cereus counts of more than 10(8) CFU/g in all three products. Aeration of cultures had a negative effect on cereulide production, causing concentrations more than 10-fold lower than in some statically incubated samples. Cereulide production remained undetectable in shaken milk, whereas it reached 1,140 ng/ml in statically incubated milk. At 12 and 22 degrees C, presence of background flora was also a determinative factor. A total B. cereus count of more than 106 CFU/ml did not necessarily lead to uniform cereulide production and was also dependent on the B. cereus strain involved. In this study, we confirm that a number of factors play a crucial role in the determination of the extent to which, if at all, cereulide will be produced. Among those, type of the food, temperature, pH, and whether additional aeration (via incubation on an orbital shaker) is induced had an important role. An important effect was also induced by the cereulide-producing strain involved.