Development of new plant type for pinto beans: Progress, problem and future prospects

Research and development of a reliable dry land production system for common bean (Phaseolus vulgarisL.) based on low-cost direct seeding and direct harvest methods was initiated at the Crop Development Centre at the University of Saskatchewan in the late 1980s. The target production area is a dry land spring wheat farming region in which lentil and pea production is well established. Effort is focussed on production of the pinto class. Three major potential improvements to the production system were identified: harvest equipment modification to improve direct harvest capability, development of early maturing germplasm with reliable expression of a crop canopy suitable for direct harvesting systems, and appropriate agronomy to improve the reliability of production. The research effort in harvest equipment modifications resulted in commercialization of a new design of lifter and reel assembly for combines equipped with floating cutter bar headers. Field scale evaluations showed that a 50% reduction in cutter bar loss is possible with cultivars with Type III growth habit. Agronomy research for new production systems has been limited to development of improved rhizobial strains, but new areas of research will be explored as appropriate cultivars become available. Research in the area of germplasm development is specifically focussed on gains in early maturity and improvements in canopy structure, particularly for the pinto class. The ideal canopy structure for the production system is one in which all pods are situated above the combine cutter bar at the time of harvest. Specific improvements to the canopy structure include development of early maturing genotypes with elongated Type I growth habit, Type II growth habit or Type III growth habit without basal clustering of pods. In addition, an effort is underway to develop genotypes with shorter pods to maximize cutter bar clearance are under development and with pods with reduced lignin to minimize shattering and maximize cutter bar clearance. Reduction of lignin in pods may help reduce shattering at the time of harvest due to reduced dehiscence. Pods with reduced lignin tend to curve upward at the time of maturity, allowing better clearance of the cutter bar. Agronomic comparisons of F2-derived F4 and F5 lines showed that in some populations cutter bar losses can be reduced by up to 50%

Nucleation and Growth Kinetics for the Nanoparticle Precipitation of Barium Sulfate in Microemulsions

The formation of nanoparticles in microemulsion droplets is a promising technology for the control of the particle properties, e.g. the particle size distribution or particle shape [1]. Results from barium sulfate precipitation experiments in a semi-batch rushton tank reactor [2] confirmed that the particle size distribution can be controlled by the variation of the initial reactant concentrations inside the droplets. A population balance model was used to analyze this behavior paying particular attention to the nucleation and growth kinetics. The challenge in the model derivation of this process originates from the occurrence of two nested populations (particles inside droplets) and a high number of distributed properties, e.g. the concentrations of the reactants and the particle size. The two populations with their properties are strongly coupled by phenomena like the droplet exchange (coalescence/ redispersion or also named fusion/ fission), the chemical reaction, nucleation and growth of particles. Especially the droplet exchange concerning more than two properties (internal coordinates of the population balance) makes the solution of the resulting deterministic partial integro-differential equation via numerical methods difficult and computationally expensive [3]. Without any model reduction this system is only solvable by Monte-Carlo simulations [2,4], which have as well a high computational demand and are therefore not appropriate for an extensive study of the nucleation and growth kinetics. A significant model reduction can be obtained by the assumption that the time constant for the droplet exchange is much smaller than the time constants for nucleation and growth. This means that the concentrations of the liquid species inside the droplet are distributed following an equilibrium distribution, which is in the case of microemulsions Poissonian [5]. Further assuming that only one particle can exist per droplet and that the chemical reaction proceeds instantaneously the population balance model has to consider two internal coordinates, namely the particle size and the number of the liquid barium sulfate molecules within one droplet, which are distributed inside the droplet population according to the discrete Poisson distribution. Mathematically speaking the model is reduced to a partial differential equation with a high number (20 - 30) of convective terms, representing particle growth, for each number of barium sulfate molecules due to the dependence of the growth kinetics on the supersaturation. Different rate approaches obtained from bulk precipitation experiments for nucleation and growth kinetics [6-8] were implemented in this model and simulations using the same process parameters as described by [2] were performed. The comparison of particle size distributions from experiments and the simulations shows that the kinetics from literature for the bulk phase process are not applicable in the nanosized droplets of a microemulsion without any modification. A simultaneous parameter estimation of the rate constants for nucleation and growth with the whole set of experimental data has been performed and a good agreement with the experimental data could be achieved. The location as well as the broadness of the particle size distribution could be adapted by the two rate constants. These corrected parameters were several order of magnitude smaller than the original ones in the bulk phase process. Possible explanations for this slow-down effect are that the kinetics derived for particle sizes in the micrometer range cannot be directly applied at the nanoscale or that the assumption of an instantaneous droplet exchange is wrong. In fact many theoretical studies assume that the droplet exchange is the rate determining step [4], but the high computational demand constricts such models too much. With the present model the whole process can be simulated in less than ten seconds on a standard 3 GHz PC in Matlab, which utilizes this very flexible and accurate model for further applications in CFD codes and online process control strategies. In addition to the parameter estimations the sensitivity of the nucleation and growth kinetics concerning the critical number of molecules needed to form a stable nucleus and the droplet size have been investigated. The present model is currently extended to take excess of one reactant into account, too. Therefore two liquid species, both Poissonian distributed, have to be considered, leading to 400 - 900 convective terms in the partial differential equation. This will result in more reliable kinetics at high concentration gradients. [1] Kumar, P.; Mittal, K. L. (Eds): Handbook of Microemulsion Science and Technology, Marcel Dekker Inc., New York, 1999 [2] Adityawarman, D.; Voigt, A.; Veit, P.; Sundmacher, K.: Precipitation of barium sulfate nanoparticles in a non-ionic microemulsion: Identification of suitable control parameters. In: Chem. Eng. Sci. 60 (2005), 12, p. 3373-3381 [3] Niemann, B.; Adityawarman, D.; Sundmacher, K.: Multidimensional population balance modeling of barium sulfate precipitation in microemulsions. AIChE 2004 Annual Meeting, Austin, TX [4] Bandyopadhyaya, R.; Kumar, R.; Gandhi, K. S.: Simulation of precipitation reactions in reverse micelles. In: Langmuir 16 (2000), 18, p. 7139-7149 [5] Bandyopadhyaya, R.; Kumar, R.; Gandhi, K. S.; Ramkrishna, D.: Modeling of precipitation in reverse micellar systems. In: Langmuir 13 (1997), 14, p. 3610-3620 [6] Baldyga, J.; Podgorska, W.; Pohorecki, R.: Mixing-Precipitation model with application to double feed semibatch precipitation. In: Chem. Eng. Sci. 50 (1995), 8, p. 1281-1300 [7] Fitchett, D. E.; Tarbell, J. M.: Effect of mixing on the precipitation of barium sulfate in an MSMPR reactor. In: AIChE J. 36 (1990), 4, p. 511-52

Combination of IL-17A/F and TNF-alpha uniquely alters the bronchial epithelial cell proteome to enhance proteins that augment neutrophil migration

Background: The heterodimer interleukin (IL)-17A/F is elevated in the lungs in chronic respiratory disease such as severe asthma, along with the pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha). Although IL-17A/F and TNF-alpha are known to functionally cooperate to exacerbate airway inflammation, proteins altered by their interaction in the lungs are not fully elucidated.Results: We used Slow Off-rate Modified Aptamer-based proteomic array to identify proteins that are uniquely and/or synergistically enhanced by concurrent stimulation with IL-17A/F and TNF-alpha in human bronchial epithelial cells (HBEC). The abundance of 38 proteins was significantly enhanced by the combination of IL-17A/F and TNF-alpha, compared to either cytokine alone. Four out of seven proteins that were increased > 2-fold were those that promote neutrophil migration; host defence peptides (HDP; Lipocalin-2 (LCN-2) and Elafin) and chemokines (IL-8, GRO alpha). We independently confirmed the synergistic increase of these four proteins by western blots and ELISA. We also functionally confirmed that factors secreted by HBEC stimulated with the combination of IL-17A/F and TNF-alpha uniquely enhances neutrophil migration. We further showed that PI3K and PKC pathways selectively control IL-17A/F + TNF-alpha-mediated synergistic production of HDPs LCN-2 and Elafin, but not chemokines IL-8 and GRO alpha. Using a murine model of airway inflammation, we demonstrated enhancement of IL-17A/F, TNF-alpha, LCN-2 and neutrophil chemokine KC in the lungs, thus corroborating our findings in-vivo.Conclusion: This study identifies proteins and signaling mediated by concurrent IL-17A/F and TNF-alpha exposure in the lungs, relevant to respiratory diseases characterized by chronic inflammation, especially neutrophilic airway inflammation such as severe asthma