Pathogenicity of three species of entomopathogenic nematodes to some major stored-product insect pests

Entomopathogenic nematodes (Nematoda: Heterorhabditidae and Steinernematidae) are commonly used biological control agents of insects in cryptic habitats, but their potential for suppressing stored-product insects in these habitats has not been explored previously. Here, we provide data from the first step in a program to evaluate entomopathogenic nematodes in the genus Steinernema as biological control agents of stored-product pests by determining their pathogenicity to some of the major stored-product pest species. When evaluated against larvae, pupae and adults of six pest species (Plodia interpunctella, Ephestia kuehniella, Oryzaephilus surinamensis, Tenebrio molitor, Tribolium castaneum, and Trogoderma variabile), and the adults of two additional pest species (Sitophilus oryzae and Rhyzopertha dominica), Steinernema riobrave was either the most pathogenic or of similar pathogenicity compared to S. carpocapsae and S. feltiae. A dose of 10 infective juveniles of S. riobrave caused 80% or higher mortality against larvae of P. interpunctella, E. kuehniella, T. castaneum, and O. surinamensis, pupae of T. castaneum and T. molitor, and adults of T. molitor and the two moth species. All stages of Trogoderma variabile exhibited 70% or higher mortality. Adults of S. oryzae and R. dominica exhibited low susceptibility with 15% and 35% mortality, respectively. On the basis of these results, S. riobrave was selected for further evaluation under more field-like conditions.     

Effect of curing agents on some properties of a polysulfide sealant

The effect of curing agents on the properties of a polysulfide sealant composition was investigated. Commercially used curing agents, namely, lead dioxide, manganese dioxide, and ammonium dichromate, were selected for this study. It was established that curing agents affect joint strengths, stress–strain properties, dynamic mechanical properties, and thermal stability of the sealant. Sealant cured with ammonium dichromate had highest shear bond strength, ultimate tensile strength, modulus, and thermal stability, whereas these properties were lowest for lead-dioxide-cured sealant. Peel bond strength and elongation at break were highest for lead-dioxide-cured sealant. The observed changes in properties were attributed to the difference in crosslink density of the cured sealant, produced by the curing agents. The curing agents have no appreciable effect on the fuel resistance of the polysulfide sealant.     

Thermal barrier coating application of zircon sand

Naturally occurring zircon sand was plasma spray coated on steel substrates previously coated with NiCrAlY bond coat. The coatings were characterized for their microstructure, chemical composition, thermal shock resistance, and the nature of structural phases present. The as-sprayed coatings consisted of t-ZrO₂ (major phase), m-ZrO₂, ZrSiO₄ (minor phases), and amorphous SiO₂. These coatings, when annealed at 1200 °C/1.44 × 10⁴s yielded a ZrSiO₄ phase as a result of the reaction between ZrO₂ and SiO₂. Dramatic changes occurred in the characteristics of the coatings when a mixture of zircon sand and Y₂O₃ was plasma spray coated and annealed at 1400 °C/1.44 × 10⁴s. The t-ZrO₂ phase was completely stabilized, and these coatings were found to have considerable potential for thermal barrier applications.     

Effect of elastomer modification on the adhesive characteristics of maleimide‐functional phenolic resins

The effect of addition of elastomeric modifiers on the adhesive properties like lap shear strength and T‐peel strength of an addition curable, maleimide functional novolac phenolic resin (PMF), self‐cured and cocured with a novolac epoxy resin, was studied using aluminium adherends. The modifiers used were (1) two grades of carboxyl terminated butadiene acrylonitrile copolymer (CTBN) of different molecular weights, (2) a low molecular weight, epoxidized hydroxyl‐terminated polybutadiene, and (3) a high molecular weight acrylate terpolymer containing pendant epoxy functionality. The adhesive properties, when examined as a function of the varying concentrations of the additives, ranging from 10 to 30 parts per hundred parts (phr) of the resin, were found to depend on the nature of the matrix being modified as well as on the nature and concentration of the elastomer. The adhesive properties at ambient temperature of the self‐cured, highly brittle PMF resin were dramatically improved by the inclusion of all the elastomers, the increase being substantial in the case of high molecular weight CTBN. For the more rigid, less ductile, epoxy‐cured PMF system, the adhesive properties were marginally improved by the high molecular weight CTBN, whereas the other elastomers were practically ineffective. For both self‐cured and epoxy‐cured PMF systems, the inclusion of these elastomers generally decreased the high‐temperature adhesive properties, implying impairment of thermal characteristics, evidenced also from their dynamic mechanical spectra. The presence of phase‐separated elastomer particles in the modified systems has been evidenced from scanning electron micrographs. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2321–2332, 1999     

Physicochemical Properties of Garden Cress (<Emphasis Type="Italic">Lepidium sativum</Emphasis> L.) Seed Oil

Garden cress (Lepidium sativum L.) is an edible, underutilised herb, grown mainly for its seeds in India. Physicochemical properties, minor components (unsaponifiable matter, tocopherols, carotenoids), fatty acid composition and storage stability of garden cress seed oil (GCO) were studied. Cold press, solvent and supercritical CO₂ extraction methods were employed to extract the oil. The total oil content of garden cress (GC) seeds was 21.54, 18.15 and 12.60% respectively by solvent, supercritical CO₂ and cold press methods. The physical properties of GCO extracted by the above methods were similar in terms of refractive index, specific gravity and viscosity. However, cold pressed oil showed low PV and FFA compared to the oil extracted by other methods. α-Linolenic acid (34%) was the major fatty acid in GCO followed by oleic (22%), linoleic (11.8%), eicosanoic (12%), palmitic (10.1%) erucic (4.4%), arachidic (3.4%) and stearic acids (2.9%). Oleic acid (39.9%) and α-linolenic acid (42.1%) were the predominant fatty acids at the sn-2 position. The total tocopherol and carotenoid content of GCO was 327.42 and 1.0 μmol/100 g oil, respectively. The oil was stable up to 4 months at 4 °C. Tocopherol and BHT offered the least protection, while ascorbyl palmitate (200 ppm) offered the maximum protection to the oil, when subjected to the accelerated oxidative stability test. Thus GCO can be considered as a fairly stable oil with a high content of α-linolenic acid.     

An Object-Oriented Modeling and Simulation Environment for Reactive Systems Development

An environment to support the modeling, analysis, simulation, and development of state transition models, SMOOCHES (State Machines for Object-Oriented Concurrent Hierarchical Engineering Specifications), is presented. SMOOCHES allows the hierarchical construction, analysis, and simulation of state transition models in an object-oriented distributed environment. Statecharts (see Harel 1987b), a powerful mechanism for state transition specification, are fundamental to the development of SMOOCHES. To assist in the specification of hierarchical state transition models for distributed and reactive systems, statecharts are extended by introducing the concept of exit-safe states. SMOOCHES allows the specification of objects in the system with hierarchical state transition models and the derivation of new classes of objects through inheritance. A graphical monitoring system has been developed to represent and simulate the object state life cycles and monitor event generations. The example presented illustrates the modeling and simulation of different state life cycles of an assembly robot.     

Color and Texture Change Kinetics in Ripening Bananas

Kinetics of color and texture changes in ripening bananas were investigated as a function of storage temperature (10, 16, 22, 28 °C). Color was evaluated in terms of L, a and b values as well as the total color difference (ΔE) representing the residual deviations from the ripe stage. Puncture force (PF) was used to evaluate the texture properties of banana. The results indicated that the time dependence of L, ΔE and PF values followed a logistic model, while a and b values were well described by a simple zero-order and fraction conversion models, respectively. The Arrhenius equation adequately described the temperature dependence of the reaction rate constants for both color and texture parameters, from which the activation energies and rate constant at reference temperature 15 °C were obtained. There were significant linear correlations between color parameters (L, a, b, ΔE) and texture parameter (PF).     

In vitro bioactivity evaluation of nano- and micro-crystalline anodic TiO2: HA formation,cellular affinity and organ culture

Anodization is an easily viable technique useful for producing TiO₂ coatings on titanium substrates. Nano-crystalline anodic TiO₂ structure was produced on titanium at 20 V using 1 M Na₂SO₄ and 0.5% NaF and consolidated by a further heat-treatment. Micro-crystalline anodic TiO₂ was produced on titanium by applying a galvanostatic current density of 70 A/m² in water medium. To assess the usefulness of these nano- and micro-oxides for bone implant stability, physical properties and bone in vitro bioactivity including HA formation, cellular affinity and mouse-tissue morphogenesis, were evaluated. Bioactivity of the different anodic surfaces was evaluated by treating them in a simulated body fluid (SBF) to form hydroxyapatite (HA) and the rates of HA formation were compared. Deposits of HA could be seen on the nano-oxide surface within 7 days, whereas HA was detected only after 14 days on the micro-oxide surface. In vitro cell culture tests done using mouse osteoblasts indicated that the nano-oxides showed statistically significant cell activity than the micro-oxides and the machined titanium. Branching morphogenesis test done for 72 h on these surfaces showed more branching on the micro- and nano-oxides as compared with titanium surface.     

Effect of lipid excipients on in vitro pancreatic lipase activity

PURPOSE: To study the effects of two lipid excipients, Peceol and Gelucire 44/14 on the in vitro pancreatic lipase activity. METHODS: A 50 microL reaction mixture, consisting of 45 microL (3H) triolein as the radiolabeled substrate, 2.5 microL Peceol or Gelucire 44/14 (0.05-0.5%), either alone or in combination, 2.5 microL colipase (100 microg/mL), and 2.5 microL pancreatic lipase (1 mg/mL), was incubated for 10 min at room temperature. At the end of incubation, the reaction was stopped by the addition of an extraction solvent containing chloroform, methanol, and n-heptane (12.5:14:10), and the mixture vortexed briefly. Subsequently, 250 microL of 50 mM sodium carbonate was added and the aqueous and organic phase separated by centrifugation for 5 min at 1000 g. One hundred microliters of the supernatant was transferred to a scintillation counter and then radioactivity measured after the addition of 3.6 mL of scintillation fluid. Pancreatic lipase activity was determined by measuring the amount of free fatty acid released into the incubation medium and expressed as micromol free fatty acid released/min. RESULTS: When used alone, Peceol inhibited the pancreatic lipase activity significantly in a concentration-dependent manner, with a maximum inhibition of 57% at 0.4% of the excipient [p < 0.05, one-way analysis of variance (ANOVA)]. Similarly, Gelucire 44/14 alone caused inhibition of lipase activity in a concentration-dependent manner. However, the maximum inhibition (30%) was smaller in magnitude compared with the former agent. When the two excipients were used in combination, the inhibitory effects on the enzyme activity were similar to those observed with the individual agents (p < 0.05, one-way ANOVA). However, the maximum inhibition of 30% was lower than that observed with Peceol alone. CONCLUSIONS: The results from this study suggest that these lipid excipients inhibit in vitro pancreatic lipase activity and should be taken into consideration when developing oral formulations using these agents.