Novel RDX-Based Cage and Cage-Like Nitramines

1,3,5-Trinitroperhydro-1,3,5-triazine (RDX)-based cage and cage-like nitramines in which two RDX molecules are linked to each other via three and two carbon atoms, respectively, have been investigated computationally using density functional theory (DFT) at a B3LYP/6-31G(d,p) theoretical level. The study focused on finding out how the quantum chemical and detonation properties of RDX change if two RDX molecules come together and form these structures. Both considered nitramines exhibited higher heats of formation (calculated via both PM3 and isodesmic methods) and Kamlet-Jacobs detonation performances and were found to be more sensitive than the reference compounds RDX and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX).     

NUMERICAL SOLUTION OF GRAETZ PROBLEM WITH AXIAL CONDUCTION

Heat transfer in the thermal entrance region of pipes is analyzed by the finite-difference method including the effect of axial fluid conduction. A hydrodynamically developed flow through a two-region pipe is investigated for constant surface temperatures by a step change and for insulated upstream and uniform wall heat flux in the downstream region. The rate of convergence is enhanced by discretizing the governing differential equation by an exact profile obtained from the analytical solution of the one-dimensional conduction-convection problem.     

Fractionation of Caseins by Anion-exchange Chromatography Using Food-grade Buffers

: Caseins prepared by microfiltration of bovine skim milk were fractionated using anion‐exchange chromatography. Laser densitometry of electrophoresis gels was shown to be sufficiently quantitative to perform accurate mass balance calculations detailing the fate of each casein fraction. L‐cysteine was successfully used as a reducing agent instead of traditional toxic agents, such as dithiothreitol or β‐mercaptoethanol, enabling development of the first food‐grade buffer system for casein fractionation. More salt was required for elution of the casein fractions having a greater charge: α_s‐casein > β‐casein > κ‐casein. Increasing flow rate decreased the extent of separation. Use of smaller beads was suggested as a method to maintain separation at increased flow rate.     

Modeling the Direct Synthesis of Dimethyl Ether using Artificial Neural Networks

Artificial neural networks (ANNs) are designed and implemented to model the direct synthesis of dimethyl ether (DME) from syngas over a commercial catalyst system. The predictive power of the ANNs is assessed by comparison with the predictions of a lumped model parameterized to fit the same data used for ANN training. The ANN training converges much faster than the parameter estimation of the lumped model, and the predictions show a higher degree of accuracy under all conditions. Furthermore, the simulations show that the ANN predictions are also accurate even at some conditions beyond the validity range.     

Metabolic transformations of leukotriene B4 in primary cultures of human hepatocytes

Analytic expressions for plasma total titratable base, base excess (DeltaCB), strong-ion difference, change in strong-ion difference (DeltaSID), change in Van Slyke standard bicarbonate (DeltaVSSB), anion gap, and change in anion gap are derived as a function of pH, total buffer ion concentration, and conditional molar equilibrium constants. The behavior of these various parameters under respiratory and metabolic acid-base disturbances for constant and variable buffer ion concentrations is considered. For constant noncarbonate buffer concentrations, DeltaSID = DeltaCB = DeltaVSSB, whereas these equalities no longer hold under changes in noncarbonate buffer concentration. The equivalence is restored if the reference state is changed to include the new buffer concentrations.     

Gluten contamination in manufactured gluten-free foods in Turkey

ABSTRACT

Gluten contamination in manufactured gluten-free foods (mGFFs) is a major health, well-being and economic issue worldwide for both mandatory and voluntary GFF-consumers. Although scarce, a number of surveys have shown that up to 21.5 % of mGFFs in circulation in the market are contaminated with gluten. However, at the present time there is no published work reporting gluten contamination in mGFFs produced in Turkey. In this paper miscellaneous mGFFs produced in Turkey were analysed for gluten concentration (G) to fill this knowledge gap, and to compare the situation in Turkey with worldwide efforts on this issue. A total of 200 mGFFs from 8 product categories (snack, pasta, bread, cookie, cracker, farina, traditional and others), and manufactured using 7 main ingredients (cereal mixture, buckwheat, corn, rice, locust bean, potato, and others) were analysed. A significant portion of mGFFs (17.5 %) were contaminated with gluten and therefore unacceptable as being GFF. The results point to buckwheat as the main cause of this contamination. If buckwheat is excluded, the ratio of unacceptable mGFFs dramatically decreases to 6.3 % and probably to 1.8 %, which are comparable figures to those reported for other countries. Almost all countries are subjected to the same regulations on GFFs, and the problem of gluten contamination could readily be solved to a great extent if pre-market measures are mandated. Enforcing mGFF-producers to screen their raw materials and final products to detect the presence of gluten, and preventing the release of contaminated mGFFs into the market would be a practical measure in favour of all stakeholders involved in GFF-consumption.     

Utilization of hazelnut pellicle in low-fat beef burgers

Hazelnut pellicle was used as a dietary fiber in the production of beef burgers. The effects of hazelnut pellicle addition on proximate composition, pH, cook loss, dimensional changes, color and sensory characteristics of beef burgers were evaluated. Hazelnut pellicle addition affected some quality parameters of beef burgers. The control samples had the lowest moisture and protein contents (P<0.05). The cooking yield and reduction in diameter and thickness of beef burgers improved by the addition of hazelnut pellicle. Beef burgers formulated with hazelnut pellicle had lower L, a and b values than control samples (P<0.05). There were differences among beef burger samples in respect to sensory properties, control samples and 1% and 2% pellicle added samples had high acceptability. The results indicate that, 1-2% hazelnut pellicle can be used as a suitable dietary fiber source in low-fat beef burger production.     

Characterization of antimicrobial polylactic acid based films

Olive leaf extract (OLE) (Olea europaea L.), which has antimicrobial effect on many food pathogens, was incorporated as antimicrobial agent into polylactic acid (PLA) films. Antimicrobial activities of films were tested against Staphylococcus aureus. Increasing amount of the OLE in the film discs from 0.9 mg to 5.4 mg caused a significant increase in inhibitory zones from 9.10 mm to 16.20 mm, respectively. Moreover, incorporation of OLE and/or increasing the amount in the film formulation significantly enhanced the water vapor permeability (WVP). The water solubility and the degradation rates of films increased up to 19.3% and 22.4%, respectively. Thus, OLE incorporated PLA films have a prospectively potential in antimicrobial food packaging to reduce post-process growth of S. aureus with improved properties.