The occurrence of struvite (magnesium ammonium phosphate hexahydrate) in microbial cultures.
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Magnesium↗
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Differential adsorption of occluded and nonoccluded insect-pathogenic viruses to soil-forming minerals.
Soil represents the principal environmental reservoir of many insect-pathogenic viruses. We compared the adsorption and infectivity of one occluded and two nonoccluded viruses, Helicoverpa armigera single nucleopolyhedrovirus (HaSNPV) (Baculoviridae), Cricket paralysis virus (CrPV) (Dicistroviridae), and Invertebrate iridescent virus 6 (IIV-6) (Iridoviridae), respectively, in mixtures with a selection of soil-forming minerals. The relative infective titers of HaSNPV and CrPV were unchanged or slightly reduced in the presence of different minerals compared to their titers in the absence of the mineral. In contrast, the infective titer of IIV-6 varied according to the mineral being tested. In adsorption studies, over 98% of HaSNPV occlusion bodies were adsorbed by all the minerals, and a particularly high affinity was observed with ferric oxide, attapulgite, and kaolinite. In contrast, the adsorption of CrPV and IIV-6 differed markedly with mineral type, with low affinity to bentonites and high affinity to ferric oxide and kaolinite. We conclude that interactions between soil-forming minerals and insect viruses appear to be most important in nucleopolyhedroviruses, followed by invertebrate iridescent viruses, and least important in CrPV, which may reflect the ecology of these pathogens. Moreover, soils with a high content of iron oxides or kaolinite would likely represent highly effective reservoirs for insect-pathogenic viruses.
Adsorption↗
Amorphization of Indomethacin by Co-Grinding with Neusilin US2: amorphization kinetics, physical stability and mechanism.
PURPOSE: To quantify the effects of the ratio of indomethacin to Neusilin US2 and the processing humidity on the amorphization kinetics, stability and nature of the interaction. MATERIALS AND METHODS: A porcelain jar mill with zirconia balls was used to affect conversion of the physical mixtures (48 g) of indomethacin and Neusilin US2 (in the ratios 1:1 to 1:5) to amorphous states at room temperature (25 degrees C) employing either 0% RH or 75% RH. The percent crystallinity in the samples was determined from ATR-FTIR scans chemometrically. The physical stability of these co-ground amorphous powders was evaluated at 40 degrees C/75% RH and 40 degrees C/0% RH. RESULTS: The lower the ratio of indomethacin to Neusilin US2, the faster is the amorphization during co-grinding. Higher humidity facilitates amorphization with a more pronounced effect at the lower ratio of indomethacin to Neusilin US2. There is further amorphization of some of the partially amorphized samples on storage at 40 degrees C/75% RH for 3 months. Hydrogen bonding and surface interaction between metal ions of Neusilin US2 and indomethacin can explain changes in the FTIR spectra. CONCLUSIONS: The processing humidity and the ratio of indomethacin to Neusilin US2 are important factors to be considered to affect amorphization during ball milling. Amorphous indomethacin can be stabilized by co-grinding with Neusilin US2.
Aluminum Compounds↗
Double addition of grignard reagents to N-glycosyl nitrones: a new tool for the construction of enantiopure azaheterocycles.
[Reaction: see text] C-Phenyl-N-erythrosylnitrone 3 behaves as a C1,C1' bis-electrophile, undergoing a double addition of Grignard reagents in a domino fashion to afford acyclic hydroxylamines 4. The reaction proceeds at 0 degrees C with variable degrees of diastereoselectivity, from moderate to good, mainly depending on the organomagnesium reagent used. The usefulness of compounds 4 has been exemplified with the synthesis of pyrroloazepine 12 through a ring closing metathesis key step.
Anions↗
3,3-Diethyl-and 3,3-dibenzyl-1,2-diferrocenylcyclopropenes.
Reactions of 2,3-diferrocenylcyclopropenone 1 with ethyl- and benzylmagnesium chlorides afford 3,3-diethyl-and 3,3-dibenzyl- 1,2-diferrocenylcyclopropenes 2 and 3, respectively, and products of nucleophilic opening of the three-membered ring resulting from the addition of RMgCl to the carbonyl group, viz., saturated ketones(4,5-diferrocenylheptan-3-ones 4a,b and 3,4-diferrocenyl-1,5-diphenylpentan-2-ones 5a,b as ca. 3: 1 mixtures of two diastereomers) and other products. The spatial structures of compounds 2 and 4a were established by X-ray diffraction analysis of single crystals. Protonation of the cyclopropenes 2 and 3 with tetrafluoroboric acid at -40 degrees C yields the corresponding 3,3-dialkyl-1 ,2-diferrocenylcyclopropylium tetrafluoroborates. Transformation of the latter into diferrocenylallylic cations upon increasing the temperature to 20 degrees C and their eprotonation under the action of N,N-dimethylaniline were studied. Electrochemical investigation of 1 and 2 shows that in both complexes the cyclopropene spacer allows electronic communication between the two outer ferrocenyl groups, this being notably greater for 2 than for 1.
Crystallography, X-Ray↗
[Spectra and crystallographic sites of Ce3+ in Ca3MgSi2O8].
An efficiency purplish blue phosphor Ca3MgSi2O8:Ce3+ has been synthesized. The emission and excitation spectra of Ca3MgSi2O8:Ce3+ under 260 nm and 360 nm excitations show that they have their common broad band emission characters, but the maximums and the band widths of the emission spectra are different. The excitation spectra of Ce3+ 350 nm emission and 460 nm emission clearly show that there are remarkable differences. These results indicate that there are two kinds of Ce3+ emission centers in the host of Ca3MgSi2O8. According the analysis of the crystal structure and the Van Uitert's empirical equation, we have a conclusion that two centers occupy two kinds of octacoordinated Ca sites, respectively.
Calcium Compounds↗
Montmorillonite as a drug carrier: surface deposition of papaverine on the papaverine-veegum complex.
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Aluminum Compounds↗
[Swelling heterogeneous matrices: physical properties and mechanisms of release].
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Aluminum Compounds↗
Lung disease secondary to inhalation of nonfibrous minerals.
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Aluminum Compounds↗
Adsorption characteristics of certain antibiotics to veegum and activated charcoal.
Adsorption of streptomycin sulphate and neomycin sulphate to veegum and activated charcoal in water or buffered solution was studied. Both antibiotics demonstrated a significant reduction in their activity, particularly in water. The activity of streptomycin sulphate decreased in the following order: veegum in water greater than activated charcoal in water greater than veegum in buffer greater than activated charcoal in buffer and their calculated adsorption coefficients were 111 X 10(-3), 57 X 10(-3), 33 X 10(-3) and 25 X 10(-3) (respectively), while neomycin sulphate was affected in the following decreasing order: activated charcoal in water greater than activated charcoal in buffer greater than veegum in water greater than veegum in buffer. The calculated adsorption coefficients were 64 X 10(-3), 47 X 10(-3), 34 X 10(-3) and 26 X 10(-3) (respectively). The mechanism of adsorption was discussed.
Adsorption↗
Iron-catalyzed carbometalation of propargylic and homopropargylic alcohols.
Nucleophilic addition to alkynes represents an attractive approach to the synthesis of olefins. Obstacles to this strategy include the low reactivity of alkynes toward many organometallic reagents and difficulties associated with controlling the regioselectivity of addition. Here we demonstrate that Fe(III) salts are effective precatalysts for the carbometalation of alkynes. Primary and secondary propargylic and homopropargylic alcohols react with alkyl and aryl Grignard reagents to provide Z-allylic and -homoallylic alcohols as single stereo and regioisomers. Alkylation and arylation occur distal to the alcohol. Common oxygen protecting groups and tertiary nitrogens are tolerated. The intermediate vinyl magnesium or iron species can be trapped with a variety of electrophiles including aldehydes, allyl bromide, and N-bromosuccinimide. Diyne substrates undergo an unusual addition/cyclization reaction to generate cyclic dienes. A brief discussion of mechanism is included.
Alkynes↗
A new multifunctional ferrocenyl-substituted ferrocenophane derivative: optical and electronic properties and selective recognition of Mg2+ ions.
The synthesis, characterisation, and X-ray structure of a new strained asymmetric diferrocene derivative (2) is reported. Compound 2 acts as a highly specific electrochemical and optical Mg(2+) ion sensor, as revealed by spectroscopic and electrochemical techniques. Thus, in the presence of Mg(2+), a new redox peak appears in the cyclic voltammogram (CV) that is anodically shifted compared to the E(1/2) of the free receptor (DeltaE(1/2)=340 mV). Diferrocene derivative 2 also gives a highly visual response upon addition of Mg(2+), namely a change of colour from orange to deep purple. In addition, compound 2 does not show any significant sensing activity in the presence of Ca(2+) or alkaline ions. On protonation, it is converted into the stable diferrocenylcarbenium salt 4, in which two different modes of stabilisation of the alpha-carbocationic centre are clearly demonstrated by a combination of (1)H NMR and (57)Fe Mössbauer spectroscopic measurements. Finally, by a partial (chemical or electrochemical) oxidation, compound 2 forms the asymmetric mixed-valence species 2(+), which can be isolated as the solid salt 6 by using CF(3)SO(3) (-) as a counterion. This mixed-valence species shows a fast intramolecular electron-transfer process, as ascertained by several spectroscopic techniques.
Electrons↗
Studies on the sorption and desorption characteristics of Zn(II) on the surface soils of nuclear power plant sites in India using a radiotracer technique.
Zinc adsorption was studied in the soils of three nuclear power plant sites of India. 65Zn was used as a radiotracer to study the sorption characteristics of Zn(II). The sorption of zinc was determined at 25 and 45 degrees C at pH 7.8+/-0.2 in the solution of 0.01 M Ca(NO3)2 as supporting electrolyte. The sorption data was tested both in Freundlich and Langmuir isotherms and could be described satisfactorily. The effect of organic matter and other physico-chemical properties on the uptake of zinc was also studied in all the soil samples. The results showed that the cation exchange capacity, organic matter, pH and clay content were the main contributors to zinc sorption in these soils. The adsorption maximum was found to be higher in the soil on Kakarpara Atomic Power Plant sites soils having high organic matter and clay content. The zinc supply parameters of the soils are also discussed. In the desorption studies, the sequential extraction of the adsorbed zinc from soils showed that the diethylene triamine penta acetic acid extracted maximum amount of adsorbed zinc than CaCl2 and Mg(NO3)2. The zinc sorption on the soil and amount of zinc retention after extractants desorption shows a positively correlation with vermiculite and smectite mineral content present in the clay fraction of the soil. The amount desorbed by strong base (NaOH) and demineralised water was almost negligible from soils of all the sites, whereas the desorption by strong acid (HNO3) was 75-96% of the adsorbed zinc.
Adsorption↗
Rat lung reactivity to natural and man-made fibrous silicates following short-term exposure.
The inflammatory and fibrogenic potential of three naturally occurring and two man-made industrial minerals were compared. Groups of five rats each received respectively a single intratracheal instillation of saline (control), UICC chrysotile B asbestos, short chrysotile 4T30, attapulgite, xonotlite (a calcium silicate), and Fiberfrax (an aluminum silicate) at doses of 1, 5, and 10 mg. One month after the treatment, assessment of lung morphology and bronchoalveolar lavage were performed on each animal. Under these conditions, UICC chrysotile B at all doses tested (1, 5, and 10 mg) induced fibrotic lesions in bronchiolar tissues while short chrysotile 4T30 (1, 5, and 10 mg) caused focal accumulation of inflammatory cells in the alveolar structures but no apparent fibrosis. Compared to these positive reactions with different fibrogenicity, xonotlite caused minimal inflammatory reactions detectable only at high dose (10 mg) and by bronchoalveolar analysis. By contrast, the rat lung reacted more significantly to attapulgite and Fiberfrax although the tissue reaction differed considerably for these two materials. While attapulgite, at doses up to 10 mg caused minimal reactions characterized by mononuclear cell infiltration mainly in the alveolar structures, Fiberfrax at 1 mg and higher caused significant granulomatous reactions and the appearance of early fibrosis. Overall the order of lung biological reactivity observed for the various silicates was xonotlite much less than attapulgite less than short chrysotile 4T30 less than Fiberfrax less than UICC chrysotile B. These observations indicate that Fiberfrax, attapulgite, and, to a lesser extent, xonotlite are biologically active within the time span studied and potentially deleterious for lung tissue.
Animals↗
Reactivity of iron(II) 5,10,15,20-tetraaryl-21-oxaporphyrin with arylmagnesium bromide: formation of paramagnetic six-coordinate complexes with two axial aryl groups.
Coordination of sigma-aryl carbanions by chloroiron(II) 5,20-ditolyl-10,15-diphenyl-21-oxaporphyrin (ODTDPP)Fe(II)Cl has been followed by (1)H NMR spectroscopy. Addition of pentafluorophenyl Grignard reagent (C(6)F(5))MgBr to the toluene solution of (ODTDPP)Fe(II)Cl in the absence of dioxygen at 205 K resulted in the formation of the high-spin (ODTDPP)Fe(II)(C(6)F(5)). The titration of (ODTDPP)Fe(II)Cl with a solution of (C(6)H(5))MgBr carried at 205 K yields a rare six-coordinate species which binds two sigma-aryl ligands [(ODTDPP)Fe(II)(C(6)H(5))(2)](-). Warming of the [(ODTDPP)Fe(II)(C(6)H(5))(2)](-) solution above 270 K results in the decomposition to mono-sigma-phenyliron species (ODTDPP)Fe(II)(C(6)H(5)). Controlled oxidation of [(ODTDPP)Fe(II)(C(6)H(5))(2)](-) with Br(2) affords (ODTDPP)Fe(III)(C(6)H(5))Br, which demonstrates a typical (1)H NMR pattern of low-spin sigma-aryl iron(III) porphyrin. The considered oxidation mechanism involves the (ODTDPP)Fe(III)(C(6)H(5))(2) species, which is readily reduced to the iron(I) 21-oxaporphyrin, followed by oxidation with Br(2) and replacement of one bromide anion by aryl substituent. The (1)H NMR spectra of paramagnetic iron complexes have been examined in detail. Functional group assignments have been made with the use of selective deuteration. The peculiar (1)H NMR spectral features of [(ODTDPP)Fe(II)(p-CH(3)C(6)H(4))(2)](-) (sigma-p-tolyl: ortho, 30.8; meta, 53.6; para-CH(3), 42.1; furan: -16.0; beta-H pyrrole: -27.5, -34.3, -41.8 ppm, at 205 K) are without a parallel to any iron(II) porphyrin or heteroporphyrin and indicate a profound alteration of the electronic structure of iron(II) porphyrin upon the coordination of two sigma-aryls.
Bromine↗
Effects of Fuller's Earth and activated charcoal on oral absorption of paraquat in rabbits.
1. Thirty male rabbits of local strain (weighing 1.5-2 kg) were divided into five groups. Four groups were treated with an oral dose of paraquat, which was followed by either Fuller's Earth or activated charcoal 0.5 or 2.0 h later. The remaining group acted as the control group and was treated only with an oral dose of paraquat. The dose of paraquat was 20.0 mg/kg given in a concentration of 20.0 mg/mL. 2. Both adsorbents were administered in 15 mL normal saline as a 30% slurry. Blood was sampled from the ear vein 0.5, 1, 2, 4, 8 and 24h after the administration of paraquat. 3. Paraquat concentration was determined spectophotometrically at 600 nm by comparing against a standard curve of paraquat obtained by the addition of standard paraquat into normal rabbit serum and extracting interfering substances with ether. 4. The results of the present study show that either adsorbent can bring down the serum paraquat level. There was no significant difference found in the effectiveness of either adsorbent. 5. It is concluded that the administration of an adsorbent as early as possible will help in the reduction of paraquat absorption from the gastrointestinal tract. 6. Activated charcoal is still effective in lowering serum paraquat concentration when given more than 1 h after ingestion of paraquat.
Adsorption↗
Interaction of metals in nickel-sensitive patients.
Nickel (Ni) dermatitis is thought to involve the formation of complexes between Ni ions and suitable proteins. 4 groups of 30 subjects who gave positive patch test responses to NiSO4 2.9% aq. were each retested to 1 of 4 different solutions containing equimolar (0.1 M) amounts of NiSO4 plus MgSO4, NiSO4 plus CuSO4, NiSO4 plus ZnSO4, and NiSO4 plus Li2SO4, respectively. The results, evaluated at 2 days by visual scoring only, demonstrated that the 4 metals exerted a different influence on the nickel reactions, perhaps interfering with one or more factors affecting the formation of Ni+ + complexes.
Copper↗
The growth of Paracoccus halodenitrificans in a defined medium.
A synthetic medium, consisting of inorganic salts and any of a number of carbon sources, supported the aerobic growth of Paracoccus halodenitrificans when supplemented with thiamine. The same medium plus an appropriate nitrogenous oxide supported anaerobic growth when additionally supplemented with methionine. The observation that vitamin B12 or betaine replaced methionine suggested that P. halodenitrificans had a defect in the cobalamin-dependent pathway for methionine biosynthesis, as well as the inability to synthesize betaine when growing anaerobically.
Ammonium Sulfate↗