Biomimetic 3D printed lightweight constructions: a comparison of profiles with various geometries for efficient material usage inspired by square-shaped plant stems.

Within a bottom-up approach in biomimetics, this study was inspired by the plant motherwort (Leonurus cardiaca), which has stems divided longitudinally into hollow internodes and solid nodes, a lightweight concept well-known in biology. The square cross-sections show a specific geometric arrangement of various tissues, each with different mechanical properties. We have used CAD software and selective laser sintering technology to produce (1) extruded hollow profiles with various cross-sections analogous to internodes, and (2) integrated additional elements mimicking nodes. The design of the individual profiles with their different geometries is based on an increasing degree of abstraction, starting with profile A, which comes closest to the plant model, through profile B in the form of a greatly simplified material distribution, to profile C with the simplest geometry of a square hollow profile. In the context of resource-saving constructions, we have determined the flexural and torsional stiffness, the twist to bend ratio, and the lightweight efficiency of each individual profile. In general, profiles A, B, and C and all profiles from the A- and C-family show higher torsional stiffness than flexural stiffness. However, the profiles of the B-family exhibit no such uniform mechanical behavior. Interestingly, profile A has a higher lightweight efficiency than profile B but a lower efficiency than the most abstracted profile C. This indicates that a simple blueprint of nature is not useful, because, in plants, the geometric designs of various tissues and of globally and locally adaptable material properties are coupled to optimize performance based on multifunctionality. In contrast, 3D laser sintered profiles consist of a single isotropic and homogeneous material with defined material properties and therefore show different flexural and torsional efficiency because of their diverse geometries alone. These results reveal the influences of the geometric arrangement on the bending and torsional stiffness of the plant without interference from variations in material properties (reverse biomimetics).

Microscopic and Phytochemical Comparison of the Three Leonurus Species L. cardiaca, L. japonicus, and L. sibiricus.

At least three Leonurus species, Leonurus cardiaca, Leonurus japonicus, and Leonurus sibiricus, are used in various traditional medicinal systems for different therapeutic purposes. The plant names "L. sibiricus" and "L. japonicus" are often used as synonyms, which causes confusion in literature and implies that several studies may be based on improperly identified plant material. To avoid further confusion, the current status of the identification of these three species is illustrated. Characteristics for their unequivocal identification are presented using stereo and light microscopy as well as HPTLC.The establishment of the species-specific anatomical, morphological, and phytochemical characters was based on reference specimens in comparison with wild collected or commercially obtained material. Morphologically, the species differed in shape and length ratio of the upper and lower lip of the corolla. Differentiating anatomical characters involve the presence, density, and dimension of trichomes on different organs. Detailed anatomical descriptions of the leaves and corollae of L. japonicus and L. sibiricus are given and compared to L. cardiaca. These three sets of characters facilitate fast and reliable identification. Complementary HPTLC fingerprints show type-specific patterns that allow the differentiation of L. japonicus from the other two species. For the distinction of L. cardiaca and L. sibiricus, flower morphology has to be considered.The presented data contribute to the quality control of the three Leonurus species and additionally meet a definite and timely need regarding the introduction of L. japonicus to the European Pharmacopoeia in addition to the already existing monograph of L. cardiaca.

[The descriptions identification of "yimu cao"].

Remained but entire bracts beneath the inflorescence and the persistent calyxes were selected as primary characteristics to distinguish "Yimu Cao", which derived from 8 species and 1 variety in the same genus Leonurus. The results were reliable.

[Identification on crude drugs from genus Leonurus: II. Leaf and flower surface characters].

OBJECTIVE: To identify the crude drugs originated from 9 species and 1 variety of genus Leonurus (called Yimucao) through leaf and flower surface characters. METHOD: Routine slide processing and the characters under microscope were observed and compared. RESULTS: Obvious characteristics for identification were revealed. CONCLUSION: The shape and length of non-glandular hairs are useful in identifying this sort of crude drugs. Leaf constants and cluster crystals are also useful as reference. However, pollen grains and secretory tissues are worthless.

[Identification of crude drugs from genus Leonurus].

The structure in cross section of stem and lamina of 9 species and 1 variety from genus Leonurus, whose herb used as Yimu Cao, were reported. Diagnostic characteristics were listed out in a key for identification.