Effects of Desolvating Agent Types,Ratios, and Temperature on Size and Nanostructure of Nanoparticles from α‐Lactalbumin and Ovalbumin

In this study, we compare the preparation of ovalbumin (OVA) and α‐lactalbumin (α‐LA) nanoparticles using different desolvating agents (ethanol, acetone, and methanol) and water: desolvating agent volume ratios (1:3, 1:4, 1:5, 1:10, and 1:20). Also the effects of protein solution temperature (25, 50, and 80 ℃) on the size of nanoparticles and the stability of crosslinked nanoparticles for 30 d were studied. OVA and α‐LA were shown to be good candidates for nanoparticulation and nanoparticles in the range of 60 to 230 nm were obtained. The comparison between the 2 proteins offers guidance to optimize OVA and α‐LA nanoparticle fabrication and to efficiently obtain nanoparticles with desired characteristics. The particle sizes of OVA nanoparticles were found to be in the range of 60 to 160 nm, and the particle sizes of α‐LA were between 150 and 230 nm. The sizes varied with different desolvating agents: for OVA, ethanol, and methanol both produced nanoparticles smaller than 100 nm; for α‐LA, methanol produced the smallest nanoparticles. Water: desolvating agent ratios, in the studied range, did not show a significant effect on the particle sizes for both OVA and α‐LA nanoparticles. The size and morphology of the nanoparticles were found to change when the protein solutions were heated up to 50 and 80 ℃ and cooled down before nanoparticulation and most nanoparticles had a smaller diameter.     

Synthesis and properties of corn zein/montmorillonite nanocomposite films

The objectives of this study were to apply fabrication techniques for the zein montmorillonite (MMT) nanocomposite films and characterize the obtained nanocomposite films. Zein MMT nanocomposite films were successfully produced from solvent casting and blown extrusion methods. The two methods could mix the zein MMT resulting in partially exfoliated nanocomposite structures according to X-ray diffraction and transmission electron microscopy. The thermal resistant of the zein nanocomposite films fabricated from both methods improved as the MMT content increased. However, the mechanical and barrier properties showed non-linear relationships with the MMT loadings. The impact of MMT on properties of zein films strongly depended on the preparation techniques. This can be the good starting point to further study in depth insight of the controllable MMT rearrangement in zein films which will remarkably improve zein film properties for packaging applications.     

Knockdown of the Halloween Genes spook,shadow and shade Influences Oocyte Development,Egg Shape,Oviposition and Hatching in the Desert Locust

Ecdysteroids are widely investigated for their role during the molting cascade in insects; however, they are also involved in the development of the female reproductive system. Ecdysteroids are synthesized from cholesterol, which is further converted via a series of enzymatic steps into the main molting hormone, 20-hydoxyecdysone. Most of these biosynthetic conversion steps involve the activity of cytochrome P450 (CYP) hydroxylases, which are encoded by the Halloween genes. Three of these genes, spook (spo), phantom (phm) and shade (shd), were previously characterized in the desert locust, Schistocerca gregaria. Based on recent sequencing data, we have now identified the sequences of disembodied (dib) and shadow (sad), for which we also analyzed spatiotemporal expression profiles using qRT-PCR. Furthermore, we investigated the possible role(s) of five different Halloween genes in the oogenesis process by means of RNA interference mediated knockdown experiments. Our results showed that depleting the expression of SchgrSpo, SchgrSad and SchgrShd had a significant impact on oocyte development, oviposition and hatching of the eggs. Moreover, the shape of the growing oocytes, as well as the deposited eggs, was very drastically altered by the experimental treatments. Consequently, it can be proposed that these three enzymes play an important role in oogenesis.     

Single Amino Acid Exchange in ACTIN2 Confers Increased Tolerance to Oxidative Stress in Arabidopsis der1–3 Mutant

Single-point mutation in the ACTIN2 gene of the der1–3 mutant revealed that ACTIN2 is an essential actin isovariant required for root hair tip growth, and leads to shorter, thinner and more randomly oriented actin filaments in comparison to the wild-type C24 genotype. The actin cytoskeleton has been linked to plant defense against oxidative stress, but it is not clear how altered structural organization and dynamics of actin filaments may help plants to cope with oxidative stress. In this study, we characterized root growth, plant biomass, actin organization and antioxidant activity of the der1–3 mutant under oxidative stress induced by paraquat and H₂O₂. Under these conditions, plant growth was better in the der1–3 mutant, while the actin cytoskeleton in the der1–3 carrying pro35S::GFP:FABD2 construct showed a lower bundling rate and higher dynamicity. Biochemical analyses documented a lower degree of lipid peroxidation, and an elevated capacity to decompose superoxide and hydrogen peroxide. These results support the view that the der1–3 mutant is more resistant to oxidative stress. We propose that alterations in the actin cytoskeleton, increased sensitivity of ACTIN to reducing agent dithiothreitol (DTT), along with the increased capacity to decompose reactive oxygen species encourage the enhanced tolerance of this mutant against oxidative stress.     

Development of an iterative procedure with a flow solver for optimizing the yarn speed in a main nozzle of an air jet loom

In this research, a fluid–structure interaction (FSI) framework was established to estimate the velocity of a yarn as it is propelled by the main nozzle. To allow the methodology to be used in an optimization context, the computational time was limited as much as possible. The methodology was first validated on polymer coated yarns to avoid any influence of yarn hairiness. Results from the calculations were compared to experiments and adequate agreement was found without tuning. Subsequently, an extension to hairy yarns was made by representing the hairiness as a wall roughness. The roughness height was determined by matching the simulated to the experimental velocity for a single case. The approach was validated by applying the obtained roughness height to different setups and comparing the simulations to the corresponding experiments. Taking into account some limitations, the methodology can be applied for optimization purposes using either smooth or hairy yarns.     

Chemiluminescence and thermo-oxidation stability of poly(2,6-dimethyl-p-phenylene ether) in blends with polystyrene and polybutadiene

It has been ascertained that chemiluminescence-time curves for samples of poly(2,6-dimethyl-p-phenylene ether) blended with high-impact polystyrene containing polybutadiene yield a very reproducible pattern even at a temperature of 190°C. The chemiluminescence light emission has been associated with consumption of double bonds in polybutadiene, and a corresponding rate constant and activation energies of chemiluminescence decay from both the isothermal and nonisothermal parts of chemiluminescence-time curves have been determined. As demonstrated by these curves, an attempt, to stabilize the blends toward thermooxidation by the peroxide decomposer and stabilizer led to retardation of the oxidation process only and further investigation searching for an optimum stabilizing system is required. © 1993 John Wiley & Sons, Inc.     

Analysis of triazine herbicides residues in butter and pasteurized milk

Summary A method has been developed for the determination of atrazine, cyanazine, prometryn, simazine, and terbutryn residues in butter. The residues were extracted from the matrix with a mixture of petroleum ether/methanol (3 + 1), and from the separated water-methanol phase extraction was carried out with chloroform. The extract was cleaned up on an alumina column. Capillary glass liquid chromatography using a 15 m × 0.32 mm glass capillary column coated with OV-1 and an alcali flame ionization detector were employed for the analysis of the residues. The analyses were evaluated by the internal standard method, using metribuzin as the internal standard. The recovery of the method was 68.7%–79.8% for the individual herbicides under study at the fortification level of 0.1 mg · kg^–1 and 79.2%–91.9% at the fortification level of 0.02 mg · kg^–1. The determination limit of the method was 0.005 mg · kg^–1.When centrifuging full milk, residues of triazines were partitioned between the water and fat phases, whereby 17%–82% of the residues were transferred to the milk fat. Samples of commercial butter were analysed and found to contain 0.005–0.023 mg · kg^–1 atrazine.

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Analyse der Rückstände der Triazin-Herbicide in Butter und Milch

Zusammenfassung Es wird eine Methode für die Bestimmung der Rückstände von Atrazin, Cyanazin, Prometryn, Simazin und Terbutryn in Butter beschrieben. Die Rückstände werden aus der Butter mit einem Petrolether/Methanol-Gemisch (3 + 1) und weiter aus der geschiedenen Wasser-Methanol-Phase mittels Chloroform ausgezogen. Der Extrakt wird auf einer Aluminiumoxid-Säule gereinigt. Für die End-Analyse wird Capillargaschromatographie auf einer Glasscapillar-Säule (15 m × 0,32 mm) mit der OV-1-Stationärphase und einem thermoionischen Alkaliflammenlonisations-Detektor (N/P-FID) verwendet. Die Auswertung der Analyse geschieht mit der Standardmethode, wobei Metribuzin als innerer Standard dient. Die Wiederfmdungsraten der Methode sind 68,7 bis 79,8% für die einzelnen Herbicide in Modellversuchen bei Zugabe von 0,1 mg · kg^–1 und 79,2 bis 91,9% bei Zugabe von 0,02 mg · kg^–1. Die Empfindlichkeit der Methode ist 0,005 mg · kg^–1.Bei der Zentrifugierung von Milch wurde die Verteilung der Triazin-Herbicidrückstände zwischen der Wasser- und Fett-Phase festgestellt, wobei der Anteil der Herbicide in Milchfett 17 bis 82% betrug. In den analysierten Proben von Butter des Handels wurden medrigere Konzentrationen (0,005–0,023 mg · kg^–1) von Atrazin gefunden.

     

Annealing of intrinsic stresses in sputtered TiN films: The role of thickness-dependent gradients of point defect density

Morphology, structure and thermal behavior of magnetron sputtered TiN thin films with the thickness in the range 100-2900 nm are characterized. The films are thermally cycled and the relationship between film thickness, defect density and the intrinsic stress relaxation is analyzed. The results indicate that the residual stresses in the as-deposited films and the amount of stress relaxation depend decisively on the specific depth gradient of point defects originating from film evolution during growth. The compressive stresses, representing different driving forces and the amount of stress relaxation decrease, while the onset temperature of stress relaxation increases with increasing film thickness.