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Nature has evolved efficient strategies to synthesize complex mineralized structures that exhibit exceptional damage tolerance. One such example is found in the hypermineralized hammer-like dactyl clubs of the stomatopods, a group of highly aggressive marine crustaceans. The dactyl clubs from one species, Odontodactylus scyllarus, exhibit an impressive set of characteristics adapted for surviving high-velocity impacts on the heavily mineralized prey on which they feed. Consisting of a multiphase composite of oriented crystalline hydroxyapatite and amorphous calcium phosphate and carbonate, in conjunction with a highly expanded helicoidal organization of the fibrillar chitinous organic matrix, these structures display several effective lines of defense against catastrophic failure during repetitive high-energy loading events.

Among older men in Denmark, the incidence of death from any cause at a median follow-up of 5.6 years was not significantly lower among those randomly invited to undergo screening for subclinical cardiovascular disease.

Soluble maize fibre (SCF) has been found to significantly improve bone mineral density and strength in growing rats compared with several other novel prebiotic fibres. The objective of the present study was to investigate the effect of SCF on Ca absorption and retention in pubertal children by studying the potential absorption mechanisms of the intestinal microbiota. A total of twenty-four adolescent boys and girls (12–15 years) participated in two 3-week metabolic balance studies testing 0 g/d SCF (control (CON) treatment) and 12 g/d SCF (SCF treatment) in a random order by inclusion in a low-Ca diet (600 mg/d). Fractional Ca absorption was measured at the end of the two intervention periods using a dual-stable isotope method. Diet composites and faecal and urine samples were collected daily and analysed for Ca content. Ca retention was calculated as dietary Ca intake minus Ca excretion in faeces and urine over the last 2 weeks. Microbial community composition in the faecal samples collected at the beginning and end of each session was determined by 454 pyrosequencing of the PCR-amplified 16S ribosomal RNA gene. Fractional Ca absorption was 12 % higher (41 mg/d) after the SCF treatment compared with that after the CON treatment (0·664 (sd 0·129) and 0·595 (sd 0·142), respectively; P= 0·02), but Ca retention was unaffected. The average proportion of bacteria of the phylum Bacteroidetes was significantly greater in the participants after the SCF treatment than after the CON treatment. These results suggest that moderate daily intake of SCF, a well-tolerated prebiotic fibre, increases short-term Ca absorption in adolescents consuming less than the recommended amounts of Ca.

The purpose of this study was to profile elemental composition of calcium-based urinary stones using laser-induced breakdown spectroscopy (LIBS) and develop a machine learning model to distinguish recurrence-associated profiles by integrating elemental and clinical data. A total of 122 calcium-based stones (41 calcium oxalate, 11 calcium phosphate, 49 calcium oxalate/calcium phosphate, 8 calcium oxalate/uric acid, 13 calcium phosphate/struvite) were analyzed via LIBS. Elemental intensity ratios (H/Ca, P/Ca, Mg/Ca, Sr/Ca, Na/Ca, K/Ca) were calculated using Ca (396.847 nm) as reference. Clinical variables (demographics, laboratory and imaging results, recurrence status) were retrospectively collected. A back propagation neural network (BPNN) model was trained using four data strategies: clinical-only, spectral principal components (PCs), combined PCs plus clinical, and merged raw spectral plus clinical data. The performance of these four models was evaluated. Sixteen stone samples from other medical centers were used as external validation sets. Mg and Sr were detected in most of stones. Significant correlations existed among P, Mg, Sr, and K ratios. Recurrent patients showed elevated elemental ratios ( p  < 0.01), higher urine pH ( p  < 0.01), and lower stone CT density ( p  = 0.044). The BPNN model with merged spectral plus clinical data achieved optimal performance in classification (test set accuracy: 94.37%), significantly outperforming clinical-only models (test set accuracy: 73.37%). The results of external validation indicate that the model has good generalization ability. LIBS reveals ubiquitous Mg and Sr in calcium-based stones and elevated elemental ratios in recurrent cases. Integration of elemental profiles with clinical data enables high-accuracy classification of recurrence-associated profiles, providing insights for potential risk stratification in urolithiasis management.

Background Human milk palmitic acid (PA) is mainly esterified at the sn-2 position of triacylglycerols, while infant formula contains palmitate predominantly in the sn-1/3 positions. Current evidence on long-term health effects of increasing sn-2 palmitate in formula remains insufficient. This study investigated the effects of high sn-2 PA formula (> 40%) on fecal saponified fatty acid, calcium, magnesium and stool characteristics in healthy full-term infants. Methods In this cluster-randomized controlled trial, healthy infants < 14 d were assigned to breastfeeding (BF group, n  = 66), high sn-2 palmitate formula (sn-2 group, n  = 66, 46.3% sn-2 PA) or low sn-2 palmitate formula (control group, n  = 67, 10.3% sn-2 PA). Infant demographics, feeding status, stool characteristics, physical exams, and stool samples were collected at 6, 16, and 24 weeks. Per-protocol analysis was used. Results The sn-2 group exhibited a significant time-dependent decline in fecal saponified PA and calcium over time ( P h for Trend < 0.001). The BF group declined faster than the sn-2 group ( P adjusted for Group*Time < 0.001). Fecal saponified PA proportion in sn-2 group was significantly lower than controls at all timepoints. At week 24, fecal calcium was lower in the sn-2 group vs. control (0.9 vs. 1.3 mg/g, P  = 0.010). No significant difference was found in stool frequency, consistency or size between sn-2 and control groups at any point. Conclusion Infant formula enriched with > 40% sn-2 palmitate reduces fecal fatty acid and calcium excretion, supports efficient lipid and calcium absorption, shows a fecal magnesium pattern similar to breastfed infants, but does not alter stool characteristics relative to the control formula. Trial registration The trial is registered at Chinese Clinical Trial Registry: ChiCTR1800014479; 30/Jan./2018.

Dietary calcium (Ca) concentrations might affect regulatory pathways within the Ca and vitamin D metabolism and consequently excretory mechanisms. Considering large variations in Ca concentrations of feline diets, the physiological impact on Ca homeostasis has not been evaluated to date. In the present study, diets with increasing concentrations of dicalcium phosphate were offered to ten healthy adult cats (Ca/phosphorus (P): 6.23/6.02, 7.77/7.56, 15.0/12.7, 19.0/17.3, 22.2/19.9, 24.3/21.6 g/kg dry matter). Each feeding period was divided into a 10-day adaptation and an 8-day sampling period in order to collect urine and faeces. On the last day of each feeding period, blood samples were taken. Urinary Ca concentrations remained unaffected, but faecal Ca concentrations increased (P < 0.001) with increasing dietary Ca levels. No effect on whole and intact parathyroid hormone levels, fibroblast growth factor 23 and calcitriol concentrations in the blood of the cats were observed. However, the calcitriol precursors 25(OH)D2 and 25(OH)D3, which are considered the most useful indicators for the vitamin D status, decreased with higher dietary Ca levels (P = 0.013 and P = 0.033). Increasing dietary levels of dicalcium phosphate revealed an acidifying effect on urinary fasting pH (6.02) and postprandial pH (6.01) (P < 0.001), possibly mediated by an increase of urinary phosphorus (P) concentrations (P < 0.001). In conclusion, calcitriol precursors were linearly affected by increasing dietary Ca concentrations. The increase in faecal Ca excretion indicates that Ca homeostasis of cats is mainly regulated in the intestine and not by the kidneys. Long-term studies should investigate the physiological relevance of the acidifying effect observed when feeding diets high in Ca and P.

Accurately predicting phosphorous (P) and calcium (Ca) dietary requirements is critical for optimizing dairy cattle performance, and minimizing mineral excretions and ecosystems eutrophication. This study provides a new factorial system to determine net and dietary P and Ca requirements for maintenance and lactation, derived from a meta-regression of mineral trials involving lactating dairy cows. A comprehensive global database was constructed from 57 peer-reviewed articles of mineral balance trials, with a wide range of dietary and animal performance data. We estimated the net requirements for maintenance from the intercept of a nonlinear equation between mineral intake and the sum of total fecal and urinary excretions, which is an estimate of endogenous mineral loss. Mineral secreted in milk was used to obtain net requirements for lactation. The mineral metabolizable coefficient was quantified through observed (treatment means) mineral intake and total fecal and urinary excretions, discounting the estimated endogenous excretions from our proposed models. The nonlinear models of total fecal and urinary mineral excretion were evaluated (observed versus predicted values) using a 5-fold cross validation approach. The models to estimate the sum of endogenous fecal and urinary excretions of P (0.135 ±0.043 g P/kg BW 0.75 ) and Ca (0.360 ±0.144 g Ca/kg BW 0.75 ) exhibited suitable precision and accuracy; r = 0.89 and 0.79, concordance correlation coefficient = 0.85 and 0.77, and root mean square prediction error = 24.1 and 20.5% observed means, respectively. Dietary variables (forage level, fiber, starch, crude protein, and ether extract) did not affect the metabolizable coefficient (MC) of P and Ca; therefore, an overall dietary MC of P (0.69 ±0.01 ) and Ca (0.65 ±0.02 ) were proposed. Our new system estimates lower net and dietary P requirements for lactating dairy cows compared to the NASEM-2021 and NRC-2001 models, but slightly higher Ca requirements than NASEM-2021.This proposed system holds potential to reduce the use of phosphorus in diets for dairy cows, and thus to enhance economic efficiency and environmental sustainability of the dairy industry.

Minimally invasive caries-removal procedures remove only caries-infected dentin and preserve caries-affected dentin that becomes remineralized. Dental cements containing calcium phosphate promote remineralization. This study evaluated the in vivo remineralization capacity of resin-based calcium-phosphate cement (Ca-P) used for indirect pulp-capping. Carious and sound teeth indicated for extraction were randomly restored with the Ca-P base or without base (control), followed by adhesive restoration. Study teeth were extracted after three months, followed by elemental analysis of the cavity floor. Mineral content of affected or sound dentin at the cavity floor was quantified by electron probe micro-analysis to 100-μm depth. After three months, caries-affected dentin underneath the Ca-P base showed significantly increased calcium and phosphorus content to a depth of 30 μm. Mineral content of treated caries-affected dentin was in the range of healthy dentin, revealing the capacity of Ca-P base to promote remineralization of caries-affected dentin.

The dentin exposure always leads to dentin hypersensitivity and/or caries. Given the dentin's tubular structure and low mineralization degree, reestablishing an effective biobarrier to stably protect dentin remains significantly challenging. This study reports a versatile dentin surface biobarrier consisting of a mesoporous silica-based epigallocatechin-3-gallate (EGCG)/nanohydroxyapatite delivery system and evaluates its stability on the dentinal tubule occlusion and the ( ) biofilm inhibition. The mesoporous delivery system was fabricated and characterized. Sensitive dentin discs were prepared and randomly allocated to three groups: 1, control group; 2, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) group; and 3, the mesoporous delivery system group. The dentin permeability, dentinal tubule occlusion, acid and abrasion resistance, and biofilm inhibition were determined for 1 week and 1 month. The in vitro release profiles of EGCG, Ca, and P were also monitored. The mesoporous delivery system held the ability to sustainably release EGCG, Ca, and P and could persistently occlude dentinal tubules with acid and abrasion resistance, reduce the dentin permeability, and inhibit the biofilm formation for up to 1 month compared with the two other groups. The system provided prolonged stability to combat oral adverse challenges and served as an effective surface biobarrier to protect the exposed dentin. The establishment of the dentin surface biobarrier consisting of a mesoporous delivery system indicates a promising strategy for the prevention and the management of dentin hypersensitivity and caries after enamel loss.

This study evaluated the adherence of bacteria, calcium, and magnesium to three different ureteral stents after endoscopic surgery for urinary calculi. We randomly assigned 61 patients requiring the insertion of ureteral stents after urinary calculi treatment into three groups: Percuflex with a coating composition of Hydroplus ( n  = 21); Tria with a coating composition of Percushied ( n  = 22); and InLay Optima, which had a proprietary pHreeCoat coating ( n  = 18). All stents were removed and evaluated 1 month after treatment. The primary outcome was biomineral attachment to the ureteral stent. Calcium and magnesium contents were measured using atomic absorption spectrometry after the stent had been vortexed in a solution of saline and hydrochloric acid at pH 2. Bacteria were measured through flow cytometry of the washing solution collected by decantation after stent fragments had been immersed and vortexed in a saline solution. Median amounts of calcium and magnesium adhered to Percuflex were significantly higher than those adhered to Tria and InLay Optima. The median number of bacteria adhered was also highest in Percuflex compared to that in the other two groups, although without a statistically significant difference. These findings suggest that selecting stents with superior coating materials enhances patient outcomes and reduces stent-related complications.