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transient ACC"), which later transforms into a more crystalline form (calcite or aragonite) or as a stabilized phase ("stable ACC") sometimes coexisting with crystalline polymorphs. [9, 10] Biogenic ACCs are known to be stabilized by organic, and inorganic additives and when confined in space. [9,      However, despite extensive research, it is still not fully understood how they are stabilized and what are the mechanisms that control their crystallization.  Thedoi:10.1002/advs.201701000 pmid:29876222 pmcid:PMC5980180 fatcat:3bahozt7cbgnrn2mrnloe26wkm
more »... " of ACC has been investigated as it is expected to affect its stabilization and exhibits short-and medium-range order (SRO and MRO) up to 10 Å.    Species-specific SRO (up to 4 Å) around the Ca 2+ -ion were identified using Ca K-edge X-ray absorption spectroscopy [11,     in different biogenic ACCs and a correlation was found between their SRO and their stability. Moreover, anhydrous transient ACCs showed similar shortrange structure to that of the final polymorph. [22, 23] Alternatively, it was also suggested that the phase identified as prestructured ACC is in fact poorly ordered calcite nanocrystals. [24, 25] In sea urchin larval spicules, [26, 27] as well as in gastropod shell nacre,  a transformation mechanism from hydrated ACC via a short-lived anhydrous ACC to the final polymorph was suggested where the crystalline phase propagates via secondary nucleation from one domain to its neighbor. The energetics of this process was later deduced as a favorable downhill sequence by calorimetric analysis of both biogenic and synthetic ACCs.  Secondary nucleation of ACC nanoparticles were also observed in vitro, [26, 30] where the ACC precursor was transiently stabilized by organic and inorganic additives. Gal et al.  suggested a crystallization mechanism by particle accretion involving partial dissolution-re-precipitation and solid-state rearrangement. This process is one case of crystallization by particle attachment mechanisms recently reviewed by De Yoreo et al.  The heterogeneity of biogenic minerals introduces difficulties in interpreting the mechanistic details of the stabilization and transformation of ACC, specifically when the precursor phases and the end products are intermixed at a nanometric scale. Therefore, synthetic ACC has been extensively studied as a model system. [18, 29,       As their biogenic counterparts, synthetic ACCs present S/MRO up to 10 Å that are different [17,    or similar [33, 37] to the one of the crystalline phases of CaCO 3 . In Many organisms use amorphous calcium carbonate (ACC) and control its stability by various additives and water; however, the underlying mechanisms are yet unclear. Here, the effect of water and inorganic additives commonly found in biology on the dynamics of the structure of ACC during crystallization and on the energetics of this process is studied. Total X-ray scattering and pair distribution function analysis show that the short-and mediumrange order of all studied ACC samples are similar; however, the use of in situ methodologies allow the observation of small structural modifications that are otherwise easily overlooked. Isothermal calorimetric coupled with microgravimetric measurements show that the presence of Mg 2+ and of PO 4 3− in ACC retards the crystallization whereas increased water content accelerates the transformation. The enthalpy of ACC with respect to calcite appears, however, independent of the additive concentration but decreases with water content. Surprisingly, the enthalpic contribution of water is compensated for by an equal and opposite entropic term leading to a net independence of ACC thermodynamic stability on its hydration level. Together, these results point toward a kinetic stabilization effect of inorganic additives and water, and may contribute to the understanding of the biological control of mineral stability. Calcium Carbonate
The research leading to these results received funding from the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme (FP7/2007-2013) under REA grant agreement (PCOFUND-GA ...doi:10.1016/j.neuroimage.2018.09.071 fatcat:nkhgcgwtlrhcfkm5yxmauwzk4e
SummaryThe geometrical similarity of helicoidal fiber arrangement in many biological fibrous extracellular matrices, such as bone, plant cell wall or arthropod cuticle, to that of cholesteric liquid mesophases has led to the hypothesis that they may form passively through a mesophase precursor rather than by direct cellular control. In search of direct evidence to support or refute this hypothesis, here, we studied the process of cuticle formation in the tibia of the migratory locust, Locustadoi:10.1101/793992 fatcat:54ybx3vr5rfa5ddabokzmfxiui
more »... gratoria, where daily growth layers arise by the deposition of fiber arrangements alternating between unidirectional and helicoidal structures. Using FIB/SEM volume imaging and scanning X-ray scattering, we show that the epidermal cells determine an initial fiber orientation from which the final architecture emerges by the self-organized co-assembly of chitin and proteins. Fiber orientation in the locust cuticle is therefore determined by both active and passive processes.
The mechanisms by which organisms control the stability of amorphous calcium carbonate (ACC) are yet not fully understood. Previous studies have shown that the intrinsic properties of ACC and its environment are critical in determining ACC stability. Here, the question, what is the effect of bulk incorporation versus surface adsorption of additives on the stability of synthetic ACC, is addressed. Using a wide range of in situ characterization techniques, it is shown that surface adsorption ofdoi:10.1002/adfm.202000003 fatcat:vgcuunsb3vbuzoycizddrxue34
more »... ly(Aspartic acid) (pAsp) has a much larger stabilization effect than bulk incorporation of pAsp and only 1.5% pAsp could dramatically increase the crystallization temperature from 141 to 350 °C. On the contrary, surface adsorption of PO 4 3− ions and OH − ions does not effectively stabilize ACC. However, bulk incorporation of these ions could significantly improve the ACC stability. It is concluded that the stabilization mechanism of pAsp is entirely different from that of PO 4 3− and OH − ions: while pAsp is effectively inhibiting calcite nucleation at the surface of ACC particle, the latter acts to modify the ion mobility and delay crystal propagation. Thus, new insights on controlling the stability and crystallization processes of metastable amorphous materials are provided.
In various mineralizing marine organisms, calcite or aragonite crystals form through the initial deposition of amorphous calcium carbonate (ACC) phases with different hydration levels. Using X-ray PhotoEmission Electron spectroMicroscopy (X-PEEM), ACCs with varied spectroscopic signatures were previously identified. In particular, ACC type I and II were recognized in embryonic sea urchin spicules. ACC type I was assigned to hydrated ACC based on spectral similarity with synthetic hydrated ACC.doi:10.1016/j.yjsbx.2019.100004 pmid:32647811 pmcid:PMC7337052 fatcat:f3ggfi7ee5c2dmst7lugvpsjz4
more »... owever, the identity of ACC type II has never been unequivocally determined experimentally. In the present study we show that synthetic anhydrous ACC and ACC type II identified here in sea urchin spines, have similar Ca L 2,3-edge spectra. Moreover, using X-PEEM chemical mapping, we revealed the presence of ACC-H2O and anhydrous ACC in growing stereom and septa regions of sea urchin spines, supporting their role as precursor phases in both structures. However, the distribution and the abundance of the two ACC phases differ substantially between the two growing structures, suggesting a variation in the crystal growth mechanism; in particular, ACC dehydration, in the two-step reaction ACC-H2O → ACC → calcite, presents different kinetics, which are proposed to be controlled biologically.
National Union Catalog
ng Jacques, font author, u Title, m rite: Ansoctations “aécla tees. 29-12315 Library of Congress 2 405 Bertinetti Bertin, Théodore Pierre 1751 1s1¥. ‘ami des Bourbons. ... Petite histoire des voyages; poésies de Marcelle Bertin, images de Denise Mary. ,Paris, Gallimard (1935, 30, p. illus (part col.) 19225". (On cover: Albums du gai sa- voir. 2) 1. ...
The Journal of American History
XXVI, 109-11 Benson, Jared, quoted, XX XV, 77 Benson, Mary S., revs.. ... Under 4 Flags, noted, XXXIII, 363 Bertinetti, Eugenia P., claim against govt., XXXII, 201 Beston, Henry, St. ...
de respirer suivi du registre d'activités 1979-80 (cahier bleu cartonné) 17) Notes et croquis de mise en scène (cahier cartonné de luxe) 18) Une vie en arbre et en Chars Bonds 19) ADIAFFI Jean-Marie ... P] Oswald BENEDETTO André, Saint-Feniant et Dame Paresse, Actes Sud BENEDETTO André, Carnaval-Express, Editions Provence BENN, 72 dessins prémonitoires, Editions Terre d'Europe (dédicacé avec dessin) BERTINETTI ...doi:10.7202/1041670ar fatcat:4zkvoy5lmng3rkjgha52gtdi4i
., 2919 Belfie, Mary J., 3814 Bell, Philip, 3115 Bellack, Alan S., 3278 Bellingham,, W. P., 2661 Bellur, S. N., 2919 Bender, Bruce G., 2573 Bender, M. ... W., 3201 Berry, John C., 4164 Berry, Maureen, 3495 Berry, Maurie M., 3116 Berstein, Marcos, 3716 Bertelsen, A., 3500 Bertelsen, Aksel, 3539 Bertinetti, Joseph F., 2375 Besing, Steven, 2420 Bess, James ...
Kipling ne illustra le conseguenze in un formidabile e spiazzante racconto, Mary Postgate 7 , pubblicato nel marzo del 1915. ... Il giovane Wynn, al quale Mary, zitella di mezza età, ha fatto quasi da madre, è morto durante un'esercitazione aerea all'inizio della guerra. ...doi:10.20318/revhisto.2016.3094 fatcat:jdzvwcfj2bgdbm3ekmxfx2jl3m
Mari Z. 2012, “Il santuario rurale della Bona Dea a San Gregorio di Sassola (RM)”, in E. ... For an example in which the identity of the goddess is confirmed by the dedicatory inscription ( CIL, XIV 2251 = EDR137776): Bertinetti, Candilio 2013. ...doi:10.4000/antafr.4024 fatcat:mklmzuyejne7ln6zyztbvo62xq
Saarbrücken, Novas Edições Acadêmicas, p. 601-631. -« Unidades Fraseológicas e Ensino de Língua Estrangeira: Algumas Reflexões em Torno das Expressões Idiomáticas e dos Provérbios », in Osório, P. & Bertinetti ... -(avec Marie-Aude Lefer), « N-grams in multilingual corpora: extracting and analyzing lexical bundles in contrastive studies », EUROPHRAS 2015 . ...doi:10.4000/methodos.4554 fatcat:pzxmagbwzbfm3l3klfu7aqylba
Bertinetti, R. ... Il reprend à son compte la formule discutée: «par Marie à Jésus» et, avec Montfort, nous invite à «vivre par Marie, en Marie, avec Marie et pour Marie», car elle représente le modèle de l'Église et nous ...doi:10.3917/nrt.254.0636 fatcat:narzghyblrdb7m6m54uw5utw4e
Besides the effect of Sr 2+ on bone cells (stimulating bone formation and decreasing bone resorption) (Grynpas & Marie 1990; Marie et al., 1993) , the presence of Sr 2+ is shown in the bone mineral formed ... Moreover, it was shown that apatites enriched with Mg 2+ retain more water at their surface than Mg 2+ -free apatites (Bertinetti et al., 2009) . ...doi:10.5772/29091 fatcat:7ltpfte4vzhv3aosm2r62qaoru
These increases in variation are most likely caused by increased internal 7 strains as a result of drying (Bertinetti et al., 2015; Masic et al., 2015). ... 18/21 Funding from Academy of Finland (project 286091), the strategic funding of University of 1 Eastern Finland, Swedish Foundation for Strategic Research, Marie Curie Intra-European 2 Fellowship for ...doi:10.1016/j.jsb.2017.07.009 pmid:28760694 fatcat:3ub6w3ytt5grxjfivstcauct2i
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