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![Fig. 2 Crystal structure of weddellite viewed down [001] based on the...](profile/M-Realini/publication/47371114/figure/fig1/AS:306069986398212@1449984179560/Crystal-structure-of-weddellite-viewed-down-001-based-on-the-single-crystal-structure_Q320.jpg)
This study is focused on the stability of weddellite, the dihydrate phase of calcium oxalate [CaC(2)O(4)·(2 + x)H(2)O], mainly detected in kidney stones and in oxalate films found on the surfaces of several ancient monuments. Its occurrence is a critical issue since, at environmental conditions, weddellite is unstable and quickly changes into whewe...
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... crystal X-ray diffraction experiments: kidney stones of 10 patients have been provided by Genoa Hospital in order to obtain single crystals of whewellite and weddellite. Stereo- microscopic examination of stones has revealed the presence of different morphologies (Fig. 1); the stones were first examined by powder X-ray diffraction and then divided into three groups based on their whewellite/weddellite relative ratios: stones of only whewellite, stones of only weddellite and stones of a mixture of the two forms. The first two groups of samples have been considered and 20 single crystals have been ...
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... Fig. 10, FTIR spectra of weddellite immersed in D 2 O are shown. After 1 hour, weddellite does not show any change; the spectrum is comparable to that of weddellite collected immediately after the synthesis in H 2 O. After 22 and 31 hours, in the OD stretching range (2200-2700 cm À1 ) some new bands appear; unexpectedly these bands are not ...
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... OH stretching vibrations (3600-3200 cm À1 ) weddellite shows only a broad band, while whewellite has five well distinct bands. has been exposed to the laboratory environment and kept on the sample holder of the FTIR interferometer. After 2 hours, the infrared spectrum showed the leaking of deuterated water and the increase of hydrogenated water (Fig. 11). This result confirms the strong selectivity of calcium oxalates towards H 2 O. This journal is c the Owner Societies ...
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... suggest that the instability of weddellite is due to two main reasons: (1) the large size of its channel, of approximately 4.7 A ˚ in diameter (with ''free diameter of B2.1 A ˚ '') and (2) the presence of ''zeolitic water'' at the extra-framework W3 site (Fig. 2, Table 1), which is strongly under-bonded, with partial site occupancy (B60%) and with a significantly high static or dynamic disorder (as shown by its high thermal displacement parameter). The W3 molecule is weakly bonded to the W1 sites via H-bonds (with W3Á Á ÁW1 of about 3.2 A ˚ ). All these factors influence the stability of the ...
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Introduction
Crystalluria is thought to be associated with kidney stone formation and can occur when urine becomes supersaturated with calcium, oxalate, and phosphate. The principal method used to identify urinary crystals is microscopy, with or without a polarized light source. This method can detect crystals above 1 μm in diameter (microcrystals)...
Citations
... This parent-to-product phase transformation may take different times depending on the surrounding environmental conditions 14,48,52 and studies on their stability showed a relationship with humidity. 48,[53][54][55] In previous studies, 14,48,52 OCP crystals formed by DAP treatments appeared quite stable even after years while WD crystals formed by AmOx treatments were detected in the initial steps of the AmOx reaction with calcite, and then they were completely transformed to WHE after a few seconds or tens of minutes during the reaction. Here, the novelty is that (i) the OCP crystallites are stable when only DAP treatments are carried out or when DAP treatments are applied to AmOx substrates (AmOx → DAP); (ii) WD crystals are stable for up to several months only in DAP → AmOxtreatments. ...
SR X-ray diffraction computed tomography (XRDCT) was used to non-destructively analyse the effects of sequential inorganic-mineral re-treatments on decayed cultural heritage carbonatic stones. It offers new analytical perspectives for conservation science.
... Cariate et al. have concluded that environmental pH is the sole factor on which the stability of the film depends [16]. It has also been reported that whewellite is most stable at room temperature, and weddelite, on hydration, transforms into whewellite in one step [17,18]. A study suggests that the stability of Ca-oxalate phases depends on internal water molecules, while external water molecules lead to the transformation of weddelite to whewellite [19]. ...
This work reports calcium oxalate film formation on basaltic stone surfaces of the 17th-century western India Raigad Hill Fort. Nine stone samples extracted from the exterior surfaces of different historical structures of the fort were investigated under FTIR, optical microscopy, XRD, and SEM-EDX. The FTIR spectroscopy revealed intense peaks for Ca-oxalate patinas on basaltic stone surfaces. Observation under optical microscopy clearly showed milky white oxalate films, and peaks for crystalline calcium oxalate, including rock silicates, were prominently observed through XRD investigations. The surface morphology, the origin of the oxalate film, and the state of conservation of the basalt rock were investigated through SEM-EDX. The massive structures at Raigad, at a height of about 800 m, have hardly been chemically cleaned or coated with preservatives in the past. The presence of organic filaments in SEM photomicrographs indicated the biological origin of the oxalate patina due to the thick growth of microbiota on the monument stone during very heavy monsoons. The oxalic acid secreted by microbes dislodged the Ca-rich plagioclase of the stone, ensuring Ca-ions’ availability for film formation. The optical and mineralogical analyses suggest that the film is not the result of simple deposition but of the surface transformation of basaltic stone.
... This result indicates that whewellite may have been formed by the conversion of weddellite, which is consistent with the greater thermodynamic stability of whewellite at the experimental conditions applied in the study. 49 Additionally, the near-constant values for whewellite after 4 days are likely to indicate that the conversion of the reactive Ca into oxalate phases was complete. ...
... Nevertheless, only FTIR measurements could not fully discriminate between these two biominerals when they occur as mixtures or not in pure form, although a first discrimination may be provided by an accurate micro-morphological observation of both internal and external parts of the calculus. The best analytical method to distinguish these oxalates is doubtless X-ray diffraction (XRD) since it highlights the different crystallographic features of whewellite (monoclinic, P21/c) and weddellite (tetragonal, I4/m) [39]. However, FTIR still represents the most common spectroscopic technique used for stone analysis as it provides very useful information for clinical purposes by means of a less expensive and time-consuming approach, and requiring very low amounts of biominerals (<10 mg) [40]. ...
... oxalates is doubtless X-ray diffraction (XRD) since it highlights the different crystallographic features of whewellite (monoclinic, P21/c) and weddellite (tetragonal, I4/m) [39]. However, FTIR still represents the most common spectroscopic technique used for stone analysis as it provides very useful information for clinical purposes by means of a less expensive and time-consuming approach, and requiring very low amounts of biominerals (<10 mg) [40]. ...
... As aforementioned, COD crystals form in patients with idiopathic hypercalciuria and negligible or moderate hyperoxaluria. Nevertheless, from a mineralogical point of view, weddellite is unstable and easily converts, by a partial dehydration, in whewellite [39,48,49]. During this transformation, whewellite often preserves the initial crystal habit of weddellite (pseudomorphism) but calcium content increases from ca. 24 wt.% (weddellite) to ca. 27 wt.% ...
The present investigation exposes the main results raised from an active collaboration started in 2018 with the San Pio Hospital (Benevento, Southern Italy), aiming at a detailed mineralogical investigation of urinary stones of patients from the Campania region. Forty-nine uroliths (both bladder and kidney stones) have been surgically collected from patients admitted between 2018 and 2020 at the Department of Urology of the San Pio Hospital and characterized for clinical purposes and environmental biomonitoring from a mineralogical point of view. Possible causes and environmental implications were inferred according to the morpho-constitutional classification of the uroliths carried out by means of a conventional analytical approach. The mineralogical frequency distribution of uroliths from the Campanian region can be discussed as a function of dietary, socio-demographic, and environmental risk factors. Whewellite [CaC2O4·H2O] and weddellite [CaC2O4·(2+x)H2O], along with anhydrous calcium oxalate, represent the main mineralogical phases forming the biominerals examined here. Worth to note is that the percentage of oxalates in the Campanian region (ca. 51%) is quite comparable to those of other Mediterranean areas. Frequent uricite [C5H4N4O3] (ca. 33%), mainly observed in bladder stones of older male patients, could be related to an incorrect lifestyle and dietary habits. Occurrence of lower percentages of phosphate (i.e., brushite [CaHPO4·2(H2O)] and carbonated apatite [Ca10(PO4CO3)6(OH)8]) and mixed stones (such as, for example, a mixture of ammonium urate [NH4C5H3N4O3] and calcium oxalates) indicates specific etiopathogenetic mechanisms, suggesting proper therapeutical approaches.
... A BMC chemical classification exists and discriminates BMCs based on the basis of their chemical composition [14]. Two types of BMCs are distinguished: type I made of calcium oxalate dihydrate (COD), also called weddellite [15][16][17][18][19][20], and type II composed of carbonated calcium phosphate apatite (CA) [21][22][23][24][25][26][27][28]. Microcalcifications of type I are acknowledged to be associated with benign lesions, whereas type II with either benign or malignant lesions. ...
Despite the incidence of breast cancer among women, mammography and anatomopathology investigations are still the gold standard method for preventive screening and diagnosis. Several criteria are used to diagnose precisely the severity of the pathology like the distribution and shape of breast microcalcifications (BMCs). However, the link between the different chemical phases of BMCs and the cancer stage remains unclear. As BMCs physicochemical speciation has the potential to help clinicians during their diagnosis, this study aims to propose a methodology using advanced spectroscopical analysis techniques to finely characterize BMCs and uncover the relationship between mineralization processes and breast cancer. A state of the art in the domain is first proposed to highlight the role of BMCs and the importance of extensive analytical analysis using electron microscopy and vibrational techniques. Secondly, a detailed methodology for BMCs multiscale analysis is proposed and the relevance of each technique illustrated through the study of a biopsy from a patient suffering of an infiltrating low-grade ductal carcinoma: scanning electron microscopy analysis was used for the morphological description of BMCs, infrared micro and nanospectroscopy techniques for their chemical speciation at the micrometric and sub-micrometric scales.
... In [92] mainly due to the transition between the laser stages. In both cases, around 1200 cm −1 , the incident IR signals by the mIRage™ experimental set up are quite noisy in line with weak intensity of the IR laser in this part of the spectra. ...
... More precisely, high absorbance at 1618 and 1312 cm −1 belong to C=O and C-O, respectively. Regarding calcium oxalate dehydrated (COD) (Figure 4b), the most intense vibrations are shifted at 1643 cm −1 and 1325 cm −1 [91,92]. ...
2 Dominique Bazin et al. Abstract. Understanding the physico-chemistry related to cristalline pathologies constitutes a challenge in several medical specialities such as nephrology, dermatology or oncology. Regarding nephrol-ogy, the chemical diversity of concretions such as kidney stones calls for characterization techniques to determine the chemical composition of concretions. The starting point of this contribution is given by Fourier Transform InfraRed (FTIR) spectroscopy which is routinely used at the hospital to determine the chemical composition of kidney stones as well as ectopic calcifications present in kidney biopsy. For kidney stones, the quantity of sample is sufficient to perform a significant analysis through classical FTIR. For ectopic calcifications, µFTIR can be inefficient in the case of µcalcification in the tissue when their size is less than 10 µm. For such samples, Optical PhotoThermal IR (OPT-IR) spec-troscopy may constitute a way to overcome this experimental difficulty through the acquisition of IR spectrum with a spatial resolution close to 500 nm. To illustrate such opportunity, we first compare the IR spectrum acquired with a classical experimental setup related to classical IR spectroscopy to IR spectrum collected with a OPT-IR one for different compounds namely calcium oxalate monohydrate, calcium oxalate dehydrate, calcium phosphate apatite and magnesium ammonium phosphate hexahydrate. Such comparison helps us to assess specificity of OPT-IR. Then, we consider several pathological calcifications associated to hyperox-aluria, adenine phosphoribosyltransferase (APRT) deficiency or the presence of Randall's plaque. We will see that the nanometer spatial resolution constitutes a major advantage versus a micrometre one. Also, in the case of Randall's plaque, we show that OPT-IR can determine the chemical composition of microscopic concretion without any kind of preparation. Such experimental fact is clearly a major advantage. Finally, we also extended this first investigation in nephrology by considering breast calci-fications. In that case, if the number of chemical phases is quite low compared to the number of chemical phases identified in ectopic calcifications present in kidney (four instead of 24), the challenge is related to the possibility to distinguish between the different calcium phosphate namely amorphous carbonated calcium phosphate, CA and whitlockite. The complete set of data indicates the limitations and the advantages of OPT-IR spectroscopy.
... 37 Lastly, 13 C NMR (spin-1/2 nucleus of moderate receptivity, γ = 6.7281 × 10 7 rad s −1 T −1 ) studies on COM have shown that the NMR signature of this nucleus is particularly sensitive to temperature, as attested by the changes in the resolution of the four peaks belonging to the two inequivalent oxalate ions, and 13 C was further used to follow structural transformations from COT to COM. 36,41 A tentative assignment of all carbon signals was then proposed with the help of density functional theory (DFT) and gauge including projector augmented wave (GIPAW) calculations of NMR parameters. 36 To date, XRD has been the main analytical tool used to follow the different temperature phase transitions of calcium oxalates: 11,12,21,24 for example, the LT to HT structural change was shown to induce the disappearance of two peaks at 2θ ≈ 30°in the XRD pattern (Co Kα radiation). 24 However, as mentioned before, the involvement of water in the formation of the oxalate crystal structures and the mechanisms of phase transitions are still unclear. ...
Calcium oxalate minerals of the general formula CaC2O4 . xH2O are widely present in nature and usually associated with pathological calcifications, constituting up to 70-80% of the mineral component of renal calculi. The monohydrate phase (CaC2O4 .H2O, COM) is the most stable form, accounting for the majority of the hydrated calcium oxalates found. These mineral phases have been studied extensively via X-ray diffraction and IR spectroscopy and, to a lesser extent, using 1H, 13C, and 43Ca solid-state NMR spectroscopy. However, several aspects of their structure and reactivity are still unclear, such as the evolution from low- to high-temperature COM structures (LT-COM and HT-COM, respectively) and the involvement of water molecules in this phase transition. Here, we report for the first time a 17O and 2H solid-state NMR investigation of the local structure and dynamics of water in the COM phase. A new procedure for the selective 17O- and 2H-isotopic enrichment of water molecules within the COM mineral is presented using mechanochemistry, which employs only microliter quantities of enriched water and leads to exchange yields up to ∼30%. 17O NMR allows both crystallographically inequivalent water molecules in the LT-COM structure to be resolved, while 2H NMR studies provide unambiguous evidence that these water molecules are undergoing different types of motions at high temperatures without exchanging with one another. Dynamics appear to be essential for water molecules in these structures, which have not been accounted for in previous structural studies on the HT-COM structure due to lack of available tools, highlighting the importance of such NMR investigations for refining the overall knowledge on biologically relevant minerals like calcium oxalates.
... 3H2O, calcium oxalate trihydrate, COT), 10 where the dihydrate and trihydrate phases are known to be less stable and transform to the monohydrate phase over time. [11][12][13][14] Other phases, like amorphous calcium oxalates, have also been observed in synthetic samples, [15][16][17][18][19] and recently, their role in kidney stones has been investigated. 20 Moreover, synthetic anhydrous forms are known, which tend to rehydrate quickly to reform the monohydrate phase under ambient conditions. ...
... The structures of calcium oxalates and even kidney stones have been studied extensively using X-ray diffraction (XRD), [7][8][9][10][11]24,[27][28][29] scanning electron microscopy (SEM), 18,27,30,31 infrared (IR) and Raman spectroscopies, 11,12,16,[32][33][34][35] and more recently solid-state NMR spectroscopy. 16,19,[36][37][38][39][40][41] Moreover, computational studies have been carried out to help understand the polymorphism of anhydrous and monohydrate phases, and to rationalize the shapes of the crystallites. ...
... The structures of calcium oxalates and even kidney stones have been studied extensively using X-ray diffraction (XRD), [7][8][9][10][11]24,[27][28][29] scanning electron microscopy (SEM), 18,27,30,31 infrared (IR) and Raman spectroscopies, 11,12,16,[32][33][34][35] and more recently solid-state NMR spectroscopy. 16,19,[36][37][38][39][40][41] Moreover, computational studies have been carried out to help understand the polymorphism of anhydrous and monohydrate phases, and to rationalize the shapes of the crystallites. ...
Calcium oxalate minerals of general formula CaC2O4.xH2O are widely present in nature and usually associated with pathological calcifications, constituting up to 70 – 80% of the mineral component of renal calculi. The monohydrate phase (CaC2O4.H2O, COM) is the most stable form, accounting for the majority of the hydrated calcium oxalates found. These mineral phases have been studied extensively via X-ray diffraction, IR spectroscopy and, to a lesser extent, using 1H, 13C and 43Ca solid-state NMR spectroscopy. However, several aspects of their structure and reactivity are still unclear, such as the evolution from low- to high-temperature COM structures (LT-COM and HT-COM, respectively), and the involvement of water molecules in this phase transition. Here, we report for the first time a 17O and 2H solid-state NMR investigation of the local structure and dynamics of water in the COM phase. A new procedure for the selective 17O- and 2H-isotopic enrichment of water molecules within the COM mineral is presented using mechanochemistry, which employs only microliter quantities of enriched water, and leads to exchange yields up to ~30%. 17O NMR allows both crystallographically inequivalent water molecules in the LT-COM structure to be resolved, while 2H NMR studies provide unambiguous evidence that these water molecules are undergoing different types of motions at high temperatures without exchanging with one another. Dynamics appear to be essential for water molecules in these structures, which have not been accounted for in previous structural studies on the HT-COM structure due to lack of available tools — highlighting the importance of such NMR investigations for studying the crystallographic structure of biologically relevant minerals like calcium oxalates.
... 3H2O, calcium oxalate trihydrate, COT), 10 where the dihydrate and trihydrate phases are known to be less stable and transform to the monohydrate phase over time. [11][12][13][14] Other phases, like amorphous calcium oxalates, have also been observed in synthetic samples, [15][16][17][18][19] and recently, their role in kidney stones has been investigated. 20 Moreover, synthetic anhydrous forms are known, which tend to rehydrate quickly to reform the monohydrate phase under ambient conditions. ...
... The structures of calcium oxalates and even kidney stones have been studied extensively using X-ray diffraction (XRD), [7][8][9][10][11]24,[27][28][29] scanning electron microscopy (SEM), 18,27,30,31 infrared (IR) and Raman spectroscopies, 11,12,16,[32][33][34][35] and more recently solid-state NMR spectroscopy. 16,19,[36][37][38][39][40][41] Moreover, computational studies have been carried out to help understand the polymorphism of anhydrous and monohydrate phases, and to rationalize the shapes of the crystallites. ...
... The structures of calcium oxalates and even kidney stones have been studied extensively using X-ray diffraction (XRD), [7][8][9][10][11]24,[27][28][29] scanning electron microscopy (SEM), 18,27,30,31 infrared (IR) and Raman spectroscopies, 11,12,16,[32][33][34][35] and more recently solid-state NMR spectroscopy. 16,19,[36][37][38][39][40][41] Moreover, computational studies have been carried out to help understand the polymorphism of anhydrous and monohydrate phases, and to rationalize the shapes of the crystallites. ...
Calcium oxalate minerals of general formula CaC2O4.xH2O are widely present in nature and usually associated with pathological calcifications, constituting up to 70 – 80% of the mineral component of renal calculi. The monohydrate phase (CaC2O4.H2O, COM) is the most stable form, accounting for the majority of the hydrated calcium oxalates found. These mineral phases have been studied extensively via X-ray diffraction, IR spectroscopy and, to a lesser extent, using 1H, 13C and 43Ca solid-state NMR spectroscopy. However, several aspects of their structure and reactivity are still unclear, such as the evolution from low- to high-temperature COM structures (LT-COM and HT-COM, respectively), and the involvement of water molecules in this phase transition. Here, we report for the first time a 17O and 2H solid-state NMR investigation of the local structure and dynamics of water in the COM phase. A new procedure for the selective 17O- and 2H-isotopic enrichment of water molecules within the COM mineral is presented using mechanochemistry, which employs only microliter quantities of enriched water, and leads to exchange yields up to ~30%. 17O NMR allows both crystallographically inequivalent water molecules in the LT-COM structure to be resolved, while 2H NMR studies provide unambiguous evidence that these water molecules are undergoing different types of motions at high temperatures without exchanging with one another. Dynamics appear to be essential for water molecules in these structures, which have not been accounted for in previous structural studies on the HT-COM structure due to lack of available tools — highlighting the importance of such NMR investigations for refining the crystallographic data of biologically relevant minerals like calcium oxalates.
... Oil shale was subjected to the same analysis. The results are shown in Table 2, and they display that (Conti et al., 2010). While sodium nitrate in solids could be expected, the calcium oxalate under such circumstances has not been described prior to this work to the best of our knowledge. ...
... FTIR spectra revealed the presence of carbonates and silicates in the oil shale sample as described previously (Palayangoda and Nguyen, 2012;Washburn and Birdwell, 2013). Calcium oxalate minerals are evident (Conti et al., 2010) in the products formed. All in all, FTIR results ...
Oxidation has been a long sought-after alternative to classical thermal processing of oil shale, in order to obtain valuable raw materials for the chemical industry. A number of different methods have been applied, but thus far, one of the most effective ways to transform oil shale to value added products, such as aliphatic terminal dicarboxylic acids, is oxidation with nitric acid. In order to obtain insight into the reactivity of oil shale in nitric acid, a study focusing on the kinetics and behavior of oil shale particles during oxidative leaching was performed. To that end, the particle size distribution, surface area, and carbon content were measured during the leaching process in addition to the amount of total residual solids. Determining the carbon content of the solid residue was proposed as a simple measure of the reaction progress, based on the hypothesis that all carbon measured by elemental analysis correspond to organic carbon since inorganic carbon is present as carbonate in the starting material and would have dissolved under the acidic conditions. To our surprise, the solid residue had a significant amount of organic carbon in the form of calcium oxalate mineral. Thus, measuring carbon content in the solid residue could provide only an indirect measure of the overall oxidation degree provided that the amount of oxalates was known. In general, the results revealed that the total solid residue amounts to between 20% and 34% of the initial values after 24 h of the reaction, while the total carbon content ranges from 4% to 14% of the starting values. These results show that we were able to extract around 90% of the organic carbon present in the solid phase.
