Identifying spatial influence of urban elements on road-deposited sediment and the associated phosphorus by coupling Geodetector and Bayesian Networks.

Elevated particles and phosphorus washed from road-deposited sediment (RDS) are noteworthy causes of eutrophication in urban water bodies. Identifying how urban elements (e.g., dwellings, roads) spatially influence RDS and the associated phosphorus can help pinpoint the primary management areas for RDS pollution and therefore effectively mitigate this problem. This study investigated spatial influence of urban elements on RDS build-up load and phosphorus load in Hanyang district of Wuhan city in central China. Bayesian Networks (BNs), combined with geographical detector (Geodetector) and correlation analysis, were applied to quantify spatial association between kernel density of urban elements, RDS build-up load and phosphorus load in RDS. Results showed that (1) areas with higher density of factories related elements usually had elevated level of RDS build-up load, aluminum-bound phosphorus (Al-P), occluded phosphorus (Oc-P), organophosphorus (Or-P). Higher load of RDS associated iron-bound phosphorus (Fe-P) and apatite phosphorus (Ca-P) usually occurred where dwellings, catering, and entertainment related elements were concentrated. (2) Urban elements mainly showed positive correlation with RDS build-up load, Fe-P, Ca-P, De-P (detrital apatite phosphorus), while they chiefly showed negative correlation with Ex-P (exchangeable phosphorus), Al-P, Oc-P, and Or-P. Bus stations, dwellings, and factories related elements had relatively strong determinant power over spatial stratified heterogeneity of RDS and RDS-associated phosphorus. (3) Geodetector and correlation analysis could boost factors filtering and construction of network structures in the process of developing BNs models. The developed BNs resulted in sound prediction of <150 µm RDS build-up load and phosphorus load, given that the prediction accuracy of models ranged from 0.532 to 0.657. These findings demonstrate that urban elements are useful spatial predictors of RDS pollution, and coupling Geodetector and BNs is promising in RDS pollution prediction and supporting urban nonpoint source pollution management.

Functional role of inorganic trace elements in dentin apatite tissue-part III: Se, F, Ag, and B.

Dentin hydroxyapatite possesses a unique versatile structure which allows it to undergo ionic substitutions. Trace elements play pivotal roles within the oral cavity, especially in dentin apatite tissue. Therefore, it is critical to explore the role of these elements in dentin apatite structure. The roles of other inorganic elements in dentin apatite were discussed in part I (Mg, Sr, Zn, and Fe) and part II (Cu, Mn, Si, and Li) of these series. In the last part of the review series, the role of selenium, fluorine, silver, and boron in the regulation of dentin apatite structure and function was discussed. We evaluated how these elements affect the overall size, morphology, and crystallinity of dentin apatite crystals. Moreover, we investigated the importance of these elements in regulating the solubility of dentin apatite. An electronic search was performed on the role of these trace elements in dentin apatite from January 2010 to January 2022. The concentration of selenium in teeth has been explored only recently, particularly its incorporation into dentin apatite. Silver nanomaterials inhibit the growth of cariogenic microorganisms as well as arrest the degradation of collagen. Fluorine was found to have important roles in dentin remineralization and dentinal tubule occlusion, making it widely used for hydroxyapatite doping. Boron is critical for mineralized tissues like bone, dentin, and enamel, but its exact role in dentin apatite is unknown. Therefore, understanding the impact of these elements on dentin apatite is potentially transformative, as it may help to fill a significant knowledge gap in teeth mechanics.

Studies of Peculiar Mg-Containing and Oscillating Bioapatites in Sheep and Horse Teeth.

New types of biological apatites have been discovered in molar sheep and horse teeth and are divided in two types. In the first and more general type, the release of Mg ions is parallel to the changes in composition of apatite leading to a final stoichiometric ratio of Ca to P ions, going from dentin depth towards the boundary of enamel with air. Inside dentin, another apatite sub-types were discovered with alternating layers of Mg-rich and C-rich apatites. The approximate formal stoichiometric relationships for these peculiar types of bioapatites are suggested. We identified two kinds of ion-exchanges responsible for formation of peculiar apatites. Various combinations of main and minor elements lead to new versions of biological apatites.

First finding of tiemannite, HgSe, in human bladder stones: An electron microprobe study.

Human bladder stones, surgically removed from a 4 years old boy, were studied by X-ray diffraction (XRD) and by electron microprobe analyses (EPMA). XRD data show that the bladder stones are mainly composed of struvite with minor apatite. Tiny particles, <10 µm in size, composed of mercury (Hg) and selenium (Se) were found using scanning electron microscopy (SEM) and quantitative analysis by wave-length dispersive system (WDS). On the basis of their composition, the particles consist of tiemannite, a rare mineral with the ideal formula HgSe. The young patient was not exposed to relevant mercury contamination and has no teeth fillings of amalgam. Although this observation is not conclusive, we suggest that Hg was introduced as methylmercury by food. The discovered tiemannite can be classified as endogenous mineral, i.e., directly precipitated from the same fluids that formed the host bladder stones. This assumption is supported by the fact that tiemannite and struvite can crystallize at the same temperature and pH values. As proposed for the formation of tiemannite previously reported in the liver of cetaceans, we suggest that the tiemannite in the human body represents a probable product of demethylation of Hg. In this contribution, we suggest that Hg and Se were initially collected by urine in the human body and finally precipitated to form tiemannite under appropriate chemical-physical conditions together with the formation of the host bladder stone. This observation suggests that the precipitation and accumulation of metals, including Hg and Se, in the human body can be considered a physiological response to eliminate part of these trace elements, thus enabling detoxification.

Dietary inferences through stable isotope analysis at the Neolithic and Bronze Age in the southern Caucasus (sixth to first millenium BC, Azerbaijan): From environmental adaptation to social impacts.

OBJECTIVES: Subsistence strategies are of great interest for understanding how prehistoric societies adapted to their environment. This is particularly the case for the southern Caucasus where relationships have been shown with the northern Caucasus and Mesopotamia since the Neolithic and where societies are alternately described as sedentary and mobile. This article aims, for the first time, to characterize human diets and their evolution using biochemical markers, from the Neolithic to the Bronze Age (sixth-first millenium BC), at Mentesh Tepe, a site in the middle Kura valley in Azerbaijan. MATERIALS AND METHODS: The data set belongs to 40 humans, 32 domestic and wild animals, and 42 charred seeds discovered in situ and perfectly dated. Stable isotope analyses were performed, including (a) δ13 Cco and δ15 N for animal and human bone collagens and for seeds, and (b) δ13 Cap for human bone apatite. RESULTS: Almost all the data (25/31) suggest an increased contribution of cereals, lentils, and freshwater fish during the Neolithic, whereas afterwards, until the Late Bronze Age, all individuals consumed more animal proteins from their livestock. None of the biological criteria (age at death and sex) and burial types (mass/single graves) were found to be related to a specific diet over time. Comparisons with other isotopic data from contemporary sites in Georgia argue in favor of a wide variety of dietary sources in the vicinity of the Kura valley and for highly mobile populations. Clear evidence of millet consumption has only been found for the Late Bronze Age.

Authigenesis of biomorphic apatite particles from Benguela upwelling zone sediments off Namibia: The role of organic matter in sedimentary apatite nucleation and growth.

Sedimentary phosphorites comprise a major phosphorus (P) ore, yet their formation remains poorly understood. Extant polyphosphate-metabolizing bacterial communities are known to act as bacterial phosphate-pumps, leading to episodically high dissolved phosphate concentrations in pore waters of organic-rich sediment. These conditions can promote the precipitation of amorphous precursor phases that are quickly converted to apatite-usually in carbonate fluorapatite form [Ca10 (PO4 ,CO3 )6 F2-3 ]. To assess the mechanisms underpinning the nucleation and growth of sedimentary apatite, we sampled P-rich sediments from the Namibian shelf, a modern environment where phosphogenesis presently occurs. The P-rich fraction of the topmost centimetres of sediment mainly consists of pellets about 50-400 µm in size, which in turn are comprised of micron-sized apatite particles that are often arranged into radial structures with diameters ranging from 2 to 4 µm, and morphologies that range from rod-shapes to dumbbells to spheres that resemble laboratory-grown fluorapatite-gelatin nanocomposites known from double-diffusion experiments in organic matrices. The nucleation and growth of authigenic apatite on the Namibian shelf is likely analogous to these laboratory-produced precipitates, where organic macromolecules play a central role in apatite nucleation and growth. The high density of apatite nucleation sites within the pellets (>109 particles per cm3 ) suggests precipitation at high pore water phosphate concentrations that have been reported from the Namibian shelf and may be attributed to microbial phosphate pumping. The intimate association of organic material with the apatite could suggest a possible role of biological substrata, such as exopolymeric substances (EPS), in the nucleation of apatite precursors. Importantly, we do not observe any evidence that the apatite particles are actual phosphatized microbes, contradicting some earlier studies. Nevertheless, these results further evidence the potential importance of microbially derived (extracellular) organic matter as a template for phosphatic mineral nucleation in both recent and ancient phosphorites.

Morphological, chemical and structural characterisation of deciduous enamel: SEM, EDS, XRD, FTIR and XPS analysis.

AIM: The purpose of this study was to characterise the enamel surface of sound deciduous teeth in terms of morphology, chemical composition, structure and crystalline phases. MATERIALS AND METHODS: The enamel of 30 human deciduous teeth was examined by: Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), X-ray Powder Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Photoelectron Spectroscopy (XPS). Chemical differences between incisors and canines were statistically evaluated using the Mann-Whitney U test (p ≤ 0.05). RESULTS: Three enamel patterns were observed by SEM: 'mostly smooth with some groves', 'abundant microporosities' and 'exposed prisms'. The average Ca/P molar ratios were 1.37 and 1.03 by EDS and XPS, respectively. The crystallite size determined by XRD was 210.82 ± 16.78 Å. The mean ratio between Ca bonded to phosphate and Ca bonded to hydroxyl was approximately 10:1. CONCLUSION: The enamel of sound deciduous teeth showed two main patterns: 'mostly smooth with some groves' and 'abundant microporosities'. 'Exposed prisms' was a secondary pattern. There were slight variations among the Ca/P molar ratios found by EDS and XPS, suggesting differences in the mineral content from the enamel surface to the interior. The crystalline phases found in enamel were hydroxyapatite and carbonate apatite, with major type B than type A carbonate incorporation.

Probable hepatic capillariosis and hydatidosis in an adolescent from the late Roman period buried in Amiens (France).

Two calcified objects recovered from a 3rd to 4th-century grave of an adolescent in Amiens (Northern France) were identified as probable hydatid cysts. By using thin-section petrographic techniques, probable Calodium hepaticum (syn. Capillaria hepatica) eggs were identified in the wall of the cysts. Human hepatic capillariosis has not been reported from archaeological material so far, but could be expected given the poor level of environmental hygiene prevalent in this period. Identification of tissue-dwelling parasites such as C. hepaticum in archaeological remains is particularly dependent on preservation conditions and taphonomic changes and should be interpreted with caution due to morphological similarities with Trichuris sp. eggs.

Crystallographic texture and elemental composition mapped in bovine root dentin at the 200 nm level.

The relationship between the mineralization of peritubular dentin (PTD) and intertubular dentin (ITD) is not well understood. Tubules are quite small, diameter ∼2 µm, and this makes the near-tubule region of dentin difficult to study. Here, advanced characterization techniques are applied in a novel way to examine what organic or nanostructural signatures may indicate the end of ITD or the beginning of PTD mineralization. X-ray fluorescence intensity (Ca, P, and Zn) and X-ray diffraction patterns from carbonated apatite (cAp) were mapped around dentintubules at resolutions ten times smaller than the feature size (200 nm pixels), representing a 36% increase in resolution over earlier work. In the near tubule volumes of near-pulp, root dentin, Zn intensity was higher than in ITD remote from the tubules. This increase in Zn(2+), as determined by X-ray absorption near edge structure analysis, may indicate the presence of metalloenzymes or transcription factors important to ITD or PTD mineralization. The profiles of the cAp 00.2 X-ray diffraction rings were fitted with a pseudo-Voigt function, and the spatial and azimuthal distribution of these rings' integrated intensities indicated that the cAp platelets were arranged with their c-axes aligned tangential to the edge of the tubule lumen. This texture was continuous throughout the dentin indicating a lack of structural difference between in the Zn rich near-tubular region and the remote ITD.

Apatite formation: why it may not work as planned, and how to conclusively identify apatite compounds.

Calcium phosphate apatites are inorganic compounds encountered in many different mineralized tissues. Bone mineral, for example, is constituted of nanocrystalline nonstoichiometric apatite, and the production of "analogs" through a variety of methods is frequently reported. In another context, the ability of solid surfaces to favor the nucleation and growth of "bone-like" apatite upon immersion in supersaturated fluids such as SFB is commonly used as one evaluation index of the "bioactivity" of such surfaces. Yet, the compounds or deposits obtained are not always thoroughly characterized, and their apatitic nature is sometimes not firmly assessed by appropriate physicochemical analyses. Of particular importance are the "actual" conditions in which the precipitation takes place. The precipitation of a white solid does not automatically indicate the formation of a "bone-like carbonate apatite layer" as is sometimes too hastily concluded: "all that glitters is not gold." The identification of an apatite phase should be carefully demonstrated by appropriate characterization, preferably using complementary techniques. This review considers the fundamentals of calcium phosphate apatite characterization discussing several techniques: electron microscopy/EDX, XRD, FTIR/Raman spectroscopies, chemical analyses, and solid state NMR. It also underlines frequent problems that should be kept in mind when making "bone-like apatites."

Apatite accumulation enhances the mechanical property of anammox granules.

The strength of granular sludge is essential for the mechanical stability of the granules. Inorganic precipitants form a major factor influencing the strength of the granules. To check the possibility of apatite accumulation in anammox granules, and study its contribution to the mechanical strength of granules, anammox granular sludge was collected from Dokhaven municipal wastewater treatment plant, the Netherlands. Mineral precipitation inside the granules was visualized by micro-computed tomography, and apatite was identified by electron probe microanalysis and X-ray powder diffraction. The mechanical strength of anammox granules was measured by a low load compression tester. The contribution of apatite to the mechanical strength was evaluated by the generalized Maxwell model. Ca-PO4 minerals are reported to accumulate in anammox granules. A transformation of Ca-PO4 happens, and apatite is the final stable form. The accumulation of apatite increases the mechanical strength of anammox granules. A fast method to monitor and evaluate the accumulation of minerals in anammox granules was proposed.

The color change in artificial white spot lesions measured using a spectroradiometer.

OBJECTIVES: The purpose of this study was to determine the color of white spot lesions. MATERIALS AND METHODS: Human premolars were subjected to a pH cycling to produce artificial caries lesions and classified into groups (n = 10/group): group 1, immersion in deionized water; group 2, pH cycling without fluoride (F) application; group 3, pH cycling with immersion in 1,000 ppm NaF solution; and group 4, pH cycling with immersion in 5,000 ppm NaF solution. CIE L*a*b* color parameters of the tooth were determined using a spectroradiometer at baseline, after demineralization and after pH cycling. The extent of demineralization was evaluated by scanning electron microscopy (SEM) and electron microprobe analysis (EPMA). RESULTS: Significant degrees of color change (ΔE*) were observed after demineralization (p < 0.05). The changes were mainly due to an increase in lightness (L*) and a decrease in yellowness (b*). F application induced a significantly large ΔE* in group 4 (p < 0.05). The color reversal after remineralization was mostly due to the recovery of L*. SEM and EPMA verified that net mineral gains occurred in the subsurface lesions. CONCLUSIONS: The initially white appearance of enamel caries was a result of changes of L* and b*. F treatment partially restored the color of white spot lesions. CLINICAL RELEVANCE: F-driven remineralization induced both mineral gains and esthetic enhancement of artificially produced enamel white spot lesions. The increase of L* and the decrease of b* contributed to the color changes.

Ion concentration adjacent to glass-ionomer restorations in primary molars.

OBJECTIVES: The aim was to compare the levels of fluoride, calcium and phosphorus in enamel and dentin alongside glass-ionomer-based restorations over time. METHODS: This CCT consisted of children with cavities in the occlusal surface of primary molars that were restored with either a high-viscosity (Fuji IX GP(®)) or a resin-modified glass-ionomer (Vitremer(®)), being the test groups. Sound teeth (controls) were harvested from the children belonging to the test groups. Sampled teeth were cut in half and the ion concentration measured using EPMA. ANOVAs, and Newman-Keuls tests were performed to analyze the data. The study sample consisted of 35 children having 29 teeth per group available for analyses. RESULTS: Although statistically significantly higher, the mean ion-concentration of calcium in enamel and dentin, and that of phosphorous in dentin hardly differed between the tests and control groups. The mean fluoride concentration in enamel (0.20ppm×10(3) and 0.24ppm×10(3)) and dentin (0.71ppm×10(3) and 0.78ppm×10(3)) surrounding the Fuji IX GP(®) and Vitremer(®) restored teeth, respectively was statistically significantly higher than in enamel (0.12ppm×10(3)) and dentin (0.12ppm×10(3)) for the control teeth. SIGNIFICANCE: The present in vivo investigation showed that fluoride ions are released from high-viscosity and resin-modified glass-ionomer primary restoration into the restorations' surrounding enamel and, and in particular, dentin.

Dose-response effects of zinc and fluoride on caries lesion remineralization.

The present mechanistic in vitro study aimed to investigate dose-response effects of zinc and fluoride on caries lesion remineralization and subsequent protection from demineralization. Artificial caries lesions were created using a methylcellulose acid gel system. Lesions were remineralized for 2 weeks using citrate-containing artificial saliva which was supplemented with zinc (0-153 µmol/l) and fluoride (1.1 or 52.6 µmol/l) in a 7 × 2 factorial design. Lesions were also remineralized in the absence of zinc and citrate, but in the presence of fluoride. After remineralization, all lesions were demineralized for 1 day under identical conditions. Changes in mineral distribution characteristics of caries lesions after remineralization and secondary demineralization were studied using transverse microradiography. At 1.1 µmol/l fluoride, zinc exhibited detrimental effects on remineralization in a dose-response manner and mainly by preventing remineralization near the lesion surface. At 52.6 µmol/l fluoride, zinc retarded remineralization only at the highest concentration tested. Zinc enhanced overall remineralization at 3.8-15.3 µmol/l. At 76.5 and less so at 153 µmol/l, zinc showed extensive remineralization of deeper parts within the lesions at the expense of remineralization near the surface. Citrate did not interfere with remineralization at 1.1 µmol/l fluoride, but enhanced remineralization at 52.6 µmol/l fluoride. Lesions exhibiting preferential remineralization in deeper parts showed higher mineral loss after secondary demineralization, suggesting the formation of more soluble mineral phases during remineralization. In summary, zinc and fluoride showed synergistic effects in enhancing lesion remineralization, however only at elevated fluoride concentrations.

Morphological and chemical characterization of tooth enamel exposed to alkaline agents.

OBJECTIVES: In this study, morphological and chemical changes in teeth enamel exposed to alkaline agents, with or without surfactants, have been investigated. In addition, chemical effects of the organic surface layer, i.e. plaque and pellicle, were also investigated. METHODS: The present study was conducted using several techniques: Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopy (SEM). RESULTS: From XPS-measurements, it was found that exposure to alkaline solutions resulted in a massive removal of carbon from the tooth surface, and that the addition of surfactants increased the rate under present conditions. Based on the results from the FTIR-analysis, no substitution reactions between phosphate, carbonate and hydroxide ions in the enamel apatite could be detected. From a minor SEM-analysis, degradation and loss of substance of the enamel surface was found for the exposed samples. From XRD-analysis, no changes in crystallinity of the enamel apatite could be found between the samples. CONCLUSIONS: The findings in this study show that exposure to alkaline solutions results in a degradation of enamel surfaces very dissimilar from acidic erosion. No significant erosion or chemical substitution of the apatite crystals themselves could be discerned. However, significant loss of organic carbon at the enamel surface was found in all exposed samples. The degradation of the protective organic layer at the enamel surface may profoundly increase the risk for caries and dental erosion from acidic foods and beverages.

Bone formation ability of carbonate apatite-collagen scaffolds with different carbonate contents.

Hydroxyapatite and carbonate apatites with different carbonate contents were synthesized, mixed with atelocollagen, and made into sponge scaffolds. The scaffolds were implanted into the bone sockets of the femurs of male New Zealand white rabbits for 2, 3, 12 and 24 weeks. carbonate apatite-collagen scaffold with 4.8 wt% carbonate content appeared to have similar crystallinity and chemical composition to human bone. When the scaffolds were implanted into the rabbit femurs, histological observation indicated that the carbonate apatites-collagen scaffolds with relatively higher carbonate contents were gradually deformed throughout the implantation period, and showed uniform surrounding bone after 24 weeks and could not be distinguished. The carbonate apatite-collagen scaffold with 4.8 wt% carbonate content showed the highest bone area ratio of all of the scaffolds. It is suggested that a carbonate apatite-collagen scaffold with carbonate content similar to that of human bone may have optimal bone formation ability.

A comparison of the physical and chemical differences between cancellous and cortical bovine bone mineral at two ages.

To assess possible differences between the mineral phases of cortical and cancellous bone, the structure and composition of isolated bovine mineral crystals from young (1-3 months) and old (4-5 years) postnatal bovine animals were analyzed by a variety of complementary techniques: chemical analyses, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and (31)P solid-state magic angle spinning nuclear magnetic resonance spectroscopy (NMR). This combination of methods represents the most complete physicochemical characterization of cancellous and cortical bone mineral completed thus far. Spectra obtained from XRD, FTIR, and (31)P NMR all confirmed that the mineral was calcium phosphate in the form of carbonated apatite; however, a crystal maturation process was evident between the young and old and between cancellous and cortical mineral crystals. Two-way analyses of variance showed larger increases of crystal size and Ca/P ratio for the cortical vs. cancellous bone of 1-3 month than the 4-5 year animals. The Ca/(P + CO(3)) remained nearly constant within a given bone type and in both bone types at 4-5 years. The carbonate and phosphate FTIR band ratios revealed a decrease of labile ions with age and in cortical, relative to cancellous, bone. Overall, the same aging or maturation trends were observed for young vs. old and cancellous vs. cortical. Based on the larger proportion of newly formed bone in cancellous bone relative to cortical bone, the major differences between the cancellous and cortical mineral crystals must be ascribed to differences in average age of the crystals.

Ectomycorrhizal mycelial species composition in apatite amended and non-amended mesh bags buried in a phosphorus-poor spruce forest.

We studied the effect of apatite amendment on ectomycorrhizal (EM) mycelial biomass production and species composition in a phosphorus-poor spruce forest using sand-filled mesh bags. Control and apatite-amended bags were buried in pairs in the lower part of the organic horizon for one growth season. DNA extraction, PCR of the ITS region, cloning and random sequencing were used to examine the fungal species composition in each bag. Sequences were identified by comparison with the UNITE database and GenBank. Our study confirmed previous results that the major fungal ingrowth in mesh bags was of EM origin. On average 13 species were detected in each bag. Tylospora fibrillosa, Amphinema sp., Tomentellopsis submollis, and Xerocomus badius made up almost 80% of the EM sequences. High biomass was related to increased dominance of specific species. There were no statistically significant differences in biomass production estimated from PLFA 18:2omega6, 9, or between fungal communities of apatite-amended and control bags estimated from DNA after one growth season. The potential of the mesh bag method in studies of functional diversity of EM mycelia in the field is discussed.

Uremic tumoral calcinosis in hemodialysis patients: clinicopathological findings and identification of calcific deposits.

OBJECTIVE: Extraskeletal calcifications generally develop in uremic patients. Periarticular massive calcifications, referred to as uremic tumoral calcinosis (UTC), represent solitary or multifocal calcium phosphate deposits. Our objectives were to clinically analyze a series of 8 patients with UTC undergoing hemodialysis, and to characterize calcium deposits in UTC. METHODS: The clinical, radiological, and pathological features of 8 consecutive patients (4 men and 4 women, mean age 49 yrs) with UTC were analyzed, and treatment and outcome were evaluated. Calcific specimens from the 8 patients were analyzed by x-ray diffraction, Raman spectroscopy, and infrared spectroscopy. RESULTS: Unifocal UTC was observed in 5 patients, whereas multifocal lesions occurred in 3 patients. The most common sites of UTC were the shoulders, elbows, and hands. Elevated serum calcium and phosphorus and intact parathyroid hormone were detected in 63% (n = 5), 100% (n = 8), and 63% (n = 5) of the patients, respectively. An increased calcium-phosphorus (Ca P) product was observed in 6 patients. Medical intervention to decrease the Ca P product achieved complete remission in 3 of 5 patients with solitary UTC, whereas this treatment was ineffective for multiple UTC. The 8 calcium deposits were identified as carbonate apatite. CONCLUSION: The most important pathogenic factors in UTC are an increased Ca P product and hyperphosphoremia, which is not necessarily related to hyperparathyroidism. Medical intervention is effective for solitary UTC, but combined treatment (surgery and medical therapy) is required for multiple UTC. Calcium deposits in UTC are composed of carbonate apatite.

Distribution and partitioning of phosphorus in solid waste and sediments from drainage canals in the industrial belt of Delhi, India.

Phosphorus is an essential and often limiting nutrient in both marine and freshwater ecosystems. However, its oversupply is of great concern in many environments due to its role in eutrophication. The concentration and distribution of sediment bound phosphorus species not only record its input into the environment, but also suggest their possible sources. It is recognized that the features of phosphorus behaviour have not been extensively studied in urban environments. In this study, phosphorus in solid waste and sediments from drainage canals within the industrial belt of Delhi were fractionated into five operationally defined forms, i.e., exchangeable or loosely sorbed phosphorus (Exch-P), Fe-bound phosphorus (Fe-P), authigenic apatite, CaCO3-bound phosphorus and biogenic apatite (Acet-P), detrital apatite (Det-P) and organic-bound phosphorus (Org-P), in order to assess the potential bioavailability status in these systems.