Ca Deposition Research Articles

The sparing effect of phytase in plant-protein-based diets with decreasing supplementation of dietary NaH2PO4for juvenile yellow catfishPelteobagrus fulvidraco

An 8-week feeding trial was conducted to evaluate the sparing effect of dietary phytase on decreasing supplement of dietary sodium dihydrogen phosphate (NaH2PO4) in the diets of juvenile yellow catfish Pelteobagrus fulvidraco. Seven diets were formulated: one reference group that contained only 2% NaH2PO4; one control group that consisted of neither NaH2PO4 nor phytase; and five treatment groups supplemented with 1000 IU kg−1 phytase and 2%, 1.5%, 1%, 0.5%, 0% concentrations of NaH2PO4. Thus, dietary NaH2PO4 was substituted with phytase at ratios of 0%, 25%, 50%, 75% and 100% respectively. Triplicate tanks were each filled with 50 juvenile fish (3.5 ± 0.1 g), which were fed one of the seven experimental diets. Substituting phytase for NaH2PO4 didn't diminish the growth performance, protein, dry matter, lipid and ash deposit and protein retention in the whole body and reduced feed conversion ratio compared to the reference diet. Moreover, phytase substitution at level of 0–50% enhanced P, Mg and Ca deposit. However, weigh gain had a tendendy of decreasing with increasing substituted level. Phytase substituted level exceeding 75% decreased serum P concentration compared to the control group. Apparent digestibility of P peaked when 1000 IU kg−1 phytase substituted 50% NaH2PO4. Phytase also increased apparent digestibility of protein. The improvement of digestibility of protein and P resulted in the decrease in N load by 25% and P load by 31% to environment. Therefore, 50% dietary NaH2PO4 can be substituted by 1000 IU kg−1 feed phytase for juvenile yellow catfish.

Surface modification of stainless steel implants using nanostructured forsterite (Mg2SiO4) coating for biomaterial applications

The main aim of this research was the preparation of the forsterite (Mg2SiO4) coating on the surface of 316L stainless steel (316L SS) substrate. For this purpose, the nanostructured forsterite was coated on the 316L SS substrate using the sol–gel dip coating technique. Structural characterization techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDX) were utilized to investigate the phase structure, morphology and elemental composition of the uncoated and coated samples. Corrosion properties of samples were studied using the electrochemical measurements in simulated body fluid (SBF). The in vitro bioactivity evaluation of the forsterite coated samples was conducted by soaking the samples in the SBF at the temperature of 37°C. The results showed that, a crack-free and homogeneous forsterite coating with the crystallite size of around 40nm was successfully achieved on the surface of 316L SS substrate. The corrosion current density of the forsterite coated samples was lesser than that of the uncoated ones indicating the improvement of corrosion resistance of the metallic substrate using the forsterite coating. Deposition of Ca and P-contained products on the surface of coated samples during the incubation in the SBF solution confirmed the bioactivity behavior of the forsterite coated samples. Consequently, the 316L SS substrate coated with nanostructured forsterite may be an appropriate selection for dental and orthopedic implant applications.

Comparison of the deposition of Ca and P on the surface of Ti, Ti6Al4V and Ti6Al7Nb after SLA treatment

In the present study, the in vitro biological responses of Titanium (Ti) and two competitive titanium alloys (Ti6Al4V and Ti6Al7Nb) were investigated after modifying their surfaces by sandblasting and acid etching. The sandblasting and acid etching process was sandblasted by Al2O3 particles and acid etched by a mixture of hydrochloric acid and sulphuric acid. After the process, the surfaces of Ti, Ti6Al4 V and Ti6Al7Nb were porous of micrometres. Simulated body fluid tests were conducted to compare the biological performance of the samples. The sample surface morphologies were characterised by SEM, surface crystal structure of the samples was analysed by X-ray diffractometer. Even though microstructure of the alloys exhibited somewhat similar, the deposition of calcium (Ca), and phosphate (P) on the surface of Ti6Al7Nb alloy was greater and faster than that of Ti6Al4V and Ti, which is significant for implant surface modification.

Mechanism of calcium phosphate deposition in a hydrothermal coating process

Hydrothermal process is a useful method for deposition of corrosion protective calcium–phosphate (Ca–P) coating on magnesium alloy (AZ31) substrate. Since the deposition mechanism determines the coating properties to a considerable extent, the present work studied the key steps in the formation of Ca–P during the hydrothermal process. Ca–P was deposited on four different metallic substrates: AZ31, zinc (Zn), titanium (Ti) and stainless steel (SS). The Ca–P coatings were studied by means of Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and energy dispersive spectroscopy (EDS) to determine the various steps in the coating formation and growth. The deposition of Ca–P layer was found to strongly depend on the substrate material. Little or no deposition took place on corrosion resistant SS and Ti substrates while thick layers formed on more reactive AZ31 and Zn substrates. The deposition mechanism changed with increasing temperature in the case of the AZ31 substrate. At lower temperature, the coatings consisted of tricalcium phosphate and monetite phases. Increase in deposition temperatures resulted in the formation of an additional thick magnesium hydroxide layer below a mixture of tricalcium phosphate and monetite layer when magnesium substrate was used.

Growth responses of native chicken Sentul G-3 on diet containing high rice-bran supplemented with phytase enzyme and ZnO

This study was conducted to determine the effect of phytase enzymes and ZnO supplementation on the performance of native chicken Sentul-G3 fed high rice-bran diet. Two hundred and seventy day old chicks (DOC) native chicken Sentul-G3 from three different hatcheries were used in this study. Factorial randomized block design (3 x 3) was applied in this study. The first factor was the enzyme phytase supplementation levels (0; 1000; 2000 U/kg), the second factor was the level of supplementation of ZnO (0; 1.5; 3.2 g/kg), so that there are nine treatment given, namely R1 = 50% commercial diet : 50% rice bran; R2 = R1 + 1.5 g ZnO/kg; R3 = R1 + 3.2 g ZnO/kg; R4 = R1 + phytase enzyme 1000 U/kg; R5 = R1 + (phytase enzyme 1000 U/kg + 1.5 g ZnO/kg); R6 = R1 + (phytase enzyme 1000 U/kg + 3.2 g ZnO/kg); R7 = R1 + phytase enzyme 2000 U/kg; R8 = R1 + (phytase enzyme 2000 U/kg + 1.5 g ZnO/kg); R9 = R1 + (phytase enzyme 2000 U/kg + 3.2 g ZnO/kg). Each experimental unit consisted of 6 head unsexed native chicken Sentul-G3. The experimental diet was fed for 10 weeks. The variables measured were body weight, body weight gain, feed intake, feed conversion ratio, mortality, mineral deposition of Ca, P, Zn in the tibia bone, alkaline phosfatase enzyme activity in serum. Results showed that there was significant interaction (P 0.05) between phytase enzyme and ZnO supplementation on feed intake, mortality, alkaline phosphatase enzyme activity in serum, and deposition of calcium and phosphorus in the tibia bone. It was concluded that supplementation of phytase enzyme and ZnO were not able to increase the growth of native chicken Sentul-G3 on fed diet containing high rice bran.

Mineral Metabolism in Singleton and Twin-pregnant Dairy Goats.

During pregnancy, the maternal body undergoes significant physiological changes. The present study assessed the changes on calcium (Ca), phosphorus (P), magnesium (Mg), sodium (Na) and potassium (K) metabolism in singleton and twin-pregnant dairy goats. The 42 goats used (49.5 kg±7.6 body weight [BW]) were assigned at random to treatments that were factorially arranged to account for 2 breeds (Oberhasli and Saanen), 2 pregnancy types (singleton and twin) and 3 gestation periods (80, 110, and 140 days). Digestibility trials were performed at 80, 110, and 140 days of gestation. Mineral retention during pregnancy was determined in the maternal body, femur, uterus, mammary gland, fetus and fetal fluid. Blood samples were taken during pregnancy before and after a meal, and Ca, P, Mg, Na, K ions and alkaline phosphatase activity determined in serum. Bone mineral density was determined in the right femur. Statistical analyses were performed using the SAS MIXED procedure. Dry matter intake decreased linearly up to 140 days of gestation. Maternal BW gain, and Ca, P, and Mg retention (g/kg) decreased linearly with the advance of gestation days. Macromineral retention in maternal body (g/kg) was greater in Oberhasli than Saanen goats, and their fetuses had higher Ca, P, and Mg deposition (mg/g). Mineral retention (mg/g) increased in fetuses according to pregnancy development, with no differences between singleton and twin pregnancy. In the mammary gland, the retention of all minerals (g) increased with the days of pregnancy. In conclusion, related to Ca, P, and Mg metabolism can be divided into two stages. Up to 80 days of gestation, was characterized by the preparation of the maternal body reserves for future mineral demands. From 80 days of gestation onward, was characterized by the transfer of maternal body reserves for fetal development and colostrum production. Na and K supply was provided by adjustments in endogenous excretion and an increase in intestinal absorption. Finally, mineral metabolism was specific to each genotype and, except for Na, was not affected by the number of fetuses.

Early aortic valve inflammation precedes calcification: A longitudinal FDG-PET/CT study

Objectives: Recent data shows a relationship between aortic valve (AV) inflammation and calcification. However, direct evidence linking early valve inflammation (prior to hemodynamic compromise) to subsequent calcium (Ca) deposition is lacking in humans. We sought to test the hypothesis whether local AV inflammation predisposes to subsequent AV Ca deposition. Methods: We identified 111 individuals (age 60[49, 68], 50.5% male) without active cancer or aortic stenosis who underwent 2 PET/CT studies 1–5 years apart for cancer surveillance. AV inflammation was determined by measuring FDG uptake (maximum standardized uptake value, SUVmax) within the AV on baseline PET/CT. Subsequent deposition of AV Ca was determined by comparing baseline and follow-up CT scans, determined as an increase in AV Ca volume score (CaVS). Patients were classified as “non-progressors” or “progressors” based on Square Root difference in CaVS (using a pre-determined cut-off value of 2.5). CT and PET measurements were conducted by 2 mutually blinded laboratories. Results: During follow-up, AV Ca increased in 23 patients (20.2%) classified as “progressors”, of whom 9 (9.2%) demonstrated subsequent ‘incident’ AV Ca. The AV SUVmax (mean ± SD) was higher in progressors vs. non-progressors (2.03 ± 0.52 vs.1.74 ± 0.36, p = 0.02) and especially in patients with-vs. without-incident AV Ca (2.28 ± 0.42 vs. 1.73 ± 0.36, p < 0.001). Moreover, AV inflammation (AV SUVmax) independently predicted subsequent calcification after adjusting for cardiovascular risk factors [OR (95%CI): 4.99 (1.30–19.15), p = 0.02]. Conclusion: The findings suggest that early AV inflammation may predispose to AV sclerosis. The evaluation of valvular metabolic activity may prove useful for developing a better understanding of calcific valve disease.

Smad3 plays an inhibitory role in phosphate-induced vascular smooth muscle cell calcification

Arterial medial calcification is a major complication in patients with chronic kidney disease and diabetes. It has been hypothesized that a high concentration of inorganic phosphate (Pi) induces calcification in vascular smooth muscle cells (vSMCs). However, the role of transforming growth factor-β (TGF-β)/Smad3 signaling in Pi-induced vascular calcification remains controversial. The aim of this study was to investigate the possible involvement of Smad3 in Pi-induced vascular calcification. We compared the degree of Pi-induced vSMC calcification between vSMCs isolated from wild-type (Smad3+/+) and Smad3-deficient (Smad3−/−) mice. We found that vSMCs from Smad3+/+ mice had less calcium (Ca) than those from Smad3−/− mice when they were exposed to high concentrations of Pi and Ca (Pi+Ca). The phosphorylation of Smad3 was induced in Smad3+/+ vSMCs by exposure to Pi+Ca. The concentration of extracellular pyrophosphate (ePPi) was lower in Smad3−/− vSMCs than in Smad3+/+ vSMCs and was significantly increased in Smad3+/+ vSMCs by treatment with TGF-β1. Also, the addition of a small amount of PPi to culture medium significantly decreased the deposition of Ca in both Smad3+/+ and Smad3−/− vSMCs. Ectonucleotide phosphatase/phosphodiesterase1 (Enpp1) was decreased at the mRNA, protein, and enzymatic activity levels in Smad3−/− vSMCs compared with Smad3+/+ vSMCs. A ChIP assay showed that phosphorylated Smad3 directly binds to the Enpp1 gene. Furthermore, the calcification of aortic segments was attenuated by treatment with TGF-β1 only in Smad3+/+ mice. Taken together, we conclude that Pi-induced vSMC calcification is suppressed by Smad3 via an increase in ePPi.

Risk Factors for Hypocalcemia in Patients with Cancer Receiving Denosumab

ABSTRACT Aim: The potent RANK ligand inhibitor denosumab (Dmab) can cause hypocalcemia (hypoCa). Patients (pts) with inadequate intake of Ca and vitamin D are at increased risk for hypoCa. Additional baseline risk factors for hypoCa in pts with metastatic bone disease (MBD) were evaluated to aid clinical risk assessment for this adverse event. Methods: A post hoc analysis used data from three identically designed, randomized, blinded phase 3 trials comparing monthly dosing of 4 mg zoledronic acid (ZA) to 120 mg Dmab in pts with MBD to identify lab events of grade≥2 hypoCa (CTCAE: Results: The overall incidence of lab grade≥2 hypoCa events in those treated with Dmab was equal to or greater than in those treated with ZA and occurred in 12.4% of Dmab-treated pts. Baseline pt characteristics with the greatest incidence of hypoCa include: male gender (15.4%), prostate cancer (20.5%), small cell lung cancer (18.0%), and CrCl 30 – 2 bone mets and those with higher BSAP or uNTx levels (Table). Osseous lesion type did not significantly increase the risk of developing hypoCa (P ≥ 0.23). Baseline Factor Hazard Ratio 95% CI P-value > 2 bone mets 1.329 (1.044, 1.692) 0.021 BSAP>median (20.77 mg/L) 2.078 (1.579, 2.734) BSAP>median vs≤median > 2 bone mets 4.236 (2.117, 8.479) ≤ 2 bone mets 1.773 (1.312, 2.395) Interaction of baseline BSAP and # of bone mets 0.021 uNTX>50 nmol/mmol 1.316 (1.031, 1.680) 0.027 Interaction of baseline uNTX and # of bone mets 0.21 Conclusions: The risk of hypoCa after Dmab for MBD is associated with the # of bone mets and elevated bone turnover markers, especially high BSAP with>2 mets. BSAP may indicate the potential for deposition of Ca in undermineralized matrix. Pts with high bone turnover may be more susceptible to hypoCa when osteoclasts are rapidly inhibited, particularly when Ca and vitamin D intake is insufficient. Disclosure: J. Body: Consultant for and received research funding from Amgen; received honoraria from Amgen and Novartis; H.G. Bone: Consultant for and received honoraria from Amgen and Novartis; C. van Poznak: Received research funding from Amgen and Novartis; R.H. De Boer: Consultant for and received honoraria from Novartis; received research funding and other remuneration from Amgen and Novartis; A. Stopeck: Consultant for Amgen; honoraria from Amgen and GlaxoSmithKline; research funding from Amgen and Novartis; K. Fizazi: Consultant for Amgen and Novartis; honoraria from Amgen; D.H. Henry: Consultant for and received research funding and honoraria from Amgen, Ortho Biotech, and Watson; T. Ibrahim: Consultant for Amgen; A. Lipton: Honoraria and research funding from Amgen; F. Saad: Consultant for and received research funding and honoraria from Amgen and Novartis; N.D. Shore: Consultant for Amgen, Astellas, Bayer, Dendreon, Janssen, and Medivation; T. Takano: Consultant for and received honoraria from Daiichi-Sankyo; H. Wang: Employee of and owns stock or stock options in Amgen; O.L. Bracco: Employee of and owns stock or stock options in Amgen; A. Balakumaran: Employee of and owns stock or stock options in Amgen; P.J. Kostenuik: Employee of and owns stock or stock options in Amgen. All other authors have declared no conflicts of interest.

Efficiency of microbial phytase supplementation in diets formulated with different calcium:phosphorus ratios, supplied to broilers from 22 to 33 days old

An experiment was conducted with broilers from 22 to 33 days of age to evaluate the efficiency of six microbial phytases supplemented in diets (1500 FTU/kg) that were formulated with three different calcium:available phosphorus (Ca:P(avail)) ratios (4.5:1.0, 6.0:1.0 and 7.5:1.0). A positive control diet without phytase was formulated with a Ca:P(avail) ratio of 7.5:3.4 to meet the nutritional requirements of the broilers. The P and ash contents of the tibia, magnesium in the plasma, performance, balance and retention of phytate phosphorus (P(phyt)), intake of total P and nitrogen (N), nitrogen-corrected apparent metabolizable energy and apparent digestibility of dry matter of the diets were not influenced (p > 0.05) by the type of phytase or the dietary Ca:P(avail) ratio. However, there was an interaction (p < 0.05) between the phytase type and the Ca:P(avail) ratio for the retention coefficients of total P, Ca and N. Phytase B resulted in the highest Ca deposition in the tibia (p < 0.01). Phytases D, E and F reduced the Ca concentrations in the tibia (p < 0.01) and plasma (p < 0.05). Phytase D increased the P level in the plasma and decreased the total P excretion (p < 0.01). Phytases E and F increased Ca excretion, while phytase A reduced it (p < 0.01). Regardless of the phytase type, increasing the dietary Ca:P(avail) ratio reduced (p < 0.05) the plasma P concentration and the excretion of total P and N and, conversely, increased (p < 0.05) the plasma concentration, intake and excretion of Ca. For the rearing period evaluated, it is possible to reduce the P(avail) of the diet to 1.0 g/kg when Ca is maintained at 7.5 g/kg, and the diet is supplemented with 1500 FTU of phytase A, C, D or E/kg. This diet allows the maintenance of performance and adequate bone mineralization, and it improves the Ca, total P and P(phyt) utilization in addition to reducing the excretion of N and P into the environment.

Bioactivity potential of calcium alumino-silicate glasses and glass–ceramics containing nitrogen and fluorine

Calcium alumino-silicate glasses of general composition (in eq.%) 28Ca:57Si:15Al:[100 − (x + y)]O:xN:yF (x = 0 or 20 and y = 0, 3 or 5) and their glass–ceramic counterparts were immersed in simulated body fluid (SBF) at 37 ± 0.5 °C for 28 days to assess their potential bioactivity. The glasses showed no Ca release or surface calcium phosphate deposition due to their high network connectivities (>2.55). The glass–ceramics all showed potential bioactivity, as the SBF became enriched in Ca and calcium phosphate deposits formed on their surfaces. This was a result of Ca release from crystalline phases (predominantly wollastonite in the case of CaSiAlOF glass–ceramics and gehlenite in the case of CaSiAlONF glass–ceramics). No aluminium was leached from the glass–ceramics into the SBF, due to its pH always exceeding 7.0.

Alteration of macronutrients, metal translocation and bioaccumulation as potential indicators of nickel tolerance in three Vigna species

Macronutrients (Na + , K + , Ca 2+ , Mg 2+ ), yield and yield components, bioaccumulation and translocation of metal in plant parts of three Vigna species (V. cylindrica, V. mungo, V. radiata) were evaluated at 0, 50, 100 and 150 mg kg −1 soil of Nickel (Ni). A marked inhibition (p shoot > leaves > seeds. Scoring for percentage stimulation and inhibition (respective to control) at varying levels of Ni revealed tolerance of the species in an order of V. radiata > V. cylindrica > V. mungo. The acquisition of Ni tolerance in V. radiata seems to occur through an integrated mechanism of metal tolerance that includes sustainable macronutrients uptake, stronger roots due to greater deposition of Ca 2+ in the roots, restricted transfer of Ni to above ground tissues and seeds as well as exclusion capacity of the roots to bind appreciable amount of metal to them. Thus, metal tolerant potential of V. radiata could be of great significance to remediate metal contaminated soil owing lesser impact of Ni on macro-nutrients, hence the yield.

Structure and Optical Properties of Ca Silicide Films and Si/Ca&lt;sub&gt;3&lt;/sub&gt;Si&lt;sub&gt;4&lt;/sub&gt;/Si(111) Heterostructures

Thick, thin films and island of Ca silicide have been grown by Ca deposition onto 500 °C Si (111)7x7 substrates. The crystal structure of the grown layers strongly differs from the known Ca silicides (Ca2Si, CaSi, Ca5Si3, Ca14Si19, CaSi2). The phonon peaks at 389 and 416 cm-1 and the interband transition peaks (0.9-1.0, 1.3-1.7 and 2.0-2.5 eV) belongs to another silicide - Ca3Si4. Peculiarities of crystal, electronic, and phonon structure and optical properties of the grown Ca silicide films were measured by in situ and ex situ methods permit to state that the formed Ca silicide film has a composition Ca3Si4. Heterostructures with embedded Ca3Si4 films with different thicknesses have been formed atop the Ca3Si4 films by MBE and SPE at 500 °C. The observed density of pinholes with different sizes suggests the Si growth atop the Ca silicide follows a 3D mechanism. Photoluminescence was found first time in Si/Ca3Si4/Si (111) heterostructures.

The dynamics of calcium and magnesium inputs by throughfall in a forest ecosystem on base poor soil are very slow and conservative: evidence from an isotopic tracing experiment (26Mg and 44Ca)

Using nutrient budgets, it has been proven that atmospheric deposition of Mg and Ca sustains the fertility of forest ecosystems on base-poor soils. However the fate of this nutrient input within the ecosystem was presently unknown. Our hypothesis is that the biological cycling of these nutrients is very rapid and conservative to prevent further Mg and Ca losses most especially in ecosystems on base-poor soils. Stable isotopes of magnesium and calcium (26Mg and 44Ca) were used to trace the dynamics of throughfall Mg and Ca in the forest soil of a 35-year-old beech stand. The aim of the present study was to (1) understand the processes and the velocity of the incorporation of tracers in the biogeochemical cycles and (2) compute Mg and Ca budgets for the ecosystem by isotope dilution. Rainfall Mg and Ca were strongly and rapidly retained mainly by ion exchange in the thin OL litter-layer. However, Ca was much more strongly retained in the litter-layer than Mg. As a result, 2 years after the application of tracers (2012), 92 % of 26Mg and 67 % of 44Ca was released and transferred to the soil or taken up by trees. The vertical transfer of Mg was very slow only 15 % of 26Mg was found below 15 cm depth in 2012. Ca was slower than 26Mg only 9 % of 44Ca was found below 5 cm depth. Although matrix flow was the main vertical transfer process of Ca and Mg, preferential transfer in macropores occurred. Overall, Mg was more rapidly leached through the soil profile than Ca because the soil CEC was mainly composed of organic charges which affinity for Ca is much higher than for Mg. 27 % of 26Mg and 20 % of 44Ca was found in tree biomass and total tracer recovery was close to 100 %. These results suggest that no tracers were lost to drainage over the 2 years. Finally, applying the isotopic dilution theory to the whole-ecosystem enabled us to estimate Mg and Ca budgets −0.9 kg ha−1 year−1 for Mg, which was close to computed input–output budgets −0.8 and 0 kg ha−1 year−1 for Ca, which was very different from input–output budgets (−3.1 kg ha−1 year−1). Our results suggest that a Ca source is underestimated or not taken into account. Over all, organic matter of the litter-layer and in the soil profile played an essential role in the retention of throughfall Mg and Ca and their cycling within the forest ecosystem.

Litterfall Production and Nutrient Deposition Through Leaf Fallen in three Tamaulipan Thornscrub Communities, North-eastern Mexico

Litterfall and the contents of macro- and micro-nutrients derived from its decomposition contribute greatly to the growth and productivity of forest ecosystem. The present study was undertaken to know the variability during two years in the deposition of litterfall and deposition of nutrients through leaf fallen litterfall in three sites of the state of Nuevo Leon (Los Ramones, China and Linares), north-eastern Mexico, which encompasses the Tamaulipan thornscrub plant community. The quantities of litterfall production and its constituents varied between 2009 and 2010, being the year 2010 where higher litterfall and nutrients occured. Mean litterfall production during the two years showed the following trend: Los Ramones (364.8), China (522.7) and Linares (583.1 g m-2 year-1). For leaf constituent, mean deposition ranged from 200.9 (Los Ramones) to 409.8 g m-2 year-1 (Linares), twigs from 62.4 (Los Ramones) to 89.3 (Linares), reproductive structures from 62.5 (Linares) to 80.3 (Los Ramones) and the miscellaneous component, constituted by unidentified plant material, body and insect feces, ranged from 21.1 (Linares) to 32.7 g m-2 year-1 (China). During the two years, mean annual deposition of Ca+K+Mg+P+N for Los Ramones, China and Linares was 10.1, 21.5 and 24.8 g m-2 year-1, respectively. Regardless of the research site, the order of macro and micro-nutrients deposition was as follows: Ca>N>K>Mg>P and Fe>Mn>Zn>Cu, respectively. There were spatial and temporal variations in litterfall deposition in terms of quantity, quality and potential nutrient returns. It is documented that the variability of litterfall and contents of nutrients derived from litterfall is influenced by the physioco-chemical characteristics of soils, diversity in vegetation and climatic conditions prevailing in different sites and years

Morphological and chemical evaluation of bone with apatite-coated Al2O3 implants as scaffolds for bone repair

The clinical challenge in the reconstruction of bone defects has stimulated several studies in search of alternatives to repair these defects. The ceramics are considered as synthetic scaffolds and are used in dentistry and orthopedics. This study aimed to evaluate by micro energy-dispersive X-ray fluorescence spectrometry (µ-EDXRF) and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), the influence of uncoated and apatite-coated Al2O3 implants on bone regeneration. Twelve samples of Al2O3 implants were prepared and half of this samples (n = 6) were apatite-coated by the modified biomimetic method and then the ceramic material were implanted in the tibia of rabbits. Three experimental groups were tested: Group C - control, surgery procedure without ceramic implant, Group Ce - uncoated Al2O3 implants (n = 6) and Group CeHA - apatite-coated Al2O3 implants (n = 6). The deposition of bone tissue was determined by measuring the weight content of Ca and P through surface mapping of bone-implant interface by µ-EDXRF and through point analysis by EDS. It was observed after thirty days of treatment a greater deposition of Ca and P in the group treated with CeHA (p &lt;0.001) compared to group C. The results suggest that ceramic coated with hydroxyapatite (CeHA) can be an auxiliary to bone deposition in tibia defect model in rabbits.

Enhancing Hydrophilicity of Anatase TiO2 Surfaces by Deposition of Alkaline Earths: The Case of Ca

We show with DFT calculations within the COSMO framework that the wetting energy of clean or hydroxylated anatase TiO2 surfaces is strongly enhanced by Ca deposition at low coverage. Two mechanisms contribute to this behavior: the ionic character of Ca adsorption and the inhomogeneity of the transferred charge density, leading together to a strong polarization of the embedding medium. In turn, this polarization is responsible for a large wetting energy and the predicted hydrophilicity. By increasing coverage, Ca adsorption becomes more and more neutral and the transferred charge density is progressively more homogeneous: the effects of the two mechanisms are gradually reduced, leading eventually to surface hydrophobicity at full coverage. In order to support this theory, investigations of the wetting properties of TiO2 slabs in the presence of methane are presented.

Formation and optical properties of semiconducting thick Ca silicide films and Si/CaxSi/Si heterostructures on Si(111) substrate

AbstractSi/Ca2Si/Si(111) and Si/Ca3Si4/Si(111) heterostructures have been formed by procedure of layer‐by‐layer deposition of Ca at 130 °C or 500 °C on previously formed layer of amorphous Si or on a polycrystalline Si layers. Features of electronic structure, optical and electrical properties were established by in situ and ex situ methods. Strong direct interband transitions at 0.89 and 0.912 eV were firstly found for Ca3Si4 film grown at 500 °C. (© 2013 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Potential Contribution of Combined Atmospheric Ca2+ and Mg2+ Wet Deposition Within the Continental U.S. to Soil Inorganic Carbon Sequestration

Abstract Soil inorganic carbon (SIC) stocks continuously change from the formation of pedogenic carbonates, a process requiring inputs of Ca 2+ and Mg 2+ ions. This study ranked the soil orders in terms of potential inorganic carbon sequestration resulting from wet Ca 2+ and Mg 2+ deposition from 1994 to 2003 within the continental United States. The analysis revealed that average annual atmospheric wet deposition of Ca 2+ and Mg 2+ was the highest in the Central Midwest-Great Plains region, likely due to soil particle input from loess-derived soils. The soil orders receiving the highest total average annual atmospheric wet Ca 2+ and Mg 2+ deposition, expressed as potential inorganic carbon formation (barring losses from erosion and leaching), were: 1) Mollisols (1.1 × 10 8 kg C), 2) Alfisols (8.4 × 10 7 kg C), 3) Entisols (3.8 × 10 7 kg C), and 4) Aridisols (2.8 × 10 7 kg C). In terms of area-normalized result, the soil orders were ranked: 1) Histosols (73 kg C km −2 ), 2) Alfisols and Vertisols (64 kg C km −2 ), 3) Mollisols (62 kg C km −2 ), and 4) Spodosols (52 kg C km −2 ). The results of this study provide an estimate of potential soil inorganic carbon sequestration as a result of atmospheric wet Ca 2+ and Mg 2+ deposition, and this information may be useful in assessing dynamic nature of soil inorganic carbon pools.

Metformin Inhibits Vascular Calcification in Female Rat Aortic Smooth Muscle Cells via the AMPK-eNOS-NO Pathway

Metformin exhibits diverse protective effects against diabetic complications, such as bone loss. Here, we investigated the effect of metformin on vascular calcification, another type 2 diabetes complication. In female rat aortic smooth muscle cells (RASMCs), we observed that metformin significantly alleviated β-glycerophosphate-induced Ca deposition and alkaline phosphatase activity, corresponding with reduced expression of some specific genes in osteoblast-like cells, including Runx2 and bone morphogenetic protein-2, and positive effects on α-actin expression, a specific marker of smooth muscle cells. Mechanistic analysis showed that phosphorylation levels of both AMP-activated protein kinase (AMPK) and endothelial nitric oxide synthase (eNOS) were increased with NO overproduction. After inhibition of either AMPK or eNOS with the pharmacologic inhibitors, compound C or Nω-Nitro-L-arginine methyl ester, NO production was lowered and metformin-meditated vascular protection against β-glycerophosphate-induced Ca deposition was removed. Our results support that metformin prevents vascular calcification via AMPK-eNOS-NO pathway.