Cell separation is thought to involve degradation of pectin by several hydrolytic enzymes, particularly polygalacturonase (PG). Here, we characterize an activation tagging line with reduced growth and male sterility caused by increased expression of a PG encoded by QUARTET2 (QRT2). QRT2 is essential for pollen grain separation and is part of a small family of three closely related endo-PGs in t...

An increase in starch content of cells in the abscission zone of the cotton explant appeared correlated with an increase in number of cells. A large increase in the number of cells in the abscission zone, concomitant with an increase in starch content, followed treatment with gibberellin as compared to auxin. In the final stages of abscission starch was hydrolyzed in the cells of the separation...

Presence of the hull significantly increases the sideforces on a propulsor in crashback below J=-0.7 (Bridges, 2004). Large Eddy Simulation (LES) reproduces the experimentally observed behavior. LES is performed for an open propulsor with and without hull at two advance ratios, J=-1.0 and J=-0.5. At J=-1.0, two noticeable flow features are found with the hull a recirculation zone upstream in th...

The applicability of capillary electrophoresis for the analysis of four extensively used penicillin derivatives (benzylpenicillin, ampicillin, amoxicillin, oxacilllin) has been studied. Because of structural similarities, the electrophoretic behavior of these derivatives is very similar; consequently an efficient separation using the conventional capillary zone electrophoresis is hard to be ach...

Capillary zone electrophoresis provides a rapid method for the analysis of minute amounts of amino acids. A laser-based absorbance technique is used to determine phenylthiohydantoin amino acids with detection limits of 10.15 mot; separation of 20 amino acids, based on micelle modified zone electrophoresis, requires 13 minutes. The amino acid sequence of a protein is of fundamental value in the ...

Elongation of sporangiophores marked with numerous starch grains was photographically recorded in the steady state and during the light-growth response when the rate is more than doubled. From these records the spatial distribution of growth within the cell's growth zone was derived. Stimulation by a single saturating flash of light speeds growth proportionally in all parts of the growing zone,...

In this contribution we present the first diffractive optical elements for soft x-ray differential interference contrast microscopy. Due to an improved calculation method the nanofabrication accuracy of these optics is the same as for comparable normal zone plate optics with the same outermost zone width. Different diffractive optical elements were fabricated with outermost zone width of 100 nm...

In this work we develop a method of straight lines for a one-dimensional Bingham problem. A Bingham fluid has viscosity properties that produce a separation into two regions, a rigid zone and a viscous zone. We propose a method of lines with the time as a discrete variable. We prove that the method is well defined, a monotone property, and a convergence theorem. Behavior of the numerical soluti...

In this paper Cohesive Zone Model (CZM) concepts are applied in order to study mode I fracture in a pre-cracked bonded Double Cantilever Beam (DCB) specimen. A cohesive surface element is implemented in a Finite Element commercial code using intrinsic cohesive zone models: exponential, bilinear and trapezoidal traction-separation laws. The sensitivity of cohesive zone parameters in predicting t...