Oxide Needles Research Articles

In situ microscopy of composite Germanium/Germanium oxide microneedle growth

Composite germanium/germanium oxide needles with a carcass/filler structure, thicknesses of 0.25–10 µm and lengths up to 450 µm were grown by chemical transport involving gaseous GeO. The synthesis was carried out at temperatures of 897–1100 K in a newly developed miniature cell. Through a top window one can observe the growth process in situ via video microscopy. The cell can be evacuated and sealed, enclosing all products generated in reactions, but can easily be opened afterwards for an ex situ analysis of the needles. The in situ observations show that the needles grow with longitudinal velocities of up to 30 µm/s, depending on temperature and needle thickness, and with lateral velocities of up to 0.11 µm/s. The surface structure and the cross-sections of the needles were studied ex situ by SEM as well as EDX spectroscopy combined with element mapping. The surface structure of needles exhibits highly regular arrays of germanium/germanium oxide microunits but also shows irregularities and defects. The study of the longitudinal section and the lamella showed that this regularity is remarkable also inside the needle all way down to the core. Furthermore, according to the SAED and Raman spectroscopy, the needle carcass (core with branches) is mainly composed of a cubic Ge and an amorphous filling mass of Ge and O, which presumably corresponds to GeO2.

Comparison of a novel form of zinc with zinc oxide bolus licensed for prevention of facial eczema, and interaction with copper oxide in sheep.

To evaluate a novel elemental zinc bolus compared with a registered positive control zinc oxide bolus and assess serum zinc concentrations following concomitant treatment with a capsule containing copper oxide needles. Forty Romney-cross ewes were randomly allocated in a 2 × 2 factorial design study. On Day 0, 20 ewes received novel boluses containing elemental zinc (Investigational Veterinary Product, IVP) while 20 received a zinc oxide bolus (control; CP). Half the animals in each zinc treatment group (n=10) were treated with a copper oxide needle capsule [Copasure® - Ewe]. Weekly, from Day -7 to 56, all ewes were assessed for signs of photosensitization, and for 10 ewes from each zinc treatment groups, samples were collected for analysis of serum GGT activity, serum zinc concentrations, faecal zinc concentrations and on Days -7 and 56, liver copper concentrations. Multivariable random-effects models assessed the effects of zinc treatment, copper treatment, treatment interactions and time on all analytes. Regression models examined associations between serum and faecal zinc concentrations and GGT activity. Low spore numbers indicated low Pithomyces chartarum challenge. Serum zinc levels were significantly higher in the IVP than in the CP group [p < 0.0001] and varied by time [p < 0.001] and positively associated with faecal zinc concentration [p < 0.001]. Copper treatment did not affect serum zinc [p=0.82] or faecal zinc [p=0.92] concentrations. Liver copper concentrations did not differ between zinc treatment groups on Day -7 [p=0.6] or Day 56 [p=0.95]. Only the CP/no copper group had no increase in liver copper concentrations.

One-Pot Synthesis of MnOx-SiO2 Porous Composites as Nanozymes with ROS-Scavenging Properties.

The development of nanomaterials that mimic the activity of enzymes is a topic of interest, for the decomposition of reactive oxygen species (ROS). We report the preparation of a novel nanocomposite of MnOx needles covered with SiO2 porous material. The material was prepared in one pot with a two-step procedure. The material was characterized by EDX, SEM, TEM, XRD, nitrogen adsorption–desorption isotherms, and XPS. The synthesis protocol took advantage of the atrane method, favoring the nucleation and initial growth of manganese oxide needles that remained embedded and homogeneously dispersed in a mesoporous silica matrix. The final composite had a high concentration of Mn (Si/Mn molar ratio of ca. 1). The nanozyme presented bimodal porosity: intraparticle and interparticle association with the surfactant micelles and the gaps between silica particles and MnOx needles, respectively. The porosity favored the migration of the reagent to the surface of the catalytic MnOx. The nanozyme showed very efficient SOD and catalase activities, thus improving other materials previously described. The kinetics were studied in detail, and the reaction mechanisms were proposed. It was shown that silica does not play an innocent role in the case of catalase activity, increasing the reaction rate.

High-efficiency and fast removal of As(III) from water by cerium oxide needles decorated macroporous carbon sponge

The deep removal of highly toxic and mobile As(III) from water is challenging but urgently needed. Herein, a cerium oxide (CeO2) needles decorated macroporous carbon sponge (Ce-Ns/MCS) with a strong affinity for As(III) was fabricated for highly efficient removal of As(III). The open structure of Ce-Ns/MCS allows the decorated CeO2 highly accessible for As(III). Ce-Ns/MCS (1 g/L) could remove the As(III) levels (826 μg/L) to less than 10 μg/L within 20 min. Moreover, similar removal efficiency could achieve in a wide pH range (3–11), and the water environmental interference such as coexisting anions and natural organic matter exhibited negligible influence on As(III) removal. The As(III) (68 μg/L) in natural water matrices can be removed to below 10 μg/L within 5 min. Ce-Ns/MCS also possesses structural stability and excellent reusability. In addition, Ce-Ns/MCS could be effectively applied to the fixed-bed operation, and the Ce-Ns/MCS column could purify 4035 bed volume (BV) and 1605 BV effluent from the As(III)-spiked groundwater containing 100 μg/L and 600 μg/L of As(III), respectively. Ce-Ns/MCS could be a prospective practical adsorbent for As(III) remediation because of its excellent performance, without pre-oxidation requirement, and excellent anti-interference.

Characteristics and formation of corundum within syenite in the Yushishan rare metal deposits in the northeastern Tibetan Plateau

Abstract Corundum is rarely found in situ within alkali syenites. A corundum-bearing syenite was found in the Yushishan rare metal deposits of the eastern section of the Altyn Tagh fault in the northeastern Tibetan Plateau, but the characteristics and formation of corundum remain unknown. We describe a corundum-bearing syenite dike emplaced in biotite plagioclase gneiss that suffered overprinted deformation with characteristics of mylonitization. The corundum crystals have variable grain sizes, and the largest ones are megacrystic with growth zoning. The corundum crystals contain a variety of mineral inclusions that are divided into primary and secondary. The primary mineral inclusions within the corundum include variable contents of Fe-Ti oxide needles, ilmenite, zircon, monazite-(Ce), potassium feldspar, pyrochlore, columbite-(Fe), magnetite, samarskite-(Y), and pyrite that indicate corundum crystallized in peraluminous Zr-rich and Si-poor alkali rock with variable TiO2 contents. Secondary mineral inclusions include Zn-rich hercynite, ilmenite, magnetite, annite, fluorapatite, and intergrowths of ilmenite with columbite-(Fe) and goethite that reveal late-stage influx of Zn-, Ti-, Fe-, and F-bearing fluids into corundum that caused metasomatism and element migration and mineral precipitation. The trace element analysis of corundum shows high-Fe and -Ga contents and low-Mg and -Cr contents that are consistent with the characteristics of corundum of magmatic origin. The trace element characteristics and the oxygen isotopes (6.2–8.2‰) results indicate that corundum crystallized in melts with the involvement of Al-rich and Si-poor crustal material.

The origin of needle-like rutile inclusions in natural gem corundum: A combined EPMA, LA-ICP-MS, and nanoSIMS investigation

Trace-element chemistry and microscopic observations of included gem corundum (α-Al2O3) suggests a new model of syngenetic growth of oriented rutile inclusions rather than the usual interpretation of their growth through exsolution. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) is now a robust method for measuring trace elements in gem-quality corundum (ruby and sapphire). Nonetheless, the corundum structure is relatively unforgiving for substitutional components and typically only a small handful of minor to trace elements are measured by LA-ICP-MS (Mg, Ti, V, Cr, Fe, Ga). Less commonly, trace elements such as Be, Zr, Nb, Sn, La, Ce, Ta, and W are found in natural corundum. Their concentrations are typically correlated with high contents of Ti and silky or cloudy zones in the corundum that contain a high concentration of needle-like rutile or other oxide inclusions. Three metamorphic-type sapphires from Sri Lanka, Madagascar, and Tanzania were studied here using LA-ICP-MS, electronprobe microanalysis (EPMA), and nanoSIMS to document correlations between the various trace elements and their distribution between the corundum and included, oriented rutile TiO2 needles. NanoSIMS and EPMA measurements show concentration of Be, Mg, Fe, V, Zr, Nb, Ce, Ta, and W in the rutile needles. The relative atomic concentrations of Mg and Ti from LA-ICP-MS measurements suggest the corundum-rutile intergrowth grew as a mechanical mixture of the two phases as opposed to rutile formation through exsolution from the corundum host. This scenario is also suggested for the three magmatic-type sapphires studied here based on the presence of glassy melt inclusions in close association with included, oriented oxide needles. The preservation of a glassy melt inclusion requires fast cooling, whereas exsolution of the oxide inclusions would require slow cooling and annealing at a temperature lower than sapphire formation. The studied sapphires suggest the likely origin of the oriented, needle-like rutile inclusions to be syngenetic epitaxial coprecipitation of both rutile and corundum. The interpretation of such oriented oxide inclusions has important implications for understanding the geological formation conditions based on trace element data or using such data to separate sapphires and rubies based on their geographic origin.

Bismuth oxide nanoparticles decorated Graphene layers for the degradation of Methylene blue dye under visible light irradiations and antimicrobial activities

RGO-Bi2O3 nanocomposite was synthesized by chemical oxidation of graphite into graphene oxide followed by a solvothermal method. Bismuth nitrate was used as a precursor for bismuth oxide. The prepared photocatalyst was characterized by XRD, FT-IR, UV–vis DRS, Raman and FE-SEM analyses. The XRD pattern showed the photocatalyst to be crystalline in nature. The morphology of the photocatalyst as revealed by FE-SEM images showed the bismuth oxide needles decorated on the layers of graphene oxide. The visible light photocatalytic activity of the prepared nanocomposite was tested by the degradation of a model organic dye molecule – methylene blue (MB). The preliminary studies on the effect of pH, initial dye concentration, catalyst dosage were studied. Maximum degradation of 98% was achieved at neutral pH for 10ml of 10ppm dye solution with 10mg of catalyst. The photocatalytic study proves the enhanced activity of the RGO-Bi2O3 nanocomposite compared with the pristine Bi2O3 under visible light irradiation. The maximum degradation percentage was achieved at 240min. The antimicrobial studies were carried out against gram negative and gram positive species by well diffusion method which showed the material to possess antimicrobial activity.

Oxide evolution on Alloy X-750 in simulated BWR environment

In order to simulate the environment experienced by spacer grids in a boiling water reactor (BWR), specimens of the Ni-based Alloy X-750 were exposed to a water jet in an autoclave at a temperature of 286 °C and a pressure of 80 bar. The oxide microstructure of specimens exposed for 2 h, 24 h, 168 h and 840 h has been investigated mainly using electron microscopy. The specimens suffer mass loss due to dissolution during exposure. At the same time a complex layered oxide develops. After the longest exposure the oxide consists of two outer spinel layers consisting of blocky crystals, one intermediate layer of nickel oxide interspersed with Ti-rich oxide needles, and an inner layer of oxidized base metal. The evolution of the oxide leading up to this structure is discussed and a model is presented.

Oriented multiphase needles in garnet from ultrahigh-temperature granulites, Connecticut, U.S.A.

This study investigates distinctive oriented, needle-shaped multiphase inclusions found within cores of garnets from felsic granulites of the Upper Member of the Bigelow Brook Formation and the Brimfield Schist (northeastern Connecticut, U.S.A.). The rocks crop out in the southern end of the Central Maine Terrane and thus are a part of the Acadian/Neoacadian Orogen. The typical mineral assemblage is garnet + sillimanite + K-feldspar + plagioclase + quartz + cordierite + biotite ± spinel. The sillimanite is commonly pseudomorphous after kyanite. The multiphase needle inclusions and associated exsolved needles of rutile and ilmenite are mostly oriented parallel to of garnet. The multiphase needles contain various combinations of quartz, micas, chlorite, rutile, graphite, a siliceous compositionally variable phase (“Phase-CV”), Zn-spinel, apatite, zircon, and rare ilmenite. We hypothesize that they represent inclusions of fluid that adhered to exsolving Ti±Fe oxide needles (mostly rutile) or extended along zones of weakness in garnet. This requires that multiphase needle formation occurred in response to cooling and/or decompression. The needles ultimately decrepitated during retrogression. We note that micaceous needle-shaped multiphase inclusions are rarely described; the closest analogs of which we are aware are found in UHP garnets of the Erzgebirge (Perchuk 2008). The Brimfield Schist in this area underwent ultrahigh-temperature metamorphism (UHTM) of ~1000 °C at a minimum pressure of ~1 GPa (Ague et al. 2013). Here we provide new temperature estimates for the adjacent Upper Member of the Bigelow Brook Formation. Ternary feldspar reintegration using the activity model of Benisek et al. (2004) and Zr-in-rutile thermometry (Tomkins et al. 2007) give average temperatures of ~990 and ~1010 °C, respectively, at 1 GPa for this unit. Therefore, the recently discovered UHT zone in the Brimfield Schist of northeastern Connecticut extends to the east to include the Upper Member of the Bigelow Brook Formation. Consequently, the first confirmed regional UHT locality in the United States is larger than initially recognized, and is at least 25 km long and 5–10 km wide. The oriented, elongate multiphase inclusions and petrographically obvious oriented Ti±Fe oxide needles may be useful indicators of extreme temperature and/or pressure rocks in other field areas.

Needle-like Co3O4 Anchored on the Graphene with Enhanced Electrochemical Performance for Aqueous Supercapacitors

We synthesized the needle-like cobalt oxide/graphene composites with different mass ratios, which are composed of cobalt oxide (Co3O4 or CoO) needle homogeneously anchored on graphene nanosheets as the template, by a facile hydrothermal method. Without the graphene as the template, the cobalt precursor tends to group into urchin-like spheres formed by many fine needles. When used as electrode materials of aqueous supercapacitor, the composites of the needle-like Co3O4/graphene (the mass ratio of graphene oxide(GO) and Co(NO3)2·6H2O is 1:5) exhibit a high specific capacitance of 157.7 F g(-1) at a current density of 0.1 A g(-1) in 2 mol L(-1) KOH aqueous solution as well as good rate capability. Meanwhile, the capacitance retention keeps about 70% of the initial value after 4000 cycles at a current density of 0.2 A g(-1). The enhancement of excellent electrochemical performances may be attributed to the synergistic effect of graphene and cobalt oxide components in the unique multiscale structure of the composites.

Precipitation of rutile and ilmenite needles in garnet: Implications for extreme metamorphic conditions in the Acadian Orogen, U.S.A.

We report the discovery of oriented needles of rutile and ilmenite in garnet crystals from granulite facies metapelitic rocks of the Merrimack synclinorium, Connecticut, and present a precipitation model for their origin. The rocks were strongly metamorphosed and deformed during the Devonian Acadian orogeny. The needles are primarily elongated parallel to in garnet. Rutile has anomalous extinction angles as great as ~35° (cf. Griffin et al. 1971). Rutile and ilmenite needles are typically a few hundred nanometers to several micrometers in diameter and are several tens of micrometers to nearly a millimeter long. Other oxide inclusions that may be present include submicrometer- to micrometer-scale twinned rutile bicrystals, as well as srilankite and a crichtonite group mineral. Some garnet cores have unusual, box-shaped quartz inclusions, which coexist with Ti±Fe oxide needles and commonly contain micrometer-scale rods of F-OH-Cl apatite. Negative garnet crystal “pores” are also widespread. Ti±Fe oxide needles are restricted to garnet core regions; rims have a distinctly different inclusion population dominated by granulite facies minerals including sillimanite, spinel, cordierite, and K-feldspar. Consequently, the garnet core regions represent an earlier, distinct period of growth relative to the rims. Garnet cores contain ~25–35% pyrope, and a host of minor and trace constituents including TiO2 (0.07–0.6 wt%), Cr2O3 (0.01–0.10 wt%), Na2O (0.01–0.03 wt%), P2O5 (0.01–0.09 wt%), and ZrO2 (up to ~150 ppm). Na2O and ZrO2 correlate positively with TiO2. Titanium zoning is preserved in some garnets; zoning profiles and two-dimensional chemical mapping show that Ti and, to a lesser degree, Cr are depleted around Ti±Fe oxide inclusions. Therefore, we conclude that the needles are precipitates that formed from Ti-bearing garnet during exhumation and cooling. Garnet contained sufficient Ti to form precipitates; no Ti source external to garnet was necessary. Titanium-bearing garnets that contain oriented Ti±Fe oxide needles are known primarily from ultrahigh-pressure metamorphic rocks, mantle peridotites and pyroxenites, and high-pressure granulites. Thus, the presence of needle-bearing garnets in Connecticut strongly suggests that a previously unrecognized domain of extreme pressure and/or temperature metamorphism exists in the Acadian orogen.

Morphology and microstructure of magnetite and ilmenite inclusions in plagioclase from Adirondack anorthositic gneiss

It is well known that oriented iron and titanium oxide inclusions occur in pyroxenes and plagioclase of anorthosites and granulites, and they are attributed to exsolution at subsolidus conditions. The oxides occur as needles or platelets. In this study, we determine the morphology of oxide needles as well as their orientation in plagioclase (An 30–35) in anorthosite gneiss from the Adirondack mountains (New York). The investigation was done with electron backscatter diffraction (EBSD) in a scanning electron microscope, as well as Laue diffraction with a microfocus synchrotron X-ray beam at the Advanced Light Source in Berkeley. It was observed that the needle direction is [110] in magnetite and [1010] in ilmenite. The needle direction is consistently parallel to [001] of plagioclase. Furthermore, (111) of magnetite and (0001) of ilmenite are sub-parallel to (120) and (120) of plagioclase. We note that for directions [110] in the magnetite structure and [1010] in ilmenite, O atoms are close-packed, and (111) and (0001) are close-packed planes, correspondingly. In plagioclase, [001] is a direction with open channels as well as approximate alignment of Si tetrahedral edges, thus providing nucleation sites with a coincidence lattice relationship. (120) and (120) in this triclinic mineral are planes with approximate tetrahedral sides so that the relationship is structurally plausible. From Laue diffraction, we can determine that the magnetite needle axis is subject to an extensional stress, most likely attained during cooling of the inclusions within the plagioclase host.

Copper status in breeding and racing camels (Camelus dromedarius) and response to cupric oxide needle capsules

Copper was determined in the blood of breeding camels, camel calves and racing camels to evaluate copper status in these animals in UAE. Low blood copper concentrations were reported in newly born camel calves (100%) and calves 2-4 months old (68%), breeding camels at early (55.6%) and at mid lactation (48%) and at late pregnancy (69%). This is attributed to the low copper and high sulfate in the Rhodes grass which is the only diet offered to the breeding camels. On the other hand only 9.7% of racing camels showed low copper levels. This is because copper is routinely offered to racing camels when their blood copper is low. Cupric oxide needle capsules orally administered at the rate of 8 g per adult camel was effective in elevating blood copper from 7.083 micromol/L at day zero to 10.074 micromol/L at day 28 after dosing.

Combining the effects of supplementary feeding and copper oxide needles for the control of gastrointestinal nematodes in browsing goats

The aim was to assess the benefits obtained from combining supplementary feeding and copper needles (COWP), compared to the use of both approaches independently, for the control of gastrointestinal nematode (GIN) infections in browsing kids. Forty-four nematode free Criollo kids were exposed to natural parasite infection. The kids were divided into six experimental groups: not treated, supplemented (NT-S), not treated, not supplemented (NT-NS), moxidectin treated, supplemented (M-S), moxidectin treated not supplemented (M-NS), copper treated, supplemented (COWP-S) and copper treated, non-supplemented (COWP-NS). Copper treated groups received Copinox ® (2 g capsules) on day 0 and on day 60 of the trial. Moxidectin treated groups received Cydectin ® (0.2 mg/kg of body weight sc) every 28 days. Three of the groups received individual supplementation (100 g of feed/day fresh basis; 74% sorghum: 26% soybean meal; NT-S, M-S and COWP-S) and the other three groups were not supplemented (NT-NS, M-NS and COWP-NS). Animals browsed native vegetation (6.5 h/day) during the wet season (154 days). Kids were weighed every 14 days to determine live weight gain (LWG) and blood and faecal samples were obtained to determine packed cell volume (PCV), haemoglobin (Hb), peripheral eosinophil counts (PEC) and faecal egg counts (FEC). At the end of the trial, four kids of each group were euthanatized (six kids in each COWP treated group). Worm burdens, female worm lengths and prolificacy were determined. Liver samples were used to determine copper concentration and were stained with haematoxylin–eosin to determine microscopic lesions. Animals receiving the combination of supplementary feeding and COWP improved their LWG, PCV and Hb to similar levels of animals with suppressive AH treatment. This was not the case when COWP was used without supplementation. Liver copper concentration in COWP treated groups increased significantly especially in the COWP-NS kids but this was not associated with liver lesions or clinical signs. Post-mortem Haemonchus contortus and Trichostrongylus colubriformis worm counts had a tendency to be reduced in the different groups (66–35% reduction) compared to NT-NS group at the end of the trial ( P > 0.05). Also, COWP treatment and/or supplementation reduced female worm length of T. colubriformis and prolificacy of H. contortus and T. colubriformis. This study, confirmed the value of nutritional supplementation in the control of GIN in growing kids. The use of COWP in addition to supplementation had a limited contribution on the kids’ resilience against GIN. This may be due to the reduced infection of H. contortus during this trial.

Pinching of alkoxide jets—a route for preparing nanometre level sharp oxide fibres

The pinching phenomenon is used to shape jets ofSn(OBu)4 based viscous oligomeric melts into nanometre range sharp oxide needles. Theinfluence of viscosity of the liquid, humidity of surrounding environment andpulling speed on formation of the needles is investigated. Optimal conditions enablereproducible preparation of needles that have tip radii down to 15–25 nm, i.e. in therange that is of considerable interest for many nanotechnological applications.

Synthesis of tungsten oxide tapered needles with nanotips

Tungsten oxide tapered needles with nanotips were synthesized on a large scale by reacting tungsten nanopowders with hydrous nickel nitrate in hydrogen atmosphere. The resultant tungsten oxide needles have lengths more than 100 μm, root diameters of several hundred nanometers and tip diameters of several nanometers, showing a perfectly axisymmetric configuration. HRTEM and SAED analyses showed that the synthesized tungsten oxide tapered needles have a single-crystalline structure with growth direction of [0 1 0]. The effects of the experimental conditions (the ratio between tungsten and hydrous nickel nitrate, the size of tungsten powders, and the reaction atmosphere) on the morphology of the products were systematically investigated. It was found that tungsten oxide nanowires, submicro-/micro-whiskers and microtubules could be facilely obtained under different experimental conditions. The unique configuration and the single-crystal structure of the tapered needles may make them a potential candidate for field emitters and probing tips.

Sol-Gel Derived SnO2 Nanometric Fibers

AbstractThe applicability of Sn(OBu)4 based viscous oligomeric concentrates in fabrication of thin oxide fibers and needles is demonstrated. Influence of several crucial parameters like viscosity of the concentrate, humidity of surrounding atmosphere and pulling speed on formation of the structures is discussed. We show that the method enables to obtain fibers less than a micron in diameter and needles with tip radii down to 15 nm, i.e. in range that is of considerable interest for many nanotechnological applications.

Effect of chromium supplementation and copper status on glucose and lipid metabolism in Angus and Simmental beef cows

Pregnant Angus ( n = 83) and Simmental ( n = 69) cows were blocked by age into three blocks and then randomly assigned by breed to one of two free choice mineral supplements to determine effects of dietary Cr and Cu status on glucose metabolism and blood metabolites in beef cows. Supplements consisted of: (1) control (no supplemental Cr) and (2) 40 mg Cr/kg of mineral (from Cr picolinate). Mineral supplements were formulated to contain all minerals typically supplemented to cattle diets with the exception of Cu. The study began approximately 75 days prepartum, at which time half of the cows in each treatment received a 25 g Cu oxide needle bolus. Blood was collected from 36 cows on days 28, 58, 97 (approximately 20-day postpartum), 155, 210, and 279 for plasma glucose and non-esterified fatty acid (NEFA) determination. Chromium supplementation reduced (P<0.05) plasma glucose concentrations. Plasma glucose concentrations were also affected by breed × Cu bolus (P<0.05). In non-Cu supplemented cows, plasma glucose levels were higher (P<0.05) in Angus versus Simmental cows. In cows receiving a Cu bolus, plasma glucose levels were similar between breeds. Plasma NEFA concentrations were affected by time (P<0.01), Cr × Cu bolus (P<0.05), Cr × time (P<0.01), and Cr × block (P<0.01). On days 97 and 155, plasma NEFA concentrations were lower (P<0.01) in cows receiving Cr relative to control cows. Chromium supplementation reduced (P<0.01) plasma NEFA concentrations in 2 and 3 and 4 and 5-year-old cows but not in older cows, relative to control cows in those blocks. Chromium supplemented cows had lower (P<0.05) plasma NEFA concentrations than control cows that did not receive a Cu bolus. No differences in plasma NEFA concentrations occurred between treatments in cows that received a Cu bolus. At approximately 1-month prepartum and 1-month postpartum, 12 cows were cannulated in their jugular vein and glucose tolerance tests (GTT) were conducted. Cows used in GTT received 0.15 g of glucose/kg body weight as a 500 g/L dextrose solution. Chromium supplemented cows had lower plasma glucose (P<0.01), serum insulin (P<0.05) and NEFA (P<0.01) concentrations following the GTT conducted prepartum versus control cows. Clearance rates for glucose were not affected by treatment. In the postpartum GTT, plasma glucose was affected by an interaction between Cr supplementation and Cu status, as Cr supplemented cows that received a Cu bolus had higher (P<0.001) plasma glucose after glucose administration than cows not supplemented with Cu. No differences in plasma glucose occurred between control cows regardless of Cu status. Chromium supplemented cows had lower (P<0.05) serum insulin concentrations 10–45 min after glucose administration versus control cows. Results indicate that plasma glucose is lower in cows receiving supplemental Cr, and that an interaction between Cr and Cu status may alter glucose metabolism.

Effect of chromium supplementation and copper status on performance and reproduction of beef cows

Pregnant Angus ( n = 83) and Simmental ( n = 69) cows were blocked by age into three age blocks and then randomly assigned by breed within a block to one of two free choice mineral supplements to determine effects of dietary Cr and Cu status on performance and reproduction of beef cows. Supplements consisted of: (1) control (no supplemental Cr) and (2) 40 mg Cr/kg of mineral (from Cr picolinate). Mineral supplements were formulated to contain all minerals typically supplemented to cattle diets with the exception of Cu. The study began approximately 75 days prepartum, at which time half of the cows in each treatment received a 25 g Cu oxide needle bolus. Blood was collected from 36 cows on days 0, 28, 58, 97 (approximately 20 days postpartum), 155, 210, and 279, and from 36 calves on days 196 and 279 for plasma Cu determination. Liver biopsies were taken on days 0 and 279 to determine initial and final liver Cu concentrations in cows. Plasma Cu concentrations were affected by Cu bolus × time ( P < 0.05), breed × time ( P < 0.01), and breed × bolus ( P < 0.01) interactions in cows, and by a treatment × time interaction ( P < 0.05) in calves. Liver Cu concentrations were affected by breed × time ( P < 0.01) and Cu bolus × time ( P < 0.05) in cows. Cows receiving a Cu bolus had higher ( P < 0.05) plasma Cu on day 97, and higher ( P < 0.05) liver Cu on day 279 relative to cows that did not receive a bolus. Simmental cows had lower ( P < 0.01) plasma Cu at day 28 and at subsequent sampling days, and lower ( P < 0.01) liver Cu on days 0 and 279 than Angus cows. Simmental cows that received a Cu bolus had higher ( P < 0.01) plasma Cu concentrations than Simmentals that did not receive supplemental Cu. Supplemental Cr resulted in higher ( P < 0.05) plasma Cu concentrations in calves on day 279 versus controls. Overall body weight loss and body weight loss postpartum in cows was affected by breed ( P < 0.05) and treatment × block ( P < 0.01). Overall and postpartum body weight loss was lower in Angus cows ( P < 0.05). Chromium supplementation reduced ( P < 0.01) overall and postpartum body weight loss in 2 and 3 years old cows, but not in older cows. Cows supplemented with Cr tended ( P < 0.06) to have higher pregnancy rates than controls. Calf birth weights and weaning weights were not affected by Cr or Cu bolus. Results indicate that Cr supplementation may improve fertility and decrease postpartum body weight loss especially in young beef cows.

Determination of the oxidation state for iron oxide minerals by energy-filtering TEM

The oxidation state of iron oxide nanoparticles was determined using the two principally different technical realisations of energy filtering TEM, in one case using the JEOL 3010 equipped with a LaB6 cathode and a post-column GIF and in the second, the newly designed LIBRA 200FE equipped with an corrected in-column 90° energy filter and a field emission gun (Schottky emitter). The samples studied were oxide-coated iron nanoparticles, and iron oxide inclusions in feldspars in granites.Five possible candidates exist for the iron-oxide phases: FeO, α-Fe2O3 (hematite), γ-Fe2O3 (maghemite), Fe3O4 (magnetite) or α-FeO(OH) (goethite). Fingerprinting the O K-edge ELNES allows to distinguish between oxide phases with the same stochiometry and enables to make a first selection of possible candidates. The additional determination of the chemical composition allows unique identification of the phase present. For the oxide coated iron nanoparticles the most probable iron oxide phase of the shell is maghemite, which was additionally confirmed by HRTEM studies. The second studied system were iron oxide needles in alkali feldspar, where we obtained hematite as the most probable phase. There we additionally demonstrated the drastic changes of the ELNES of the O K-edge for the alkali feldspar and iron oxide needle by spatially resolved EELS.