Application of Synchrotron Radiation Technology in Marine Biochemistry and Food Science Studies
Se-Kwon Kim in Marine Biochemistry, 2023
CaCO3 crystals include aragonite, calcite, and vaterite. More than 95% of otoliths are composed of aragonite crystals of CaCO3. In addition to Ca, over 30 elements, including sodium (Na), potassium (K), strontium (Sr), zinc (Zn), phosphorus (P), manganese (Mn), magnesium (Mg), silicon (Si), and iron (Fe), are present in otoliths at extremely low concentrations. However, the mechanism of trace element accumulation in otoliths remains unclear. Organic substances, such as glycoproteins, are present in otoliths (Thomas and Swearer 2019; Katayama 2021; Campana and Thorrold 2001; Otake 2010; Campana 1999). The construction of CaCO3 in otoliths is regulated by enzymes. Therefore, the formation of otoliths occurs via biomineralization and may play an important role in governing otolith chemical patterns and element incorporation (Hüssy et al. 2020; Cook et al. 2018).
Biomedical Applications of Raman Scattering
R. Michael Gendreau in Spectroscopy in the Biomedical Sciences, 1986
An obvious difficulty with biological samples is microscopic heterogeneity. The normal spot size of a focused laser beam is about 0.1 mm, which would yield Raman spectra averaged over a diverse variety of structural elements. The coupling of a microscope and an image intensifier with a Raman spectrometer permits the examination of biological materials in situ and provides a solution to this problem. Microscope objectives produce a 1-μm spot on a sample with a depth of focus of 5 μm. Spatial resolution to this level may therefore be achieved, assuming proper design of the Raman optical system. To prevent sample degradation during the long exposure time when spectra are recorded using a monochromator and single photomultiplier, the latter is replaced by a multichannel detector. This approach, pioneered by Delhaye and co-workers in France,30,31 can yield a two-dimensional “image” of an object according to the Raman spectrum of its constituents. The potential of a nondestructive method, which combines chemical identification of a structure with physical location in a complex environment is clear. Although biomedical applications of the method are scarce, Buiteveld et al.32 have examined microscopic particles in human lung tissue. Paraffinized unstained sections were deposited on microscope slides and 5145 Å radiation from an Argon ion laser was focused to diameters of laser spots ranging from 1.6 to 4 μm. Particles of CaCO3 (calcite) were unambiguously identified in the tissue.
Miscellaneous Applications
Vlado Valković in Low Energy Particle Accelerator-Based Technologies and Their Applications, 2022
At present, a mortar dating collaboration is in progress between the conventional 14C Dating Laboratory in Helsinki and the AMS 14C Dating Laboratory in Aarhus. The Helsinki laboratory has been working on mortar dating for several years and obtained convincing results by conventional 14C dating, see for example (Sonninen et al. 1989). The risk of contamination from unburnt limestone is reduced by mechanical separation. The mortar samples are gently crushed and wet sieved using a mesh width of 65 microns. The grains of mortar are small, 1–10 microns, and they easily pass through the sieve, whereas the fractions of calcite crystals of the unburnt limestone are so much larger and harder that they can be well separated.
Scylla Sp. Shell: a potential green adsorbent for wastewater treatment
Published in Toxin Reviews, 2022
Azrul Nurfaiz Mohd Faizal, Nicky Rahmana Putra, Muhammad Abbas Ahmad Zaini
Crab shell is rich in calcium carbonate. Two polymorphs of calcium carbonate, namely calcite (a trigonal shape) and aragonite (an orthorhombic shape) are present with similar crystal structure and thermodynamic stability (Van et al.2019). Calcite is the primary constituent of shells of marine organism while aragonite forms naturally in almost all mollusk shells (Du et al.2011). Van et al. (2019) and Lin et al. (2020) recognized the roles of calcite and aragonite as active sites for ion-exchange with divalent metal ions, Pb2+ and Cd2+. When calcite and aragonite are in contact with water, the calcareous layer in crab shell dissolves to release Ca2+ and CO32- ions into the solution (Zhou et al.2017; Van et al.2019). The Ca2+ ions interchange with cations in bulk solution, while CO32- ions form solid-solution nuclei (Van et al.2019). On the other hand, the increase of solution temperature encourages the dissolution of calcite and aragonite to release bicarbonate anions. Consequently, the interactions with cations lead to the precipitation of metal carbonate on the adsorbent surface (Sdiri et al.2012, Van et al.2019). Du et al. (2011), Van et al. (2019) and Pap et al. (2020) suggested that the adsorption mechanisms of heavy metals by crab shell adsorbent are primarily due to ion-exchange and surface complexation at low concentration, and dissolution-precipitation at high concentration.
Assessment of an anti-scale low-frequency electromagnetic field device on drinking water biofilms
Published in Biofouling, 2018
F. Gosselin, L. Mathieu, J.-C. Block, C. Carteret, H. Muhr, F. P. A. Jorand
In order to know whether EMF treatment had any effect on CaCO3 crystallization, the precipitates formed on the surface of coupons exposed to oversaturated water, with or without exposure to the EMF were analysed. Aragonite was the primary CaCO3 polymorph found on coupons exposed to the EMF, whereas calcite was dominant on the control (no EMF). Calcite and aragonite were identified from Raman spectroscopy by major peaks specific to aragonite at 205 cm−1 and 152 cm−1, and by a peak at 281 cm−1 specific to calcite (De La Pierre et al., 2014) (Figure 2). The peak for calcite was relatively higher in intensity in the Control than in the Assay when curative or preventive EMF treatments were applied. Moreover, crystal morphologies were in accordance with aragonite and calcite as showed by SEM (Figure S3). Consequently, surfaces in contact with water exposed to the EMF contribute to the deposition of aragonite at the expense of calcite.
Recoverable impacts of ocean acidification on the tubeworm, Hydroides elegans: implication for biofouling in future coastal oceans
Published in Biofouling, 2019
Yuan Meng, Chaoyi Li, Hangkong Li, Kaimin Shih, Chong He, Haimin Yao, V. Thiyagarajan
The FTIR analysis showed that the tubes built by tubeworms in all four treatment groups had both inorganic and organic matrices, regardless of the pH treatments (Figure 4). The FTIR spectra showed IR bands at 1,644 cm−1 attributed to C=O stretching (amide I) groups and at 1158 cm−1 attributed to C–C stretching groups, which were both related to the organic content of the tubes. The carbonate ion content in the tubes was demonstrated by the presence of internal vibration modes of the CO32− ions: ν4 (700 cm−1 and 714 cm−1), ν2 (860 cm−1 and 874 cm−1), ν1 (1082 cm−1), and ν3 (1,429 cm−1 and 1,496 cm−1). Specifically, IR bands around 700, 860 and 1,082 cm−1 are characteristic of aragonite structures, whereas IR bands around 874 and 1,429 cm−1 are characteristic of calcite structures. IR bands around 714, 1,496 and 1,788 cm−1 are common features of CO32− compounds that can indicate both types of calcium polymorphs. A calcite peak at 874 cm−1 was evident in the spectra of tubes built at pH 7.8 during stage 1 compared to the control (Figure 4(a)), which indicates increased formation of calcite at pH 7.8 over other mineral forms. In stage 2, the peaks of the spectra of the TC group were similar to those of the CC group (Figure 4(b)), which indicates that the tubes cultured at pH 7.8 recovered their normal mineral composition after switching back to the control conditions.
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