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Abiogenic metals Pb and Hg are highly toxic since chronic and/or acute exposure often leads to severe neuropathologies. Mn2+ is an essential metal ion but in excess can impair neuronal function. In this study, we address in vitro the interactions between neuronal calcium sensor 1 (NCS1) and divalent cations. Results showed that non-physiological ions (Pb2+ and Mn2+) bind to EF-hands in NCS1 with nanomolar affinity and lower equilibrium dissociation constant than the physiological Ca2+ ion. (Kd, Pb2+ = 7.0 ± 1.0 nM; Kd, Mn2+ = 34.0 ± 6.0 nM; K). Native ultra-high resolution mass spectrometry (FT-ICR MS) and trapped ion mobility spectrometry—mass spectrometry (nESI-TIMS-MS) studies provided the NCS1-metal complex compositions—up to four Ca2+ or Mn2+ ions and three Pb2+ ions (M⋅Pb1-3Ca1-3, M⋅Mn1-4Ca1-2, and M⋅Ca1-4) were observed in complex—and similarity across the mobility profiles suggests that the overall native structure is preserved regardless of the number and type of cations. However, the non-physiological metal ions (Pb2+, Mn2+, and Hg2+) binding to NCS1 leads to more efficient quenching of Trp emission and a decrease in W30 and W103 solvent exposure compared to the apo and Ca2+ bound form, although the secondary structural rearrangement and exposure of hydrophobic sites are analogous to those for Ca2+ bound protein. Only Pb2+ and Hg2+ binding to EF-hands leads to the NCS1 dimerization whereas Mn2+ bound NCS1 remains in the monomeric form, suggesting that other factors in addition to metal ion coordination, are required for protein dimerization.

Pancreatic beta-cells synthesize and secrete insulin maintaining an organism's energy homeostasis. In humans, beta-cell dysfunction and death contribute to the pathogenesis of type 2 diabetes (T2D). Although the causes of beta-cell dysfunction are complex, obesity-induced low-grade systemic inflammation plays a role. For example, obese individuals exhibiting increased levels of proinflammatory cytokines IL-6 and IL-1beta have a higher risk of beta-cell dysfunction and T2D. Interestingly, obesity-induced inflammation changes the expression of several cellular metal regulating genes, prompting this study to examine changes in the beta-cell metallome after exposure to proinflammatory-cytokines. Primary mouse beta-cells were exposed to a combination of IL-6 and IL-1beta for 48 hours, were chemically fixed and imaged by synchrotron X-ray fluorescent microscopy. Quantitative analysis showed a surprising 2.4-fold decrease in the mean total cellular content of zinc from 158 ± 57.7 femtograms (fg) to 65.7 ± 29.7 fg; calcium decreased from 216 ± 67.4 to 154.3 ± 68.7 fg (control vs. cytokines, respectively). The mean total cellular iron content slightly increased from 30.4 ± 12.2 to 47.2 ± 36.4 fg after cytokine treatment; a sub-population of cells (38%) exhibited larger increases of iron density. Changes in the subcellular distributions of zinc and calcium were observed after cytokine exposure. Beta-cells contained numerous iron puncta that accumulated still more iron after exposure to cytokines. These findings provide evidence that exposure to low levels of cytokines is sufficient to cause changes in the total cellular content and/or subcellular distribution of several metals known to be critical for normal beta-cell function.

Significance: Research in tissue engineering and in vitro organ formation has recently intensified. To assess tissue morphology, the method of choice today is restricted primarily to histology. Thus novel tools are required to enable noninvasive, and preferably label-free, three-dimensional imaging that is more compatible with futuristic organ-on-a-chip models. Aim: We investigate the potential for using multiphoton microscopy (MPM) as a label-free in vitro approach to monitor calcium-induced epidermal differentiation. Approach: In vitro epidermis was cultured at the air–liquid interface in varying calcium concentrations. Morphology and tissue architecture were investigated using MPM based on visualizing cellular autofluorescence. Results: Distinct morphologies corresponding to epidermal differentiation were observed. In addition, Ca2+-induced effects could be distinguished based on the architectural differences in stratification in the tissue cultures. Conclusions: Our study shows that MPM based on cellular autofluorescence enables visualization of Ca2+-induced differentiation in epidermal skin models in vitro. The technique has potential to be further adapted as a noninvasive, label-free, and real-time tool to monitor tissue regeneration and organ formation in vitro.

Pulp and paper mill effluent can cause changes in the morphology and energy metabolism in the zebrafish (Danio rerio) testis. Betulin, a naturally occurring triterpene is commonly present in this type of effluent and is suspected of being involved in these effects. The aim of this study was to compare the effects pulp and paper mill effluent and betulin on various aspects of testicular physiology in the zebrafish. This included the in vitro effects of effluent and betulin on testicular lactate content and lactate dehydrogenase (LDH) activity. In addition, the effects of betulin on glucose uptake, glycogen, alanine aminotransferase (ALT), reactive oxygen and nitrogen species formation and oxidative damage in the testes were determined. Furthermore, we compared the effects and mechanism of action of betulin and effluent on calcium homeostasis in testes. In vitro exposure to both effluent and betulin decreased lactate and calcium influx, possibly due to the activation of the sodium‑calcium exchanger (NCX) pump. Additionally, betulin-treated testes had higher reactive oxygen species (ROS) and reduced glutathione (GSH) content, as well as increased glutathione transferase (GST) activity and a tendency towards decreased catalase (CAT) activity. Thus, this study shows that alterations in testis physiology caused by the pulp and paper mill effluent in the testis may be due in part to the actions of betulin.

Lime mud is a kind of solid waste in the papermaking industry, which has been a source of serious environmental pollution. Ceramsites containing anorthite and gehlenite were prepared from lime mud and fly ash through the solid state reaction method at 1050°C. The objective of this study was to explore the efficiency of Ca 2 + and OH − release and assess the phosphorus and copper ion removal performance of the ceramsites via batch experiments, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that Ca 2 + and OH − were released from the ceramsites due to the dissolution of anorthite, gehlenite and available lime. It is also concluded that gehlenite had stronger capacity for Ca 2 + and OH − release compared with anorthite. The Ca 2 + release could be fit well by the Avrami kinetic model. Increases of porosity, dosage and temperature were associated with increases in the concentrations of Ca 2 + and OH − released. Under different conditions, the ceramsites could maintain aqueous solutions in alkaline conditions (pH = 9.3–10.9) and the release of Ca 2 + was not affected. The removal rates of phosphorus and copper ions were as high as 96.88% and 96.81%, respectively. The final pH values of both phosphorus and copper ions solutions changed slightly. The reuse of lime mud in the form of ceramsites is an effective strategy.

Deacidification is an established conservation treatment for the prolongation of the acidic paper stability. Several different deacidification systems are in use today, such as the dispersions of alkaline nanoparticles in organic solvents. The aim of the study was to compare the effects of different calcium nanoparticle dispersions in alcohols on lignocellulosic paper. Commercially available nano calcium hydroxide dispersions for paper deacidification, and laboratory prepared nano calcium carbonate dispersions in ethanol and 2-propanol were investigated and compared as to their effectiveness in increasing the stability of paper. The FE-SEM analyses were used to determine the size of Ca(OH)2 and CaCO3 particles in the dispersions. The SEM–EDS analyses were performed both on the paper surface and its cross-section in order to ascertain the distribution of calcium ions following the deacidification treatment. An evaluation of the changes of color, molecular weight, pH and alkaline reserve on different lignocellulosic papers was performed. In comparison to untreated samples, our results indicate all the investigated deacidification treatments decrease the degradation rate constant of cellulose, as determined by accelerated degradation. However, the treatments involving nano calcium hydroxides in both alcohols noticeably affect the color of the treated lignocellulosic papers. According to the obtained results, nano calcium carbonate is therefore the more suitable deacidification agent for the lignin containing papers.

Modulation of brain state, e.g., by anesthesia, alters the correlation structure of spontaneous activity, especially in the delta band. This effect has largely been attributed to the ∼1 Hz slow oscillation that is characteristic of anesthesia and nonrapid eye movement (NREM) sleep. However, the effect of the slow oscillation on correlation structures and the spectral content of spontaneous activity across brain states (including NREM) has not been comprehensively examined. Further, discrepancies between activity dynamics observed with hemoglobin versus calcium (GCaMP6) imaging have not been reconciled. Lastly, whether the slow oscillation replaces functional connectivity (FC) patterns typical of the alert state, or superimposes on them, remains unclear. Here, we use wide-field calcium imaging to study spontaneous cortical activity in awake, anesthetized, and naturally sleeping mice. We find modest brain state-dependent changes in infraslow correlations but larger changes in GCaMP6 delta correlations. Principal component analysis of GCaMP6 sleep/anesthesia data in the delta band revealed that the slow oscillation is largely confined to the first three components. Removal of these components revealed a correlation structure strikingly similar to that observed during wake. These results indicate that, during NREM sleep/anesthesia, the slow oscillation superimposes onto a canonical FC architecture.

Background: Development of cost-effective platforms for identification of biomarkers is of paramount importance in low-income settings. The present work focuses on the development of a microfluidic paper-based analytical device (μPADs) for the diagnosis of osteoporosis by measuring three important bone biomarkers – calcium, alkaline phosphatase and vitamin D. Methods: Antibody-based detection is realized in μPAD reservoirs based on principle of colorimetric sensing, where μPAD images are captured using a smartphone. The results are compared with the calibration curves to give proper quantification of analytes. Conclusion: This device can be potentially developed into a point-of-care diagnostic device for low-income settings. To the best of our understanding, a μPAD platform for simultaneous diagnosis of multiple osteoporosis markers is not reported yet.

In this communication a prototype of paper-based analytical device designed for simultaneous determination of orthophosphate and calcium ions, which levels are significant for hyperphosphatemia diagnostics, is presented. The laboratory-on-paper structure for two analytes detection was wax-printed on the surface of filter paper. These two-analyte disposable paper strips are combined with two paired LED-based fluorescence detectors and simple voltmeter used as recorder of analytical signal, what makes the developed device miniature, extremely low-cost, portable and user-friendly. Thus the developed device allows usage outside of specialized clinical laboratory. Moreover, each paper strip is disposable and its utilization is easy and fast and, additionally, burnt strip tests ensure waste non-infectious. The presented LED&Paper-based analytical device provides low detection limits: 1.4 μmol L−1 and 7.4 μmol L−1 for orthophosphate and calcium ions, respectively. The practical utility of the developed device for calcemia/phosphatemia diagnostics is demonstrated using control serum standards and real human serum.

Significance: Photobiomodulation is a well-established therapeutic modality. However, the mechanism of action is poorly understood, due to lack of research in the causal relationship between the near-infrared (NIR) light irradiation and its specific biological effects, hindering broader applications of this technology. Aim: Since biological chromophores typically show several absorption peaks, we determined whether specific effects of photobiomodulation are induced with a combination of two wavelengths at a certain range of irradiance only, rather than a single wavelength of NIR light. Approach: In order to analyze a wide array of combinations of multispectral NIR light at various irradiances efficiently, we developed a new optical platform equipped with two distinct wavelengths of NIR lasers by high-throughput multiple dosing for single-cell live imaging. Two wavelengths of 1064 and 1270 nm were selected based on their photobiomodulatory effects reported in the literature. Results: A specific combination of wavelengths at low irradiances (250 to 400 mW/cm2 for 1064 nm and 55 to 65 mW/cm2 for 1270 nm) modulates mitochondrial retrograde signaling, including intracellular calcium and reactive oxygen species in T cells. The time-dependent density functional theory computation of binding of nitric oxide (NO) to cytochrome c oxidase indicates that the illumination with NIR light could result in the NO release, which might be involved in these changes. Conclusions: This optical platform is a powerful tool to study causal relationship between a specific parameter of NIR light and its biological effects. Such a platform is useful for a further mechanistic study on not only photobiomodulation but also other modalities in photomedicine.

Clinical and subclinical hypocalcaemia are common in dairy cows, yet evidence in the literature assessing their impact on fertility is inconsistent. The aim of this prospective cohort study was to examine associations between blood ionised calcium concentration at calving and fertility outcomes in dairy cattle. Blood samples were taken from 137 Holstein cows from four commercial dairy herds within 24 hours of calving and analysed for blood ionised calcium using an Epocal Point of Care Analyser (Epocal, Ottawa, Canada). Data collected from routine veterinary fertility examinations and herd records were used to investigate the association of ionised calcium with the outcomes: time to first service, time to conception and endometritis. There were significant negative associations between blood ionised calcium concentration and time to first service (HR 1.33, P=0.001) and blood ionised calcium concentration and time to conception (HR 1.16, P=0.04). There was no significant association between blood ionised calcium concentration and endometritis. The results of this study imply that management policies that minimise the reduction in blood ionised calcium concentration in the periparturient dairy cow are likely to improve reproductive outcomes and should be considered as part of the multifactorial approach to optimising dairy cow fertility.

Lignosulfonates are important by-products of the paper industry and may be transformed into different commodities. We studied the molecular properties of ammonium (LS-AM) and calcium Lignosulfonates (LS-C) and evaluated their bioactivity towards the early development of maize plantlets. The FT-IR, 13C NMR and 1H-13C-HSQC-NMR spectra showed that the two lignosulfonates varied in hydroxyl, sulfonate and phenolic content, while DOSY-NMR spectroscopy suggested a similar diffusivity. High Performance Size Exclusion Chromatography (HPSEC) was used to simulate the effects of root-exuded acids and describe the conformational dynamics of both LS substrates in acidic aqueous solutions. This technique showed that LS-C was stabilized by the divalent Ca2+ counterion, thus showing a greater conformational stability than LS-AM, whose components could not be as efficiently aggregated by the monovalent NH4+ counter-ion. The plant bioassays revealed that LS-AM enhanced the elongation of the root system, whereas LS-C significantly increased both total and shoot plant weights. We concluded that the lignosulfonate bioactivity on plant growth depended on the applied concentrations, their molecular properties and conformational stability.

We employ transcranial wide-field single-photon imaging to compare genetically encoded calcium sensors under transgenic or viral vector expression strategies. Awake, head-fixed animals and brief visual flash stimuli are used to assess function. The use of awake transcranial imaging may reduce confounds attributed to cranial window implantation or anesthesia states. We report differences in wide-field epifluorescence brightness and peak ΔF/F0 response to visual stimulation between expression strategies. Other metrics for indicator performance include fluctuation analysis (standard deviation) and regional correlation maps made from spontaneous activity. We suggest that multiple measures, such as stimulus-evoked signal-to-noise ratio, brightness, and averaged visual ΔF/F0 response, may be necessary to characterize indicator sensitivity and methods of expression. Furthermore, we show that strategies using blood brain barrier-permeable viruses, such as PHP.eB, yield comparable expression and function as those derived from transgenic mice. We suggest that testing of new genetically engineered activity sensors could employ a single-photon, wide-field imaging pipeline involving visual stimulation in awake mice that have been intravenously injected with PHP.eB.

Recycled paper mills produce large quantities of fibrous rejects and fines which are usually sent to landfills as solid waste. These cellulosic materials can be enzymatically hydrolyzed into sugars for the production of biofuels and biomaterials. Paper mill wastes also contain large amounts of calcium carbonate which inhibits cellulase activity. The calcium carbonate (30%, w/w) decreased 40–60% of sugar yield of unbleached softwood kraft pulp. The prime mechanisms for this are by pH variation, competitive and non-productive binding, and aggregation effect. Addition of acetic acid (pH adjustment) increased the sugar production from 19 to 22 g/L of paper mill waste fibers. Strong affinity of enzyme—calcium carbonate decreased free enzyme in solution and hindered sugar production. Electrostatic and hydrogen bond interactions are mainly possible mechanism of enzyme—calcium carbonate adsorption. The application of the nonionic surfactant Tween 80 alleviated the non-productive binding of enzyme with the higher affinity on calcium carbonate. Dissociated calcium ion also inhibited the hydrolysis by aggregation of enzyme.

In this work, we applied scanning electron microscopy (SEM), microanalysis and Raman spectroscopy to study the fungi inhabiting a richly illuminated parchment document and the damage induced by their activity. To that aim, we collected samples of fungal mycelium from the deteriorated areas on a removable adhesive tape specifically intended for lifting fungi without damaging the support. SEM analysis of the adhesive tape samples showed the co-occurrence of several species of fungi. One strain closely resembling Acremonium species was observed only in the tape micrographs but no agar cultures were obtained. Its fungal structures showed the production of abundant oxalates with an outstanding leaching of the calcium-based materials of parchment (typically manufactured with gypsum and lime). Needle-like crystals of calcium oxalate produced by the fungus forming a uniform and quite regular grid around conidial slimy heads were documented. As a result, the areas affected by moulds were weakened, stained and characterised by a powdery patina rich in calcium. Confocal μ-Raman confirmed the presence of oxalates while EDS showed the presence of calcium in crystals. We conclude that the defacement of the parchment was due to both collagenolytic activity, and to the biotransformation of calcium-based minerals by fungi.

A sample set of model graded papers containing known organic and inorganic components was used to culture an Aspergillus terreus strain able to produce acidic metabolites and cellulolytic enzymes. This study set out to document the biogenic formation of calcium oxalate crystals, as a consequence of fungal activity and growth, on a range of paper samples. Scanning electron microscopy and FTIR spectroscopy techniques were employed to achieve this end. Bioleaching processes induced by fungi on carbonate used in the manufacture of paper, together with the capacity of fungi to produce - very rapidly - significant biogenesis of monohydrate and dihydrate calcium oxalate crystals on the surface of papers, were investigated. SEM images of calcium containing paper samples disclosed a very clear difference in the pattern of inorganic material distribution when areas spoiled by fungi and those not affected by fungal growth were compared. In addition, the FTIR spectrum of CaCO(3) sized paper clearly demonstrated, following fungal growth, the FTIR absorbance of fungus and calcium oxalate, together with the disappearance of carbonate bands. (C) 2010 Elsevier Ltd. All rights reserved.

We used toxicity identification evaluation (TIE) method to confirm the combinational effects of identified toxic metals in a paper recycling mill effluent in inducing the decreased lifespan in nematode Caenorhabditis elegans. Exposure to Ca + Al caused more severely decreased lifespan than that exposed to Ca, or Al; and exposure to Ca + Fe induced more severely decreased lifespan than that exposed to Ca, or Fe. Exposure to Ca+Al+Fe caused more severely decreased lifespan than that exposed to Ca, or Ca+Fe. Moreover, the baseline toxicity on lifespan was doubled by doubling the concentration of combined metals (Ca+Al+Fe) in spiking test in original effluent (oe), and lifespan defects in oe+Ca+Al+Fe exposed nematodes were more severe than that in Ca+Al+Fe exposed nematode. Therefore, Ca+Al+Fe exposure may largely explain the formation of decreased lifespan induced by the examined industrial effluent. Furthermore, the observed reduction of lifespan induced by the combination of high level of Ca with other metals may be at least partially independent of the insulin-like pathway.

The objective of this paper is to identify deflocculation under short-term disturbances of dissolved oxygen (DO) in a continuous system, and to explore the strategies for minimizing the carry-over of biosolids. Sludge deflocculation was examined in four parallel sequencing batch reactors (SBRs) fed with primary treated effluents from a bleached kraft pulp and paper mill. Results show that the DO transients caused a reduction of soluble COD (SCOD) removal efficiency by 50–70%, increases in suspended solid (SS) concentration and turbidity by more than 100%. Under the DO disturbances, the ratio of bulk Ca2 + /K+ decreased by 10% in the treated effluents. All these changes were reversible within 24 hrs after the DO concentrations were restored up to 4 mg/L, indicating a physicochemical response of microorganisms to the DO transients. The sludge deflocculation is correlated with the decreasing ratio of Ca2 + to K+ in the extracellular environment. Addition of calcium chloride, tetraethylammonium chloride or glibenclamide promotes the formation of bioflocs bigger than 12.5 μm, but the deflocculation of biosolids under the DO transients wasn't completely prevented.

The main objective of this work is to study the technical viability of using the effluent generated in paper machines (white water) in the wash presses of the bleaching stage, reducing fresh water consumption. As a case study, the industrial process of Ripasa S.A. Celulose e Papel was evaluated. White water rate is about 700 m3/h and it is not possible to reuse all this volume in the bleaching stage without causing operational problems (fouling in tubes and clogging in the screens). A mass balance of the bleaching unit was developed in an electronic spreadsheet in order to evaluate the possibility of reducing fresh water consumption, using only a fraction of the available white water in the wash presses. To achieve this objective some physical-chemistry properties of the white water stream and of other streams of the process were determined. The maximum concentration of some non-process elements (Si, Ca, Mn and Fe), which could accumulate in the process, were determined in order to establish some parameters to allow process integration of the streams involved, considering operational constraints. The results obtained have shown that it is possible to reduce approximately by 13% the consumption of fresh water and this methodology has been satisfactory.

The objective of this study was to investigate the synthesis of zeolites from paper sludge ash, and to evaluate their applications for water purification to simultaneously remove NH4+ and PO43- in aqueous solution. Paper sludge ash had a low abundance of Si and a significant Ca content, due to the presence of calcite that was used as paper filler. Na2SiO3 was added to the NaOH solution to increase Si content in order to synthesize zeolites with high cation exchange capacity. The original ash without addition of Si yielded hydroxysodalite with a cation exchange capacity of ca. 50 cmol/kg. Addition of Si to the solution yielded Na-P1 (zeolite-P) with a higher cation exchange capacity (ca. 120 cmol/kg). The observed concentrations of Si and Al in the solution during the reaction explain crystallizations of these two phases. The product with Na-P1 could simultaneously remove NH4+ and PO43- from the solution between pH 4 and 9.

Paper sludge ash was partially converted into zeolites by reaction with 3M NaOH solution at 90 degrees C for 24 h. The paper sludge ash had a low abundance of Si and significant Ca content, due to the presence of calcite that was used as a paper filler. Diatomite was added to the NaOH solution to increase its Si content in order to synthesize zeolites with high cation exchange capacity. Diatomite residue was filtered from solution before addition of ash. The original ash without addition of diatomite yielded hydroxysodalite with a cation exchange capacity ca. 50 cmol/kg. Addition of Si to the solution yielded Na-P1 (zeolite-P) with a higher cation exchange capacity (ca. 130 cmol/kg). The observed concentrations of Si and Al in the solution during the reaction explain the crystallization of these two phases. The reaction products were tested for their capacity for PO(4)(3-) removal from solution as a function of Ca(2+) content, suggesting the formation of an insoluble Ca-phosphate salt. The product with Na-P1 exhibits the ability to remove NH(4)(+) as well as PO(4)(3-) from solution in concentrations sufficient for application in water purification. Both NH(4)(+) and PO(4)(3-) removal showed little variation with pH between 5 and 9. Alternative processing methods of zeolite synthesis, including the addition of ash to an unfiltered Si-NaOH solution and addition of a dry ash/diatomite mixture to NaOH solution, were tested. The third process yielded materials with lower cation exchange capacity due to formation of hydroxysodalite. The second process results in a product with relatively high cation exchange capacity, and reduces the number of processing steps necessary for zeolite synthesis.

Objective: To assess the correlation of serum parathyroid hormone (PTH) and vitamin D (25-OHD) levels based on different assays for measuring 25-OHD in healthy Saudi Arabians living along the east coast. Patients and Methods: A cross-sectional study was conducted in 200 patients (150 women and 50 men aged between 18-69 years) between January 2011 and December 2012, attending outpatient clinic at King Fahd Hospital of the University, Al Khobar. The first 200 patients seen without vitamin D supplementation at clinic were enrolled in the study. Serum calcium, phosphorous, alkaline phosphatase, parathormone, and 25-OHD tests were performed. 25-OHD was assessed using:chemiluminescence immunoassay (CLIA)radioimmunoassay (RIA) using Wallac 1470 Gamma CounterHPLC –LC.MS (high performance liquid chromatography-liquid chromatography with mass spectrometry. The data was collected, entered into a database and analysed using SPSS, Inc., version 14. Results: The mean age was 45.8±15.8 (18-74) years, and calcium level was 2.27±0.15 mmol/l. (range 2.125 to 2.62 mmol/l). Alkaline phosphatase was 88.91±35.94 (34-302) IU, parathormone 6.7±3.06 (1.35-21.2) (1.3-6.8 pmol/l). Of the participants, 188 were either vitamin D insufficient or deficient as measured by CLIA 11.85±6.14 (2-29.6), and 91 (48.4%) of them had secondary hyperparathyroidism 9.48±4.55 pc/l. Those with normal CLIA-measured 25-OHD levels had normal PTH levels. Of those with insufficiency, 4/21 (19%) had raised PTH levels; and of those with deficiency, 81/166 (48.79%) had raised levels, whereas with HPLC-LC.MS, 156 were shown to be insufficient and 97 deficient (with PTH level of 7.41±4.2). Thirteen of 41 patients (31.7%) with insufficiency were shown, by HPLC-LC.MS, to have raised PTH. All patients with vitamin D deficiency as diagnosed by HPLC-LC.MS had secondary hyperparathyroidism. Conclusions: The above results suggest that the method of measurement strongly influences vitamin D levels and that previous reports suggesting no association between vitamin D deficiency and secondary hyperparathyroidism should be viewed with caution.

Quantitative determination of Ca, Mg, and Zn in fingernails was performed with laser-induced breakdown spectroscopy. Two different methods of producing solid standards for calibration were explored – preparation of keratin pellets and deposition of aqueous solutions to filter papers. Measurements of the temperature and electron density of the plasma produced on keratin pellets, filter paper, and nails were performed, and it was determined that the standards prepared on filter paper gave plasma temperatures and electron densities closer to those observed on the nails. The ablation rate of the filter paper was also more similar to that of the nails. Using calibration curves produced using these filter paper standards, Ca, Mg, and Zn were determined in fingernails of 11 subjects. For comparison, the same samples were digested and atomic absorption was used to determine the same three elements. The differences in results are discussed in light of sample homogeneity and instrumental precision; the best agreement was obtained for determination of Zn. The work suggests that the filter paper method of standard preparation may be appropriate for LIBS analysis of other samples that give relatively low temperature, low electron density plasmas (i.e., polymers).

This paper describes the results of laboratory experiments using a thermophilic aerobic MBR (TMBR) at 50 °C. An innovative use of submerged flat-sheet MBR modules to treat circuit wastewater from the paper industry was studied. Two experiments were conducted with a flux of 8–13 L/m 2 /h without chemical membrane cleaning. COD and BOD 5 elimination rates were 83% and 99%, respectively. Calcium was reduced from 110 to 180 mg/L in the inflow to 35–60 mg/L in the permeate. However, only negligible membrane scaling occurred. The observed sludge yield was very low and amounted to 0.07–0.29 g MLSS/g COD eliminated . Consequently, the nutrient supply of ammonia and phosphate can be lower compared to a mesophilic process. Molecular-biological FISH analysis revealed a likewise high diversity of microorganisms in the TMBR compared to the mesophilic sludge used for start-up. Furthermore, ammonia-oxidising bacteria were detected at thermophilic operation.

The mechanism underlying the mineralization of bone is well studied and yet it remains controversial. Inherent difficulties of imaging mineralized tissues and the aqueous solubility of calcium and phosphate, the 2 ions which combine to form bone mineral crystals, limit current analyses of labile diffusible, amorphous, and crystalline intermediates by electron microscopy. To improve the retention of calcium and phosphorus, we developed a pseudo nonaqueous processing approach and used it to characterize biomineralization foci, extracellular sites of hydroxyapatite deposition in osteoblastic cell cultures. Since mineralization of UMR106-01 osteoblasts is temporally synchronized and begins 78 h after plating, we used these cultures to evaluate the effectiveness of our method when applied to cells just prior to the formation of the first mineral crystals. Our approach combines for the first time 3 well-established methods with a fourth one, i.e. dry ultrathin sectioning. Dry ultrathin sectioning with an oscillating diamond knife was used to produce electron spectroscopic images of mineralized biomineralization foci which were high-pressure frozen and freeze substituted. For comparison, cultures were also treated with conventional processing and wet sectioning. The results show that only the use of pseudo nonaqueous processing was able to detect extracellular sites of early calcium and phosphorus enrichment at 76 h, several hours prior to detection of mineral crystals within biomineralization foci.

N-terminal and C-terminal (CT) domains of amelogenin have been shown to be essential for proper enamel formation. Recent studies have also suggested that although the C-terminus plays an apparent role in protein-mineral interactions, other amelogenin structural domains are involved. The objective was to explore the role of the amelogenin N-terminus in the regulation of calcium phosphate formation in vitro. Spontaneous mineralization studies were carried out using the phosphorylated (+P) and nonphosphorylated (–P) N-terminus of the leucine-rich amelogenin peptide (LRAP) that lacks the hydrophilic CT domain. Mineralization progress was monitored via changes in solution pH. Mineral phases formed were characterized using TEM, selected area electron diffraction, and FT-IR. In controls, amorphous calcium phosphate was initially formed and subsequently transformed to randomly oriented hydroxyapatite (HA) plate-like crystals. In contrast to the control, LRAP(+P)-CT stabilized ACP formation for >1 day, while LRAP(–P)-CT accelerated the transformation of ACP to HA but had little effect on crystal shape or orientation. In conclusion, the N-terminal domain found in LRAP, as in amelogenins, appears to have the capacity to interact with forming calcium phosphate mineral phases. Results suggest that the N-terminal domain of amelogenin may play a direct role in early stages of enamel formation.

Yüksek miktarda kalsiyum içeren atıksular; su boruları, kaynama kazanları ve ısı değiştiricilerde farklı biçimde çökelekler (karbonat, sülfat ve fosfat) oluşturmakta, aerobik ve anaerobik reaktörlerin arıtım performansını olumsuz etkilemektir. Bu problemleri ortadan kaldırmak için endüstrilerde kimyasal prosesler kullanılmakta ancak bu prosesi içeren reaktörlerin işletimi ve kontrolü oldukça zordur. Ayrıca arıtılmış suyun pH değerleri de yüksektir. Sulardan Ca gideriminde biyomineralizasyon iyi bir alternatif olarak görünmektedir. Biyokatalitik Kalsifikasyon Reaktörleri (BKR) endüstriyel atıksulardan Ca’u kalsit olarak gidermek için bakterilerin gerçekleştirdiği üre hidrolizi esasına dayanır. Bu çalışmada BKR’ün Ca içeren sentetik ve gerçek şeker endüstrisi atıksularından Ca giderimindeki potansiyel kullanımı araştırılmıştır. Çalışmanın başlıca aşamaları; (1) kesikli reaktörlerde Ca+2 giderimini katalizleme yeteneğine sahip çamur üretimi, (2) kesikli reaktörlerde optimum Mikrobiyal Karbonat Çökelimi (MKÇ) için uygun süre, pH değerleri, üre, Ca, biyokütle ve organik derişimleri gibi optimum koşulların belirlenmesi, (3) sürekli beslemeli sistemde optimum tasarım ve işletme parametrelerinin araştırılması, (4) YAÇYR(Yukarı Akışlı Çamur Yatak Reaktör)’de metanojenik bakteriler üzerine Ca’un etkisinin belirlenmesi, (5) Ca’lu atıksuların arıtımı için ardışık BKR/YAÇYR sisteminin araştırılması, (6) Ca’lu atıksuların YAÇYR’de arıtımında geri döngü hattına BKR’ün ilave edilmesi ile CO2 sıyırıcı sistemin modifikasyonu. Mineral ortam ve Glikoz-KOİ’sin sürekli yenilendiği inkübasyon süresinin Ca giderimine etkisinin araştırıldığı kesikli çalışmalarda optimum inkubasyon süresi 6 gün bulunmuştur. Kesikli reaktörde Ca giderimi üzerinde ürenin etkisinin araştırıldığı çalışmada optimum üre derişiminin Ca derişiminden fazla olması gerekmektedir. Kesikli reaktörde Ca giderimi üzerinde Ca derişiminin etkisinin araştırıldığı çalışmada 900 mg/L sabit üre ve 0-2500 mg/L arasında Ca derişimleri içeren sentetik atıksuda sonuçlar Ca derişimi arttıkça giderilen miktarın da arttığını göstermiştir. Kesikli reaktörde Ca giderimi üzerinde 4-10 arası değişik başlangıç pH’larının etkisinin araştırıldığı çalışmada Ca gideriminin yüksek pH’larda daha iyi olduğu, ve çökelme ile beraber alkalinitenin tükenmesi ile birlikte son pH değerlerinin tüm reaktörlerde yaklaşık aynı olduğu (pH=7) bulunmuştur. Kesikli reaktörde Ca giderimi üzerine biyokütle derişiminin etkisinin araştırıldığı çalışmada sonuçlar Ca gideriminin biyolojik aktiviteye kesinlikle bağlı olduğunu göstermiştir. Ca giderim süreci üzerinde organik madde derişiminin etkisinin araştırıldığı çalışmada Ca giderimi için en uygun derişiminin deneysel şartlarda 750 mg/L glikoz-KOİ’si olduğu tespit edilmiştir. Ca giderimi üzerinde yaklaşık 2-20 gün arasında çamur yaşlarının araştırıldığı sürekli beslemeli çalışma kalsiyum gideriminde ÇY’nın önemli bir parametre olduğunu ve 11.5 saat’lik HBS’de Ca ve KOİ giderimi için 5 gün civarında olduğunu göstermiştir. Çalışma HBS’nin önemli bir parametre olduğunu ve kalsiyumca zengin atıksulardan Ca giderimi için 5-6 saatlik HBS’nin optimum olduğunu göstermiştir. Bu HBS’nde KOİ, TN, ve Ca giderim verimleri sırasıyla % 63, % 14 ve % 72 elde edilmiştir. Elde edilen optimum ÇY ve HBS’nde 0-1500 mg/L arasında değişen glikozKOİ’sinin etkisinin araştırıldığı sürekli beslemeli çalışmada KOİ’nin düşük değerlerinin bile Ca giderimi için yeterli olduğunu göstermektedir. 5-20 mM arasında üre derişiminin 15 mM Ca içeren sentetik atıksuyu arıtan ürolitik karışık kültür üzerindeki etkisinin araştırıldığı çalışmada Ca giderimi için optimum üre derişimi 15 mM bulunmuştur. Ca içeren bir şeker fabrikasından temin edilen gerçek atıksuyun sürekli beslemeli arıtım çalışmasında YAÇYR’ün önüne ve geri döngüsüne yerleştirilen BKR’ü atıksudan Ca’u etkin şekilde gidermiştir. Sonuç olarak çalışmada önerilen MKÇ esasına dayanan BKR’ü, Ca açısından zengin endüstriyel atıksuların yeniden kullanılacağı durumlarda kullanılabilir olmakla birlikte üreden kaynaklanan azot kirliliğine neden olması en büyük dezavantajıdır., Wastewaters having high calcium content; produce precipitates of different structure (as carbonate, sulfate or phosphate) in pipelines, boilers and heat exchangers and, affects adversely to aerobic and anaerobic reactors. As a remedy to this problem, the industry typically uses chemical crystallization reactors which are efficient but often require complex monitoring and control and, as a drawback, can give rise to highly alkaline effluents. Biomineralization are emerging as alternative mechanisms for the removal of Ca from aqueous environments. Bio-catalytic Calcification Reactors (BCR) utilize microbial urea hydrolysis by bacteria for the precipitation-removal of Ca, as calcite, from industrial wastewater. In this study, potential use of BCR for Ca removal from synthetic wastewater and real sugar wastewater were investigated. The main stages of this study were; (1) production of sludge which has ability to biocatalysing of Ca2+ removal in batch reactors, (2) determination of optimal conditions such as; time, pH value, urea, Ca, biomass, and organic matter concentrations, for effective Microbial Calcium Precipitation (MCP) (3) investigation of optimum design and operational parameters of BCR reactor in continuous feeding system, (4) determination of Ca effect on methanogenic microorganisms in UASB reactor, (5) researching of sequential BCR/UASB (Upflow Anaerobic Sludge Blanket) reactor system for treatment of Ca-rich wastewaters, (6) modification of CO2-stripper system with addition of BCR reactor installing in the recycle line at UASB treatment of Ca-rich wastewaters. In batch study, investigation of incubation time on Ca removal at synthetic wastewater where mineral medium and glucose-COD continuously refreshed, optimum incubation time was found as 6 days at these conditions. In batch study, investigation of urea effect on Ca removal, it was found that optimum urea concentration for effective Ca removal should be greater than Ca concentration required removal from water. In batch study, investigation of Ca concentration effect on Ca removal, removed Ca concentration was increased at samples containing higher Ca concentrations in synthetic wastewater with constant urea of 900 mg/L and varying Ca concentration between 0 and 2500 mg/L. In batch study, the investigation of initial pH of samples between 4-10 on calcium removal, calcium was better removed at samples with higher pH and final pHs of all samples finally were approximately same (pH=7) due to precipitation of Ca as CaCO3 and consumption of alkalinity. In batch study, investigation of biomass concentration on Ca removal, it was found that Ca removal certainly depends on biological activity. In batch study, investigation of organic matter effect on Ca removal, the most suitable concentration of glucose-COD was 750 mg/L at experimental conditions. The continuous fed study of sludge retention times between about 2 and 20 days on Ca removal showed that SRT is important parameter for Ca removal and optimum SRT was about 5 days in terms of Ca and COD removal at HRT of 11.5 hours. Study showed that HRT is important parameter and HRT of 5-6 hours is optimum for Ca removal from Ca-rich wastewaters. At this HRT, the removal efficiencies of COD, TN, and Ca were obtained a 63 %, 14 % and 72 %, respectively. At obtained optimum SRT and HRT, continuous fed study, investigation of glucose-COD between 0 and 1500 mg/L effect on Ca removal, showed that low levels of COD was also sufficient for calcium removal. The study, carried out to determine urea concentrations between 5-20 mM on ureolytic mixed culture treating synthetic wastewater containing Ca of 15 mM, showed that optimum urea concentration was found as 15 mM for effective Ca removal. In continuous study carried out with a real wastewater of a sugar fabric, BCR reactor established at prior to and recycle of UASB reactor removed efficiently Ca from wastewater. Consequently, the proposed BCR based on MCP can be used in case of reusing of treated Ca-rich industrial wastewater, however the most important disadvantage of this process is N pollution from urea., ÖNSÖZ, i – TEŞEKKÜR, iii -- İÇİNDEKİLER DİZİNİ, iv – ÖZET, vi – ABSTRACT, vii -- ŞEKİLLER DİZİNİ, viii -- ÇİZELGELER DİZİNİ, xii -- SİMGELER VE KISALTMALAR DİZİNİ, xiv -- 1. GİRİŞ, 1 -- 2. KAYNAK ÖZETLERİ, 5 -- 2.1. Kalsiyum Metalinin Özellikleri, 5 -- 2.2. Kalsiyum Bileşikleri, 5 -- 2.3. Kalsiyum Bileşiklerinin Endüstride Kullanımı ve Etkileri, 6 -- 2.4. Kalsiyum Karbonat’ın (CaCO3) Özelikleri ve Kullanım Alanları, 7 -- 2.5. Kalsiyum Hidroksit’in (Ca(OH)2) Özellikleri ve Kullanım Alanları, 8 -- 2.6. Kalsiyum Oksit’in (CaO-Kireç) Özellikleri ve Kullanım Alanları, 9 -- 2.7. Kalsiyum ve Bileşiklerinin Sağlık Etkileri, 10 -- 2.8. Endüstriyel Su Kullanımı, 11 -- 2.8.1. Kazan besleme suları, 11 -- 2.8.2. Soğutma suları, 12 -- 2.8.3. Endüstri proses suları, 14 -- 2.9. Sulardan Kalsiyum Giderim Yöntemleri, 15 -- 2.9.1. Sulardan kimyasal kalsiyum giderimi, 15 -- 2.9.1.1. Kimyasal çöktürme yöntemleri ile sertlik giderimi, 15 -- 2.9.1.2. İyon değiştirme yöntemi, 20 -- 2.9.2. Doğal mikrobiyolojik karbonat çökelim prosesleri, 21 -- 2.9.2.1. Ototrofik metabolik prosesler, 22 -- 2.9.2.2. Heterotrofik metabolik prosesler, 23 -- 2.9.2.2.1. Pasif CaCO3 çökelim prosesleri, 23 -- 2.9.2.2.2. Aktif CaCO3 çökelim prosesleri, 25 -- 2.10. Arıtım Teknolojileri Açısından Kalsiyumun Zararları, 26 -- 2.11. Kalsiyum Gideriminin Atıksu Arıtım Biyoteknolojisi Açısından Önemi, 26 -- 2.12. Çalışmanın Amacı, 27 -- 3. MATERYAL ve METOT, 29 -- 3.1. Üre Hidrolizini Gerçekleştiren Mikroorganizmaların Üretilmesi, 29 -- 3.2. Çalışmalarda Kullanılan Reaktörler, 30 -- 3.2.1. Aerobik BKR’nün özellikleri, 31 -- 3.2.2. YAÇYR’nün özellikleri, 31 -- 3.3. Çalışma Planı, 32 -- 3.3.1. Kesikli çalışmalar, 32 -- 3.3.2. Sürekli çalışmalar, 33 -- 3.3.2.1. Sürekli çalışmalarda kullanılan reaktör sistemler, 34 -- 3.3.3. Şeker fabrikası atıksuyu ile ilgili çalışmalar, 40 --3.4. Analitik Yöntemler, 42 -- 4. BULGULAR ve TARTIŞMA, 44 -- 4.1. Kesikli Çalışmalar, 44 -- 4.1.1. Zamanın kalsiyum giderimi üzerindeki etkisi, 44 -- 4.1.2. Üre miktarının kalsiyum giderimine etkisi, 47 -- 4.1.3. Kalsiyum derişiminin etkisi, 54 -- 4.1.4. Kalsiyum giderimi üzerinde pH etkisi, 60 -- 4.1.5. Kalsiyum giderimi üzerine biyokütle derişiminin etkisi, 64 -- 4.1.6. Kalsiyum giderim sürecinin üzerinde organik madde derişiminin etkisi, 68 -- 4.2. Sürekli Çalışmalar, 71 -- 4.2.1. BKR’üne çamur yaşının etkisi, 71 -- 4.2.2. BKR’üne HBS’nin etkisi, 75 -- 4.2.3. KOİ’nin BKR’ün performansı üzerindeki etkisi ,79 -- 4.2.4. Üre’nin BKR’ün performansı üzerindeki etkisi, 82 -- 4.2.5. Kalsiyumun BKR’ün performansı üzerindeki etkisi, 84 -- 4.2.6. YAÇYR performansı üzerinde kalsiyumun etkisi, 88 -- 4.2.7. BKR+YAÇYR sistemi ile simüle atıksuyun arıtımı, 93 -- 4.2.8. YAÇYR döngüsünde BKR ile simüle atıksuyun arıtımı, 95 -- 4.2.9. Kalsiyum içeren BKR’de kinetik katsayıların bulunması, 98 -- 4.3. Şeker Fabrikası Atıksuyu İle ilgili Arıtım Çalışmaları, 100 -- 4.3.1. BKR+YAÇYR sistemi ile şeker fabrikası atıksuyu arıtımı, 100 -- 4.3.2. YAÇYR döngüsünde BKR ile şeker fabrikası atıksuyu arıtımı, 102 -- 5. SONUÇ ve ÖNERİLER, 105 – KAYNAKLAR, 109 – ÖZGEÇMİŞ, 111

Simultaneous saccharification and co-fermentation (SSCF) of waste paper sludge to ethanol was investigated using two recombinant xylose-fermenting microbes: Zymomonas mobilis 8b and Saccharomyces cerevisiae RWB222. S. cerevisiae RWB222 produced over 40 g/L ethanol with a yield of 0.39 g ethanol/g carbohydrate on paper sludge at 37 degrees C, while similar titers and yields were achieved by Z. mobilis 8b at 30 degrees C. Both S. cerevisiae RWB222 and Z. mobilis 8b exhibited decreasing cell viability at 37 degrees C when producing over 40 g/L ethanol. A high ethanol concentration can account for S. cerevisiae RWB222 viability loss, but ethanol concentration was not the only factor influencing Z. mobilis 8b viability loss at 37 degrees C. Over 3 g/L residual glucose was observed at the end of paper sludge SSCF by Z. mobilis 8b, and a statistical analysis revealed that a high calcium concentration originating from paper sludge, a high ethanol concentration, and a high temperature were the key interactive factors resulting in glucose accumulation. The highest ethanol yields were achieved by SSCF of paper sludge with S. cerevisiae RWB222 at 37 degrees C and Z. mobilis 8b at 30 degrees C. With good sugar consumption at 37 degrees C, S. cerevisiae RWB222 was able to gain an improvement in the polysaccharide to sugar yield compared to that at 30 degrees C, whereas Z. mobilis 8b at 30 degrees C had a lower polysaccharide to sugar yield, but a higher sugar to ethanol yield than S. cerevisiae. Both organisms under optimal conditions achieved a 19% higher overall conversion of paper sludge to ethanol than the non-xylose utilizing S. cerevisiae D5A at its optimal process temperature of 37 degrees C.

The aim of the present study was to evaluate the significance of diffusion barriers in the development of artificial caries-like lesions. A 30-mm2 enamel surface area was covered with a layer of filter paper and exposed to a gently agitated 50 mM acetate buffer, pH 4.5, containing either 0.1 or 1.0 ppm fluoride for up to 48 h at 20 degrees C. Similar enamel surfaces, but unprotected by filter paper, served as controls. It was found that below the filter paper an approximately 60-microns-deep caries-like lesion was developed exhibiting a preserved surface layer, the mineral content of which depended on the fluoride concentration of the buffer. The lesions of the control teeth without a filter paper coverage were erosion-like surface lesions. In the filter paper calcium and phosphate released from the enamel combined with fluoride from the bulk solution had established a supersaturation with respect to fluorapatite while the undersaturation with respect to hydroxyapatite was maintained, which caused a caries lesion to develop. The lesions produced in noncovered enamel by bulk solution unsaturated with respect to both apatites were erosion-like. It was concluded that a diffusion barrier can significantly favor the establishment of supersaturation with respect to fluorapatite and thus facilitate the development of a subsurface caries-like lesion at the expense of the erosion.

Calcium-containing spherical bodies (calcospherulites) exist along the mineralization front of bone and are thought to play a role in bone formation. Existing methods to isolate calcospherulites involve harsh treatments that remove much of their organic matter. This study sought to isolate them using a less destructive approach to better preserve their organic components. Juvenile rats were injected with a low dose of calcein to label the newly formed mineral at the mineralization front of bone in vivo. Periosteum was completely dissected from the tibial diaphysis and unmineralized osteoid matrix was removed by collagenase in order to expose calcospherulites. Calcein-labeled calcospherulites of approximately 0.5 μm average diameter were observed all along the mineralization front and they exhibited a Ca/P ratio of 1.3 in situ. Calcospherulites were released from the mineralization front by a short dispase digestion and isolated via fluorescence flow sorting. X-ray diffraction revealed they contained apatite crystals (c-axis length of 17.5 ± 0.2 nm) and their Ca/P ratio was preserved during isolation. Calcospherulites treated with ice-cold ethanol exhibited a Ca/P ratio of 1.6, suggesting the presence of some extractable phospholipids. Proteins extracted from isolated calcospherulites were resolved by SDS-PAGE into more than 20 distinct bands. Western blot analyses showed the presence of matrix proteins in these preparations. These results indicate that calcospherulites can be isolated from the mineralization front of bone in a form that can be used to study their proteome and lipid composition.

Peritubular dentin (PTD) is a hypermineralized phase within the dentinal tubules in some vertebrate teeth as an interface between the intertubular dentin (ITD) and the cell processes. Our aim has been to understand the composition, structure and role of PTD as a mineralized tissue. We have utilized the technique of time of flight secondary ion mass spectrometry (TOF-SIMS) to map the distribution of positive and negative inorganic ions as well as organic components in the fully mineralized, intact PTD structure in bovine tooth cross-sections, and correlated these with scanning electron microscopy (SEM) in standard and backscatter modes. In recent work, we developed a procedure to freeze fracture the teeth and separate PTD from the less dense ITD by the use of aqueous sodium phosphotungstate step density gradients, after degrading the ITD collagen with NaOCl. Here, PTD-containing fragments were characterized by SEM and TOF-SIMS surface structure analysis. The TOF-SIMS data show that the isolated PTD does not contain collagen, but its surface is rich in glutamic acid-containing protein(s). The TOF-SIMS spectra also indicated that the intact PTD fragments contain phospholipids, and chemical analyses showed phosphatidylserine, phosphatidylinositol and phosphatidylcholine as the principal lipid components. In SEM sections, untreated PTD shows as a smooth collar around the tubule, but after digestion with ethylenediamine to remove all organic components, the porous nature of the mineral phase of small, thin platy apatite crystals becomes evident. Thus, the organic matrix of PTD appears to be a proteolipid-phospholipid complex.

Les ions corrosifs de fer et de cuivre ainsi que les acides dans les encres ferro-galliques ferriques ainsi que dans le vert-de-gris et la malachite de certains pigmenst tendent a intensifier la degradation de papier. Un recent projet europeen commun denomme INKCor propose l'utilisation de bromures d'amonium tetraalkyles combines a des ethoxudes de magnesium dans de l'ethanol afin de mieux stabiliser ces composants. Dans l'article suivant l'effet potentiellement stabilisateur d'un autre type d'antioxydants - les bromures imides d'alkyles - est compare a celui obtenu a l'aide de traitement non aqueux de bromure d'amonium tetrabutyle et lors d'un traitement aqueux a base de phytate de calcium. Les deux nouveaux antioxydants objets de cette etude a savoir: bromure imidazole 1 de methyle 3 (EMINBr) et bromure imidazole 1 dimithyle 2,3 (BDMINBr) combines avec l'alcali magnesium ethoxide dans l'ethanol ont effectivement stabilise l'encre ferro-gallique du papier traite. L'effet de stabilisation obtenu a ete meilleur que celui antoxydants deja connus, comme par exemple les bromures d'amonium tetraalkyles et les deux phytates. On n'y a pas observe d'effets secondaires nocifs sur la couleur de l'encre, ce qui fait de ces deux antioxydants des alternatives interessantes au traitement aqueux au phytate de calcium couramment employe. On a pousuivi cette etude sur des echantillons de papier presentant une pigmentation due a la corrosion par le vert-de-gris et la malachite. Le traitement le plus efficace a ete dans ce cas celui a base de bromures d'amonium tetraalkyles et d'oxyde de magnesium en suspension dans une solution d'ethanol. Bien qu'on n'ait pas observe d'effets negatifs sur le papier contenant de l'encre ferro-gallique ou une pigmentation cuivree, il reste capital d'etudier les effets de ce traitement sur un certain nombre d'echantillons historiques avant de pouvoir passer a leur utilisation dans la restauration d'objets historiques.