Wide Variation In Composition Research Articles

Aluminium phosphate and phosphate-sulphate minerals in kyanite schists of the Ichetuyskoye area, West Transbaikalia, Russia: crystal chemistry and evolution

Aluminium phosphate and aluminium phosphate-sulphate (APS) minerals occur as disseminated crystals and fine-grained aggregates in kyanite schists near Ichetuyskoye, in the Dzhida basin (West Transbaikal region, Russia). Petrographical, mineralogical and geochemical data suggest a metamorphic evolution through prograde and retrograde stages. Lazulite-scorzalite and trolleite in association with kyanite, quartz, muscovite, paragonite, topaz, rutile, magnetite and hematite formed during the prograde stage. More than 25 minerals identified in schists are genetically related to the retrograde stage. Some phosphates and all of the APS minerals belong to the alunite, beudantite and plumbogummite groups. Electron-microprobe data reveal the presence of wide compositional variations and complex solid-solution series among the members. The main crystal-chemical variations of the APS solid-solution series in the alunite supergroup concern the relative proportions of svanbergite, woodhouseite, goyazite, crandallite, florencite-(Ce) and natroalunite. Chemical analyses of APS minerals indicate extremely high amounts of LREE, Sr, Ba, Ca and Na. In some cases, APS minerals have compositions of Ba and Ca,Ba phosphates– sulphates.

Optical closure experiments for biomass smoke aerosols

Abstract. A series of laboratory experiments at the Fire Laboratory at Missoula (FLAME) investigated chemical, physical, and optical properties of fresh smoke samples from combustion of wildland fuels that are burned annually in the western and southeastern US The burns were conducted in the combustion chamber of the US Forest Service Fire Sciences Laboratory in Missoula, Montana. Here we discuss retrieval of optical properties for a variety of fuels burned in FLAME 2, using nephelometer-measured scattering coefficients, photoacoustically-measured aerosol absorption coefficients, and size distribution measurements. Uncertainties are estimated from various instrument characteristics and instrument calibration studies. Our estimates of single scattering albedo for different dry smoke samples varied from 0.428 to 0.990, indicative of observed wide variations in smoke aerosol chemical composition. In selected case studies, we retrieved the complex refractive index from measurements but show that these are highly sensitive to uncertainties in measured size distributions.

Thermodynamic investigation into the equilibrium phases in the NiCoCrAl system at elevated temperatures

NiCoCrAlY alloys, commonly used as the bond coat layer in thermal barrier coatings, have been widely studied through experimentation. It is generally agreed that the major phases in the NiCoCrAlY are γ-Ni(Co,Cr) matrix and β-NiAl, with occasional presence of γ′-Ni3Al, (Co, Cr)-rich σ, and/or α-Cr precipitates, depending on the chemical composition and the temperature. It is noted, however, that the chemical compositions of the NiCoCrAlY alloys vary from one study to another. The present work reviews the literature on the experimental descriptions of the phases present in NiCoCrAlY and the corresponding phase transformations. To complement this literature review and, more importantly, to allow for consideration of alloy compositions not yet studied experimentally, equilibrium phases within the NiCoCrAl quaternary system are investigated in terms of the change in phase fractions as a function of temperature, isotherms at elevated temperatures (700–1100°C) with a wide and continuous variation in composition (Co, Cr or Al content), and the phase compositions, through computation by Thermo-calc®. The results are in good general agreement with the experimental findings, thus validating the approach. The γ′ and the σ phases are emphasized in the analysis, because of their significant contributions to the thermo-mechanical properties of the NiCoCrAlY alloys. Results indicate that an increase in Co content leads to decreased stability of the γ′ phase in the temperature range of 700–1100°C; while appropriate Co additions increase the stability of the σ phase, with the appearance of a four-phase (γ+γ′+σ+β) co-existing region, at temperatures below 1000°C.

Native iron (–platinum) ores from the Siberian Platform trap intrusions

Native iron occurs in two forms: terrestrial (telluric) and meteoritic. The former was considered to be poor in trace elements, whereas the latter contains varying amounts of Ni–Fe alloys, including kamacite, tanite and awaruite. In the late 1950s, native iron was discovered in the Siberian Platform trap intrusions, although it is only recently that geologists became interested in native iron from the traps. We provide a brief description of intrusions containing native iron and a detailed description of its occurrence, species, mineralogy and geochemistry of ore-forming and accompanying typomorphic chemical elements. A study of Siberian native iron shows wide variations in composition from Ni-free iron to awaruite and its intergrowth with a number of minerals. Globules of glass with a ‘liquid-in-liquid’ structure were recognised in native iron and analysed. Immiscible liquids have the compositions of ferruginous and high-silicon melts which are similar to that of ferrogabbro and granophyre. Isotopic compositions, such as 4He/3He, δ13CPDB, 87Sr/86Sr, 87Rb/86Sr of native iron and host-rocks suggests participation of continental-crust material in ore formation. Native iron was found to contain high concentrations of Cu, Ni, Co, Pt, Pd, Rh and Ge. The existence of a new Fe (–Pt) type of ore is established for the first time. Native iron and related Fe (–Pt) ores formed in feeder columns as a result of the interaction of tholeiite-basalt melt with fluid reservoirs of sedimentary rocks in the platform cover. Hydrocarbon fluids and organometallic compounds play a leading role in ore formation. The finding of Fe (–Pt) ores open up new possibilities for discovering new types of ores in large igneous provinces, in which hydrocarbons are of major importance.

Identification and characterization of high‐molecular‐weight secalins from triticale seeds by capillary zone electrophoresis

A rapid and reliable method for separation and characterization of the variability of high-molecular-weight secalin subunits (HMW-SS) in hexaploid triticale (x Triticosecale Wittmack) by CZE has been developed. In this method, a mixture of two poly(ethylene oxide) polymers differing in molecular weight and a high concentration of ACN in isoelectric buffer was applied as the running electrolyte. For dynamic coating of the capillary inner wall, a low-concentration mixture of poly(vinylpyrrolidone) and hydroxypropylmethylcellulose was employed. Wide allelic variations in rye HMW-SS composition, including some novel x- and y-type HMW-SS, were detected by CZE. The CZE electropherograms of HMW-SS showed two groups of peaks in accordance with y- and x-type subunits, with migration times of 8.0-8.8 and 11.0-13.3 min, respectively. HMW-SS differed in migration times from the simultaneously resolved HMW glutenin subunits, but frequently had very similar electrophoretic mobilities during separation by SDS-PAGE. Each of the two rye subunits 2r and 6.5r detected by SDS-PAGE represents in fact two subunits (5.1r or 5.2r, and 6.4r or 6.5r, respectively). After analyzing 106 European triticale cultivars, 12 HMW-SS were identified (six x-type and six y-type). They form six allelic variants of these subunits. The simultaneous separation and identification of triticale HMW glutenin and secalin subunits by CZE is an efficient alternative to SDS-PAGE and should facilitate breeding of valuable cultivars.

The potential of the MERIS Terrestrial Chlorophyll Index for carbon flux estimation

In this study we evaluated the potential of the Medium Resolution Imaging Spectrometer (MERIS) Terrestrial Chlorophyll Index (MTCI) for monitoring gross primary productivity (GPP) across fifteen eddy covariance towers encompassing a wide variation in North American vegetation composition. The across-site relationship between MTCI and tower GPP was stronger than that between either the MODIS GPP or EVI and tower GPP, suggesting that data from the MERIS sensor can be used as a valid alternative to MODIS for estimating carbon fluxes. Correlations between tower GPP and both vegetation indices (EVI and MTCI) were similar only for deciduous vegetation, indicating that physiologically driven spectral indices, such as the MTCI, may also complement existing structurally-based indices in satellite-based carbon flux modeling efforts.

Comparative Analysis of the Physicochemical Properties of Rice Endosperm from Different Non-Glutinous Rice Varieties

The physicochemical properties of four non-glutinous rice varieties (Junambyeo, Hwayoungbyeo, Namcheonbyeo, and Andabyeo) were analyzed. The rice starch granules from Junambyeo and Hwayoungbyeo varieties were loosely packed with larger air spaces between granules than that of Namcheonbyeo and Andabyeo. The Junambyeo variety exhibited the highest total amino (840.69 ng/mg) and oleic (47.16%) acids content, the fastest rate of hydrolysis (58.34%), and the lowest blue value (0.18). The highest sugar (0.32-4.28 ώg/g), mineral (89.48-3592.00 ppm) contents, and viscosity values were found in Namcheonbyeo rice, while the Andabyeo variety showed highest pasting and blue (0.22) values and lowest amino acid content (402.10 ng/mg). No substantial difference in X-ray diffraction pattern was observed among the rice varieties analyzed. This study illustrates the wide variation in the chemical composition of non-glutinous rice varieties. The results of which could be used by food processors in assessing the quality of non-glutinous rice with a specific property suitable for specialty food processing.

Multivariant optimization, validation, and application of capillary electrophoresis for simultaneous determination of polyphenols and phenolic acids in Brazilian wines

A method for the simultaneous determination of the stilbene resveratrol, four phenolic acids (syringic, coumaric, caffeic, and gallic acids), and five flavonoids (catechin, rutin, kaempferol, myricetin, and quercetin) in wine by CE was developed and validated. The CE electrolyte composition and instrumental conditions were optimized using 2(7-3) factorial design and response surface analysis, showing sodium tetraborate, MeOH, and their interaction as the most influential variables. The optimal electrophoretic conditions, minimizing the chromatographic resolution statistic values, consisted of 17 mmol/L sodium tetraborate with 20% methanol as electrolyte, constant voltage of 25 kV, hydrodynamic injection at 50 mbar for 3 s, and temperature of 25 degrees C. The R(2) values for linearity varied from 0.994 to 0.999; LOD and LOQ were 0.1 to 0.3 mg/L and 0.4 to 0.8 mg/L, respectively. The RSDs for migration time and peak area obtained from ten consecutive injections were less than 2% and recoveries varied from 97 to 102%. The method was applied to 23 samples of inexpensive Brazilian wines, showing wide compositional variation.

Mg and Fe-rich carbonate–silicate high-density fluids in cuboid diamonds from the Internationalnaya kimberlite pipe (Yakutia)

Microinclusions in 44 cuboid diamonds from the Internationalnaya kimberlite pipe (Yakutia) show wide compositional variations. In comparison with the available worldwide database most microinclusions in diamonds from Internationalnaya define a continuous range of compositions from carbonatitic to hydrous-silicic high-density fluids (HDFs). The hydrous-silicic compositional range is reported here for the first time in Yakutian diamond-forming fluids. The hydrous-silicic end-members are rich in water, SiO 2, Al 2O 3, K 2O and P 2O 5. Carbonatitic end-members are rich in carbonate, CaO, MgO, Na 2O and FeO. Microinclusions in diamonds from Internationalnaya show a range from magnesian to extremely iron-rich compositions. There are two compositional arrays of microinclusions: (i) carbonate-rich with SiO 2 < 10 wt.% where FeO decreases without any correlation with sulfur, water, carbonate or chlorine and (ii) carbonatitic to hydrous-silicic where FeO generally decreases as SiO 2 contents increase. The trace-element patterns of the microinclusions are generally similar to those of kimberlites and carbonatites, but there are significant differences in the major elements. The relative abundance of K in the microinclusions is significantly higher. The microinclusions have smooth patterns for the LILE, normalized to a primitive mantle composition. HFSE patterns in the microinclusions show some depletion in Ti, Zr and Hf relative to Ta, Nb and Mo. Primitive mantle normalized REE patterns reveal low abundances of the heavy REE and high concentrations of light REE. The La/Dy ratio of microinclusions varies widely, decreasing from carbonatitic to hydrous-silicic compositions. A general correlation of δ 13C of diamonds with the relative abundance of carbonates in the microinclusions suggests that carbon isotope compositions are related to the evolution of the parental media. The carbonate–silicate range of high-density fluids observed in diamonds from Internationalnaya may be explained by fractional crystallization of mantle fluids/melts, or mixing between liquids with different compositions.

Proteomics Approach to Identify Unique Xylem Sap Proteins in Pierce’s Disease-Tolerant Vitis Species

Pierce's disease (PD) is a destructive bacterial disease of grapes caused by Xylella fastidiosa which is xylem-confined. The tolerance level to this disease varies among Vitis species. Our research was aimed at identifying unique xylem sap proteins present in PD-tolerant Vitis species. The results showed wide variation in the xylem sap protein composition, where a set of polypeptides with pI between 4.5 and 4.7 and M(r) of 31 kDa were present in abundant amount in muscadine (Vitis rotundifolia, PD-tolerant), in reduced levels in Florida hybrid bunch (Vitis spp., PD-tolerant) and absent in bunch grapes (Vitis vinifera, PD-susceptible). Liquid chromatography/mass spectrometry/mass spectrometry analysis of these proteins revealed their similarity to beta-1, 3-glucanase, peroxidase, and a subunit of oxygen-evolving enhancer protein 1, which are known to play role in defense and oxygen generation. In addition, the amount of free amino acids and soluble sugars was found to be significantly lower in xylem sap of muscadine genotypes compared to V. vinifera genotypes, indicating that the higher nutritional value of bunch grape sap may be more suitable for Xylella growth. These data suggest that the presence of these unique proteins in xylem sap is vital for PD tolerance in muscadine and Florida hybrid bunch grapes.

Ergot alkaloids: extent of human and animal exposure

Ergot alkaloids are formed by Claviceps spp. on grains and grasses and by fungal endophytes such as Neotyphodium spp. in grasses, notably tall fescue and perennial ryegrass. Ergots from grains and grasses show a wide variation in alkaloid composition. The main ergot alkaloids are pharmacologically active lysergic acid derivatives – e.g. ergometrine (ergonovine), ergotamine, ergosine, ergocornine, α-ergocryptine, ergocristine, and ergovaline; derivatives of isolysergic acid, e.g. ergotaminine; and clavine alkaloids, e.g. agroclavine. Other structurally unrelated toxic alkaloids such as lolitrems are formed by fungal endophytes in grasses. The present review focuses more on how man and animals are exposed to ergot alkaloids than on toxicology and methods of analysis. Ergot poisoning in humans, well known in the Middle Ages, can be of two types: convulsive ergotism and gangrenous ergotism. Since the beginning of the last century there have been outbreaks in Russia, England, India, France and Ethiopia. The principal route of human exposure to ergot alkaloids is by consumption of contaminated food; another route is inhalation of grain dust. Toxicoses in animals due to ergot alkaloids are more common, particularly poisoning of livestock grazing on endophyte infected grasses. Analyses in Canada, Germany, Switzerland, Sweden and Denmark found ergot alkaloids in human foods such as wheat and rye flours, bread, and other grain foods, often at levels greater than 1000 µg/kg. Processing studies have confirmed that the alkaloids survive baking; they also remain to some extent after brewing of beer. There is little evidence for carryover of ergot alkaloids into animal tissue and milk. As an indication of the importance of controlling ergot for the health of animals and people, Canada, the European Union, Switzerland, USA, Japan, Australia and New Zealand have regulations for ergot in grains but only Uruguay and Canada have regulations for the actual ergot alkaloids in feed.

T-cell response to different cultivars of farro wheat, Triticum turgidum ssp. dicoccum, in celiac disease patients

Celiac disease is a gluten sensitive disorder that occurs in genetically susceptible individuals. The present study deals with variation in the immune response of mucosal T-cells from celiac children to prolamins extracted from nine landraces of farro wheat (Triticum turgidum ssp. dicoccum) with contrasting storage protein compositions. The prolamin fraction from nine 'dicoccum' wheat landraces was subjected to peptic-tryptic digestion and supplied to T-cells from mucosal explants of four celiac patients. Immune reactions in terms of cell proliferation and INF-gamma secretion by intestinal T lymphocytes were then determined. T-cell lines exposed to digested prolamins from landraces L5563, L5558 and L5540 showed negligible proliferative responses and released INF-gamma amounts similar to that of untreated control cells. By contrast, landraces Ersa 6, Ersa 8, Leonessa 4 and Leonessa 5 proved to be very active in triggering the immune responses, whereas landraces Filosini and Prometeo exhibited an intermediate behavior. One-dimensional fractionations by A-PAGE or SDS-PAGE revealed distinctive prolamin patterns amongst the landraces analysed. 'Dicoccum' wheat represents a heterogeneous species showing a wide variation in both prolamin composition and T-cell immunological activation, some 'dicoccum' landraces being poor in or devoid of noxious gluten proteins.

Lazulite and Ba, Sr, Ca, K-rich phosphates–sulphates in quartz veins from metaquartzites of Tribeč Mountains, Western Carpathians, Slovakia: Compositional variations and evolution

The phosphate–sulphate mineralization occurs in quartz veins in Lower Triassic metaquartzites of the Tribeč Mts., Central Western Carpathians, Slovakia. The mineralization comprises of lazulite, Ba, Sr, Ca, K-rich phosphates–sulphates and barite in an association with muscovite, hematite, locally rutile, zircon, chlorite and tourmaline. The most widespread lazulite forms up to 10 cm large pale to deep blue aggregates in massive quartz. Electron-microprobe analyses show a relatively uniform composition with Mg/(Mg + Fe) =0.85 to 0.93. The Mössbauer spectroscopy reveals 11–30% Fe 3+/Fe total. Possible primary goedkenite–bearthite binary s.s. shows the highest known Sr contents worldwide: Sr/(Sr + Ca) = 0.67–0.71; Mg, Ba and REE contents are negligible. The lazulite is replaced by a secondary association of Ba, Sr, Ca, K-rich phosphates–sulphates: gorceixite, rarely goyazite, crandallite, svanbergite, jarosite and a rare phase, close to (Ba,K,Sr)(Fe 3+,Al) 3[(OH,H 2O) 6(PO 4)(SO 4)] composition (Ba,Fe,S,P-phase). Gorceixite exhibits more restricted compositional variations between gorceixite–goyazite and gorceixite–crandallite s.s.: Ba/(Ba + Sr) = 0.73–0.99, Ba/(Ba + Ca) = 0.78–0.99 and (P − 1)/[(P − 1) + S] = 0.84–0.99. On the contrary, the secondary Sr, Ca-dominant phosphates–sulphates of the crandallite and beudantite groups show wide compositional variations and complex quarternary solid–solution series between goyazite–crandallite and svanbergite–woodhouseite with Sr/(Sr + Ca) = 0.16 to 0.99 and (P − 1)/[(P − 1) + S] = 0.07 to 0.97. The K, Ba-dominant phosphates–sulphates of the alunite and beudantite groups occur along jarosite–Ba,Fe,S,P-phase s.s. line with Ba/(Ba + K) = 0.07 to 0.56, Fe/(Fe + Al) = 0.55 to 0.99, P/(P + S) = 0.14 to 0.57 and elevated Sr and Ca (up to 0.24 and 0.12 apfu, respectively). The compositions indicate a close relationship and mutual substitutions between the crandallite, beudantite and alunite groups. Unlike to analogous phosphate-bearing assemblages in the Alps, investigated phosphate–sulphate association doesn't contains REE, Y and Sc minerals but it is rich in Ba-phases (barite, gorceixite). The peak metamorphic conditions of the host rocks estimated using the Kübler index of phyllosilicates point to anchizone/epizone boundary, i.e. ca. 270–350 °C. Fluid inclusions study constrained the minimum formation temperatures of the lazulite to 144–257 °C and of the superimposed sulphate–phosphate mineralization to 175–289 °C. Lazulite crystallized from brines of the system H 2O–Na–Mg–Cl–CO 2 with a salinity of 17.2 to 19.8 wt.% NaCl eq. We propose, that the studied mineralization originated from fluids enriched in elements from breakdown of feldspars, biotite, apatite and other phosphates in underlying Hercynian granites. The fluids passed upwards into the metaquartzites and precipitated discrete minerals, due to absence of any suitable sink for the elements among rock-forming minerals.

Peridotite-melt interaction under transitional conditions between the spinel and plagioclase facies beneath the Mid-Atlantic Ridge: Insight from peridotites at 13°N

Peridotites (diopside-bearing harzburgites) found at 13°N of the Mid-Atlantic Ridge fall into two compositional groups. Peridotites P1 are plagioclase-free rocks with minerals of uniform composition and Capyroxene strongly depleted in highly incompatible elements. Peridotites P2 bear evidence of interaction with basic melt: mafic veinlets; wide variations in mineral composition; enrichment of minerals in highly incompatible elements (Na, Zr, and LREE); enrichment of minerals in moderately incompatible elements (Ti, Y, and HREE) from P1 level to abundances 4–10 times higher toward the contacts with mafic aggregates; and exotic mineral assemblages Cr-spinel + rutile and Cr-spinel + ilmenite in peridotite and pentlandite + rutile in mafic veinlets. Anomalous incompatible-element enrichment of minerals from peridotites P2 occurred at the spinel-plagioclase facies boundary, which corresponds to a pressure of about 0.8–0.9 GPa. The temperature and oxygen fugacity were estimated from spinel-orthopyroxene-olivine equilibria. Peridotites P1 with an uniform mineral composition record the temperature of the last complete recrystallization at 940–1050°C and FMQ buffer oxygen fugacity within the calculation error. In peridotites P2, local assemblages have different compositions of coexisting minerals, which reflects repeated partial recrystallization during heating to magmatic temperatures (above 1200°C) and subsequent reequilibration at temperatures decreasing to 910°C and an oxygen fugacity significantly higher than FMQ buffer (Δlog \( f_{O_2 } \) = 1.3–1.9). Mafic veins are considered to be a crystallization product from basic melt enriched in Mg and Ni via interaction with peridotite. The geochemical type of the melt reconstructed by the equilibrium with Ca-pyroxene is defined as T-MORB: (La/Sm)N ≈ 1.6 and (Ce/Yb)N ≈ 2.3, which is well consistent with compositional variations of modern basaltic lavas in this segment of Mid-Atlantic Ridge, including new data on quenched basaltic glasses.

Gold in the weathering crust at the Suzdal' deposit ( Kazakhstan)

A comparative analysis of morphology and geochemistry was made for gold from the primary ores and weathering crust of the Suzdal' gold deposit, Eastern Kazakhstan. The deposit is localized in Carboniferous carbonaceous-terrigenous strata and is of gold-sulfide type. Study of gold from primary ores showed that it occurs mainly in two species: free and so-called invisible. Free gold is crystallomorphic segregations and irregular-shaped grains up to tens of microns in size; it occurs in intergrowths with sulfides, quartz, carbonate, and mica-chlorite aggregate. Most of gold particles have a fineness of 930–980‰, with some grains showing wide variations in composition. Invisible gold (probably chemically combined) is present in fine-acicular arsenopyrite and, less frequently, pyrite. Being transported to the weathering crust, all this gold served as a source for “neogenic” gold of diverse morphologic forms. We recognized crystalline (isometric, prismatic, acicular, and tabular) particles and drusoid gold aggregates in the form of exotic intergrowths of crystallomorphic and sinter-shelly grains. The grains tend to coarsen from bottom to top of the weathering crust. Several generations of gold of different granulometric classes are observed. We have revealed seed and layer growth and dissolution structures in crystals of early generations overgrown with fine grains. All these gold varieties are associated with hypergene minerals. Most of this gold is of high fineness (on the average, 995‰). The hypergene gold particles are chemically homogeneous high-grade, without rims. The results of studies suggest that the high-grade hypergene gold formed in the weathering crust as a result of the dissolution of invisible gold of sulfides and its local redistribution and deposition in oxidizing media. This is also evidenced from the tendency of gold to coarsen from bottom to top of the weathering crust. A distinctive feature of secondary gold is well-expressed crystals and their great diversity.

Nature of uranium mineralisation in the Kerpura-Tiwari-ka-bas area, Sikar district, Rajasthan

Mineralisation of uraninite and brannerite occurs in the albitised metasedimentary and intrusive igneous rocks of Kerpura-Tiwari-ka-bas area in Sikar district, Rajasthan. Samples collected from well dumps contain 0.016 to 1.52% U3O8 with very low ThO2. The host rocks show wide variation in chemical composition due to varying degree of alkali metasomatism, associated alteration and composition of protoliths. The spatial distribution of uranium in groundwater as well as rock samples from well dumps indicates localisation of the uranium mineralisation along NNE-SSW and NWSE directions in Kerpura block. Petrographic and lithogeochemical studies point towards close genetic relationship between alkali metasomatism and uranium mineralisation. The mineralisation seems to be due to mobilisation of uranium and other LILEs by metasomatising fluids and their deposition along shear zones at a later stage, which may not be spatially related to zones of intense albitisation.

Goethite Morphology and Composition in Banded Iron Formation, Orissa, India

AbstractIron ore deposits are generally described in terms of size, grade and chemical composition rather than the mineralogical and microstructural characteristic of different ore types. It is essential, however, to know the morphology, microstructure and chemical composition of individual minerals for optimum mineral processing. Goethite is reported to occur as a ubiquitous phase in many iron ore types and is particularly abundant in the Precambrian banded iron ore formation of north Orissa, India. Goethite from the Bonai–Keonjhar Belt in Orissa has been examined in terms of its morphology and microstructure in relation to chemical composition. Electron microscopy indicated several goethite morphotypes including botryoidal, nodular, spheroidal, platy, stalactitic and flaky. These different morphotypes display intergranular, intragranular, wedge, reniform, comb, prismatic, cavity‐line and bead microstructures. In situ analysis using electron probe microanalyzer indicated a wide compositional variation among the different morphotypes and microstructures. Goethite replacing hematite is generally devoid of deleterious elements while re‐precipitated goethite generally contains adsorbed alumina, silica and/or phosphorus. Nodular goethite commonly has a high phosphorus level while botryoidal, spheroidal and platy goethite often contains increased combined alumina and silica. Goethite having a reniform, wedge, intergranular or intragranular microstructure is highly water bearing and cryptocrystalline in nature. During dehydration, bead, comb, cavity‐lined or prismatic goethite develop, which are more crystalline and which have a higher iron concentration. Goethite with a wedge, prismatic or bead‐type microstructure has a higher adsorption of silica (2–4%), while goethite having an intergranular, bead or prismatic microstructure invariably contains appreciable phosphorus, generally at levels deleterious to processing.

Variation in the guild composition of herbivorous insect assemblages among co-occurring plant species

Variation in plant traits among plant species may promote the development of a characteristic functional assemblage of insect herbivores associated with each plant species. However, only a small number of studies have detailed the representation of several herbivore guilds among co-occurring plant species to determine whether the functional structure of herbivorous insect assemblages varies widely and consistently among plant species. The present study provides one of the few published data sets reporting on the density of several guilds of insect herbivores among numerous plant species. Variation in guild associations with plant phenology and season are also described. Insect herbivores were divided into 10 guilds, and the representation of these guilds was examined for 18 co-occurring plant species. Guild densities and assemblage composition varied significantly among plant species, even when variation over time was taken into account. Variation in guild densities and assemblage composition were not strongly related to the taxonomic relationships of the plants. The highest densities of several guilds occurred in spring and summer, although other guilds were not strongly seasonal. Certain guilds were strongly associated with the presence of new leaves, whereas other guilds appeared to prefer mature leaves. This resulted in assemblage differences between samples containing new and mature leaves and samples containing mature leaves only. Even though the timing and duration of leaf and flower production varied among plant species, this did not explain all variation in guild densities among plant species. It is suggested that additional factors, including plant traits, are contributing to the wide and consistent variation in herbivore assemblage composition among plant species.

Nutrients and nipple aspirate fluid composition: the breast microenvironment regulates protein expression and cancer aetiology

The aetiology of breast cancer is complex and multifactorial, and may include diet and xenobiotic compounds. A change in diet affects nutrient levels in blood, but to what extent diet can affect micronutrient concentrations in the breast is not yet well established. Breast nipple aspirate fluids (NAF) can be non-invasively obtained from the breast in most women; it represents a biological tool to assess metabolic changes in the breast ductal microenvironment. A wide variation in biomolecular and hormonal composition of NAFs collected from healthy and breast cancer patient may be due to genetic and nutritional factors; however, micro- and macro-nutrients may influence the secretory status of these women, thus NAF composition and risk of breast carcinoma. The aim of this overview is to highlight the detrimental/beneficial role that diet-related compounds in nipple aspirate fluid can have in breast cancer risk.

MOLECULAR APPROACHES TO CHARACTERIZING AND IMPROVING BULB COMPOSITION IN ONION

MOLECULAR APPROACHES TO CHARACTERIZING AND IMPROVING BULB COMPOSITION IN ONION