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Physicochemical factors controlling the retention and transport of perfluorooctanoic acid (PFOA) in saturated sand and limestone porous media.
Lv, X, Sun, Y, Ji, R, Gao, B, Wu, J, Lu, Q, Jiang, H
Water research. 2018;:251-258
Abstract
Comprehensively understanding the fate and transport of perfluorooctanoic acid (PFOA) in subsurface environment is crucial to assess its environmental impacts. In this work, column experiments were conducted to investigate the effects of physicochemical factors on the retention and transport of 14C-labeled PFOA in saturated sand and limestone porous media. The retention of PFOA in limestone columns was higher than that in sand columns under the same solution chemistry conditions. This can be attributed to that the limestone had less negative zeta-potential and larger specific surface area than the sand. Changes in ionic strength (low to high) and cation type (Na+ to Ca2+) had little influences on the mobility of PFOA in sand porous media, but significantly enhanced the retention of PFOA in limestone porous media. Nearly no PFOA was retained in the sand columns, but relatively high levels of PFOA retention (28.7-48.4%) were achieved in the limestone columns. Higher input concentration resulted in lower PFOA retention in limestone porous media, reflecting the blocking effect of the sorption sites. The blocking effect was insignificant in sand porous media, probably because the experimental conditions were unfavorable for PFOA sorption on sand media. A two-site kinetic retention model effectively simulated both the breakthrough and retention behaviors of the PFOA in the sand and limestone porous media.
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Effect of calcium citrate vs calcium carbonate on elevated parathyroid hormone after Roux-en-Y gastric bypass. A double-blinded, randomized trial.
Ring Madsen, L, Espersen, R, Rejnmark, L, Richelsen, B
Clinical endocrinology. 2018;(6):734-741
Abstract
OBJECTIVE Following Roux-en-Y gastric bypass (RYGB), elevated parathyroid hormone (PTH) levels potentially harmful to bone health are commonly observed. Owing to assumed superior absorption, calcium citrate is often recommended over calcium carbonate following RYGB for the treatment of elevated PTH. We aimed to investigate the impact of either calcium carbonate or calcium citrate (1200 mg elementary calcium) in patients with elevated PTH levels following RYGB. DESIGN Clinical, double-blinded, randomized controlled trial of a 12-week duration at a Danish University Hospital. PATIENTS AND MEASUREMENTS Thirty-nine (no drop out) RYGB operated patients with elevated PTH levels (PTH > 6.9 pmol/L) and normal plasma levels of calcium and 25-hydroxyvitamin D were randomized to either calcium carbonate or calcium citrate (1200 mg elementary calcium/daily). We assessed change in PTH as the primary outcome. RESULTS The effect of the two calcium formulations on change in PTH was comparable and neutral: -1.9% (calcium citrate) vs +0.9% (calcium carbonate), P = 0.680. Compared to the carbonate-treated group, the following bone turnover markers decreased significantly in the citrate-treated group: procollagen I N-terminal propeptide (-16.6% vs -3.2%, P = 0.021), osteocalcin (-17.2% vs -4.3%, P = 0.007) and bone-specific alkaline phosphatase (-5.9% vs 3.7%, P = 0.027) and remained significantly decreased after multivariable adjustment. CONCLUSION Increasing the dose of calcium supplementation in RYGB operated patients with slightly elevated PTH levels does not normalize PTH levels, regardless of the type of supplement. Our results do not support recommending supplementation with calcium citrate over calcium carbonate in RYGB patients.
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Surface properties of PM2.5 calcite fine particulate matter in the presence of same size bacterial cells and exocellular polymeric substances (EPS) of Bacillus mucitaginosus.
Li, Q, Dong, F, Dai, Q, Zhang, C, Yu, L
Environmental science and pollution research international. 2018;(23):22429-22436
Abstract
Microorganism cells and spores are the main components of PM2.5 (fine particulate matter) as well as fine mineral particles. In the microscopic system, the microorganisms will affect the minerals through attachment, charge neutralization, and dissolution related to the cell surface structure and metabolite. To explore the process and the results of microbial cells and their extracellular polymeric substances (EPS) acting on the surface properties of minerals of PM2.5 through the metabolism, a common native soil bacterium Bacillus mucitaginosus with abundant extracellular polymers was chosen as the tested strain. Meanwhile, as one of the PM2.5 common minerals, calcite fine particles were taken as the research object to explore the influence of microbial cells and extracellular polymers on its surface properties. High performance liquid chromatography (HPLC), inductively coupled plasma spectrometry (ICP), Zeta potential analysis, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD), and scanning electron microscopy (SEM) were used to characterize the composition of EPS, the soluble ions, surface charge, surface groups, crystal form, and surface morphology of calcite residual solid after being treated by the bacterial cells and EPS. The results revealed the EPS of B. mucitaginosus mainly consisted of protein and polysaccharides. Both the whole cell and its EPS could promote the dissolution of calcite particles into calcium ions. Due to the adhesion of organic groups on the calcite surface, the surface potential shifted significantly in the negative direction and the solution pH was clearly increased. The morphology of calcite surface was significantly changed after dissolution and re-crystallization. Experimental results also showed that the existence of the bacteria cells and EPS significantly affected the surface properties of calcite and provide a theoretical basis for the mechanism of PM fine particulate matter on human health impact for further study.
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Current challenges and future directions for bacterial self-healing concrete.
Lee, YS, Park, W
Applied microbiology and biotechnology. 2018;(7):3059-3070
Abstract
Microbially induced calcium carbonate precipitation (MICP) has been widely explored and applied in the field of environmental engineering over the last decade. Calcium carbonate is naturally precipitated as a byproduct of various microbial metabolic activities. This biological process was brought into practical use to restore construction materials, strengthen and remediate soil, and sequester carbon. MICP has also been extensively examined for applications in self-healing concrete. Biogenic crack repair helps mitigate the high maintenance costs of concrete in an eco-friendly manner. In this process, calcium carbonate precipitation (CCP)-capable bacteria and nutrients are embedded inside the concrete. These bacteria are expected to increase the durability of the concrete by precipitating calcium carbonate in situ to heal cracks that develop in the concrete. However, several challenges exist with respect to embedding such bacteria; harsh conditions in concrete matrices are unsuitable for bacterial life, including high alkalinity (pH up to 13), high temperatures during manufacturing processes, and limited oxygen supply. Additionally, many biological factors, including the optimum conditions for MICP, the molecular mechanisms involved in MICP, the specific microorganisms suitable for application in concrete, the survival characteristics of the microorganisms embedded in concrete, and the amount of MICP in concrete, remain unclear. In this paper, metabolic pathways that result in conditions favorable for calcium carbonate precipitation, current and potential applications in concrete, and the remaining biological challenges are reviewed.
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Renin-Angiotensin-Aldosterone Profiles in Pregnant Women With Chronic Hypertension.
Malha, L, Sison, CP, Helseth, G, Sealey, JE, August, P
Hypertension (Dallas, Tex. : 1979). 2018;(2):417-424
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Abstract
Pregnant women with chronic hypertension are at risk for increased blood pressure and superimposed preeclampsia (SPE) in late pregnancy. Alterations in the renin-aldosterone system are a feature of normal pregnancy; however, their role in chronic hypertension with and without SPE is less clear. We performed a prospective, longitudinal trial of 108 women with chronic hypertension and measured plasma renin activity (PRA), 24-hour urine sodium, urine potassium, and urine aldosterone (Ualdo) at 12, 20, 28, and 36 weeks and postpartum. SPE developed in 34% of pregnancies. PRA was lower in women who developed SPE at weeks 28 (5.99 versus 6.22 ng/mL per hour; P<0.001) and 36 (5.71 versus 7.74 ng/mL per hour; P=0.002). Ualdo was lower in women with SPE compared with those without SPE at 28 weeks (59.6 versus 81.3 μg/d; P=0.039). Mean arterial pressure was inversely related to both PRA (r=-0.23; P<0.0001) and Ualdo (r=-0.11; P=0.029). PRA and Ualdo were positively associated with each other (r=0.5327; P<0.0001) after adjusting for urine potassium, urine sodium, serum potassium, and mean arterial pressure. PRA and Ualdo were lower in women of black race compared with other racial groups (P<0.001). Our results demonstrate that in women with chronic hypertension PRA and Ualdo increase in early pregnancy and subsequently decrease in women who develop SPE. These findings are consistent with the hypothesis that sodium retention may contribute to the elevation in blood pressure in SPE.
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Development of a whole plant bioassay to test effects of potentized calcium carbonate in pillule formulation.
Lutz, B, Heer, I, Katzensteiner, R, Raak, C, Wolf, U, Heusser, P, Frass, M, Baumgartner, S
Complementary therapies in medicine. 2018;:13-21
Abstract
OBJECTIVES From a pharmaceutical point of view, we see a need to develop stable preclinical test systems to identify and investigate effects of potentized remedies as used in Anthroposophic Medicine and Homeopathy. We evaluated a plant bioassay regarding its capacity to distinguish homeopathic remedies from placebo, applied as sucrose pillules. METHODS Pea seed (Pisum sativum L) was soaked for 24 hours in water with dissolved homeopathic or placebo pillules, or in water only. Shoot length was measured 14 days after planting and treatment groups were compared by analysis of variance (ANOVA). The stability of the system was validated by systematic negative control experiments. RESULTS The system is suitable to test a common application form - sucrose pillules - of a potentized preparation without influence of the pharmaceutical carrier substance. A screening of 13 potentized preparations revealed Calcium carbonicum to affect pea shoot growth (p < 0.05). Three independent series of main experiments were performed with potentized Calcium carbonicum to assess reproducibility. Meta-analysis of all data revealed significant effects of Calcium carbonicum 12c and 30c on pea shoot growth (p < 0.05), which were however dependent on the date of experiment and/or the experimental series. CONCLUSIONS Potentized Calcium carbonicum, applied as sucrose pillules, influenced pea shoot growth in the assay investigated. However, due to the small effect size and due to the modulation of the effects by still unknown external factors, further optimization of this bioassay is necessary to be used in pharmaceutical quality control or in investigating the biological or pharmaceutical mode of action of potentized preparations.
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Exploiting algal mineralization for nanotechnology: bringing coccoliths to the fore.
Skeffington, AW, Scheffel, A
Current opinion in biotechnology. 2018;:57-63
Abstract
Complex mineral structures are produced by many microalgal species. Pioneering work on diatom silica has demonstrated the potential of such structures in nanotechnology. The calcified scales of coccolithophores (coccoliths) have received less attention, but the large diversity of architectures make coccoliths attractive as parts for nano-devices. Currently coccolith calcite can be modified by the incorporation of metal ions or adsorption of enzymes to the surface, but genetic modification of coccolithophores may permit the production of coccoliths with customized architectures and surface properties. Further work on the laboratory cultivation of diverse species, the physiochemical properties of coccoliths and on genetic tools for coccolithophores will be necessary to realize the full potential of coccoliths in nanotechnology.
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Effect of adding B-vitamins to vitamin D and calcium supplementation on CpG methylation of epigenetic aging markers.
Obeid, R, Hübner, U, Bodis, M, Graeber, S, Geisel, J
Nutrition, metabolism, and cardiovascular diseases : NMCD. 2018;(4):411-417
Abstract
BACKGROUND AND AIM B-vitamins may influence DNA methylation. We studied the effects of vitamin D + Ca + B versus D + Ca on epigenetic age markers and biological age. METHODS AND RESULTS Participants (mean ± SD of age = 68.4 ± 10.1 years) were randomized to receive 1200 IE vitamin D3 plus 800 mg Ca-carbonate alone (n = 31) or with 0.5 mg B9, 50 mg B6, and 0.5 mg B12 (n = 32). The CpG methylation of 3 genes (ASPA, ITGA2B, and PDE4C) and the changes in methylation were compared between the groups after 1 year. The changes of ASPA methylation from baseline were higher in the D + Ca + B than in the D + Ca group (1.40 ± 4.02 vs. -0.96 ± 5.12, respectively; p = 0.046, adjusted for age, sex, and baseline methylation). The changes in PDE4C from baseline were slightly higher in the D + Ca + B group (1.95 ± 3.57 vs. 0.22 ± 3.57; adjusted p = 0.062). Methylation of ITGA2B and its changes from baseline were not different between the intervention groups. Sex-adjusted odds ratio of accelerated aging (chronological age < biological age at 1 year) was 5.26 (95% confidence interval 1.51-18.28) in the D + Ca + B compared with the D + Ca group. Accelerated aging in both groups was associated with younger age. In the D + Ca + B group, it was additionally associated with lower baseline homocysteine. CONCLUSIONS Vitamin D + Ca + B and D + Ca differentially affected epigenetic age markers, although the effect size appeared to be small after 1 year. B-vitamins effect in young subjects with low homocysteine requires further investigation. ClinicalTrials.gov ID: NCT02586181.
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Calcium and Vitamin D Supplementation in Boys with Risperidone-Induced Hyperprolactinemia: A Randomized, Placebo-Controlled Pilot Study.
Calarge, CA, Mills, JA, Ziegler, EE, Schlechte, JA
Journal of child and adolescent psychopharmacology. 2018;(2):145-150
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Abstract
BACKGROUND The chronic use of antipsychotics has been associated with impaired bone mineralization, partially mediated by hyperprolactinemia. We examined if calcium and vitamin D supplementation promote bone mineral accrual in boys with risperidone-induced hyperprolactinemia. METHODS Between February 2009 and November 2013, medically healthy, 5- to 17-year-old boys were enrolled in a 36-week double-blind, placebo-controlled study, examining the skeletal effects of supplementation with 1250 mg calcium carbonate and 400 IU of vitamin D3 in risperidone-induced hyperprolactinemia. Anthropometric, dietary, physical activity, and psychiatric assessments were conducted at baseline and week 18 and 36. Plasma prolactin and vitamin D concentrations were measured at baseline and week 36. Total body less head bone mineral content (BMC) and radius trabecular bone mineral density (BMD) were measured at baseline, week 18, and week 36, using dual-energy X-ray absorptiometry and peripheral quantitative computed tomography, respectively. Linear mixed-effects regression analysis examined the longitudinal effect of treatment on skeletal outcomes. RESULTS Forty-seven boys (mean age: 11.0 ± 2.6 years) were randomized and 38 completed the study. At study entry, the average dietary calcium intake was below the recommended limit, but the average vitamin D concentration was normal. Calcium and vitamin D supplementation failed to significantly increase BMC or trabecular BMD. It also failed to affect several other skeletal and anthropometric outcomes, including plasma vitamin D concentration. CONCLUSIONS In this 9-month long pilot study, supplementation with a modest dose of calcium and vitamin D did not increase bone mass accrual in risperidone-treated boys with hyperprolactinemia. Alternative approaches should be investigated to optimize bone health in this population to prevent future morbidity and premature mortality. ClinicalTrials.gov Identifier: NCT00799383.
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A performance-based evaluation of chemically similar (carbonate) tempers from Late Prehistoric (AD 1200-1700) Ohio: Implications for human selection and production of ceramic technology.
Bebber, MR, Spurlock, LB, Fisch, M
PloS one. 2018;(3):e0194992
Abstract
PURPOSE This study was designed to assess the mechanical properties of two calcium carbonate tempers, limestone and burnt shell. These tempers have been previously compared, in separate studies, to silicate-based grit or sand temper and, relative to the latter, are assumed to possess similar mechanical properties. However, their simultaneous use at the Morrison Village site begs the question: do these two calcium carbonate tempers indeed possess similar mechanical properties? In order to assess their performance characteristics, a side-by-side controlled experimental test was conducted to determine the degree of similarity in providing increased vessel strength and toughness. METHODS Standardized ceramic test samples were systematically prepared via a set, explicit protocol. An Instron Series IX universal testing machine configured with a four-point flexural test jig was used to perform a flexural strength test of the test samples. The Instron load and deflection data were used to calculate three values related to mechanical performance: peak load, modulus of rupture, and modulus of elasticity. RESULTS All four comparative tests clearly show substantial differences in peak load, modulus of rupture, and modulus of elasticity. These differences are statistically significant for each performance attribute in every iteration of the experiment and as indicated by Mann-Whitney U Tests. CONCLUSIONS These results do not support the hypothesis that limestone and burnt shell offer the same performance characteristics. These results have implications for our understanding of prehistoric human selection of temper and the evolution of ceramic technology. Although both carbonate-based tempers are currently thought to offer the same benefits during the initial phase of pottery production, their contrasting post firing properties would have provided distinct benefits in different contexts. Future assessments of the Morrison Village ceramic assemblage should focus on residue analysis, or other functional indicators, to support or falsify this hypothesis.