Search results for "SHELL"

The shell matrix and microstructure of the Ram's Horn squid: Molecular and structural characterization.

2020

20 pages; International audience; Molluscs are one of the most diversified phyla among metazoans. Most of them produce an external calcified shell, resulting from the secretory activity of a specialized epithelium of the calcifying mantle. This biomineralization process is controlled by a set of extracellular macromolecules, the organic matrix. In spite of several studies, these components are mainly known for bivalves and gastropods. In the present study, we investigated the physical and biochemical properties of the internal planispiral shell of the Ram's Horn squid Spirula spirula. Scanning Electron Microscope investigations of the shell reveal a complex microstructural organization. The…

Mollusc shellomes: Past, present and future.

2020

13 pages; International audience; In molluscs, the shell fabrication requires a large array of secreted macromolecules including proteins and polysaccharides. Some of them are occluded in the shell during mineralization process and constitute the shell repertoire. The protein moieties, also called shell proteomes or, more simply, 'shellomes', are nowadays analyzed via high-throughput approaches. These latter, applied so far on about thirty genera, have evidenced the huge diversity of shellomes from model to model. They also pinpoint the recurrent presence of functional domains of diverse natures. Shell proteins are not only involved in guiding the mineral deposition, but also in enzymatic a…

Localization of biomineral proteins by Atomic Force Microscopy (AFM) with functionalized tips

2021

'Shellome': Proteins involved in mollusk shell biomineralization - diversity, functions.

2011

18 pages; International audience

Byron et Shelley en Italie : représentations et réalités

2015

International audience

LEAD(II) AND CADMIUM(II) REMOVAL FROM AQUEOUS SOLUTIONS USING HAZELNUT AND ALMOND SHELLS SORBENT MATERIALS

2016

Removal of toxic metal ions from natural and waste waters is of great importance for the health of living organisms and for environmental protection. Alternatively to the conventional chemical treatments, such as precipitation, reverse osmosis, etc, biosorption shows a growing interest for toxic metal ions removal from contaminated aqueous solutions. The sorption ability of every type of biomass towards metal ions depends on many variables that characterize the solution. Among these, the ionic strength (I) is one of the most important and cannot be neglected during an accurate adsorption study. For this reason and with the aim of quantitatively define the influence of I, here are reported t…

Transnacionālo korporāciju apvienošanās un tā ietekme uz attīstību

2019

Globalizācijas ietekmē, pieaugot korporāciju iespējām veikt darbību starptautiskā mērogā, ir izveidojies ļoti dinamisks un konkurentu bagāts tirgus teju visās industrijās un nozarēs. Lai saglabātu savu konkurētspēju un spētu pielāgoties straujajām pārmaiņām, korporācijām ir bijis jāattīstās un jāaug ļoti straujā tempā. Līdz ar to, ir aktualizējušās apvienošanas un pārņemšanas stratēģijas, ko korporācijas izmanto kā ātrākas izaugsmes un attīstības rīkus, lai nodrošinātu savu konkurētspēju un ieņemtu stabilu vietu savas nozares tirgū. Līdz ar to, pētījuma mērķis ir identificēt transnacionālo korporāciju apvienošanās darījumu ietekmi uz uzņēmumu attīstību. Analizējot divus apvienošanās darījum…

Theoretical and experimental studies of some main group compounds : from closed shell interactions to singlet diradicals and stable radicals

2012

Acquiring knowledge of different interactions within and between molecules is a fascinating undertaking as it not only deepens our understanding of chemical bonding but also offers insight into electronic structures, molecular properties and the connections between these two. This dissertation combines together three main group chemistry related topics within the aforementioned theme. Research presented in the first third of this dissertation describes wave function and density functional theory studies of weak inter- and intramolecular interactions in pnictogen-based dimers X3Pn···PnX3 (Pn = N-Bi; X = F-I), dithallenes RTlTlR (R = H, Me, tBu, Ph) and octachalcogen dications Ch82+ (Ch = S, …

Microscopic calculation of the $\beta^-$ decays of $^{151}$Sm, $^{171}$Tm, and $^{210}$Pb with implications to detection of the cosmic neutrino backg…

2023

The electron spectral shapes corresponding to the low-$Q$ $\beta^-$-decay transitions $^{151}$Sm$(5/2^-_{\rm g.s.})\to\,^{151}\textrm{Eu}(5/2^+_{\rm g.s.})$, $^{151}$Sm$(5/2^-_{\rm g.s.})\to\,^{151}\textrm{Eu}(7/2^+_{1})$, $^{171}$Tm$(1/2^+_{\rm g.s.})\to\,^{171}\textrm{Yb}(1/2^-_{\rm g.s.})$, $^{171}$Tm$(1/2^+_{\rm g.s.})\to\,^{171}\textrm{Yb}(3/2^-_{1})$, $^{210}\textrm{Pb}(0^+_{\rm g.s.})\to\,^{210}\textrm{Bi}(1^-_{\rm g.s.})$, and $^{210}\textrm{Pb}(0^+_{\rm g.s.})\to\,^{210}\textrm{Bi}(0^-_{1})$ have been computed using beta-decay theory with several refinements for these first-forbidden nonunique (ff-nu) $\beta^-$ transitions. These ff-nu $\beta^-$ transitions have non-trivial electro…

Microstructures in shells of the freshwater gastropod Viviparus viviparus: a potential sensor for temperature change?

2013

Abstract Mollusk shells contain a plethora of information on past climate variability. However, only a limited toolkit is currently available to reconstruct such data from the shells. The environmental data of some proxies (e.g. Sr/Ca ratios) is obscured by physiological effects, whereas other proxies, such as δ 18 O, simultaneously provide information on two or more different environmental variables. The present study investigates whether microstructures of the freshwater gastropod Viviparus viviparus provide an alternative means to reconstruct past water temperature. Cold and highly variable temperature regimes resulted in the precipitation of highly unordered first-order lamellae of simp…