Calcium Morphology Research Articles

Pathophysiology and clinical implications of coronary artery calcifications.

To provide a summary of current understanding of coronary artery calcifications (CACs), outlining the role of calcium in atherosclerosis to comprehend the clinical implications of CAC. CAC serves as a reliable indicator of coronary artery disease (CAD) and it is associated with cardiovascular events. In recognition of its significance, recent global guidelines have integrated CAC assessment into risk evaluation protocols, highlighting its role as a noninvasive tool for evaluating and stratifying patients' risk for cardiovascular events. Beyond the amount of CAC values, also, calcium morphology had been linked to cardiovascular events.By leveraging CAC assessment, healthcare providers can effectively up or down reclassify patients' risk and tailor preventive strategies accordingly. This comprehensive approach may involve lifestyle modifications, meticulous management of risk factors, and judicious use of preventive medications to mitigate the likelihood of future cardiovascular events, or withhold treatments in those without signs of CAC, to optimize resource use. The identification of CAC burden and morphology through noninvasive imaging modalities can reclassify the prediction of future cardiovascular risk and serve as a risk modifier for atherosclerosis. These data underscore the utility of selectively using CAC assessment in both primary and secondary prevention strategies for atherosclerotic cardiovascular disease.

Nitrogen fixation and calcium activation of oyster shell during composting and its performance on acidic soil amendment

Chicken manure, corn straw and oyster shell powder (OSP) were used as raw materials for organic-inorganic combined composting. Experiments were designed by adding different amounts of OSP (0 %, 20 %, and 40 %), designed as CK, T1, and T2, respectively. In final composts, the pH value increased to 8.72–9.08, and the electrical conductivity ranged from 2.08–3.82 mS·cm−1. The co-composting could effectively reduce ammonia emissions by 54.65 % and could activate the calcium component by 37.5 %. Addition of OSP promoted the humification and the humic acid could increased 86.1 %. This calcium-based compost of oyster shells (OSs) activated by composting was used to plant Brassica napus by pot experiment. Compared with the addition of OSP after composting, the calcium-based compost activated by composting significantly promoted the growth of Brassica napus because of more nitrogen, humus and available calcium in the calcium-based compost. In addition, this calcium-based compost significantly increased pH, organic matter (OM) and exchangeable calcium content in the acidic soil. In general, composting is an effective method to realize the fertilizer utilization of OSs. This composting process could make full use of calcium in oyster shells to achieve nitrogen retention and humification enhancement during composting, meanwhile calcium morphology in oyster shells can be activated and high-quality acidic soil conditioner can be obtained.

Effect of sodium chloride on yield, purity, morphology and polymorphs of calcium or magnesium carbonate sequentially precipitated from brine solution

Oilfield brine disposal in marine environments is undesirable due to concentrated salts of calcium, magnesium, sodium, and others which endanger aquatic organisms. Thus, it is paramount to precipitate the dissolved ions into stable carbonates for industrial applications. However, the effect of NaCl in the brine solution on the quantity and quality of precipitated carbonates is not yet reported. In this study, microwave plasma atomic emission spectrometer (MIP AES), x-ray diffraction (XRD), and scanning electron microscopy (SEM) were employed to investigate the effect of 0–2 M NaCl on the yield, purity, polymorph, and morphology of calcium and magnesium carbonates. The yields of 96.2% to 98.9% and 53.7% to 69.6% and the purity of 90.9% to 92.7% and 96% to 99.5% CaCO3 and MgCO3·3H2O were obtained, respectively. Moreover, the maximum yield and purity of carbonates were obtained from a brine solution of 1 M NaCl. The concentration of 0–0.5 M NaCl favored more the formation of aragonite whiskers and rhombohedral calcite whereas the concentration of 1–2 M NaCl favored more the formation of aragonite whiskers, lamella vaterite,and rhombohedral calcite. Nevertheless, only nesquehonite (MgCO3·3H2O) precipitated regardless of brine concentration. The crystal surface and length of the precipitated nesquehonite from 1 to 2 M NaCl brine were affected.

Pulsatile Intravascular Lithotripsy: A Novel Mechanism for Peripheral Artery Calcium Fragmentation and Luminal Expansion

ObjectiveTo assess the feasibility and treatment effect of pulsatile intravascular lithotripsy (PIVL) on calcified lesions in a cadaveric model of peripheral artery disease. BackgroundPIVL represents a novel potential approach to intravascular lithotripsy for the treatment of vascular calcification. MethodsIn this preclinical device-feasibility study, technical success, calcium morphology and luminal expansion before and after PIVL treatment were evaluated in surgically isolated, perfused atherosclerotic lower-leg arteries and in perfused whole cadaveric lower legs. Analytical methods included micro-computed tomography (μCT), intravascular optical coherence tomography, digital subtraction angiography, and quantitative coronary analysis. ResultsTreatment delivery was successful in all whole-leg specimens (N = 6; mean age 74.2, 66 % female) and in the 8 excised vessels with diameter appropriate to the PIVL balloon (2 vessels exceeding diameter specifications were excluded). There were no vessel perforations. After PIVL, excised vessels showed extensive evidence of new, full-thickness fractures in lesions with calcium arc exceeding 152° and with calcium wall thickness between 0.24 mm and 1.42 mm. PIVL fractures were observed in intimal nodules, sheets, shingles, and medial plates. Vessels within whole-leg specimens also showed full-thickness fracturing and a mean of 1.9 ± 0.9 mm in acute luminal gain, 101.6 ± 99.5 % gain in total minimum cross-sectional area, and a 31.7 ± 13.4 % relative reduction in stenosis (P < 0.001 for all analyses). ConclusionsIn a cadaveric model, PIVL treatment was technically feasible, fractured both circumferential and eccentric calcium lesions, and resulted in acute luminal gain. A clinical feasibility study of PIVL is currently enrolling.

Effect of carbonic anhydrase bacteria on the carbonation process of γ-C2S

Carbonation has been proven to be a promising way to improve the mechanism properties and durability of steel slag products. Carbonic anhydrase (CA) bacteria can promote the early-age carbonation process of γ-dicalcium silicate (γ-C2S), which is one of the main mineral phases of steel slag. In this study, one kind of alkali-resistant CA bacteria was chosen to investigate its effects on the carbonation process of γ-C2S. Results showed that the bacteria could increase the compressive strength of carbonated γ-C2S by 19.0% when compared with carbonated samples without bacteria. The main products of carbonated γ-C2S were vaterite, calcite and silicon dioxide gel. The addition of bacteria could only accelerate the deposition of calcium carbonate, while hardly changing the types and properties of the carbonation products. The accelerated carbonation was found to reduce the inward diffusion of carbon dioxide. In addition, reasons for the decline of the accelerating carbonation effect were explained by X-ray computed tomography testing results. However, CA bacteria could change the morphology of calcium carbonated during the carbonation process of β-C2S and further accelerate the hydration process of β-C2S. The pore structure could also be refined with the incorporation of bacteria.

Isolation and characterization of biogenic calcium carbonate/phosphate from oral bacteria and their adhesion studies on YSZ-coated titanium substrate for dental implant application

Biogenic calcium carbonate/phosphate were isolated and characterized from oral bacteria (CPOB). The crystalline nature and morphology of calcium carbonate/phosphate were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM), respectively. XRD analysis revealed the cubic phase of YSZ coating as well as biogenic calcium carbonate (rhombohedral) and calcium phosphate oxide (hexagonal) was observed from CPOB. FESEM confirmed the extracellular synthesis of calcium compounds. Bacterial adhesion result reveals that YSZ coating drastically reduce bacterial invasion than titanium substrate.

Characterisation of calcium crystals in Abelia spp. using X-ray diffraction and electron microscopy

SummaryThe localisation, chemical composition, and morphology of calcium (Ca) oxalate crystals in the leaves and stems of Abelia mosanensis and of A. × grandiflora were analysed using a variable pressure-scanning electron microscope (VP-SEM) equipped with an X-ray diffraction system, a low temperature SEM (LT-SEM), and a transmission electron microscope (TEM). Foliar analyses of macro- and micro-elements were performed on the leaves and stems of A. mosanensis. A greater number of Ca oxalate crystals were observed in A. mosanensis than in A. × grandiflora. Three morphologically distinguishable types of crystals were observed: the prismatic crystals found inside the chloroplast, multifaceted star-like spherical and bladed aggregate crystals (druses) inside the vacuoles of the mesophyll cells, and small angular crystals (sand crystals) inside the cuticle. Semi-solid crystals that may drip and accumulate to become a solid Ca oxalate crystal were observed by LT-SEM, which indicated the growth of druses of Ca oxalate crystals. The growth of prismatic crystals and of druses were evident through the formation of crystalline lamellae. Micro-analysis indicated that the crystals were Ca oxalate and contained magnesium in A. mosanensis, or silicon in A. × grandiflora. Abelia stems with low foliar calcium concentrations showed no Ca oxalate crystal formation. This is the first report, to our knowledge, on the presence and possible growth of crystals of different morphologies and chemical compositions in Abelia.

Fabrication of bionanocomposites comprising flat nanocrystals of calcium in collagen fibers exhibiting hardness comparable to metal

In nature's biomineralization process, living organisms naturally incorporate insoluble mineral compounds into their nano and molecular scale biological structures which results in formation of unusually hard but significantly less brittle biominerals. Mimicking nature's biomineralization process, here we present a novel nanoscale design of a brick–mortar type structure constructed at room temperature that consists of two-dimensional nanocrystals of calcite and calcium polyphosphate (bricks) bound together with an amorphous soft biopolymer phase (mortar). The resulting mesocrystalline-like biomineralized nanocomposite scaffolds combine both the properties of thin calcium containing nanocrystals and the organic phase surrounding them, and accurately replicate the micro- and lamellar-level mechanical and structural properties of bone. The flat morphology of calcium containing nanocrystals (<50 nm) is shown to dramatically enhance the mechanical properties of bioscaffolds that exhibit hardness comparable to biomedical tantalum and titanium. By changing the ratio of hard to soft phases within the bionanocomposites, we demonstrate tunable hardness and modulus (stiffness) from average values of 0.21 GPa (standard deviation ∼ 0.12) to 1.2 GPa (standard deviation ∼ 0.82) and 0.24 GPa (standard deviation ∼ 0.12) to 6.6 GPa (standard deviation ∼ 6.3) respectively that are suitable for high- or low-stress environment applications of bone substitutes and tissue regeneration. This presents a promising strategy to design and synthesize advanced engineered biocomposites with exceptional mechanical properties.

Modification effects of colloidal nanoSiO2 on cement hydration and its gel property

To understand the effects of colloidal nanoSiO2 (CNS) on cement hydration and gel properties in the early and later age, hydration heat, calcium morphology, hydroxide content, non-evaporable water (NEW) content and nanoscale mechanical properties were measured. Some comparison studies were conducted on silica fume (SF) paste, as well. Results revealed that the accelerating effect of CNS on hydration in the early age is achieved by the acceleration of cement dissolution and hydrate nucleation on reacted nanoSiO2 particles. Although cement hydration can be greatly accelerated by CNS in the early age, its later age hydration is hindered. The NEW content of CNS-added paste experiences a higher rate of increase initially, but gradually becomes smaller than that of the control paste due to changes in the gel structure, making NEW content an unsuitable method for monitoring the hydration of CNS-added paste. However, nanoindentation results revealed that CNS modifies the gel structure to increase the high-stiffness C–S–H gel content.

Predicting Invasion in Mammographically Detected Microcalcification

AIM: To identify pre-operative factors which predict presence of invasive disease within mammographically detected malignant microcalcification. MATERIALS AND METHODS: A retrospective analysis was undertaken of 116 serial stereotactic core needle biopsies (SCNBs) performed on malignant mammographic calcification. Final surgical pathology was correlated with pre-operative features (clinical, radiological and core histology) in an attempt to predict the presence of an invasive component. RESULTS: Thirty-eight clusters contained invasive carcinoma. The sensitivity of SCNB for invasion was 55%. Clinical features, calcium morphology and cluster size were not shown to be predictive of invasive disease. Ductal carcinoma in situ(DCIS) of high grade on core histology and increasing number of calcifications were predictive of increased risk of invasion (high grade core biopsy DCIS and >40 calcifications 48% invasive at surgical histology; high grade core biopsy DCIS and <40 calcifications 15% invasive; non-high grade core biopsy DCIS 0% invasive). CONCLUSIONS: Identification of those clusters diagnosed as DCIS by percutaneous biopsy which are likely to harbour an invasive component is possible. It would seem reasonable to consider staging the axilla at therapeutic surgery in these patients. Bagnall, M. J. C. et al. (2001). Clinical Radiology56, 828–832.

Morphology of calcium carbonate coating on amorphous silicate powder

The amorphous silicate powders containing sodium, calcium,barium and magnesium were prepared by sol-gel and ion-exchangemethod, and calcium carbonate was coated on the powders for thepurpose of industrial re-circulation of calcium carbonate. Thecalcium carbonate powder with micro pores was obtained bycoating on amorphous CaO-SiO2 powder, and the pore sizedistribution would be influenced by calcium on the surface ofthe powder. The coating on amorphous MgO-SiO2 powderresulted in a hedgehog-like powder, which allowed needle-likecrystal extended radially, and the coated powder was the mixedphase of aragonite and calcite. The use of amorphousBaO-SiO2 and Na2O-SiO2 powders also led to the coatingpowder with the single phase of calcite. The morphology ofcalcium carbonate coating would be ascribed to cations on thesurface of the amorphous silicate powders, because the amount ofcations that would be dissolved in soaking solution was smalland insufficient to affect the morphology.

The Electrochemical Behavior of Calcium Electrodes in a Few Organic Electrolytes

The electrochemical behavior of calcium electrodes in a few important organic electrolyte has been investigated. The solvents used included acetonitrile, tetrahydrofuran, γ‐butyrolactone, and propylene carbonate, and the salts included, , , and tetrabutyl ammonium salts (, ). Various techniques, including cyclic voltammetry, Fourier transform infrared spectroscopy, scanning electron microscopy, and x‐ray microanalysis were used in order to characterize discharge processes of calcium anodes in the various systems, and to correlate them with the surface chemistry and morphology of calcium in the electrolyte solutions. Some important surface species formed in the above systems were identified. It was found that, as with lithium, discharge of calcium anodes is surface film‐controlled. In contrast to lithium systems, however, calcium deposition in these solvent systems, either on calcium or noble metal electrodes, is impossible, due to the nature of the surface films formed.