The chemistry of 5-oxodihydroisoxazoles .19. The synthesis and photolysis of N-thioacylisoxazol-5(2H)-ones

5-Oxodihydroisoxazoles react with thiocarbonyl chlorides to afford N-thioacylisoxazol-5(2H)-ones which lose carbon dioxide under photochemical conditions and undergo intramolecular cyclisation of the iminocarbene to afford thiazoles, However, in some cases loss of carbon dioxide is accompanied by loss of sulfur, giving 1,3-oxazin-6-ones.

Iron Fortification Strategies for the Control of Childhood Anemia in Brazil

This article presents data on the fortification of foods, necessary as an important public health approach for the success in reducing anemia. The use of food vehicles, iron salts and their costs, as well as recent work on iron fortification of foods in Brazil are reviewed. Recent research serves as a cornerstone for countries that attempt to implement permanent, long-lasting iron fortification programs aimed at the prevention of anemia considering cultural habits, type of iron salts and at-risk groups.

Characterization of a chromium-rich tannery waste and its potential use in ceramics

Leather industries which promote hide stabilization by the conventional chrome-tanning process are a major source of pollution because of the resultant chromium-rich wastes. In this work, an extensive characterization of such a chromium-rich waste sludge is presented, regarding its chemical composition (XRF), crystalline phase contents (XRD), organic carbon content (TOC), thermal behavior by thermogravimetry (TG) and differential scanning calorimetry (DSC), as well as its stability under chemical attack (the concentration of important ions in the leachates being determined by capillary electrophoresis) and when submitted to temperatures as high as 1100 degrees C, in air. The material showed the tendency to produce some undesirable, and previously non-detected hexavalent chromium when exposed to high temperatures, but after washing off the soluble salts and the elimination of the organic matter by firing, the resultant material was succesfully tested as a ceramic pigment in a conventional glaze composition usually employed in the ceramic the industry. (C) 2009 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Postembryonic Development of Rectal Pads in Bees (Hymenoptera, Apidae)

The morphology and development of the digestive tract of insects has been extensively studied, but little attention has been given to the development of the rectal pads. These organs are responsible for absorption of water and salts. In insects where they occur, there are usually six ovoid rectal pads located in the medial-anterior portion of the rectum. The rectal pad has three types of cells: principal, basal, and junctional. The arrangement of these three cell types delimits an intrapapillary lumen. The aim of the current study is to describe the development of the rectal pads during postembryonic development of Melipona quadrifasciata anthidioides and Melipona scutellaris. Specimens were analyzed at the following developmental stages: white-, pink-, brown-, and black-eyed pupae, and adult workers. The development of the rectal pad begins as a thickening of the epithelium in white-eyed pupae at 54 hr. At this stage, there is neither a basal cell layer nor intrapapillary lumen. The basal layers begin to form in the pink-eyed pupa and are completely formed at the end of the development of the brown-eyed pupa. In the brown-eyed pupal stage, the intrapapillary lumen is formed and the junctional cells are positioned and completely differentiated. Necrotic and apoptotic cell death were detected along with cell proliferation in the whole rectum during pupal development, suggesting that the development of the rectal pads involves cell proliferation, death, and differentiation. The rectal pads originate only from the ectoderm. Anat Rec, 292:1602-1611, 2009. (C) 2009 Wiley-Liss, Inc.

Effect of Iron on Matrix Metalloproteinase Inhibition and on the Prevention of Dentine Erosion

It is known that some metal salts can inhibit matrix metalloproteinase (MMP) activity, but the effect of iron has not been tested yet. On the other hand, it has recently been suggested that MMP inhibition might influence dentine erosion. Based on this, the aims of this study were: (1) to test in vitro the effect of FeSO(4) on MMP-2 and -9 activity, and (2) to evaluate in situ the effect of FeSO(4) gel on dentine erosion. MMP-2 and -9 activities were analysed zymographically in buffers containing FeSO(4) in concentrations ranging between 0.05 and 1.5 mmol/l or not. Volunteers (n = 10) wore devices containing bovine dentine blocks (n = 60) previously treated with the following gel treatments: FeSO(4) (1 mmol/l FeSO(4)), F (NaF 1.23%; positive control) and placebo (negative control). The gels were applied once and removed after 1 min. Erosion was performed extraorally with Coca-Cola 4 times per day for 5 min over 5 days. Dentine wear was evaluated by profilometry. The data were analysed by Kruskal-Wallis and Dunn`s tests (p < 0.05). FeSO(4) inhibited both MMP-2 (IC(50) = 0.75 mmol/l) and MMP-9 (IC(50) = 0.50 mmol/l) activities. In the in situ experiment, the mean wear (+/- SD) found for the F gel (0.79 8 +/- 0.08 mu m) was significantly reduced in more than 50% when compared to the placebo gel (1.77 +/- 0.33 mu m), but the FeSO(4) gel completely inhibited the wear (0.05 +/- 0.02 mu m). Since FeSO(4) was able to inhibit MMP in vitro, it is possible that the prevention of dentine wear by the FeSO(4) gel in situ might be due to MMP inhibition, which should be investigated in further studies. Copyright (C) 2010 S. Karger AG, Basel

Ring flexibility within tricyclic antidepressant drugs

The internal flexibility of the central seven-membered ring of a series of tricyclic antidepressant drugs (TCAs), imipramine {l}, amitriptyline {2}, doxepin {3}, and dothiepin {4}, has been investigated by H-1 and C-13 nuclear magnetic (NMR) techniques. Two dynamic processes were examined: ring inversion and bridge flexing. H-1 NMR lineshape analysis was used to obtain ring inversion barriers for 2-4. These studies yielded energy barriers of 14.3, 16.7, and 15.7 +/- 0.6 kcal/mol for the hydrochloride salts of doxepin, dothiepin, and amitriptyline, respectively. The barriers for the corresponding free bases were lower by 0.6 kcal/mol on average. (CT1)-C-13 relaxation measurements were used to determine the degree of bridge flexing associated with the central seven-membered ring for all four compounds. By fitting the T-1 data to a two-state jump model, lifetimes and amplitudes of rapid bridge flexing motions were determined. The results show that imipramine has the fastest rate of bridge flexing, followed by amitriptyline, doxepin, and dothiepin. The pharmacological profiles of the TCAs are complex and they interact with many receptor sites, resulting in numerous side effects and a general lack of understanding of their precise mode of action in different anxiety-related disorders. They all have similar three-dimensional structures, which makes it difficult to rationalize their differing relative potency in different assays/clinical settings. However, the clear finding here that there are significantly different degrees of internal mobility suggests that molecular dynamics should be an additional factor considered when trying to understand the mode of action of this clinically important family of molecules. (C) 2001 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 90:713-721, 2001.

A test of the ash-free dry weight technique on the developmental stages of Patiriella spp. (Echinodermata : Asteroidea)

Determination of the ash-free dry weight (AFDW) of marine specimens requires samples to be rinsed, soaked, and centrifuged. Problems associated with this technique were examined with the developmental stages of seastar species (Patiriella) with different modes of development. The influence of three rinsing solutions (ammonium formate [AF], filtered seawater [FSW], and reverse osmosis water [RO]) was assessed. The hypothesis that the AFDW technique is a measure of organic material was addressed by drying inorganic salts. Developmental stages of Patiriella calcar rinsed in FSW were twice as heavy as those rinsed in RO or AE indicating that samples should be rinsed in RO or AF before weighing. Soaking treatments had a significant effect on the AFDW of samples of P. calcar (planktonic developer), indicating that the rinsing period should be brief. Zygotes of Patiriella re gularis (planktonic developer) were significantly heavier than ova or gastrulae, regardless of treatment. In contrast, there were no significant differences in the AFDW of any stages or treatments of Patiriella exigua (benthic developer). This may be due to the presence of a modified fertilization envelope, which protects these benthic embryos. Inorganic salts with water of crystallization and FSW lost 20-75% and 14% of their dry weight, respectively, after ashing. We propose that salt ions may retain water, which does not evaporate during drying but is lost during ashing, resulting in the overestimation of sample AFDW. If a similar process occurs in the developmental stages of marine invertebrates, changes in the intracellular ionic composition through development may result in inaccurate estimates of biomass.

Ar-40/-Ar-39 geochronology at the Instituto de Geociencias, USP: instrumentation, analytical procedures, and calibration

Laser heating Ar-40/Ar-39 geochronology provides high analytical precision and accuracy, mum-scale spatial resolution. and statistically significant data sets for the study of geological and planetary processes, A newly commissioned Ar-40/Ar-39 laboratory at CPGeo/USP, Sao Paulo, Brazil, equips the Brazilian scientific community with a new powerful tool applicable to the study of geological and cosmochemical processes. Detailed information about laboratory layout, environmental conditions, and instrumentation provides the necessary parameters for the evaluation of the CPGeo/USp Ar-40/Ar-39 suitability to a diverse range of applications. Details about analytical procedures, including mineral separation, irradiation at the IPEN/CNEN reactor at USP, and mass spectrometric analysis enable potential researchers to design the necessary sampling and sample preparation program suitable to the objectives of their study. Finally, the results of calibration tests using Ca and K salts and glasses, international mineral standards, and in-house mineral standards show that the accuracy and precision obtained at the Ar-40/Ar-39 laboratory at CPGeo/USP are comparable to results obtained in the most respected laboratories internationally. The extensive calibration and standardization procedures under-taken ensure that the results of analytical studies carried out in our laboratories will gain immediate international credibility, enabling Brazilian students and scientists to conduct forefront research in earth and planetary sciences.

Nitrification in a Vertisol subsoil and its relationship to the accumulation of ammonium-nitrogen at depth

Unusually high concentrations of ammonium have been observed in a Vertisol below 1 m depth in southeast Queensland. This study investigated the possibility that an absence of nitrification is allowing this ammonium to accumulate and persist over time, and examined the soil environmental characteristics that may be responsible for limiting nitrifying organisms. The possibility that anaerobiosis, soil acidity, soil salinity, low organic carbon concentrations, and/or an absence of active nitrifying microorganisms were responsible for limiting nitrification was examined in laboratory and field studies. The presence/absence of anaerobic conditions was determined qualitatively using a field test to give an indication of electron lability. In addition, an incubation study was conducted and soil environmental conditions were improved for nitrifying organisms by adjusting the pH from 4.4 to 7, adjusting the electrical conductivity from 1.6 to 0.5 dS/m, amending with a soluble carbon substrate at a rate of 500 mg/kg, and using microorganisms from the surface horizon to inoculate to the subsoil. Over a 180-day period no nitrification was detected in the control samples from the incubation study, indicating that an extremely low rate of nitrification is likely to be responsible for allowing ammonium to accumulate in this soil. Analysis of the effect of soil environmental conditions on nitrification revealed that anaerobic conditions did not exist at depth and that pH, EC, organic carbon, and inoculation treatments added in isolation had no effect on nitrification. However, when inoculum was added to the soil in combination with pH, a significant increase in nitrification was observed, and the greatest amount of nitrification was observed when inoculum, pH, and EC treatments were added in combination. It was concluded that the reason for the low rate of nitrification in this soil is primarily the absence of a significant population of active nitrifying microorganisms, which may have been unable to colonise the subsoil environment due to its acidic, and to a lesser extent, its saline environment.

Nutritional strategies for the prevention of hypocalcaemia at calving for dairy cows in pasture-based systems

This review considers the current literature on the macro-mineral nutrition of the soon-to-calve, or transition, dairy cow. Calcium is the main focus, since milk fever (clinical hypocalcaemia) appears to be the most common mineral-related problem faced by the transition cow Australia-wide. The importance of minimising calcium intake and optimising the balance of the key dietary electrolytes, sodium, potassium, sulfate, and chloride, in the weeks before calving is highlighted. Excess dietary potassium can, in some situations, induce milk fever, perhaps even more effectively than excess calcium. Excess sodium remains under suspicion. In contrast, excess dietary chlorine and, to a lesser extent, sulfur can improve the ability of the cow to maintain calcium homeostasis. Diets that promote either a hypomagnesaemia or hyperphosphataemia have also the potential to precipitate milk fever at calving. Current prevention strategies focus on the use of forages with moderate to low levels of calcium, potassium, and sodium, and also rely on or utilise addition of chloride and sulfate in the form of 'anionic' feeds. Anionic salts are one example of an anionic feed. However, legitimate questions remain as to the effectiveness of anionic salts in pasture-feeding systems. The causes and prevention of milk fever are considered from the perspective of the variety of Australian feedbases. Impediments to the use of anionic feeds in Australia feeding systems are outlined. The potential for improving maternal reserves of calcium around calving to reduce the risk of milk fever is also discussed.

Conformational changes in monolayers of a cationic amphiphilic porphyrin on saline subphases

Langmuir monolayer films of the tetracationic porphyrin tetrakis(octadecyl-4-pyridin ium)porphyrinatozinc(II) bromide on various salt containing subphases were analyzed using surface pressure-area isotherms and X-ray reflectivity. The use of these complementary techniques showed that the porphyrin molecules undergo changes in conformation upon compression. Two main phases were identified, one in which the porphyrin moiety is parallel to the subphase and one in which the porphyrin moiety is tilted out of the plane. The addition of different salts into the subphase brought about changes in film behaviour, which are explained in terms of a lyotropic series. Copyright (C) 2002 Society of Porphyrins,& Phthalocyanines.

Thin films of a tetracationic porphyrin

Langmuir-Blodgett films of the tetracationic porphyrin tetrakis( octadecyl-4-pyridinium) porphinatozinc(ii) bromide transferred from subphases containing different salts were studied using X-ray photoelectron spectroscopy (XPS) and X-ray reflectometry. In contrast to previous results at the air/water interface, we found that the porphyrin adopted a fixed conformation at the air/solid interface regardless of composition of the subphase or whether the films were transferred above or below the primary phase transition. This conformation was assigned to the formation of an interdigitated bilayer structure.

Geometric isomers of chloro(6-methyl-1,4,8,11-tetraazacyclotetradecane-6-amine)cobalt(III) tetrachlorozincate(II)

The crystal structures of a pair of cis and trans isomers of the macrocyclic chloropentaamine title complex, as their tetrachlorozincate(II) salts, [CoCl(C11H27N5)][ZnCl4], are reported. The two distinct isomeric forms lead to significant variations in the Co-N bond lengths and, furthermore, hydrogen bonding between the complex ions is influenced by the folded (cis) or planar (trans) conformations of the coordinated ligand.

Comparative study of the radiation-induced grafting of styrene onto poly(tetrafluoroethylene-co-perfluoropropylvinyl ether) and polypropylene substrates. I: Kinetics and structural investigation

A comparative study has been made of the radiation grafting of styrene onto poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether) (PFA) and polypropylene (PP) substrates, using the simultaneous irradiation method. Effects of grafting conditions such as monomer concentrations, type of solvent, dose rate and irradiation dose on the grafting yield were investigated. Under the same grafting conditions it was found that a higher degree of grafting of styrene was obtained using a mixture of dichloromethane/methanol solvents for PFA and methanol for PP and the degree of grafting was higher in PP than in PFA at all doses. However, the micro-Raman spectroscopy analysis of the graft revealed that, for the same degree of grafting, the penetration depth of the grafted polystyrene into the substrate was higher in PFA than in PP substrates. In both polymers the crystallinity was hardly affected by the grafting process and the degree of crystallinity decreased slightly with grafting dose. The dependence of the initial rate of grafting on the dose rate and the monomer concentration was found to be 0.6 and 1.4 order for PFA and 0.15 and 2.2 for PP, respectively. The degree of grafting increased with increasing radiation dose in both polymers. However, the grafting yield decreased with an increase in the dose rate. The increase in the overall grafting yield for PFA and PP was accompanied by a proportional increase in the penetration depth of the graft into the substrates. (C) 2003 Society of Chemical Industry.

Low-temperature single-crystal Raman and neutron-diffraction study of the hydrogenous ammonium copper(II) tutton salt and the deuterated analogue in the metastable state

Low-temperature (15 K) single-crystal neutron-diffraction structures and Raman spectra of the salts (NX4)(2)[CU(OX2)(6)](SO4)(2), where X = H or D, are reported. This study is concerned with the origin of the structural phase change that is known to occur upon deuteration. Data for the deuterated salt were measured in the metastable state, achieved by application of 500 bar of hydrostatic pressure at similar to303 K followed by cooling to 281 K and the subsequent release of pressure. This allows for the direct comparison between the hydrogenous and deuterated salts, in the same modification, at ambient pressure and low temperature. The Raman spectra provide no intimation of any significant change in the intermolecular bonding. Furthermore, structural differences are few, the largest being for the long Cu-O bond, which is 2.2834(5) and 2.2802(4) Angstrom for the hydrogenous and the deuterated salts, respectively. Calorimetric data for the deuterated salt are also presented, providing an estimate of 0.17(2) kJ/mol for the enthalpy difference between the two structural forms at 295.8(5) K. The structural data suggest that substitution of hydrogen for deuterium gives rise to changes in the hydrogen-bonding interactions that result in a slightly reduced force field about the copper(II) center. The small structural differences suggest different relative stabilities for the hydrogenous and deuterated salts, which may be sufficient to stabilize the hydrogenous salt in the anomalous structural form.