Synthesis of Stephenson III Timed Curve Generators Using a Probabilistic Continuation Method

The kinematic synthesis equations of fairly simple planar linkage topologies are vastly nonlinear. This indicates that a large number of solutions exist, and hence a large number of design candidates might be present. Recent algorithms based in polynomial homotopy continuation have enabled the computation of entire solution sets that were previously not possible. These algorithms are based on a technique that stochastically accumulates finite roots and guarantees the exclusion of infinite roots. Here we apply the Cyclic Coefficient Parameter Continuation (CCPC) method to obtain for the first time the complete solution of a Stephenson III six-bar that traces a path and coordinates the angle of its input link along that path. Linkages of this type, called timed curve generators, are particularly useful for controlling the motion of an end effector point and influencing its transmission properties from a rotary input. For a numerically general version of the synthesis equations, we computed an approximately complete set of 1,017,708 solutions that divides into subsets of four according to the Stephenson III cognate structure. This numerically generic solution set essentially represents a design tool. It can be used in conjunction with a parameter homotopy to efficiently obtain all isolated roots of other systems of this same structure that correspond to a specific synthesis task. This is demonstrated with two example synthesis tasks.

Elicitation of Anthocyanin Production in Roots of Kalanchoe blossfeldiana by Methyl Jasmonate

The influence of methyl jasmonate on anthocyanin accumulation in roots ofKalanchoe blossfedianaplants was studied. Methyl jasmonate (JA-Me), at a concentration of 5.0 to 40.0 mg.l−1, substantially increased anthocyanin accumulation in roots of intact plants, when it was applied as a solution under natural light conditions. The production of anthocyanin depended on the concentration of methyl jasmonate and the age of the plant. The stimulatory effect was higher in older plants ofK. blossfeldianathan in younger ones. When leaves were removed methyl jasmonate slightly stimulated anthocyanin accumulation compared with intact plants. The obtained results indicate that leaves are necessary for the anthocyanin accumulation in the roots. In isolated roots methyl jasmonate did not affect the accumulation of anthocyanins in light conditions. Seven anthocyanins were documented in the roots of control plants and 8 anthocyanins in the roots of JA-Me treated ones. JA-Me increased the level of anthocyanins in roots of oldK. blossfeldianaplants 6.8, 6.0 and 3.6-folds, after 4, 8 and 14-days of treatment, respectively.

The Effect Of Some Plant Growth Regulators And Their Combination With Methyl Jasmonate On Anthocyanin Formation In Roots Of Kalanchoe Blossfeldiana

In this study, we investigated the effect of plant growth regulators (PGRs) - auxins, gibberellin, cytokinin, abscisic acid, brassinosteroid, ethylene and their interaction with methyl jasmonate (JA-Me) applied to roots of the whole plants Kalanchoe blossfeldiana on the accumulation of anthocyanins in roots. The highest stimulation of anthocyanins synthesis was stated with application of JA-Me alone. In response to treatments with the other tested PGRs, the content of anthocyanins in roots of a whole plant was different depending on the concentration of the PGR when being applied alone or together with JA-Me. Auxin, indole-3-acetic acid (IAA) at a concentration of 50 mg·L-1, indole-3-butyric acid (IBA) at 5 mg·L-1 and abscisic acid (ABA) at 10 mg·L-1 induced anthocyanin accumulation with approximately 60-115% compared to the control while 24-epibrassinolid (epiBL), gibberellic acid (GA3) and 6-benzylaminopurine (BAP) had no effect on the anthocyanin accumulation. The simultaneous administration of the PGRs with JA-Me usually resulted in the accumulation of anthocyanins in roots in a manner similar to that caused by JA-Me. PGRs applied to isolated roots did not stimulate anthocyanin accumulation, except for the combination of JA-Me with 50 mg·L-1 IAA. The results indicate that in K. blossfeldiana, the aboveground parts of the plant play an important role in the biosynthesis of anthocyanins in roots.

Biological Activity of the Agrobacterium rhizogenes–Derived trolC Gene of Nicotiana tabacum and Its Functional Relation to Other plast Genes

Agrobacterium rhizogenes induces hairy roots through the activity of three essential T-DNA genes, rolA, rolB, and rolC, whereas the orf13 gene acts as an accessory root-inducing gene. rolB, rolC, and orf13 belong to the highly diverged plast gene family with remotely related representatives in the endomycorrhizal basidiomycete Laccaria bicolor. Nicotiana glauca and N. tabacum contain A. rhizogenes–derived T-DNAs with active plast genes. Here, we report on the properties of a rolC homolog in N. tabacum, trolC. Dexamethasone-inducible trolC and A4-rolC genes from A. rhizogenes A4 induce comparable, strong growth effects affecting all parts of the plants. Several have not been described earlier and were found to be very similar to the effects of the distantly related plast gene 6b. They include leaf chlorosis and starch accumulation, enations, increase of sucrose-dependent leaf disk expansion, growth of isolated roots on low-sucrose media, and stimulation of sucrose uptake by small root fragments. Collectively, our findings indicate that enhancement of sucrose uptake plays an important role in generating the complex 6b and rolC phenotypes and might be an ancestral property of the plast genes.

Granular Size Effect of Clinoptilolite on Maize Seedlings Growth

Clinoptilolite has been successfully used in growing media for containerized horticultural and floricultural production. However, limited data exist on the effects and interaction between particle size and organic nutrient enrichment of the clinoptilolite. One granular (1-3 mm) and micronized (< 30 µm) clinoptilolite was added to quartz sand, an inert growing substrate, at two doses (0.1% and 3% v/v), without or with addition of wine vinasse as nutrient source at four concentrations (0 mgF×Lsubst-1, 10 mgF×Lsubst-1, 100 mgF×Lsubst-1 and 1000 mgF×Lsubst-1) to evaluate their effect on root growth for five days or the appearance of the second true leaf. Root mucigel was produced in zones where clinoptilolite particles adhered to the root surface. Microscopic analysis of isolated roots showed the increase of secondary roots and the proliferation of root hairs in maize treated with both micronized and granular clinoptilolite, with the contemporary production of root mucigel in zones where zeolite particles adhered to the root surface. It is hypothesized that the enhanced production of mucigel by root cells can favour not only the penetration of roots into the inert substrate, but also the solubilization of organic matter and nutrient availability, in particular when micronized clinoptilolite was present in the growing medium. Therefore, micronized clinoptilolite behaved as a sort of a “physical stimulant” for roots during seedlings, promoting, as a consequence, maize shoot development. Effectively, the highest increase in shoot growth was observed at the highest dose (3% v/v) of micronized zeolite, with the optimal rate of organic fertilizer (100 mgF×Lsubst-1).

Effect of indole-3-acetic acid on pea root growth, peroxidase profiles and hydroxyl radical formation

Changes in growth, peroxidase profiles, and hydroxyl radical formation were examined in IAA (0.5-10 mg/l) treated pea plants grown hydroponically and in isolated roots in liquid in vitro culture. IAA inhibited root elongation, both in hydroponically grown pea plants and in isolated roots in vitro. A remarkable increase in the number of POD iso?forms was noticed in isolated roots grown in vitro, compared to the roots from plants grown hydroponically. IAA induced both disappearance of several root POD isoforms and hydroxyl radical formation in the root and the root cell wall.

Advances in Polynomial Continuation for Solving Problems in Kinematics

For many mechanical systems, including nearly all robotic manipulators, the set of possible configurations that the links may assume can be described by a system of polynomial equations. Thus, solving such systems is central to many problems in analyzing the motion of a mechanism or in designing a mechanism to achieve a desired motion. This paper describes techniques, based on polynomial continuation, for numerically solving such systems. Whereas in the past, these techniques were focused on finding isolated roots, we now address the treatment of systems having higher-dimensional solution sets. Special attention is given to cases of exceptional mechanisms, which have a higher degree of freedom of motion than predicted by their mobility. In fact, such mechanisms often have several disjoint assembly modes, and the degree of freedom of motion is not necessarily the same in each mode. Our algorithms identify all such assembly modes, determine their dimension and degree, and give sample points on each.