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1.
The scanning electron microscope has been used to describe the morphology of the mature shell in a fresh-water bivalve. The structure of the organic and inorganic components within the nacre, the myostracum, and the prismatic layer is described. A transitional or intermediate zone, interposed between the prismatic layer and the nacre, was identified. In demineralized samples, the organic component of the nacre was found to consist of parallel matricial sheets interconnected by irregular transverse bridges. The structure of the mineral component of the nacre was found to vary with the method of specimen preparation. With polished-etched samples, brick-like units were seen. When shells were simply broken and fixed in osmium, the layers of nacreous material consisted of fusing rhomboidal crystals of aragonite which demonstrated subconchoidal fractures. On the inner surface of the shell, the rhomboidal crystals showed an apparent spiral growth pattern. The myostracum was characterized by regions of modified nacreous structure consisting of enlarged aragonite crystals with a pyramidal morphology. The peripheral aspect of the muscle scars was characterized by rhomboidal crystals, the latter fusing to form the typical nacreous laminae. The uniqueness of the anterior adductor scar is exemplified by the presence of pores, each pore walled by pyramidal units, for the insertion of adductor fibres. In most regions of the shell, the prismatic layer consisted of one prism unit thickness with a height of approximately 225–250 μm. However, in two specialized regions of the shell, this layer was seen to consist of multiple layers of stacked prisms. The organic matrices of the prismatic layer are arranged in a honeycomb-like arrangement and packed with mineralized spherical subunits. 相似文献
2.
2-amino-5-nitropyridinium dihydrogen monophosphate exemplifies a new crystal engineering strategy combining mineral and organic moieties towards enhanced quadratic nonlinear optical properties. This strategy is meant to combine the advantages of mineral ionic structures (cohesion, stability, optical and other damage resistance) with those of organic molecules (structural flexibility, high optical polarizability). This organic inorganic material is designed so as to favour mutual dipolar interactions between the 2-amino-5-nitropyridinium cations and the (H2PO
4
–
)
n
subnetwork interlocked by hydrogen bonding in the same crystalline lattice. This approach rests on the structural features and chemical properties of (H2PO
4
–
)
n
polyanion. The 2A5NPDP structure reveals a polar layered arrangement. The high powder SHG efficiency of 2A5NPDP, comparable to that of state-of-the-art purely organic 3-methyl-4-nitropyridine-1-oxide (POM) crystals, confirms the validity of this approach, currently generalized to a large variety of mixed organo-mineral crystals. 相似文献
3.
We have performed a macromolecular structural analysis of the interlamellar and intertabular parts of the organic framework of the nacreous part of the shell of Haliotis rufescens, including the identification of structural chitin. Using histochemical optical microscopy we have mapped the locations of carboxylates and sulfates of proteins and chitin on the surfaces and within the core of the interlamellar layers and the intertabular matrix that together form the external organic matrix of composite nacre. This extends the earlier work of Nudelmann et al. [Nudelman, F., Gotliv, B.A., Addadi, L. and Weiner, S. 2006. Mollusk shell formation: mapping the distribution of organic matrix components underlying a single aragonite tablet in nacre. J. Struct. Biol. 153, 176–187] and Crenshaw and Ristedt [Crenshaw, M.A., Ristedt, H. 1976. The histochemical localization of reactive groups in septal nacre from Nautilus pompilius. In: Omori, M., Watabe, N. (Eds.) The Mechanisms of Biomineralization in Animals and Plants. Tokai University Press, Toyko] on Nautilus pompilius. Our mapping identifies distinct regions, defined by the macromolecular groups, including what is proposed to be the sites of CaCO3 nucleation and that play a key role in nacre growth. Using AFM scanning probe microscopy we have identified a fibrous core within the framework that we associate with chitin. The structural picture that is evolved is then used to develop a simple structural model for the organic framework which is shown to be consistent with mechanical property measurements. The role of the intracrystalline matrix within the nacre tablets in mediating nacre’s mechanical response is noted within the framework of our model. 相似文献
4.
In the natural world, bottom-up hierarchical construction of complex structures results in materials with remarkable properties. A well known example is the nacre of mollusk shells, commonly called "mother of pearl", whose excellent strength and toughness has been the subject of research for many decades. A significant discovery has been the presence of periodic layers called "growth lines". These are thin distinct layers within the bulk of the shell which form periodically, with their structure affected by environmental changes. Studies of their formation and behavior offer valuable insight into the architecture of seashells. In this work, the structure and mechanical behavior of growth lines in shells of abalone Haliotis gigantea were investigated using electron microscopy and nanoindentation. Growth lines form directly out of nacre into layers of blocks and irregular particles. In comparison to nacre, they have basic structures, form rapidly, and are harder, which suggest that they serve a protective role during lifecycle transitions. This exemplifies how natural structures are able to closely control growth architecture in order to form different structures for different functions, all from the same base materials. 相似文献
5.
Mechanical properties of nacre and highly mineralized bone 总被引:2,自引:0,他引:2
Currey JD Zioupos P Davies P Casino A 《Proceedings. Biological sciences / The Royal Society》2001,268(1462):107-111
We compared the mechanical properties of 'ordinary' bovine bone, the highly mineralized bone of the rostrum of the whale Mesoplodon densirostris, and mother of pearl (nacre) of the pearl oyster Pinctada margaritifera. The rostrum and the nacre are similar in having very little organic material. However, the rostral bone is much weaker and more brittle than nacre, which in these properties is close to ordinary bone. The ability of nacre to outperform rostral bone is the result of its extremely well-ordered microstructure, with organic material forming a nearly continuous jacket round all the tiny aragonite plates, a design well adapted to produce toughness. In contrast, in the rostrum the organic material, mainly collagen, is poorly organized and discontinuous, allowing the mineral to join up to form, in effect, a brittle stony material. 相似文献
6.
Bédouet L Marie A Dubost L Péduzzi J Duplat D Berland S Puisségur M Boulzaguet H Rousseau M Milet C Lopez E 《Marine biotechnology (New York, N.Y.)》2007,9(5):638-649
Shell nacre is laid upon an organic cell-free matrix, part of which, paradoxically, is water soluble and displays biological
activities. Proteins in the native shell also constitute an insoluble network and offer a model for studying supramolecular
organization as a means of self-ordering. Consequently, difficulties are encountered in extraction and purification strategies
for protein characterization. In this work, water-soluble proteins and the insoluble conhiolin residue of the nacre of Pinctada margaritifera matrix were analyzed via a proteomics approach. Two sequences homologous to nacre matrix proteins of other Pinctada species were identified in the water-soluble extract. One of them is known as a fundamental component of the insoluble organic
matrix of nacre. In the conchiolin, the insoluble residue, four homologs of Pinctada nacre matrix proteins were found. Two of them were the same as the molecules characterized in the water-soluble extract.
Results established that soluble and insoluble proteins of the nacre organic matrix share constitutive material. Surprisingly,
a peptide in the conchiolin residue was found homologous to a prismatic matrix protein of Pinctada fucata, suggesting that prismatic and nacre matrices may share common proteins. The insoluble properties of shell matrix proteins
appear to arise from structural organization via multimerization. The oxidative activity, found in the water-soluble fraction
of the nacre matrix, is proposed as a leading process in the transformation of transient soluble proteins into the insoluble
network of conchiolin during nacre growth. 相似文献
7.
Chinese hickory (Carya cathayensis Sarg.) is a popular nut tree in China, but there is little information about the
influences of fertilization on soil CO2 efflux and soil microbial biomass. This study evaluated the short-term
effects of different fertilizer applications on soil CO2 efflux and soil microbial biomass in Chinese hickory stands.
Four fertilizer treatments were established: control (CK, no fertilizer), inorganic fertilizer (IF), organic fertilizer
(OF), and equal parts organic and inorganic N fertilizers (OIF). A field experiment was conducted to measure
soil CO2 effluxes using closed chamber and gas chromatography techniques. Regardless of the fertilization practices, soil CO2 effluxes of all the treatments showed a similar temporal pattern, with the highest value in summer
and the lowest in winter. The mean annual soil CO2 efflux in the IF treatment was significantly higher than that in
the CK, OIF, and OF treatments. There was no significant difference in soil CO2 efflux between the OIF, OF, and
CK treatments. Soil CO2 effluxes were significantly affected by soil temperature. Soil dissolved organic carbon
(DOC) was positively correlated with soil CO2 efflux only in the CK treatment. Regression analysis, including soil
temperature, moisture, and DOC, showed that soil temperature was the primary factor influencing soil CO2
effluxes. Both OF and OIF treatments increased concentrations of soil microbial biomass carbon (MBC) and
microbial biomass nitrogen (MBN), but decreased the ratio of MBC:MBN. These results reveal that applying
organic fertilizer, either alone or combined with inorganic fertilizer, may be the optimal strategy for mitigating
soil CO2 emission and improving soil quality in Chinese hickory stands. 相似文献
8.
The nacre of mollusk shells is distinguished by an exceptional mechanical efficiency which is derived essentially from its lamellar structure and frequently acts as a source of inspiration for the development of biomimetic materials. The structure and mechanical properties of nacre have been intensively investigated with a special focus on its toughening strategies; nevertheless, the fracture mechanisms, more specifically the critical stress/strain conditions for the failure of nacre, and the effects of structural orientation and hydration state remain largely unexplored. Here uniaxial compression tests were performed on nacre of both dry and hydrated states with different off-axis angles, i.e., the inclination of loading axis with respect to the lamellar structure, ranging from 0° to 90°. The mechanical properties and fracture characteristics of nacre and their dependences on the structural orientation and hydration state were elucidated in terms of mechanics behind failure. Quantitative relationships were established between the mechanical properties and off-axis angle based on different failure criteria. The competition between the fracture modes of fragmentation and shearing was quantified by comparing their respective driving force and resistance on the interfacial plane. This study may aid the understanding on the mechanical behavior of nacre and nacre-inspired synthetic materials and promote a better replication of the underlying design principles of nacre in man-made systems. 相似文献
9.
Shuai Liu Zepeng Liu Xi Shen Xuelong Wang Sheng‐Chieh Liao Richeng Yu Zhaoxiang Wang Zhiwei Hu Chien‐Te Chen Xiqian Yu Xiaoqing Yang Liquan Chen 《Liver Transplantation》2019,9(32)
Li‐rich layered metal oxides are one type of the most promising cathode materials in lithium‐ion batteries but suffer from severe voltage decay during cycling because of the continuous transition metal (TM) migration into the Li layers. A Li‐rich layered metal oxide Li1.2Ti0.26Ni0.18Co0.18Mn0.18O2 (LTR) is hereby designed, in which some of the Ti4+ cations are intrinsically present in the Li layers. The native Li–Ti cation mixing structure enhances the tolerance for structural distortion and inhibits the migration of the TM ions in the TMO2 slabs during (de)lithiation. Consequently, LTR exhibits a remarkable cycling stability of 97% capacity retention after 182 cycles, and the average discharge potential drops only 90 mV in 100 cycles. In‐depth studies by electron energy loss spectroscopy and aberration‐corrected scanning transmission electron microscopy demonstrate the Li–Ti mixing structure. The charge compensation mechanism is uncovered with X‐ray absorption spectroscopy and explained with the density function theory calculations. These results show the superiority of introducing transition metal ions into the Li layers in reinforcing the structural stability of the Li‐rich layered metal oxides. These findings shed light on a possible path to the development of Li‐rich materials with better potential retention and a longer lifespan. 相似文献
10.
11.
Mohamed H. El-Newehy Ali Aldalbahi Badr M. Thamer Meera Moydeen Abdulhameed 《Luminescence》2024,39(3):e4688
Nano-biocomposites of inorganic and organic components wereprepared to produce long-persistent phosphorescent artificial nacre-like materials. Biodegradable polylactic acid (PLA), graphene oxide (GO), and nanoparticles (13–20 nm) of lanthanide-doped aluminate pigment (NLAP) were used in a simple production procedure of an organic/inorganic hybrid nano-biocomposite. Both polylactic acid and GO nanosheets were chemically modified to form covalent and hydrogen bonding. The high toughness, good tensile strength, and great endurance of those bonds were achieved by their interactions at the interfaces. Long-persistent and reversible photoluminescence was shown by the prepared nacre substrates. Upon excitation at 365 nm, the nacre substrates generated an emission peak at 517 nm. When ultraviolet light was shone on luminescent nacres, they displayed a bright green colour. The high superhydrophobicity of the generated nacres was obtained without altering their mechanical characteristics. 相似文献
12.
13.
Andreas Bubel 《Tissue & cell》1983,15(3):457-476
The structure of the organic material and inorganic elements of the opercular plate and associated cells in the serpulid annelid, Pomatoceros lamarckii Quatrefages, have been described by transmission and scanning electron microscopy. After decalcification the organic material of the opercular plate was found to consist of three major structurally different components, an outer, thin, electron-dense layer, parallel rows of rectangular profiles partitioned into large units by cross-walls, and layers of orthogonally arranged fibres. The inorganic aragonite components were found, in contrast, to consist of two structurally different elements namely, highly ordered crystals with a prismatic-like morphology and smaller needle-like crystallites. Two morphologically distinct cell types, columnar opercular rim and cuboidal opercular plate cells, are responsible for the formation of the opercular plate. Both possess membrane-bound bodies containing filamentous material. However, in addition, membrane-bound bodies, containing calcium carbonate crystals, are found in some cells. Such bodies are seen to be closely related to the Golgi system. Based on the cytoarchitecture of the cells, the mechanisms involved in the formation and calcification of the opercular plate are discussed. 相似文献
14.
Cheng Liu Yi Yang Xin Xia Yong Ding Zulqarnain Arain Shijie An Xuepeng Liu Roldn Carmona Cristina Songyuan Dai Mohammad Khaja Nazeeruddin 《Liver Transplantation》2020,10(9)
The unfavorable morphology and inefficient utilization of phase transition reversibility have limited the high‐temperature‐processed inorganic perovskite films in both efficiency and stability. Here, a simple soft template‐controlled growth (STCG) method is reported by introducing (adamantan‐1‐yl)methanammonium to control the nucleation and growth rate of CsPbI3 crystals, which gives rise to pinhole‐free CsPbI3 film with a grain size on a micrometer scale. The STCG‐based CsPbI3 perovskite solar cell exhibits a power conversion efficiency of 16.04% with significantly reduced defect densities and charge recombination. More importantly, an all‐inorganic solar cell with the architecture fluorine‐doped tin oxide (FTO)/NiOx/STCG‐CsPbI3/ZnO/indium‐doped tin oxide (ITO) is successfully fabricated to demonstrate its real advantage in thermal stability. By suppressing the inductive effect of defects during the phase transition and utilizing the unique reversibility of the phase transition for the high‐temperature‐processed CsPbI3 film, the all‐inorganic solar cell retains 90% of its initial efficiency after 3000 h of continuous light soaking and heating. 相似文献
15.
Djordje Stojakovic Nevenka Rajic Natasa Zabukovec Logar 《Inorganica chimica acta》2009,362(6):1991-404
A zinc phosphate with the composition [NH3-CH2-CH(NH3)-CH3](ZnPO4)2, containing the doubly protonated 1,2-diaminopropane (abbr. HDAP), was synthesized by hydrothermal crystallization of zinc nitrate, phosphoric acid, 1,2-diaminopropane and trimethylenedipiperidine. The single crystal analysis shows a layered inorganic-organic structure built up of a sandwich-like motif of alternating inorganic layers and HDAP cations (trimethylenedipiperidine not being a constituent of the structure). The HDAP species are found to be disordered and serve as bridges between two adjacent inorganic layers which are separated by 3.95 Å. The bridging interaction occurs via a hydrogen-bonding network. The inorganic layer features a pattern of four-membered rings involving two ZnO4 and two PO4 tetrahedra connected by sharing O atoms. Thermal analysis shows that the compound is stable up to 370 °C and that the thermal decomposition of HDAP occurs in two steps between 370 and 460 °C, causing the collapse of the structure. The first decomposition step corresponds to ammonia removal which proceeds with a high activation energy (Ea = 282 kJ mol−1). The high Ea value is mainly attributed to strong electrostatic interactions between organic cations and anionic inorganic layers, the disruption of the interactions being the main reason for structural collapse after the HDAP removal. 相似文献
16.
Gastropod nacre: structure, properties and growth--biological, chemical and physical basics 总被引:1,自引:0,他引:1
The biogenic polymer/mineral composite nacre is a non-brittle biological ceramic, which self-organizes in aqueous environment and under ambient conditions. It is therefore an important model for new sustainable materials. Its highly controlled structural organization of mineral and organic components at all scales down to the nano- and molecular scales is guided by organic molecules. These molecules then get incorporated into the material to be responsible for properties like fracture mechanics, beauty and corrosion resistance. We report here on structure, properties and growth of columnar (gastropod) nacre with emphasis on the genus Haliotis in contrast to sheet nacre of many bivalves. 相似文献
17.
Interfacial Effects of Tin Oxide Atomic Layer Deposition in Metal Halide Perovskite Photovoltaics
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Axel F. Palmstrom James A. Raiford Rohit Prasanna Kevin A. Bush Melany Sponseller Rongrong Cheacharoen Maxmillian C. Minichetti David S. Bergsman Tomas Leijtens Hsin‐Ping Wang Vladimir Bulović Michael D. McGehee Stacey F. Bent 《Liver Transplantation》2018,8(23)
Metal halide perovskites offer a wide and tunable bandgap, making them promising candidates for top‐cell absorbers in tandem photovoltaics. In this work, the authors aim to understand the atomic layer deposition (ALD) precursor–perovskite interactions of the tin oxide ALD system and the role of organic fullerenes at the perovskite–tin oxide interface while establishing a framework for developing alternative perovskite‐compatible ALD processes in the future. It is shown, in the case of tin oxide ALD growth with tetrakis(dimethylamino)tin(IV) and water on FA0.83Cs0.17Pb(I0.83Br0.17)3 perovskite, that perovskite stability is most sensitive to metal–organic exposure at elevated temperatures with an onset near 110 °C, resulting in removal of the formamidinium cation. Transitioning from ALD to pulsed‐chemical vapor deposition tin oxide growth can minimize the degradation effects. Investigation of fullerenes at the perovskite interface shows that thin fullerene layers offer minor improvements to perovskite stability under ALD conditions, but significant enhancement in carrier extraction. Fullerene materials are undesirable due to fabrication cost and poor mechanical stability. Compositional tuning of the perovskite material can improve the fullerene‐free device performance. This method is demonstrated with a bromine‐rich perovskite phase to enable an 8.2% efficient perovskite device with all‐inorganic extraction layers. 相似文献
18.
Perlucin is one of the proteins of the organic matrix of nacre (mother of pearl) playing an important role in biomineralisation. This nacreous layer can be predominately found in the mollusc lineages and is most intensively studied as a compound of the shell of the marine Australian abalone Haliotis laevigata. A more detailed analysis of Perlucin will elucidate some of the still unknown processes in the complex interplay of the organic/inorganic compounds involved in the formation of nacre as a very interesting composite material not only from a life science-based point of view. Within this study we discovered three unknown Perlucin splice variants of the Australian abalone H. laevigata. The amplified cDNAs vary from 562 to 815 base pairs and the resulting translation products differ predominantly in the absence or presence of a varying number of a 10 mer peptide C-terminal repeat. The splice variants could further be confirmed by matrix-assisted laser desorption ionisation time of flight mass spectrometry (MALDI-ToF MS) analysis as endogenous Perlucin, purified from decalcified abalone shell. Interestingly, we observed that the different variants expressed as maltose-binding protein (MBP) fusion proteins in E. coli showed strong differences in their influence on precipitating CaCO3 and that these differences might be due to a splice variant-specific formation of large protein aggregates influenced by the number of the 10 mer peptide repeats. Our results are evidence for a more complex situation with respect to Perlucin functional regulation by demonstrating that Perlucin splice variants modulate the crystallisation of calcium carbonate. The identification of differentially behaving Perlucin variants may open a completely new perspective for the field of nacre biomineralisation. 相似文献
19.
Summary A study has been made of the influence of waterlogging on the distribution of trace metals between the various reservoirs in which they are held in a soil. Selective extractants have been used to remove metals held in 4 ways: soil solution and exchangeable; specifically adsorbed by inorganic sites; adsorbed or chelated by organic sites; adsorbed onto oxide surfaces.Waterlogging over a period of 16 weeks resulted in the release of both manganese and iron from the organic — and oxide — bound reservoirs to the soluble, exchangeable and inorganic reservoirs. Addition of both 1% dried grass (as an actively decomposing organic material) and 1% CaCO3 to the soil resulted in an acceleration of the metal redistribution.For manganese, selective extraction methods accounted for the distribution of all the metal in the reservoirs studied. In the case of iron however, there appeared to be some release from a reservoir not being extracted. 相似文献
20.
A Hierarchically Organized Photoelectrode Architecture for Highly Efficient CdS/CdSe‐Sensitized Solar Cells
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Jong Hoon Park Dong Hoe Kim Seong Sik Shin Hyun Soo Han Myeong Hwan Lee Hyun Suk Jung Jun Hong Noh Kug Sun Hong 《Liver Transplantation》2014,4(3)
A form of photoelectrode architecture suitable for inorganic semiconductor solar cells is reported. The developed architecture consists of hierarchically organized TiO2 nanostructures with several tens of nanometer‐sized particles that have a large surface area and open channels with several hundred‐nanometer‐gaps perpendicular to the substrate. These are tailored by controlling the kinetic energy of the ablated species during pulsed laser deposition (PLD). To fabricate the solar cells, CdS and CdSe inorganic sensitizers are assembled onto the architecture by successive ionic layer adsorption and reaction and polysulfide solution is used as an electrolyte with lead sulfide counter‐electrodes. The inorganic semiconductor solar cells using the developed architecture (PLD‐TiO2) show high energy conversion efficiencies of 5.57% compared to a conventional mesoporous TiO2 film(NP‐TiO2) (3.84%) with an optical mask at 1 sun of illumination. The improved cell performance of PLD‐TiO2 is attributed to greater light‐harvesting ability, which results in the enhancement of the Jsc value. PLD‐TiO2 absorbs more CdS/CdSe because of its larger surface area and excellent adhesion properties with fluorine‐doped tin oxide (FTO) substrates. Additionally, due to its unique channel‐shaped architecture, PLD‐TiO2 has a longer electron lifetime compared to NP‐TiO2. 相似文献