Structure-function studies of an IGF-I analogue that can be chemically cleaved to a two-chain mini-IGF-I

The structure and biological activities of two disulphide isomersof a C-region deletion mutant of insulin-like growth factor-I(IGF-I) which has an Asn–Gly link engineered at the junctionof the A- and B-regions were studied before and after chemicalcleavage. Circular dichroism (CD) spectra and binding affinityto IGF binding protein 3 (IGFBP3) indicated that the treatmentwith hydroxylamine did not disrupt the overall tertiary foldof the hormones. Cleavage restored some binding affinity forthe IGF-I receptor in both isomers and weakly restored the abilityto stimulate incorporation of tritiated thymidine into DNA inNIH 3T3 fibroblasts transfected with the human IGF-I receptor.Cleavage also restored metabolic capacity, as measured by theability of the isomers to promote lipogenesis in isolated ratadipocytes through the insulin receptor. These results are consistentwith the theory that binding of IGF-I to the IGF-I receptorrequires a conformational change similar to that involved ininsulin binding the insulin receptor. The weak affinity forthe IGF-I receptor after cleavage is consistent with the beliefthat residues in the C-region interact with the IGF-I receptor.This structural difference between insulin and IGF-I gives eacha higher binding affinity for its own receptor.     

Nitrogen budget for fescue pastures fertilized with broiler litter in Major Land Resource Areas of the southeastern US

The southeast US produces a tremendous number of broiler chickens (Gallus gallus), which in turn produce massive quantities of litter (manure and bedding materials). In the Southeast, litter is most often disposed of via land application to pastures, however, the ultimate fate of much of the applied nitrogen (N) is not known. We have constructed N budgets for three sites across the southeastern U.S. in an effort to determine how much of the applied N is useful for plant production and how much is left to be absorbed by the environment. Study sites were located in the Coastal Plain (Alabama), Piedmont (Georgia), and Cumberland Plateau (Tennessee) Major Land Resource Areas (MLRA) of the southeastern US. Litter was applied in the Spring of two consecutive years at a rate to supply 70 kg of available N ha^–1. The total amount of N applied ranged from 103 to 252 kg N ha^–1 depending on site and year. Nitrogen fluxes monitored in this study were broiler litter N, ammonia (NH₃) volatilization, denitrification, plant uptake, and leaching. Plant uptake represented the largest flux of applied N, averaging 43% of applied N. Losses due to NH₃ volatilization and denitrification combined were only 6% of applied N on average. Loss of N due to NO₃-N leaching appeared to be significant only at the Coastal Plain site where NO₃-N concentrations in the groundwater peaked at 38 mg N l^–1. We believe the majority of excess N shown in these budgets is likely accounted for by leaching losses and soil accumulation. Regardless of these assumptions and low gaseous losses, it is apparent that on average, 57% of applied N is destined for a fate other than plant uptake. The results of this study indicate that land-application of broiler litter at currently recommended rates has the potential for negative impacts on the environment of the southeastern U.S. in the long-term.     

Effects of Enantiomeric Blend of Verbenone on Response ofIps paraconfusus to Naturally Produced Aggregation Pheromone in the Laboratory

The aggregation pheromone produced by maleIps paraconfusus (Coleoptera: Scolytidae) tunneling in Monterey pine,Pinus radiata, logs was trapped on Porapak Q. A concentration of an extract of trapped volatiles that attracted beetles was determined in the laboratory through a concentration–response analysis of walking behavior of males and females. The interruptant effects of four concentrations of verbenone on response to a constant concentration of this naturally produced aggregation pheromone were tested with males and females. Independent of its enantiomeric composition [99.5% (S)-(–), 93.1 % (S)-(–), and 98.3% (R)-(+)], verbenone significantly reduced the percentage of females (but not males) reaching the attractant source. However, when the time required for beetles of both sexes taken together to reach the attractant source was considered, verbenone of higher enantiomeric purity had a greater effect on beetle behavior. Solutions of 99.5% (S)-(–)- and 98.3% (R)-(+)-verbenone increased the time required for beetles to reach the attractive source when compared to 93.1% (S)-(–)-verbenone. When pooled across enantiomeric blends, increasing concentrations of verbenone resulted in slower responses in beetles that reached the attractant source within 2 min. Males and females did not respond to verbenone alone.     

Effect of montmorillonite clay addition on the morphological and physical properties of Jatropha curcas L. and Glycine max L. protein concentrate films

Protein concentrates from jatropha (JPC) and soy seeds (SPC) were obtained by solubilization and acid precipitation of proteins. JPC and SPC films were prepared by the casting method, using two different montmorillonite (MMT) clay concentrations and plasticized with glycerol. Film properties were evaluated by scanning electron microscopy, transmission electron microscopy, X‐ray diffraction (XRD), Fourier transform infrared spectroscopy, thermogravimetric analysis, tensile properties, water retention, and water vapor transmission rate (WVRT). Typical tactoid microcomposite structures were found to be heterogeneously dispersed in the films containing MMT. A small XRD peak was found in films with MMT. Slight improvements in thermal stability and tensile strength were observed in the films with MMT. Reductions in water retention and WVRT were obtained when MMT was added into the films. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44459.     

A Blend of Ethanol and (−)-α-Pinene were Highly Attractive to Native Siricid Woodwasps (Siricidae,Siricinae) Infesting Conifers of the Sierra Nevada and the Allegheny Mountains

Woodwasps in Sirex and related genera are well-represented in North American conifer forests, but the chemical ecology of native woodwasps is limited to a few studies demonstrating their attraction to volatile host tree compounds, primarily monoterpene hydrocarbons and monoterpene alcohols. Thus, we systematically investigated woodwasp-host chemical interactions in California’s Sierra Nevada and West Virginia’s Allegheny Mountains. We first tested common conifer monoterpene hydrocarbons and found that (?)-α-pinene, (+)-3-carene, and (?)-β-pinene were the three most attractive compounds. Based on these results and those of earlier studies, we further tested three monoterpene hydrocarbons and four monoterpene alcohols along with ethanol in California: monoterpene hydrocarbons caught 72.3% of all woodwasps. Among monoterpene hydrocarbons, (+)-3-carene was the most attractive followed by (?)-β-pinene and (?)-α-pinene. Among alcohols, ethanol was the most attractive, catching 41.4% of woodwasps trapped. Subsequent tests were done with fewer selected compounds, including ethanol, 3-carene, and ethanol plus (?)-α-pinene in both Sierra Nevada and Allegheny Mountains. In both locations, ethanol plus (?)-α-pinene caught more woodwasps than other treatments. We discussed the implications of these results for understanding the chemical ecology of native woodwasps and invasive Sirex noctilio in North America. In California, 749 woodwasps were caught, representing five species: Sirex areolatus Cresson, Sirex behrensii Cresson, Sirex cyaneus Fabricius, Sirex longicauda Middlekauff, and Urocerus californicus Norton. In West Virginia 411 woodwasps were caught representing four species: Sirex edwardsii Brullé, Tremex columba Linnaeus, Sirex nigricornis F., and Urocerus cressoni Norton.     

Modeling of Multiphase Transport during Drying of Honeycomb Ceramic Substrates

Multiphase transport model to simulate drying of honeycomb ceramic substrates in a conventional (hot air) drier is developed. Heat and moisture transport in the honeycomb walls as well as channels is modeled. The model predictions are validated against experiments done for drying of cylinder-shaped substrates by comparing histories and axial profiles of moisture loss and point temperature histories at various locations. Drying experiments are performed at two different values of air temperature, 103°C and 137°C, at a relative humidity value of 5%. Sensitivity analysis reveals that the drying process is controlled by heat and water vapor transport. External heat transfer is the dominant resistance mechanism for energy transport, whereas internal convection and binary diffusion dominate the resistance to vapor transport.     

Influence of Fluorine Content in Apatite–Mullite Glass-Ceramics

The nucleation and crystallization of a series of glasses based on 4.5SiO₂·3Al₂O₃·1.5P₂O₅·(5 − z )CaO · z CaF₂ with a Ca:P ratio corresponding to apatite were studied. In these glasses, the objective was to investigate the influence of fluorine content and z was varied from 3 to 0. All the glasses studied crystallized to fluorapatite (FAP) and mullite with the exception of the glass containing no fluorine, which crystallized to β-tricalcium phosphate (Ca₃(PO₄)₂) and anorthite (CaAl₂Si₂O₈). Glasses that contained sufficient fluorine to form FAP bulk nucleated to give FAP without a nucleation hold. Thermal gravimetric analysis demonstrated a significant weight loss corresponding to the crystallization of mullite, which increased with the fluorine content of the glass and also with decreased particle size. The loss was attributed to volatile SiF₄. The glass transition temperature decreased with increased fluorine content of the glass.     

Self‐sustained oscillations in opposed impinging jets in an enclosure

The flow of jets in confining enclosures has significant application in many engineering processes. In particular, the impingement of axisymmetric jets in a confined space has been examined using flow visualization, laser Doppler anemometry, and numerical simulations. Several flow regions were found; stable steady, regular oscillatory, and irregular oscillatory. Initially, a steady flow field existed for all arrangements for Re_d < ?90 (based on the nozzle diameter d, the fluid kinematic viscosity v and the volumetric flow rate Q through the nozzle (Q = πd²/4U_avg)) but subsequent increments in the fluid velocity caused a regularly oscillating flow field to emerge. The onset of the oscillations and the upper limit of finite oscillations were found to be a function of the Re_d, and the nozzle diameter to chamber dimension ratio. Steady numerical simulations predicted the steady flow field well and good agreement was obtained in unsteady simulations of the oscillating flow field. The oscillating flow field is considered to be a class of self‐sustaining oscillations where instabilities in the jet shear layer are amplified because of feed back from pressure disturbances in the impingement region.     

Biodegradable composites based on starch/EVOH/glycerol blends and coconut fibers

Unripe coconut fibers were used as fillers in a biodegradable polymer matrix of starch/ethylene vinyl alcohol (EVOH)/glycerol. The effects of fiber content on the mechanical, thermal, and structural properties were evaluated. The addition of coconut fiber into starch/EVOH/glycerol blends reduced the ductile behavior of the matrix by making the composites more brittle. At low fiber content, blends were more flexible, with higher tensile strength than at higher fiber levels. The temperature at the maximum degradation rate slightly shifted to lower values as fiber content increased. Comparing blends with and without fibers, there was no drastic change in melt temperature of the matrix with increase of fiber content, indicating that fibers did not lead to significant changes in crystalline structure. The micrographs of the tensile fractured specimens showed a large number of holes resulting from fiber pull‐out from the matrix, indicating poor adhesion between fiber and matrix. Although starch alone degraded readily, starch/EVOH/glycerol blends exhibited much slower degradation in compost. Composites produced 24.4–28.8% less CO₂ compared with starch in a closed‐circuit respirometer. Addition of increasing amount of fiber in starch/EVOH/glycerol composite had no impact on its biodegradation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

A computer-aided design tool for developing digital controllers andrelays

The design, development, and implementation of a computer-aided design (CAD) tool for developing digital controllers and relays are presented. The development includes modeling A/D converters, software, and the necessary logic. Procedures for modeling A/D converters and simulating the software are described. Application of the CAD tool is demonstrated by evaluating and comparing three different designs of a digital overcurrent relay. The designs are evaluated to determine both the speed and accuracy of the relays. The effects of the size of the A/D converters, the word-size used in computations, and the truncation/rounding are included in the simulation. Also described is the algorithm used in the relay design