Amorphous Mineral Research Articles

Chemical and mineralogical characterization of portuguese ceramic tiles in the historic center of São Luís do Maranhão (Brazil): an approximation of the mineralogy and firing temperature of the raw materials

This work involved the first-ever characterization of antique Portuguese ceramic wall tiles in the Historic Center of São Luis do Maranhão, Brazil. The tiles were characterized by optical microscopy, X-ray diffraction (XRD) and chemical analysis to identify the possible raw materials used in the fabrication process, as well as the firing temperature of these materials. The results indicate that the microstructure of these materials consists of pores of varying sizes with calcite incrustations and quartz grain sizes smaller than 500 µm distributed in a pinkish yellow matrix, which were identified by XRD as calcite, gehlenite, wollastonite, quartz, and amorphous mineral phases. Based on this information, it can be inferred that the original raw materials probably consisted of a mixture of kaolinitic clays (Al2O3·2SiO2·2H2O) rich in calcium carbonates and quartz, or mixtures of kaolinitic clays, quartz and calcite, which did not reach the pre-firing temperature of 950ºC.

Study on the Property of Silica Minerals Supported NanoTiO<sub>2</sub>

In the study, porous amorphous silica minerals including Porous Silicon (PS), Diatomite Filter Aid (DFA) and Opal (Op) were chosen as carriers or supports to prepare TiO2/PS, TiO2/DFA and TiO2/Op composites by chemical co-precipitation method. The compound materials were characterized by SEM, TEM, and the photo-catalytic property of the prepared composites was investigated by degradation of Rhodamine B (RhB). Characterization showed that nanoTiO2 was coated on the surface of porous amorphous silica minerals. The crystal form of TiO2 was mainly anatase, and the size of which was nanoscale. Through comparative analysis, the photo-catalytic efficiency of TiO2/PS composite was the best, followed by TiO2/ DFA, and then TiO2/Op.

“Liquid-like” biomineralization protein assemblies: a key to the regulation of non-classical nucleation

Over the past several decades, numerous studies have attempted to define the general role that proteins play in the nucleation of biominerals in organisms. Recently, with the emergence of the non-classical nucleation scheme involving pre-nucleation cluster formation, amorphous mineral cluster assembly, and maturation/stabilization scenarios, there is a growing realization that proteins could efficiently regulate many steps in this process, resulting in precise control over the development of biogenic crystals or the indefinite stabilization of amorphous mineral phases in a wide variety of organisms. In this Highlight, we present a generic scheme where nucleation-specific biomineralization proteins containing intrinsically disordered and aggregation-prone sequences assemble to form a liquid- or fluid-like phase similar to that formed in the polymer-induced liquid phase (PILP) and in vitro liquid protein systems. This assembled protein phase is compatible with the physical-chemical properties of prenucleation clusters and amorphous mineral clusters, and can provide an environment for subsequent stabilization and/or transformation of the mineral phase under appropriate conditions and locations. We foresee some important applications arising from Nature's use of protein assemblies to create, stabilize, and transform amorphous mineral precursor phases.

Remineralization of dentin collagen by meta-stabilized amorphous calcium phosphate

Biomineralization of collagenous mineralized tissues (CMT), in vivo, stands as a precisely cell-controlled process. An organic insoluble collagenous matrix forms, then inorganic mineral is deposited on the matrix. The exact mechanism of action remains elusive and most researchers agree the amorphous mineral phase is crucial in CMT's development. Artificial demineralized dentin can be remineralized via amorphous calcium phosphate (ACP) precursor stage stabilized by 500 μg ml−1 polyacrylic acid (PAA). This remineralization is a step-by-step progression. ACP initially forms in the collagen matrix at its base, transforms into hydroxyapatite, and migrates towards the surface. The state of ACP, which is labile in liquid environments, can be controlled by PAA in a dose-dependent manner. Thus, the concentration of PAA is a key parameter influencing dentin remineralization. Low concentration of PAA (100 μg ml−1) fails to maintain liquidity of ACP, resulting in superficial remineralization. Conversely, high concentration of PAA (1000 μg ml−1) retards phase transformation of ACP and, thereby, inhibits remineralization. The purpose of this study is to demonstrate the balance between meta-stability and crystallization of ACP precursor phase. Our findings also provide evidence for the role of ACP during biomineralization and reveal a possible approach to repair CMT.

Combined effects of estrogen deficiency and cadmium exposure on calcified hard tissues: Animal model relating to itai-itai disease in postmenopausal women

Using ovariectomized rats as a model of postmenopausal women, we studied the effects of estrogen (Es) deficiency and in combination with cadmium (Cd) exposure on the calcified hard tissues related to the development of itai-itai disease. Es deficiency suppressed the synthesis of carbonic anhydrase required for the crystal nucleation process, causing the crystal structure defects in the tooth enamel. Regarding the combined effects of Es deficiency and Cd exposure on the bone, in which rats were given drinking water containing Cd ions, soft X-ray radiography revealed a development of labyrinthine pattern in the calvaria, and micro-computed tomography demonstrated the declining trabecular architecture of the tibia, suggesting Cd–induced osteoporotic change. Further, electron microscopy showed the increase of amorphous minerals in the calvaria. In conclusion, the combined effects of Es deficiency and Cd exposure can be responsible for accelerating the declining bone strength together with the crystal structure defects resulting in the preferential occurrence of itai-itai disease in postmenopausal women.

The Role of Fetuin-A in Physiological and Pathological Mineralization

Mineralization in higher vertebrates is restricted to bones and teeth. Pathological calcification is mostly known in vasculature but can basically affect all soft tissues. Simply put, tissue mineralization occurs through the interplay of three key determinants: extracellular matrix suitable for mineralization, extracellular levels of inorganic phosphate and calcium, and the levels of mineralization inhibitors that may be expressed systemically or locally. In this article we describe the role of a prototypic systemic inhibitor protein of mineralization, the hepatic plasma protein α2-Heremans-Schmid glycoprotein/fetuin-A. Fetuin-A mediates the formation of stable colloidal mineral-protein complexes called calciprotein particles (CPPs). Thus, fetuin-A is important in the stabilization and clearance of amorphous mineral precursor phases. Efficient clearance of CPPs and, thus, of excess mineral from circulation prevents local buildup of mineral and calcification of soft tissue. Besides calcium phosphate binding, fetuin-A also acts as a carrier for lipids, which may influence calcification, inflammation, and apoptosis. Fetuin-A-deficient (Ahsg(-/-)) mice show impaired growth of their long bones and premature growth plate closure. We posit that the absence of fetuin-A in the growth plate causes simultaneous lack of calcification inhibition and excess lipid hormone signaling, leading to premature growth plate mineralization and shortened long bones. This suggests that fetuin-A regulates endochondral ossification through mineralization inhibition and lipid (hormone) binding.

Lead adsorption in the clay fraction of two soil profiles from Fildes Peninsula, King George Island

AbstractAntarctica is considered the most isolated continent, but it is not free of pollution, which arrives at specific localities mainly as a result of tourism and research activities. Among environmentally harmful substances, heavy metals are especially important because of their high toxicity to organisms. The aim of this study was to estimate the maximum adsorption of lead (Pb) onto the clay fraction of samples from two soil profiles from the Fildes Peninsula, King George Island, South Shetland Islands. Experimental data were fitted to the Langmuir isotherm, and the adsorption parameters were correlated to mineralogical attributes of this soil fraction characterized by chemical extractions and X-ray diffraction. Values of maximum adsorption of Pb in the clay fraction were extremely high (maximum value: 322 581 mg kg-1) when compared to those of soil samples from other regions of the world. Adsorption occurred in two stages: first stage in which a high percentage of Pb was adsorbed, and second stage in which adsorption was lower. From an environmental point of view, soils with high contents of clay and amorphous minerals, ones usually associated with ornithogenic activity in Antarctica, should have greater efficiency in filtering Pb, thus reducing risks of leaching and groundwater contamination.

Influence of non‐crystalline minerals in the total amount, resilience and molecular composition of the organic matter in volcanic ash soils (Tenerife Island, Spain)

The influence of short‐range ordered minerals, especially allophane or ferrihydrite, in the total amount, resilience and molecular structure of the soil organic matter (SOM) was determined in a series of volcanic ash soils from Tenerife Island (Spain), with a range of amorphous minerals, organic carbon (C) and clay minerals. Up to 120 main analytical descriptors of the SOM were processed by uni‐ and multivariate statistical analyses. Short‐range ordered minerals were estimated from the (Alo + ½ Feo) index, organo‐metallic complexes were calculated from the Alp:Alo ratio and crystalline minerals were determined by X‐ray diffraction. The humic acids (HAs) were isolated, purified and analysed by visible, infrared and 13C nuclear magnetic resonance spectroscopy and analytical pyrolysis. In addition, CO2 release curves from whole soil samples were used to obtain indices of SOM resilience. The results revealed that the amount and resilience of the SOM depended on the presence of short‐range ordered minerals: the greater the content of non‐crystalline minerals, the greater the C stabilization. However, no significant relationships were found between these amorphous minerals and aromatic compounds, which are indicators of resilience in HAs. Conversely, certain molecular characteristics of the HAs, such as the optical density at 465 nm, the concentration of quinone‐type fungal pigments, the yields of carbohydrate‐derivatives and N‐compounds, highlighted the role of allophane‐sized nanoparticles in the protection of microbial metabolites produced during the decomposition, and are also likely to provide active sites for soil C stabilization at the colloidal scale.

Chemical Speciation of Heavy Metals in the Fractionated Rhizosphere Soils of Sunflower Cultivated in a Humic Andosol

Chemical speciation and bioaccumulation factor of iron (Fe), manganese (Mn), and zinc (Zn) were investigated in the fractionated rhizosphere soils and tissues of sunflower plants grown in a humic Andosol. The experiment was conducted for a period of 35 days in the greenhouse, and at harvest the soil system was differentiated into bulk, rhizosphere, and rhizoplane soils based on the collection of root-attaching soil aggregates. The chemical speciations of heavy metals in the soil samples were determined after extraction sequentially into fractions classified as exchangeable, carbonate bound, metal–organic complex bound, easily reducible metal oxide bound, hydrogen peroxide (H2O2)–extractable organically bound, amorphous mineral colloid bound, and crystalline Fe oxide bound. Iron and Zn were predominantly crystalline Fe oxide bound in the initial bulk soils whereas Mn was mainly organically bound. Heavy metals in the exchangeable form accumulated in the rhizosphere and rhizoplane soils, comprising <4% of the total content, suggesting their relatively low availability in humic Andosol. Concentrations of organically bound Fe and Mn in soils decreased with the proximity to roots, suggesting that organic fraction is the main source for plant uptake. Concentrations of Mn and Zn in the metal–organic complex also decreased, indicating a greater ability of sunflower to access Mn from more soil pools. Sunflower showed bioaccumulation factors for Zn, Fe, and Mn as large as 0.39, 0.05, and 0.04 respectively, defining the plant as a metal excluder species. This result suggests that access to multiple metal pools in soil is not necessarily a major factor that governs metal accumulation in the plant.

Elemental composition of biomineralized amorphous mineral granules isolated from ants: Correlation with ingested mineral particles from the soil

Amorphous mineral granules are formed by concentric mineral layers containing polyphosphate, pyrophosphate and/or orthophosphate and several metallic cations such as Mg2+, Ca2+, K+, Mn2+, Fe3+, Cu2+, and Zn2+. In this work, we analyzed amorphous mineral granules isolated from the ant species Camponotus abdominalis, Camponotus sp., Acromyrmex subterraneus and Pachycondyla marginata by energy-dispersive X-ray analysis. The elemental composition of the granules was compared to that of mineral particles, probably soil particles, to access the influence of the environment and of specific characteristics of each ant species in the elemental composition of the amorphous mineral granules. Both the granules and mineral particles presented Mg, Ca, Fe, and Zn in the four species. Additionally, Al tended to be present in both (or none) of the two types of material in a given ant species, suggesting that the aluminum found in the amorphous mineral granules could be derived from ingested soil particles. On the other hand, Sr was found in the amorphous mineral granules of some of the studied ant species, but not in the mineral particles. The fact that 3/4 of the elements found in the granules were found also in the mineral particles suggests that the mineral composition of the soil plays a fundamental role in the accumulation of some elements in the amorphous mineral granules of ants. These results suggest a major role of soil particles as a source of micronutrients for the four ant species.

Calcium bodies of Titanethes albus (Crustacea: Isopoda): Molt-related structural dynamics and calcified matrix-associated bacteria

Crustaceans form a variety of calcium deposits in which they store calcium necessary for the mineralization of their exoskeletons. Calcium bodies, organs containing large amounts of calcium, have been reported in some terrestrial isopod crustaceans, but have not yet been extensively studied. We analyzed the architecture of these organs during the molt cycle in the isopod Titanethes albus. Two pairs of calcium bodies are positioned ventrolaterally in posterior pereonites of T. albus. Individual organs are epithelial sacs that contain material arranged in concentric layers delimited by thin laminae. As demonstrated by electron microscopy and fluorescence in situ hybridization, abundant bacteria are present within the calcium bodies. Regardless of the molt cycle stage, crystalline concretions are present in the central areas of the calcium bodies. Energy dispersive X-ray spectrometry of the concretions demonstrated that they are composed predominantly of calcium and phosphorus and selected area electron diffraction indicated the presence of hydroxyapatite. In molting animals, a glassy layer of mineralized matrix is formed between the envelope and the outermost lamina of the calcium body. This layer consists of an amorphous calcium mineral which contains less phosphorus than the central concretions and is resorbed after molt. Since changes in the mineralized matrix are synchronized with the molt cycle, the calcium bodies likely function as a storage compartment that complements sternal deposits as a source of calcium for the mineralization of the exoskeleton. Bacteria associated with the mineralized matrix of calcium bodies are evidently involved in calcium dynamics.

Characterization of melamine-associated urinary stones in children with consumption of melamine-contaminated infant formula

BackgroundCrystalline morphology and compositions of melamine-associated urinary stones caused by consumption of melamine-contaminated infant formula are reported. MethodsTwelve melamine-associated urinary stone samples were obtained from 12 children aged from 3 to 36months who were treated in Lanzhou University Second Hospital. The crystalline morphology and compositions of these stone samples were analyzed using a combination of infrared spectrum, SEM and XRD. The presence of melamine in 12 stones was determined by HPLC. ResultsDiversity of crystalline morphology in 10 stone samples was revealed by SEM observation. Infrared spectral data revealed that 8 of the 10 stone samples predominantly consisted of the crystal forms of urate: 1 of sodium urate monohydrate, 2 of uricite and 5 of uric acid dihydrate and ammonium urate. However, ammonium magnesium phosphate hexahydrate, ammonium urate and carbonate apatite were also identified in 1 stone sample. The content of melamine in all of the 12 stone samples was determined by HPLC and found to range from 200 to 339,000μg/g. XRD analysis in 6 stone samples showed that amorphous mineral phase was involved in the calculogenesis. ConclusionsMelamine and uric acid are the main possible etiologic factors closely related to melamine-associated urinary stone formation in humans.

Effects of vegetation on chemical and mineralogical characteristics of soils developed on a decantation bank from a copper mine

Open cast mining has a strong impact on the environment, the intensity depending on the morphology of the deposit and on the nature of the minerals. At Touro mine (NW Spain) there is a large area covered by tailings, one of which, called the “sedimentation bank”, was used to deposit sludge resulting from the extraction of copper in the flotation plant. Three zones were selected and the soils were sampled to analyse the changes brought about by vegetation on the chemical and mineralogical properties of the soils developed over the sedimentation bank and its development over time. The vegetation increased the pH, contents of organic material, nitrogen, clay and free oxides of Fe and Al, and the cationic exchange capacity of the soils. The decrease in the sulphide content, benefited by the vegetation process, led to a reduction in the total content of Cr and Cu. The vegetation also contributed towards the alteration of the primary minerals. The transformation of jarosite, the formation of nanocrystals of hematite, goethite, hydroxypolymers, and amorphous minerals that contained Cu, Cr and Pb were observed. Nevertheless the high Cu and Cr contents indicate that it is advisable to change the restoration process.

Enamel-like apatite crown covering amorphous mineral in a crayfish mandible

Carbonated hydroxyapatite is the mineral found in vertebrate bones and teeth, whereas invertebrates utilize calcium carbonate in their mineralized organs. In particular, stable amorphous calcium carbonate is found in many crustaceans. Here we report on an unusual, crystalline enamel-like apatite layer found in the mandibles of the arthropod Cherax quadricarinatus (freshwater crayfish). Despite their very different thermodynamic stabilities, amorphous calcium carbonate, amorphous calcium phosphate, calcite and fluorapatite coexist in well-defined functional layers in close proximity within the mandible. The softer amorphous minerals are found primarily in the bulk of the mandible whereas apatite, the harder and less soluble mineral, forms a wear-resistant, enamel-like coating of the molar tooth. Our findings suggest a unique case of convergent evolution, where similar functional challenges of mastication led to independent developments of structurally and mechanically similar, apatite-based layers in the teeth of genetically remote phyla: vertebrates and crustaceans.

ANALYSIS OF C&lt;sub&gt;3&lt;/sub&gt;A HYDRATION IN CONSIDERATION OF FORMATION OF AMORPHOUS COMPOUNDS

System in C₃A-Gypsum, hydration analysis was carried out by ²⁷Al MAS-NMR (nuclear magnetic resonance) analysis and X-ray diffraction Rietveld analysis. As a result, in the presence of Gypsum, C₃A hydration divided into three stages. First stage, degree of C₃A hydration remains at constant value. Second stage, C₃A hydration rapidly proceeds. Third stage, C₃A hydration calms down. In first stage, amorphous phase remains at constant amount and AFt is formed until second stage. In second stage, amorphous phase rapidly increase at the same time of converting AFt into AFm. In third stage, AFt increase and amorphous phase slowly decrease. It has been shown that the amorphous phase which is generated in the early period of C₃A hydration should be a low crystallinity AFm, the amount of amorphous material remained at nearly constant amount until the disappearance of Ettringite, and rapidly increase at the same time as the disappearance of Ettringite. Composition of amorphous minerals is determined from the results which are obtained from X-ray diffraction Rietveld analysis. In addition, the amount of minerals in amorphous phase was calculated by measurements of ²⁷Al MAS-NMR and separation each materials of chemical shifts which are include Al. As a result, it was implied that there was the possibility of existence of aluminum hydroxide gel in the amorphous phase. At an early period, it was implied that the amorphous materials was C-A-H including sulfate ion. At a latter period, it was implied that crystal AFm is produced from AFt-like gel through AFm-like gel. C₃A-Gypsum系において、XRD・リートベルト解析および²⁷Al MAS-NMR測定により水和解析を行った。その結果、非晶質量はAFtが消失するまでほぼ一定量で推移し、AFtの消失と同時に急激に増加することが示された。XRDより得られた結果から非晶質物質の組成を決定した。また、NMRスペクトルをAlの化学シフト値で分離することで、非晶質物質中の鉱物量を算出した。その結果、非晶質物質中にアルミナゲルが存在する可能性が示唆された。材齢初期における非晶質物質は硫酸イオンを含むC-A-Hであることが示唆された。材齢後期では、AFt様のゲル状水和物からAFm様のゲル状水和物を経てAFmを生成する可能性が示唆された。

Structure-property-function relationships in triple-helical collagen hydrogels

ABSTRACTIn order to establish defined biomimetic systems, type I collagen was functionalised with 1,3-Phenylenediacetic acid (Ph) as aromatic, bifunctional segment. Following investigation on molecular organization and macroscopic properties, material functionalities, i.e. degradability and bioactivity, were addressed, aiming at elucidating the potential of this collagen system as mineralization template. Functionalised collagen hydrogels demonstrated a preserved triple helix conformation. Decreased swelling ratio and increased thermo-mechanical properties were observed in comparison to state-of-the-art carbodiimide (EDC)-crosslinked collagen controls. Ph-crosslinked samples displayed no optical damage and only a slight mass decrease (∼ 4 wt.-%) following 1-week incubation in simulated body fluid (SBF), while nearly 50 wt.-% degradation was observed in EDC-crosslinked collagen. SEM/EDS revealed amorphous mineral deposition, whereby increased calcium phosphate ratio was suggested in hydrogels with increased Ph content. This investigation provides valuable insights for the synthesis of triple helical collagen materials with enhanced macroscopic properties and controlled degradation. In light of these features, this system will be applied for the design of tissue-like scaffolds for mineralized tissue formation.

Madouzi-type (nodular) sedimentary copper deposit associated with the Emeishan basalt

Ore minerals in the sedimentary-type Cu deposits in the Xuanwei Formation overlying the Emeishan basalt are dominated by copper sulfides and native copper. As the ores mostly exhibit concretionary structure, previous researchers named them the “Madouzi-type Copper Deposit”. Here the authors carried out mineralogical and isotopic studies on copper nodules in this ore deposit. The mineralogical study shows that copper nodules are composed of copper sulfides that have been cemented by ferruginous amorphous minerals, clay, and carbonaceous fragments in the modes of metasomatism and sedimentation. The nodules are preliminarily present as aggregates of gelatinous material. The isotopic analysis shows that the δ13CPDB values of anthraxolite are within the range of −24.8‰–−23.9‰, indicating that the anthraxolite is the product of sedimentary metamorphism of in-situ plants. The δ34SV-CDT values of chalcocite are within the range of 7.6‰–13.1‰, close to those (about 11‰) of Permian seawater. The δ34SV-CDT values of bornite and chalcopyrite are 21.6‰–22.2‰, similar to the sulfur isotopic composition (20‰) of marine sulfate, indicative of different sources of sulfur. The above characteristics indicate that the copper nodules were formed in such a process that Cu-bearing basalt underwent weathering-leaching and copper-bearing material was transported into waters (e.g., rivers, lakes, and swamps) and then adsorbed on clay and ferruginous amorphous mineral fragments. Then, the copper-bearing material was suspended and transported in the form of gelinite. In lake or swamp environment, it was co-deposited with sediments to form copper nodules. At later stages there occurred metasomatism and hydrothermal superimposition, followed by the replacement of chalcocite by bornite and the superimposition of chalcopyrite over bornite, finally resulting in the formation of the “Madouzi-type” nodular copper deposit.

Biogeochemical factors related with organic matter degradation and C storage in agricultural volcanic ash soils

Laboratory incubation experiments in addition to physicochemical analyses of volcanic ash soils were carried out in order to identify biogeochemical factors related with soil organic C (SOC) stabilization in the long term and with the potential for C sequestration of agroecosystems. Up to 24 vineyard plots under similar subtropical conditions in Tenerife Island (Spain) were sampled. Soil samples were incubated for 30 days in laboratory conditions (27 °C and 66% water holding capacity) and the CO2 released was periodically measured to plot C mineralization curves. Soil organic matter (SOM) with special emphasis paid on the humic acid (HA) was characterized by elemental composition, spectroscopic techniques: visible, infrared (IR) and 13C nuclear magnetic resonance (13C NMR) and analytical pyrolysis–gas chromatography/mass spectrometry (GC/MS). The dependent variables examined were either the total mineralization coefficient (TMC, g C · kg C soil−1 day−1) in laboratory incubations, or the SOC. A very significant negative correlation was found between SOC and TMC, i.e., in our soils, the higher the biodegradation rates under laboratory conditions, the lower the soil C sequestered in the corresponding plots. In it was also observed that the concentration of amorphous minerals (Alo + ½ Feo index) and the water holding capacity at 0.033 MPa were associated with lower CO2 release; the latter could suggest microanaerobic conditions hampering biodegradation in these thixotropic soils. Conversely, no correlation was found between SOC or TMC and typical soil physical and chemical factors, such as granulometric fractions or exchangeable calcium. The molecular characteristics of the HAs showed also predictive potential as regards SOC resilience, reflecting the comparatively fast biodegradation of SOM composed mainly of biomass constituents (prominent lignin signature and O-alkyl 13C NMR region). The poor correlation between total aromaticity of the HAs and SOM resistance against biodegradation could be explained by a dual origin of aromatic structures in HAs, either consisting of methoxyl-containing non-decomposed lignin structures or condensed black carbon-like polyaromatic structures. The results suggested the possibility of predicting the vulnerability of SOC to biodegradation from laboratory incubation experiments, which results of interest for modeling global change scenarios.

Subtleties of biomineralisation revealed by manipulation of the eggshell membrane

Biocalcification of collagen matrices with calcium phosphate and biosilicification of diatom frustules with amorphous silica are two discrete processes that have intrigued biologists and materials scientists for decades. Recent advancements in the understanding of the mechanisms involved in these two biomineralisation processes have resulted in the use of biomimetic strategies to replicate these processes separately using polyanionic, polycationic or zwitterionic analogues of extracellular matrix proteins to stabilise amorphous mineral precursor phases. To date, there is a lack of a universal model that enables the subtleties of these two apparently dissimilar biomineralisation processes to be studied together. Here, we utilise the eggshell membrane as a universal model for differential biomimetic calcification and silicification. By manipulating the eggshell membrane to render it permeable to stabilised mineral precursors, it is possible to introduce nanostructured calcium phosphate or silica into eggshell membrane fibre cores or mantles. We provide a model for infiltrating the two compartmental niches of a biopolymer membrane with different intrafibre minerals to obtain materials with potentially improved structure-property relationships.

Orthopaedic Case of the Month: Painful Lower-leg Mass in a 76-year-old Man

Orthopaedic Case of the Month: Painful Lower-leg Mass in a 76-year-old Man