Biological control of crystallographic architecture: hierarchy and co-alignment parameters

An architecture-oriented kansei engineering system for innovative long chi inkstone design

With more and more attention to people's psychological cognition and emotion in design, the concept of kansei engineering has been widely used in all kinds of product design. Based on the concepts and methods of kansei engineering, the research chooses the long chi inkstone as an example to seek a holistic explanation for the proposed architecture-oriented innovative system in obtaining a series of new design schemes. The system architecture integrates the design method of kansei engineering system into the structure-behavior coalescence (SBC) system architecture description language to show the behavior and components of product characteristics. A model of architecture-oriented kansei engineering long chi inkstone system specification was established. The model will clearly explain how the qualitative and quantitative methods are applied to determine the characteristics, process and kansei information of long chi inkstone design. The design specifications of long chi inkstone is described by the architecture-oriented kansei engineering system. The psychological kansei imagery of consumer groups are explored under the mode of qualitative analysis and quantitative research, and the design elements and details of physical properties of products are obtained. The aesthetic attributes of products are raised to a high level of respect for human nature and reflect its new value. The results indicate that the proposed architecture-oriented kansei engineering system in conjunction with a long chi inkstone design can help designers make the design more effectively than traditional design methods.

Calcite crystal orientation patterns in the bilayers of laminated shells of benthic rotaliid foraminifera

Shells of calcifying foraminifera play a major role in marine biogeochemical cycles; fossil shells form important archives for paleoenvironment reconstruction. Despite their importance in many Earth science disciplines, there is still little consensus on foraminiferal shell mineralization. Geochemical, biochemical, and physiological studies showed that foraminiferal shell formation might take place through various and diverse mineralization mechanisms. In this study, we contribute to benthic foraminiferal shell calcification through deciphering crystallite organization within the shells. We base our conclusions on results gained from electron backscattered diffraction (EBSD) measurements and describe microstructure/texture characteristics within the laminated shell walls of the benthic, symbiontic foraminifera: Ammonia tepida, Amphistegina lobifera, Amphistegina lessonii. We highlight crystallite assembly patterns obtained on differently oriented cuts and discuss crystallite sizes, morphologies, interlinkages, orientations, and co-orientation strengths. We show that: (i) crystals within benthic foraminiferal shells are mesocrystals, (ii) have dendritic-fractal morphologies and (iii) interdigitate strongly. Based on crystal size, we (iv) differentiate between the two layers that comprise the shells and demonstrate that (v) crystals in the septa have different assemblies relative to those in the shell walls. We highlight that (vi) at junctions of different shell elements the axis of crystal orientation jumps abruptly such that their assembly in EBSD maps has a bimodal distribution. We prove (vii) extensive twin-formation within foraminiferal calcite; we demonstrate (viii) the presence of two twin modes: 60°/[001] and 77°/~[6 -6 1] and visualize their distributions within the shells. In a broader perspective, we draw conclusions on processes that lead to the observed microstructure/texture patterns.

Calcite fibre formation in modern brachiopod shells

The fibrous calcite layer of modern brachiopod shells is a hybrid composite material and forms a substantial part of the hard tissue. We investigated how cells of the outer mantle epithelium (OME) secrete calcite material and generate the characteristic fibre morphology and composite microstructure of the shell. We employed AFM, FE-SEM, and TEM imaging of embedded/etched, chemically fixed/decalcified and high-pressure frozen/freeze substituted samples. Calcite fibres are secreted by outer mantle epithelium (OME) cells. Biometric analysis of TEM micrographs indicates that about 50% of these cells are attached via hemidesmosomes to an extracellular organic membrane present at the proximal, convex surface of the fibres. At these sites, mineral secretion is not active. Instead, ion transport from OME cells to developing fibres occurs at regions of closest contact between cells and fibres, however only at sites where the extracellular membrane at the proximal fibre surface is not developed yet. Fibre formation requires the cooperation of several adjacent OME cells. It is a spatially and temporally changing process comprising of detachment of OME cells from the extracellular organic membrane, mineral secretion at detachment sites, termination of secretion with formation of the extracellular organic membrane, and attachment of cells via hemidesmosomes to this membrane.

Controlled crystallization of twinned crystalline guanine microplatelets

In this work, twinned anhydrous guanine β microplatelets were synthesized for the first time in the presence of a polyvinylpyrrolidone. The twinning angle of the two c axes for the synthetic and biogenic twinned guanine crystals is 84°, very similar to each other.

Biomineralization as a Paradigm of Directional Solidification: A Physical Model for Molluscan Shell Ultrastructural Morphogenesis

Molluscan shells are a model system to understand the fundamental principles of mineral formation by living organisms. The diversity of unconventional mineral morphologies and 3D mineral-organic architectures that comprise these tissues, in combination with their exceptional mechanical efficiency, offers a unique platform to study the formation-structure-function relationship in a biomineralized system. However, so far, morphogenesis of these ultrastructures is poorly understood. Here, a comprehensive physical model, based on the concept of directional solidification, is developed to describe molluscan shell biomineralization. The capacity of the model to define the forces and thermodynamic constraints that guide the morphogenesis of the entire shell construct-the prismatic and nacreous ultrastructures and their transitions-and govern the evolution of the constituent mineralized assemblies on the ultrastructural and nanostructural levels is demonstrated using the shell of the bivalve Unio pictorum. Thereby, explicit tools for novel bioinspired and biomimetic bottom-up materials design are provided.

Mesoscale twinning in shells of Pinctada martensii

Biominerals have attracted multidiscipline interest (e.g. in material, medical and bio-geosciences) due to their unique organic–inorganic microtexture. In this work, electron backscatter diffraction (EBSD) and topological analysis of pole figures show that aragonite nacreous layers of Pinctada martensii (marine bivalve) shells have a mesocrystalline organization, which consists of at least a two-level domain structure. Primary domains are related by twin laws. The twinning between the primary domains is described as “mesotwinning.” Each domain is twinned by (110) planes. Secondary domains inside the primary domains are submicrometre units, ranging from several to hundreds of microns in dimension. The secondary domains are separated by low-angle grain boundaries. Angles between primary domains are ca. 63.5° or 52.5°; angles between secondary domains range from 5° to 12°. The twin relationship is quantified and twin boundary patterns are discussed.