Structure modeling hints at a granular organization of the Vertebrate Golgi ribbon

Vertebrate cells display a specific Golgi apparatus architecture, known as the ribbon, where the functional subunits, the mini-stacks, are linked into a tri-dimensional network. The importance of the ribbon architecture is underscored by evidence of its disruption in a host of diseases, but just how it relates to the biological Golgi functions remains unclear. Are all the connections between mini-stacks functionally equal? Is the local structure of the ribbon of functional importance? These are difficult questions to address, due to the lack of a secretory cargo providing a quantifiable readout of the functional output of ribbon-embedded mini-stacks. Endothelial cells produce rod-shaped secretory granules, the Weibel-Palade bodies (WPB), whose von Willebrand Factor (VWF) cargo is central to hemostasis. In these cells, the Golgi apparatus exerts a dual control on WPB size at both mini-stack and ribbon levels. Mini-stack dimensions delimit the size of VWF boluses while the ribbon architecture allows their linear co-packaging at the trans-Golgi network generating WPBs of different lengths. This Golgi/WPB size relationship lends itself to mathematical analysis. Here, different ribbon structures were modeled and their predicted effects on WPB size distribution compared to the ground truth of experimental data. Strikingly, the best-fitting model describes a Golgi ribbon made by linked subunits corresponding to differentially functioning monomer and dimer mini-stacks. These results raise the intriguing possibility that the fine-grained structure of the Golgi ribbon is more complex than previously thought.

Additive Manufacturing of Bulk Nanocrystalline FeNdB Based Permanent Magnets

Lab scale additive manufacturing of Fe-Nd-B based powders was performed to realize bulk nanocrystalline Fe-Nd-B based permanent magnets. For fabrication a special inert gas process chamber for laser powder bed fusion was used. Inspired by the nanocrystalline ribbon structures, well-known from melt-spinning, the concept was successfully transferred to the additive manufactured parts. For example, for Nd16.5-Pr1.5-Zr2.6-Ti2.5-Co2.2-Fe65.9-B8.8 (excess rare earth (RE) = Nd, Pr; the amount of additives was chosen following Magnequench (MQ) powder composition) a maximum coercivity of µ0Hc = 1.16 T, remanence Jr = 0.58 T and maximum energy density of (BH)max = 62.3 kJ/m3 have been achieved. The most important prerequisite to develop nanocrystalline printed parts with good magnetic properties is to enable rapid solidification during selective laser melting. This is made possible by a shallow melt pool during laser melting. Melt pool depths as low as 20 to 40 µm have been achieved. The printed bulk nanocrystalline Fe-Nd-B based permanent magnets have the potential to realize magnets known so far as polymer bonded magnets without polymer.

WASP: a software package for correctly characterizing the topological development of ribbon structures

We introduce the Writhe Application Software Package (WASP) which can be used to characterisze the topology of ribbon structures, the underlying mathematical model of DNA, Biopolymers, superfluid vorticies, elastic ropes and magnetic flux ropes. This characterization is achieved by the general twist–writhe decomposition of both open and closed ribbons, in particular through a quantity termed the polar writhe. We demonstrate how this decomposition is far more natural and straightforward than artificial closure methods commonly utilized in DNA modelling. In particular, we demonstrate how the decomposition of the polar writhe into local and non-local components distinctly characterizes the local helical structure and knotting/linking of the ribbon. This decomposition provides additional information not given by alternative approaches. As example applications, the WASP routines are used to characterise the evolving topology (writhe) of DNA minicircle and open ended plectoneme formation magnetic/optical tweezer simulations, and it is shown that the decomponsition into local and non-local components is particularly important for the detection of plectonemes. Finally it is demonstrated that a number of well known alternative writhe expressions are actually simplifications of the polar writhe measure.

WASP: A software package for correctly characterizing the topological development of ribbon structures

ABSTRACTWe introduce the Writhe Application Software Package (WASP) which can be used to characterise the topology of ribbon structures, the underlying mathematical model of DNA, Biopolymers, superfluid vorticies, elastic ropes and magnetic flux ropes. This characterisation is achieved by the general twist-writhe decomposition of both open and closed ribbons, in particular through a quantity termed the polar writhe. We demonstrate how this decomposition is far more natural and straightforward than artificial closure methods commonly utilized in DNA modelling. In particular, we demonstrate how the decomposition of the polar writhe in local and non-local components distinctly characterizes local helical structure and knotting/linking of the ribbon. This decomposition provides additional information not given by alternative approaches. As an example application, the WASP routines are used to characterise the evolving topology (writhe) of DNA minicircle and open ended plectoneme formation magnetic/optical tweezer simulations. Finally it is demonstrated that a number of well known alternative writhe expressions are actually simplifications of the polar writhe measure.

Approaches to taking into account horizontal movements of foundations in the work of wooden reinforced cables

The behavior of a wooden stress ribbon structures reinforced with steel rope under the action of a load evenly distributed along the entire length of the cable was investigated. The analysis of the results of static tests of the wooden reinforced cable of the VD-3.1 series is given. A criterion is proposed according to which a wooden stress ribbon structures reinforced with steel rope can be considered according to the theory of rigid threads. To ensure the stability and geometric invariance of the structures formed by rigid threads, an important role is played by taking into account the pliability of the supports that perceive the horizontal support reactions (spacing of the cable). Deformation of the supports of rigid cables causes the appearance of significant bending moments in the body of the cable, and also leads to an increase in the deflection of the structure. Therefore, special attention was paid to the study of the pliability of supports during the tests of wooden stress ribbon structures reinforced with steel rope to the action of a load evenly distributed along the length of the cable. The pliability of supports during experimental tests of wooden stress ribbon structures reinforced with steel rope was investigated. The obtained results are compared with the calculated value of the pliability of the supports, calculated based on the deformability of the installation for testing cable structures. The methods of calculating the deflections of the cables, which take into account the pliability of the supports, were tested. The influence of the pliability of the supports on the deflection of the cable is determined. At the level of the pliability of the supports, the deformability of the cable was influenced by the pliability of the nodal joints of the wooden elements of the cable. Based on this, the deformability of the joints of the wooden elements of the cable on the punched metal plate fasteners and its effect on the deflection of the cable were investigated. The coefficient of deformability of joints was suggested, which took into account the nonlinear dependence of the deformation of joints of wooden elements of the cable on the applied load. Due to the need to take into account the joint work of the wooden body of the cable and the steel rope, the calculated characteristics of the reduced cross section of the wooden cable reinforced with steel rope were calculated. A static calculation of a wooden stress ribbon structures reinforced with steel rope according to the theory of rigid threads is performed and the results of calculations are compared with experimental data.

Ribbon entwining datum

Let (C,A,?) be an entwining structure over a field k. In this paper, we introduce the notion of the ribbon entwined datum to generalize the definition of (co)ribbon structures, and give several necessary and sufficient conditions for the category of entwined modules to be a ribbon category. We also discuss the ribbon structures in the Long dimodule category and Yetter-Drinfel?d category for applications.