Investigation of bionano additives in red algae Cyanidioschyzon merolae ultrasonified MgO/MWCNT catalyzed biodiesel in optimized engine performance.

Renewable energy research is burgeoning with the anticipation of finding neat liquid fuel. Ultra sonification assisted biodiesel was derived from red algae Cyanidioschyzon merolae, with biodiesel yield of 98.9%. The results of GC MS of the prepared biodiesel showed higher concentration of methyl palmitate, methyl oleate, and stearate. This composition is appreciable, as this plays significance in desirable pour & cloud point properties. NMR spectrum revealed the ester linkages, presence of olefins, and α methyl position in olefins. Mixture of 30 wt% of biodiesel in diesel exhibited work efficiency, and also exhibited low pour point and, lower viscosity values. CeO2 and Fe2O3 nano particles were bio reduced, and were added as nano additive in biodiesel. 1:1 ratio of CeO2 and Fe2O3 added to biodiesel maximised the combustion ability of fuel owing to the oxygen storage capacity of CeO2. Further, this combination produced a satisfactory calorific value. Imbalanced ratios disrupted the catalytic and oxygen storage effects, reduced the overall energy release and calorific value of the biodiesel blend. Pour point and cetane number value of biodiesel blend ultrasonifacted with 1:1 mass ratio of Fe2O3 and CeO2 was observed to be around -7 °C and 53 °C respectively, and was better than other compositions. 1:1 mass ratio of NPS blended with 30 wt% BD in diesel showed tremendous increase in brake thermal efficiency, torque, and power. HC, NOX, and SOX emissions were reduced by 42.8%, 19.3%, and 57% respectively with 1:1 Fe2O3 and CeO2 mixed biodiesel blend. CeO2 favourably improved the oxygen storage capacity of the fuel, whereas Fe2O3 showed decrease in formation of gums and sediments in biodiesel.

Electrochemically microplastic detection using chitosan-magnesium oxide nanosheet.

Microplastics, an invisible threat, are emerging as serious pollutants that continuously affect health by interrupting/contaminating the human cycle, mainly involving food, water, and air. Such serious scenarios raised the demand for developing efficient sensing systems to detect them at an early stage efficiently and selectively. In this direction, the proposed research reports an electrochemical hexamethylenetetramine (HMT) sensing utilizing a sensing platform fabricated using chitosan-magnesium oxide nanosheets (CHIT-MgO NS) nanocomposite. HMT is considered as a hazardous microplastic, which is used as an additive in plastic manufacturers and has been selected as a target analyte. To fabricate sensing electrodes, a facile co-precipitation technique was employed to synthesize MgO NS, which was further mixed with 1% CHIT solution to form a CHIT_MgO NS composite. Such prepared nanocomposite solution was then drop casted to an indium tin oxide (ITO) to fabricate CHIT_MgO NS/ITO sensing electrode to detect HMT electrochemically using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. To determine the limit of detection (LOD) and sensitivity, DPV was performed. The resulting calibrated curve for HMT, ranging from 0.5 µM to 4.0 µM, exhibited a sensitivity of 12.908 µA (µM)-1 cm-2 with a detection limit of 0.03 µM and a limit of quantitation (LOQ) of 0.10 µM. Further, the CHIT_MgO NS/ITO modified electrode was applied to analyze HMT in various real samples, including river water, drain water, packaged water, and tertiary processed food. The results demonstrated the method's high sensitivity and suggested its potential applications in the field of microplastic surveillance, with a focus on health management.

Can dietary magnesium sources and buffer change the ruminal microbiota composition and fermentation of lactating dairy cows?

Magnesium oxide (MgO) is one of the most used Mg supplements in livestock. However, to avoid relying upon only one Mg source, it is important to have alternative Mg sources. Therefore, the objective of this study was to evaluate the effects of the interaction of two Mg sources with buffer use on the ruminal microbiota composition, ruminal fermentation, and nutrient digestibility in lactating dairy cows. Twenty lactating Holstein cows were blocked by parity and days in milk into five blocks with four cows each, in a 2 × 2 factorial design. Within blocks, cows were assigned to one of four treatments: 1) MgO; 2) MgO + Na sesquicarbonate (MgO+); 3) calcium-magnesium hydroxide (CaMgOH); 4) CaMgOH + Na sesquicarbonate (CaMgOH+). For 60 d, cows were individually fed a corn silage-based diet, and treatments were top-dressed. Ruminal fluid was collected via an orogastric tube, for analyses of the microbiota composition, volatile fatty acids (VFA), lactate, and ammonia nitrogen (NH3-N). The microbiota composition was analyzed using V4/16S rRNA gene sequencing, and taxonomy was assigned using the Silva database. Statistical analysis was carried out following the procedures of block design analysis, where block and cow were considered random variables. Effects of Mg source, buffer, and the interaction between Mg Source × Buffer were analyzed through orthogonal contrasts. There was no interaction effect of the two factors evaluated. There was a greater concentration of NH3-N, lactate, and butyrate in the ruminal fluid of cows fed with CaMg(OH)2, regardless of the buffer use. The increase in these fermentation intermediates/ end-products can be explained by an increase in abundance of micro-organisms of the genus Prevotella, Lactobacillus, and Butyrivibrio, which are micro-organisms mainly responsible for proteolysis, lactate-production, and butyrate-production in the rumen, respectively. Also, dietary buffer use did not affect the ruminal fermentation metabolites and pH; however, an improvement of the apparent total tract digestibility of dry matter (DM), organic matter (OM), neutral fiber detergent (NDF), and acid fiber detergent (ADF) were found for animals fed with dietary buffer. In summary, there was no interaction effect of buffer use and Mg source, whereas buffer improved total tract apparent digestibility of DM and OM through an increase in NDF and ADF digestibility and CaMg(OH)2 increased ruminal concentration of butyrate and abundance of butyrate-producing bacteria.

Magnesium oxide (MgO) is extensively used as a dietary magnesium (Mg) source in dairy cow diets. However, dairy operations can benefit from other Mg sources. Thus, we evaluated the replacement of dietary MgO with calcium­magnesium hydroxide (CaMg(OH)2) in diets with and without ruminal buffer and their effects on the ruminal microbiota composition, ruminal fermentation, and nutrient digestibility in lactating dairy cows. The study used 20 lactating Holstein cows that were blocked in groups of four and randomly assigned to one of the four treatments. The ruminal content, feed, feces, and urine were collected for analysis of the microbiota composition, ruminal fermentation, nitrogen metabolism, and apparent nutrient digestibility. There was no interaction effect of dietary buffer use and Mg source, while buffer improved total tract apparent digestibility of the dry matter and fiber components; CaMg(OH)2 increased the ruminal concentration of butyrate and the abundance of butyrate-producing bacteria. In summary, we conclude that using CaMg(OH)2 can improve ruminal fermentation regardless of buffer use, which indicates that we can take advantage of the mineral formulation in the diet to modulate the ruminal microbiota composition.

On the Geochemistry of the Danube River Sediments (Serbian Sector).

To determine the nature and origin of the unconsolidated bottom sediments, as well as to demonstrate and quantify the presence of Presumably Contaminating Elements (PCE) in the Serbian Danube River, as a novelty, the mass fractions on nine major elements as oxides-SiO2, TiO2, Al2O3, FeO, MnO, MgO, CaO, Na2O, and K2O, as well as Sc, V, Cr, Co, Ni, Cu, Zn, As, Rb, Sr, Zr, Sb, Cs, Ba, La, Hf, Ta, W, Th, and U were determined by Instrumental Neutron Activation Analysis (INAA) in 13 sediment samples collected between Belgrade and Iron Gate 2 dam. INAA was chosen for its ability to perform elemental analysis without any preliminary sample treatment that could introduce systematic errors. The distribution of major elements was relatively uniform, with the sampling locations having less influence. Concerning the trace elements, excepting the PCE Cr, Ni, Cu, Zn, As, and Sb, their distributions presented the same remarkable similarity to the Upper Continental Crust (UCC), North American Shale Composite (NASC), Average Bottom Load (ABL), and Average Dobrogea Loess (AVL), and were in good concordance with the location of the Serbian Danube River in the Pannonian Plain. In the case of considered PCE, both Enrichment Factor and Pollution Load Index showed values higher than the pollution threshold, which pointed towards a significant anthropogenic contamination, and rising concern to what extent the water quality and biota could be affected.

Historical ferrous slag induces modern environmental problems in the Moravian Karst (Czech Republic).

Ferrous slag produced by a historic smelter is washed from a slagheap and transported by a creek through a cave system. Slag filling cave spaces, abrasion of cave walls / calcite speleothems, and contamination of the aquatic environment with heavy metals and other toxic components are concerns. We characterize the slag in its deposition site, map its transport through the cave system, characterize the effect of slag transport, and evaluate the risks to both cave and aqueous environments. The study was based on chemical and phase analysis supported laboratory experiments and geochemical modeling. The slag in the slagheap was dominated by amorphous glass phase (66 to 99 wt%) with mean composition of 49.8 ± 2.8 wt% SiO2, 29.9 ± 1.6 wt% CaO, 13.4 ± 1.2 wt% Al2O3, 2.7 ± 0.3 wt% K2O, and 1.2 ± 0.1 wt% MgO. Minerals such as melilite, plagioclase, anorthite, and wollastonite / pseudowollastonite with lower amounts of quartz, cristobalite, and calcite were detected. Slag enriches the cave environment with Se, As, W, Y, U, Be, Cs, Sc, Cd, Hf, Ba, Th, Cr, Zr, Zn, and V. However, only Zr, V, Co, and As exceed the specified limits for soils (US EPA and EU limits). The dissolution lifetime of a 1 mm3 volume of slag was estimated to be 27,000 years, whereas the mean residence time of the slag in the cave is much shorter, defined by a flood frequency of ca. 47 years. Consequently, the extent of slag weathering and contamination of cave environment by slag weathering products is small under given conditions. However, slag enriched in U and Th can increase radon production as a result of alpha decay. The slag has an abrasive effect on surrounding rocks and disintegrated slag can contaminate calcite speleothems.

Enhanced removal of phosphate and ammonium by MgO-biochar composites with NH3·H2O hydrolysis pretreatment.

In this study, a novel MgO-biochar composite was generated for nutrient recovery from biogas slurry using magnesium chloride (MgCl2) and ammonia hydroxide (NH3·H2O). Biochar properties, including pH, CEC, pHpzc, magnesium content, surface area, and total pore volume (Vtotal), were evaluated. Moreover, the removal of NH4+ and PO43- in both single and bi-solute system were investigated. Results indicated that NH3·H2O pretreatment and MgO-coating enhanced biochar pH, CEC, and pHpzc. Additionally, there were generally higher surface area and Vtotal in MgAWS550. The maximum adsorption capacities for NH4+ and PO43-, respectively, increased as WS550 (0.555 and 1.57 mg g-1) < MgWS550 (15.4 and 21.8 mg g-1) < MgAWS550 (17.5 and 31.3 mg g-1). Moreover, higher removal efficiencies were achieved in the bi-solute system, and over 25% and 90% of NH4+ and PO43-, respectively, was removed from biogas slurry by MgASW550. Mechanically, NH4+ removal was mainly attributed to ionic exchange, while PO43- adsorption on MgO-coated biochars was due to electrostatic attraction and precipitation. Furthermore, the formation of struvite (MgNH4PO4·6H2O) further enhanced N and P in the bi-solute system.

Mineralogy, Structure, and Habitability of Carbon-Enriched Rocky Exoplanets: A Laboratory Approach.

Carbon-enriched rocky exoplanets have been proposed to occur around dwarf stars as well as binary stars, white dwarfs, and pulsars. However, the mineralogical make up of such planets is poorly constrained. We performed high-pressure high-temperature laboratory experiments (P = 1-2 GPa, T = 1523-1823 K) on chemical mixtures representative of C-enriched rocky exoplanets based on calculations of protoplanetary disk compositions. These P-T conditions correspond to the deep interiors of Pluto- to Mars-sized planets and the upper mantles of larger planets. Our results show that these exoplanets, when fully differentiated, comprise a metallic core, a silicate mantle, and a graphite layer on top of the silicate mantle. Graphite is the dominant carbon-bearing phase at the conditions of our experiments with no traces of silicon carbide or carbonates. The silicate mineralogy comprises olivine, orthopyroxene, clinopyroxene, and spinel, which is similar to the mineralogy of the mantles of carbon-poor planets such as the Earth and largely unaffected by the amount of carbon. Metals are either two immiscible iron-rich alloys (S-rich and S-poor) or a single iron-rich alloy in the Fe-C-S system with immiscibility depending on the S/Fe ratio and core pressure. We show that, for our C-enriched compositions, the minimum carbon abundance needed for C-saturation is 0.05-0.7 wt% (molar C/O ∼0.002-0.03). Fully differentiated rocky exoplanets with C/O ratios more than that needed for C-saturation would contain graphite as an additional layer on top of the silicate mantle. For a thick enough graphite layer, diamonds would form at the bottom of this layer due to high pressures. We model the interior structure of Kepler-37b and show that a mere 10 wt% graphite layer would decrease its derived mass by 7%, which suggests that future space missions that determine both radius and mass of rocky exoplanets with insignificant gaseous envelopes could provide quantitative limits on their carbon content. Future observations of rocky exoplanets with graphite-rich surfaces would show low albedos due to the low reflectance of graphite. The absence of life-bearing elements other than carbon on the surface likely makes them uninhabitable.

Effects of Acid Mine Drainage on Calcareous Soil Characteristics and Lolium perenne L. Germination.

Acid mine drainage (AMD) is a serious environmental problem resulting from extensive sulfide mining activities. There is a lack of more comprehensive and detailed studies on the effect of AMD on calcareous soil characteristics and seed germination. In this study, five calcareous soil samples, collected from Xiaoyi, Taigu, Xiangning, Hejin, and Xixian counties in Shanxi Province, China, were used to investigate the effects of acid AMD on soil characteristics and Lolium perenne L. germination through laboratory culture experiments. The results showed that the increase in the total soil calcium oxide and magnesium oxide (CaO + MgO) contents led to a rise in the amount of Fe2+ in AMD converted into Fe3+, and that major ions (H⁺, Fe, SO42-) in AMD were trapped in the soil. The total Cao + MgO contents in the soil collected from Hejin and Taigu counties were 14.23% and 6.42%, the pH of AMD-polluted soil decreased to 7.24 and 3.10, and 98.7% and 54.0% of the Fe2+, 99.9% and 58.6% of the total Fe, and 76.0% and 26.4% of the SO42-, respectively, were trapped in the soil when the AMD volume to soil mass ratio was 10 mL/g. The results for the soil from Taigu County showed that when the soil had an AMD volume to soil mass ratio of 10 mL/g, the organic matter, available phosphorus (available P), available potassium (available K), Cr, and Cd contents in soil decreased by 16.2%, 63.0%, 97.1%, 7.8%, and 73.2%, respectively; the total phosphorus (total P) and total potassium (total K) did not significantly change; whereas the available nitrogen (available N) and total nitrogen (total N) increased to 16.1 times and 1.76 times, respectively. Compared to the initial soil collected from Taigu County, the Lolium perenne L. germination rate decreased by 81.1%, and the cumulative amount of Cr in the Lolium perenne L. increased by 7.24 times in the AMD-polluted soil when the AMD volume to soil mass ratio was 6 mL/g. The soil conditions could not support Lolium perenne L. germination when the AMD volume to soil mass ratio was 10 mL/g. The outcomes of this study could have important implication in understanding the hydrological/geochemical-behaviour of major ions of AMD in calcareous soil. The findings also have great significance in predicting plant growth behavior in AMD-polluted calcareous soil.

Degradation of paraoxon (VX chemical agent simulant) and bacteria by magnesium oxide depends on the crystalline structure of magnesium oxide.

In this work, our goal was to study the capability of a single metallic oxide to neutralize a chemical agent and to exhibit an antibacterial effect. We tested two types of magnesium oxides, MgO. The first MgO sample tested, which commercial data size characteristic was -325 mesh (MgO-1) destroyed in 3 h, 89.7% of paraoxon and 93.2% of 4-nitrophenol, the first degradation product. The second MgO sample, which commercial data size was <50 nm (MgO-2) neutralized in the same time, 19.5% of paraoxon and 10.9% of 4-nitrophenol. For MgO-1 no degradation products could be detected by GC-MS. MgO-1 had a bactericidal activity on Escherichia coli (6 log in 1 h), and showed a decrease of almost 3 log on a Staphylococcus aureus population in 3 h. MgO-2 caused a decrease of 2 log of a E.coli culture but had no activity against S. aureus. Neither of these two products had an activity on Bacillus subtilis spores. Analytical investigations showed that the real sizes of MgO nanoparticles were 11 nm for MgO-1 and 25 nm for MgO-2. Moreover, their crystalline structures were different. These results highlighted the importance of the size of the nanoparticles and their microscopic arrangements to detoxify chemical products and to inhibit or kill microbial strains.

Evaluation of raw soapstone (steatite) as adsorbent of trace elements present in Brazilian spirits.

The impact of soapstone (steatite) upon inorganic element contaminant concentrations in alcoholic beverages was investigated. Concentrations of As, Cd, Cu, Ni and Pb levels in 8 Brazilian spirits plus an alcoholic simulant were initially measured, and then measured following each 24h cycle of exposure to raw soapstone cups, for a total of 4 cycles/sample. The results were compared to the levels established by Brazilian and German regulations. The contact between the spirits and the soapstone reduced the Cu content by up to 50.4% and increased the Ni content by up to 622.2%, especially in the first contact cycle. The exposure of spirits to the soapstone exhibits a linear reduction in the Pb content (18.3-54.5%) while As and Cd levels remained unaltered throughout the experiments. In conclusion, crude soapstone in contact with alcoholic solutions acts as an adsorbent of trace elements (Cu and Pb) while releasing Ni.

Mineral phases and metals in baghouse dust from secondary aluminum production.

Baghouse dust (BHD) is a solid waste generated by air pollution control systems during secondary aluminum processing (SAP). Management and disposal of BHD can be challenging in the U.S. and elsewhere. In this study, the mineral phases, metal content and metal leachability of 78 BHD samples collected from 13 different SAP facilities across the U.S. were investigated. The XRD semi-quantitative analysis of BHD samples suggests the presence of metallic aluminum, aluminum oxide, aluminum nitride and its oxides, spinel, elpasolite as well as diaspora. BHD also contains halite, sylvite and fluorite, which are used as fluxes in SAP activities. Total aluminum (Al) in the BHD samples averaged 18% by weight. Elevated concentrations of trace metals (>100 µg L(-1) As; >1000 µg L(-1) Cu, Mn, Se, Pb, Mn and Zn) were also detected in the leachate. The U.S. toxicity characteristic leaching procedure (TCLP) results showed that some samples leached above the toxicity limit for Cd, Pb and Se. Exceeding the TCLP limits in all sample is independent of facilities generating the BHD. From the metal content perspective only, it appears that BHD has a higher potential to exhibit toxicity characteristics than salt cake (the largest waste stream generated by SAP facilities).

Minerals consumption by Acetobacter xylinum on cultivation medium on coconut water

The objective of this work is to verifying the consume of the minerals K, Na, Fe, Mg, P, S-SO4-2,B,N Total Kjedahl (NTK), NO3--N, and NH4+-N in the production of bacterial cellulose by Acetobacter xylinum, according to the medium and the manner of cultivation. The fermentative process was in ripe and green coconut water. K and Na were determined by flame emission photometry, Mg and Fe by atomic absorption spectrophotometry, P by molecular absorption spectrophotometry, S-SO4-2 by barium sulphate turbidimetry, B by Azomethin-H method, NTK by Kjeldahl method, N-NO3-and N-NH4+ by vapor distillation with magnesium oxide and Devarda's alloy, respectively. In Fermentation of ripe coconut water there were higher consumption of K (69%), Fe (84,3%), P (97,4%), S-SO2-2 (64,9%), B (56,1%), N-NO3 (94,7%) and N-NH4+ (95,2%), whereas coconut water of green fruit the most consumed ions were Na (94,5%), Mg (67,7%) and NTK (56,6%). The cultivation under agitation showed higher mineral consumption. The higher bacterial cellulose production, 6 g.L-1, was verified in the coconut water fermentative in ripe fruit, added KH2PO4, FeSO4 and NaH2PO4 kept under agitation.

Trace metal partitioning in caustic calcined magnesia produced from natural magnesite.

Caustic calcined magnesia from natural magnesite has been widely employed as a source of magnesium. This mineral, depending on the origin, may contain heavy metals and metalloids that can exceed the regulatory limits in some applications. In most cases, heavy metals and metalloids form solid solutions with the mineral phases of the main impurities, or even magnesium oxide itself, replacing other ions in the crystal lattice. Compared with magnesium oxide, most of these impurities such as silica and silicates are much more chemically stable even in concentrated mineral acids under normal temperature and pressure conditions. In this study, the partitioning of the trace metals was monitored using a sequential extraction procedure (SEP), and their potential solubility was determined using the pH-static leaching test. Only a small fraction of magnesium oxide derived from heavily calcined magnesia is soluble in slightly acidic media. The release of the trace metals and metalloids contained in the soluble fractions was less than 40% as determined by total digestion. It can be concluded that SEP is more accurate than total chemical digestion for setting the maximum limits of the undesirable trace metals.

Matrix effects in the energy dispersive X-ray analysis of CaO-Al(2)O(3)-MgO inclusions in steel.

Energy dispersive X-ray microanalysis of micron-sized inclusions in steel is of considerable industrial importance. Measured spectra and Monte Carlo simulations show a significant effect of the steel matrix on analysis of CaO-Al(2)O(3)-MgO inclusions: the steel matrix filters the softer (Al and Mg) characteristic X-rays, increasing the relative height of the Ca peak. Bulk matrix correction methods would not result in correct inclusion compositions, but operating at a lower acceleration voltage shifts the effect to smaller inclusion sizes.

Inter-species variation in bone mineral behavior upon heating.

The characterization of inter-species variation in bone mineral (b-HAP) is of relevance to forensic science and archaeology, but has not previously been widely explored. Results of an investigation into unheated bone mineral and behavior of bone upon heating for 12 animal species (including human) demonstrate that b-HAP characteristics, quantitatively measured using X-ray diffraction (XRD) analysis, exhibit significant inter-species variation. Human bone was found to be significantly different to all other species in terms of b-HAP lattice parameter values from unheated and heated bone and in terms of recrystallization behavior of b-HAP upon heating bone to 600°C. The amounts of b-HAP thermal decomposition products were also significantly different for human bone heated to 1400°C compared to those obtained for most other species. Therefore, there is potential for the development of an XRD-based method of species identification, particularly one that distinguishes human from non-human bone.

Evaluation of human osteosarcoma cell line genotoxicity effects of mineral trixoide aggregate and calcium silicate cements.

INTRODUCTION: Mineral trioxide aggregate (MTA) and calcium silicate (CS) cements exhibit acceptable levels of cytocompatibility. The aim of the present study was to evaluate MTA and CS cement genotoxicity in a human osteosarcoma cell line (MG63). METHODS: A mitochondrial colorimetric assay was used to evaluate the MG63 survival rate. A DNA precipitation assay was used to detect the MG63 DNA damage after contact with MTA or CS cement extracts. RESULTS: The results showed that MTA and CS are cytocompatible with MG63 cells. There was no significant difference in the survival rate with MTA and CS materials (P > .05). Neither MTA nor CS cements causing MG63 cell DNA damage showed significant genotoxicity (P > .05). CONCLUSIONS: Both MTA and CS cements are compatible with MG63 cells, and they are not cancer-causing agents.

Cytocompatibility and effect of increasing MgO content in a range of quaternary invert phosphate-based glasses.

Recently, phosphate-based glass (PBG) fibers have been used to reinforce the biodegradable polymers polycaprolactone and polylactic acid, in order to fabricate materials suitable for use as resorbable bone fracture fixation devices. However, the PBG fibers investigated tended to degrade too quickly for application. Therefore, more durable PBG formulations were sought with emphasis remaining firmly placed on their biocompatibility. In this study, four invert PBG formulations (in the system P2O5-CaO-MgO-Na2O) were produced with fixed phosphate and calcium content at 40 and 25 mol%, respectively. MgO was added at 10-30 mol% in place of Na2O and the maximum divalent cation to phosphate ratio obtained was 1.375. Thermal analyses showed a linear increase in T(g) with increasing MgO content. This was proposed to be due to an increase in the cross-link density of the glass network, which also improved the chemical durability of the glass. EDX analyses were also conducted to verify the final composition of the glass. XRD analyses confirmed the amorphous nature of the glasses investigated. Rapid quenching of the Mg30 glass revealed a degree of surface crystallization, which was shown to be a CaMgP2O7 phase. The degradation rates of the glasses investigated decreased with increasing MgO content. The decrease in rate seen was almost two orders of magnitude (a x 50 difference was seen between glass Mg0 and Mg30). The cytocompatibility studies of the formulations investigated showed good cellular response over time for up to 14 days. Statistical analysis revealed that the formulations investigated gave a response comparable to the tissue culture plastic control. It is suggested that invert PBG provide degradation profiles and the cytocompatibility response desired to make these glasses useful for bone repair applications.

Determination of strontium and simultaneous determination of strontium oxide, magnesium oxide and calcium oxide content of Portland cement by derivative ratio spectrophotometry.

A derivative spectrophotometric method has been developed for the determination of strontium in Portland cement. The method is applied successfully for the simultaneous determination of SrO, MgO and CaO. It is based on the use of Alizarin Complexone (AC) as a complexing agent and measurement of the derivative ratio spectra of the analytes. Interferences of manganese(II) and zinc(II) were eliminated by precipitation. The validity of the method was examined by analyzing several Standard Reference Material (SRM) Portland cement samples. The strontium complex formed at pH 9.5 allows precise and accurate determination of strontium over the concentration range of 1.5-18 mg L(-1) of strontium. The MDL (at 95% confidence level) was found to be 25 ng mL(-1) for strontium in National Institute of Standards and Technology (NIST) cement samples using the proposed method.

[Determination of major elements in superphosphate by X-ray fluorescence spectrometry].

Phosphate fertilizer is one of the most important fertilizers. The authors determined nine kinds of major elements in superphosphate, the most important phosphate fertilizer, by X-ray fluorescence spectrometry. The detection range of SiO2, Al2O3, TFe2O3, MnO, MgO, CaO, Na2O, K2O and P2O5 is 15.0%-90.0%, 0.20%-25.0%, 0.20%-25.0%, 0.01%-0.35%, 0.20%-40.0%, 0.10%-35.0%, 0.10%-7.50%, 0.05%-7.50% and 1.00%-100.00% respectively, and the precision of the method for SiO2, Al2O3, TFe2O3, MnO, MgO, CaO, Na2O, K2O and P2O5 range from 0.20% to 0.005%, so the method of X-ray fluorescence spectrometry is a fast and effectual method for detecting the composition of phosphate fertilizer. The contents of the above elements showed (1) the detected superphosphate content is 18.101% of P2O5, which is accordant to the labeled level (> or = 16%); (2) the detected superphosphate contains much SiO2, TFe2O3, MgO, CaO and K2O, which are necessary for plant growth and the content of which is 16.954%, 1.495%, 1.580%, 21.428% and 1.585% respectively. These data showed that phosphate fertilizer sometimes can supply some trace elements for plants, but we should eliminate the interference effect of these elements when we research the role of phosphorus; (3) superphosphate contains 3.225% of Al2O3, so the authors should attention to the aluminium poison when superphosphate is used chronically.

[Determination of major elements in soil from cancer village by X-ray fluorescence spectrometry].

Many social problems arise from environmental pollution, cancer village is one of the many important problems caused by pollution. The authors selected a typical cancer village where 80-100 people died of cancer in the last five years, but there are only a total of 1 200 people in this village. The authors sampled soils from crops-planted areas and detected the major elements by X-ray fluorescence spectrometry. The results showed that the contents of SiO2, TiO2, Al2O3, Fe2O3, MnO, MgO, CaO, Na2O, K2O and P2O5 in soil of this village were 66.05%, 0.66%, 11.37%, 3.93%, 0.075%, 1.97%, 5.47%, 1.90%, 2.11% and 0.20% respectively; with the precision being +/- 0.20%, +/- 0.005%, +/- 0.10%, +/- 0.10%, +/- 0.005%, +/- 0.05%, +/- 0.04%, +/- 0.08%, +/- 0.02% and +/- 0.005% respectively, which showed that X-ray fluorescence spectrometry is a good method.