Large Amounts Of Cu Research Articles

Effect of Cu Addition Above the Solubility Limit on Microstructure Formation and Cu Segregation in 800 MPa Grade Ductile Cast Iron During Solidification

In this study, the effect of 3 mass%Cu additions on microstructure formation and Cu segregation in 800 MPa grade ductile cast iron during solidification was investigated. The calculated phase diagram showed that after the addition of 3 mass%Cu, the Cu phase with a negligible amount appeared below 1000°C, and most Cu was included in the matrix. Based on optical microstructure, after the addition of 3 mass%Cu, the size of graphite nodules became finer, and the microstructure rarely had an area with α-ferrite. Image analysis showed that the fraction of pearlite increased significantly, indicating that Cu greatly promoted the formation of pearlite. Compositional analysis by scanning electron microscopy indicated that the pearlitic area also contained approximately 3 mass%Cu, which corresponds to those of primary and secondary austenite calculated. A small and bright phase particle containing a large amount of Cu was observed at the interface of graphite and matrix.

Cu microvia filling by pulse-reverse electrodeposition with a single accelerator

Cu electrodeposition processes are widely employed to achieve defect-free interconnections in electronic devices. Typically, combinations of three additives—an accelerator, a suppressor, and a leveler—are used for bottom-up filling of Cu in microscaled features. However, the use of multiple additives adds complexity to electrolyte maintenance and can lead to reliability issues in the process. To address this challenge, we have developed a single-accelerator filling technique using pulse-reverse electrodeposition for microvias. During pulse-reverse electrodeposition, the anodic steps produce a large amount of Cu+ ions near the electrode surface. These Cu+ ions can form complexes with Cl− ions or CuCl layers, thereby enhancing the adsorption of the accelerator, SPS. This phenomenon depends on the electrolyte convection. Under strong forced convection, Cu-Cl species are removed, leading to subsequent deactivation of SPS, whereas Cu-Cl species remain stable under mild convection conditions. Based on this convection-dependent behavior of SPS and Cl, Cu electrodeposition is promoted at the bottom of microvias while the SPS is selectively deactivated outside the microvias where the strong electrolyte motion exists. As a result, without any polymeric suppressor and organic leveler, the microvias are successfully filled with Cu.

O-Modified Activated Carbon Fiber Electrode Efficiently Adsorption of Cu (II) in Wastewater

At present, wastewater discharged from many industries contains a large amount of Cu (II). In this study, an O-modified activated carbon fiber (O-ACF) with high adsorption activity was prepared by oxidation modification of activated carbon fiber with 20% nitric acid. O-ACF was used to adsorb Cu (II) in water. Electrode adsorption experiments showed that O-ACF had excellent electro-adsorption performance for Cu (II), and the maximum adsorption capacity was 48.60 mg/g, which was 1.63 times that of commercial activated carbon. After optimizing and adjusting the voltage (0.6–1.2 V), pH (2–10) and electrode plate spacing (5–20 mm), it was found that the most favorable working conditions for electro-adsorption of Cu (II) by O-ACF electrode were voltage of 1.0 V, solution pH of about 6, and electrode plate spacing of 10 mm. The kinetic model fitting showed that the adsorption effect of O-ACF on Cu (II) was mainly chemical adsorption. The intraparticle diffusion model further found that the adsorption of Cu (II) by O-ACF was influenced by membrane diffusion and internal diffusion. Adsorption regeneration experiment showed that O-ACF still maintained 95% adsorption performance for Cu (II) after 5 times of adsorption regeneration, which had good practicability. This study provides an excellent material for capacitive deionization system, which is expected to be applied in sewage treatment, seawater desalination and nutrient recovery.

New insights into the relationship between Cu–Ce interaction and reactive Cu species in CuOx-CeO2 catalysts for preferential oxidation of carbon monoxide in excess hydrogen

A group of CuOx-CeO2 catalysts for preferential oxidation of carbon monoxide (CO-PROX) is designed by constructing different distribution status of Cu species on similar CeO2 support to adjust the Cu–Ce interaction strength. Cycled temperature programmed reduction by hydrogen (H2-TPR) indicates the strength of Cu–Ce interaction can impact the amount and redox properties of surface highly dispersed CuOx and strongly bonded Cu-[Ox]-Ce species, which respectively determines the catalytic performance at low and high temperature. Temperature programed desorption of H2 (H2-TPD) reveals the presence of large amounts of Cu-[Ox]-Ce species can inhibit H2 adsorption and dissociation, which increases the O2 selectivity toward CO oxidation. Moreover, temperature programmed desorption of CO2 (CO2-TPD) and in situ diffuse reflectance infrared Fourier transform spectra (DRIFTs) illustrates that H2O and CO2 influences the low-temperature catalytic performance mainly by competitive adsorption with CO on surface highly dispersed reactive Cu+ sites. This work aims to shed light on the underlying Cu–Ce interaction regime, and guide the design of high-performance CuO–CeO2 catalysts in realistic reaction conditions.

Facile fabrication of a superior electrochemical sensor with anti-fouling properties for sensitive and selective determination of glutathione

A novel electrochemical sensor was proposed for sensitive and selective detection of glutathione (GSH). The as-fabricated sensor composed of chitosan (Chit), polyethylene glycol (PEG-OH), porous magnesium metasilicate (PMMS), and silver nanoparticles (AgNPs). Chit and PEG were used as anti-fouling nanomaterials, while PMMS acted as a porous adsorbent that loads large amounts of Cu(II). AgNPs increased the conductivity and the electro-catalytic activity of nanocomposite; besides, it enhanced the adsorption of GSH. Based on the electro-catalytic ability of Cu(II) released from Cu(II)-PMMS, the platform could achieve sensitive and selective determination of GSH without the addition of free Cu(II) in the measured solution. Under optimal conditions, a characteristic peak of GSH-Cu(II) was observed at ca. 0.43 V, which was increased linearly with GSH concentration in the range 0.1 to 125 µM with a detection limit (LOD, S/N = 3) of 0.03 µM. The sensor exhibited excellent sensitivity, anti-fouling performance, good selectivity, and sufficient stability. More importantly, the sensor was successfully applied for the estimation of GSH in dietary supplements and human plasma serum samples with acceptable recoveries % (98.3–104.1%) and RSDs values not more than 3.2%. These results proved that the as-fabricated sensor can be used for monitoring of GSH during medical diagnosis.

Insight into copper-cerium catalysts with different Cu valence states for CO-SCR and in-situ DRIFTS study on reaction mechanism

Copper-cerium catalysts have received extensive attention for their excellent catalytic performance in the field of NO reduction with CO. In this work, Cu+-Ce and Cu2+-Ce systems were designed to examine the catalytic potential of Cu+ and Cu2+. A series of catalysts were characterized by XRD, BET, HRTEM, EDS, H2-TPR, Raman, XPS and in-situ DRIFTS in different NO + CO atmospheres. Cu+-Ce catalyst possesses a large amount of Cu+ that can promote the synergy between Cu+ and Ce4+ and adsorb CO to form Cu+-CO species consuming more active oxygen, thus generating more oxygen vacancies than Cu2+-Ce, which improve the catalytic performance of Cu+-Ce catalyst at low temperatures. In different NO + CO atmospheres, Cu+-Ce catalyst always maintains better catalytic performance to make an excellent universal applicability. In-situ DRIFTS in different NO + CO atmospheres provided evidence to confirm that oxygen vacancy is indeed active site for decomposing NO. And it also demonstrated that the CuCe/CuCe-S (Cu2+-Ce system) and CuCe/Ce-S (Cu+-Ce system) catalysts are dominated by L-H mechanism with different CO adsorption behavior at low temperatures.

Insights on the Effect of Heavy Metals on Subcritical Hydrothermal Recycling of Heavy Metal-Contaminated Biomass and Its Derived Porous Carbon Properties Using Cu as a Case

Subcritical hydrothermal liquefaction (HTL) technique has shown great potential in recycling heavy-metal-contaminated biomass derived from phytoremediation and biosorption. However, the effect of heavy metals on the physicochemical characteristics of HTL products and their derivatives has not been elaborated so far. Herein, various Cu content-contaminated derived biomass was recycled by HTL. We found that over 99% of Cu was enriched in hydrochar at 300 °C, enabling us to obtain clean chemicals (e.g., levulinic acid and acetic acid). Furthermore, a large amount of Cu(0) was formed, especially at high temperatures, because HTL products acted as electron donors. Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry analysis showed that Cu catalyzed the depolymerization and deoxygenation of macromolecular lignins/carboxylic-rich alicyclic molecule-like compounds, resulting in the production of more levulinic acid. Two-dimensional FTIR correlation spectroscopy analysis indicated that the intensity of C═C increased first, and the intensity of C–O–C decreased later as the Cu content increased. Notably, the low-risk hydrochar could be upgraded into porous carbon (PC) with excellent CO2 capture performance (up to 6.64 mmol/g), whereas Cu enhanced the CO2 capture capacity of PC by increasing its porosity. Undoubtedly, such findings have important implications for recycling heavy-metal-contaminated biomass into high value-added products.

Entrapment of Airborne Particles via Simulated Highway Noise-Induced Piezoelectricity in PMMA and EPDM

The US highway system features a huge flux of energy transportation in terms of weight, speed, volume, flow density, and noise levels, with accompanying environmental effects. The adverse effects of high-volume traffic cause health concerns for nearby residential areas. Both chronic and acute exposure to PM 2.5 have detrimental effects on respiratory and cardiovascular health, and motor vehicles contribute 25–35% of direct PM 2.5 emissions. In addition to traffic-related pollutants, residing near major roadways is also associated with exposure to increased noise, and both affect the health and quality of life of residents. While regulatory and policy actions may reduce some exposures, engineering means may offer novel and significant methods to address these critical health and environmental issues. The goal of this study was to harvest highway-noise energy to induce surface charge via a piezoelectric material to entrap airborne particles, including PM 2.5. In this study, we experimentally investigated the piezoelectric effect of a polymethyl methacrylate (PMMA) sheet and ethylene propylene diene monomer (EPDM) rubber foam on the entrapment of copper (II)-2,4 pentanedione powder (Cu II powder). Appreciable voltages were induced on the surfaces of the PMMA via mechanical vibrations, leading to the effective entrapment of the Cu II powder. The EPDM rubber foam was found to attract a large amount of Cu II powder under simulated highway noise in a wide range, of 30–70 dB, and at frequencies of 700–1300 Hz, generated by using a loudspeaker. The amount of Cu II powder entrapped on the EPDM rubber-foam surfaces was found to scale with the SPL, but was independent of frequency. The experimental findings from this research provide a valuable base for the design of a robust piezoelectric system that is self-powered by harvesting the wasted sound energy from highway noise and reduces the amount of airborne particles over highways for effective environmental control.

MXene-mediated electron transfer in Cu(II)/PMS process: From Cu(III) to Cu(I)

There exists an obvious contradiction between Cu(III) generation and Cu(I) contribution in reductants enhanced Cu(II)/peroxymonosulfate (PMS) process because the involved electron transfer pathways were always ignored in previous studies. This study investigated the MXene-mediated electron transfer mechanism in Cu(II)/PMS for the first time. The introduction of MXene significantly promoted atrazine degradation under acidic condition because the in-situ generation of Cu(I) was an excellent activator for PMS. Under alkaline condition, although addition of MXene generated a large amount of Cu(I), the degradation of atrazine was inhibited due to that the conversion of Cu(I) to Cu(III) was interrupted. The strong metal-support interaction (SMSI) altered the reactive intermediate species from Cu(III) (two-electron transfer) to hydroxyl radical (HO•) and sulfate radical (SO4•-) (one-electron transfer) under alkaline condition. This work proposed a novel MXene-mediated electron transfer mechanism and improved the understanding of Cu(III)/Cu(I) transformation pathway.

Nutritional and biological analysis of the peel and pulp of Pouteria campechiana fruit cultivated in Bangladesh

Pouteria campechiana fruit is newly cultivated in Bangladesh. Nutritional and biological analysis of the peel and pulp of P. campechiana species was done according to standard protocols. The physicochemical parameters revealed that specific gravity, viscosity, total soluble solids (TSS), and pH contents were more evident in the pulp than the peel. According to the nutritional analysis, 7.46% fat, 4.15% dietary fiber, 41.54% carbohydrate and 247.28% energy were found in the peel. These values were higher and significant (p < 0.01) when compared to pulp; in contrast, larger amounts of moisture (54.44%), ash (2.92%) and protein (8.75%) were observed in the pulp of P. campechiana compared to peel, and these values were highly significant (p < 0.001). Large amounts of Cu, Zn, Fe and K were present in the peel of P. campechiana (p < 0.001; p < 0.01), while Ca, Mg and Na were significantly higher in the pulp of P. campechiana . Vitamin A was enrich in pulp (51.15 mg/100g) but vitamin C was enrich in peel (106.42 mg/100g) (p < 0.01). The total phenolics and flavonoids content per 100g ranged from 84 to 205 mg GAE and 256.34–930.33 mg QE, respectively. P. campechiana peel contains a significantly (p < 0.01; p < 0.001) high amount of phenolics, flavonoids, and showed potential antioxidant, anti-inflammation activities as compared to the pulp. Furthermore, a brine shrimp ( Artemia salina L.) lethality assay revealed the peel was significantly less toxic than the pulp (LC 50 = 701.66 μg/mL). The findings suggest that P. campechiana can be a rich source of nutrition as well as potential biological activity. • Peel part are rich in essential mineral contents viz. copper, Zinc, iron, potassium and vitamin C. • P. campechiana are superior for dietary fiber, protein, energy, phenolics, flavonoids and these could be responsible for anti-oxidant, anti-inflammatory, cytotoxic effects. • P. campechiana fruit could be a good source of nutritive value as well as potential biological activity.

Suppression of pinhole defects in thin film CdS/CdTe solar cell via gelatin-based negative photoresist passivation

The existence of pinholes at the CdS/CdTe and CdTe/back contact interfaces is one of the main obstacles to achieve high power conversion efficiency (PCE) in thin film CdS/CdTe solar cells, which leads to the formation of shunt paths in the devices. In this paper, a gelatin-based negative photoresist (Gel-NP) is utilized to fill the pinhole defects of CdTe thin film in photovoltaic device with FTO/CdS/CdTe/Mo/Al/Cr structure. The results showed that the pinholes in CdTe thin film have been effectively filled via the passivation of the Gel-NP, and no residue was found on the surface of CdTe thin film, thus increasing the cell shunt resistance. In addition, the optoelectronic performance of CdS/CdTe thin film solar cell under different Cu diffusion concentrations have been investigated with and without Gel-NP treatment, in which Gel-NP passivates the surface of CdTe resulting in a large amount of Cu enriched on the back, forming CuxTe after annealing. As a result, the average PCE of FTO/CdS/CdTe/Mo/Al/Cr structured solar cell increased from 10.4% to 13.7% via Gel-NP passivation (14.1% of champion efficiency), which exhibits improved reproducibility as well.

Dioxin emission and distribution from cement kiln co-processing of hazardous solid waste.

Cement kiln collaborative disposal technology can not only dispose of hazardous waste but also provide energy for the cement industry. However, the addition of hazardous waste may promote the formation of dioxins in cement kilns. In this study, typical hazardous solid wastes, such as solidified fly ash, electroplating sludge, and industrial residue, were co-processed in a cement kiln with different feeding positions and different feeding amounts. The concentrations of dioxins in the flue gas, clinker, and precalciner furnace slag were investigated. The effect of adding mixed hazardous solid waste on the formation of dioxin was also studied. The results showed that the concentration of dioxin in the flue gas without added hazardous waste was 1.57ng/m3, and the concentration varied from 1.03 to 6.49ng/m3 after the addition of hazardous waste. In addition, the concentration of dioxin in the flue gas and solid samples increased substantially when the co-processing ratio doubled. The large amount of Cu in solidified fly ash promoted the formation of dioxins, while the higher S content in the electroplating sludge suppressed the formation of dioxins. Compared with the addition of single hazardous waste, the concentration of dioxin in precalciner furnace slag increases by about 300%. Furthermore, the distributions of isomers in the clinker and precalciner furnace slag were similar. 1,2,3,4,6,7,8-HpCDD and OCDD accounted for a large proportion of the mass concentration, and the contribution rate ranged from 48.7 to 82.0%. Most importantly, correlation analysis showed that the concentration of dioxin was closely related to the copper content, hazardous waste types and additive proportion, with correlation coefficients of 0.79, 0.83, and 0.89, respectively. This study provides a basis for exploring the high environmental benefits of disposing of hazardous solid waste by co-processing in cement kilns.

Estimation and Quantification of Toxic Metals in Hugely Consumed Chicken Livers by Advanced Diagnostic Approaches.

Contamination of toxins in chicken's liver is a serious concern for human health owing to related threats of cytotoxicity and general pathologies after their digestion. The quantitative investigations were accomplished by calibration curves plotted for all the detected toxins via typical samples arranged in the known concentrations in the chicken liver's matrix. The chicken liver samples were collected from the Khyber Pakhtunkhwa province of Pakistan and found to contain heavy metals like Cu, Mn, Ni, Pb, and Zn. The analytical estimations were performed under the suppositions of local thermodynamic equilibrium (LTE) in terms of optical thin plasma. The maximum concentrations (parts per million) of Cu, Mn, Ni, Pb, and Zn were as 2.87 ± 0.02ppm, 7.80 ± 0.13ppm, 2.84 ± 0.02ppm, 4.00 ± 0.08, and 83.5 ± 2.10ppm respectively. Abundance of Cu, and Pb was found considerably beyond the maximum accepted boundary of WHO. Likewise, the level of Ni exceeded the permitted bounds of WHO in samples 01 and 02. To validate our laser-induced breakdown spectroscopy investigation, we approximated the abundance of identical (duplicate) chicken livers through digesting the specimens in suitable solvents by a typical technique such as inductively coupled plasma/optical emission spectrometry (ICP/OES) and the results acquired were in outstanding harmony. Furthermore, the existence of detected toxins was also checked using energy dispersive X-ray spectroscopy (EDX). It is worth stating that larger amounts of Cu, Ni, and Pb in poultry may cause a severe hazard to customers which required security actions and precautions. Our findings are extremely important to make an awareness among the people due to associated health hazards after the digestion of toxins through chicken liver and to protect numerous human lives.

Toxicological mechanism of large amount of copper supplementation: Effects on endoplasmic reticulum stress and mitochondria-mediated apoptosis by Nrf2/HO-1 pathway-induced oxidative stress in the porcine myocardium

Copper (Cu) is an essential micronutrient that is required by all living organisms. However, Cu can also be a potentially toxic metal if excessive dietary supplementation occurs. The current study aimed to investigate the mechanism of Cu toxicity in the cardiomyocytes of large mammal pigs. Here, we used pigs to explore Cu toxicity in the control group (10 mg/kg Cu) and treatment groups (125 mg/kg and 250 mg/kg Cu) for a period of 80 days. Consequently, we identified that large amount intake of Cu led to in oxidative damage, and activation of the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1)-mediated antioxidant pathway, indicating an imbalanced redox status in the myocardium. Furthermore, Cu exposure activated endoplasmic reticulum (ER) stress through upregulating levels of glucose-regulated protein 78 (GRP78), c-Jun N-terminal kinase (JNK), glucose-regulated protein 94 (GRP94), X-box binding protein 1 (XBP1), and C/EBP homologous protein (CHOP). Additionally, mitochondrial fission and fusion homeostasis was disrupted and the copy number of mitochondrial DNA (mtDNA) was reduced under Cu exposure. Furthermore, Cu exposure could induce apoptosis, evidenced by the increased terminal deoxynucleotidyl transferase biotin-d UTP nick end labeling (TUNEL)-positive staining, the upregulated expression levels of Cytoplasm-cytochrome C (Cytc), Bcl-2-associated X protein (Bax), and Cleaved-caspase3, and decreased expression level of B-cell lymphoma-2 (Bcl-2) and Mitochondrial-cytc. In summary, large amount of Cu could trigger Nrf2/HO-1 pathway-mediated oxidative stress, which promotes ER stress and mitochondrial damage pathways, causing apoptosis in cardiomyocytes.

Promotion Effect of Cu for CO Oxidation on Ceria Supported PdxCuy Bimetallic Catalysts

The surface composition and structure of bimetallic catalysts are important for the catalytic performance. In this work, PdxCuy/CeO2 catalysts with various Pd/Cu ratios were prepared and characterized by surface-sensitive techniques combined with ex-situ pretreatment. CO oxidation was used to correlate the surface composition with the catalytic performance. Compared with the monometallic Pd/CeO2 and Cu/CeO2, the PdxCuy/CeO2 bimetallic catalysts with a small amount of Cu show much higher CO oxidation activities. High-sensitivity low-energy ion scattering spectroscopy (HS-LEIS) combinded with X-ray photoelelctron spectroscopy (XPS) and temperature-programmed reduction (H2-TPR) results indicate that adding a small amount of Cu can efficiently promote the surface dispersion of Pd and affect the redox properties, whereas the CO oxidation activity is significantly suppresssed after adding a larger amount of Cu, which may be mainly induced by the preference for surface segregation of Cu that blocks the active site of Pd.

Facile synthesis of a glutathione-depleting Cu(II)-half-salamo-based coordination polymer for enhanced chemodynamic therapy.

Chemodynamic therapy (CDT), utilizing Fenton catalysts to convert intracellular H2O2 into toxic hydroxyl radicals (˙OH) to kill cancer cells, has a wide application prospect in tumor treatment because of its high selectivity. Its anticancer effect, however, is unsatisfactory due to the overexpressed glutathione (GSH). Herein, a GSH-depleting Cu(II)-half-salamo-based coordination polymer (CuCP) was prepared and validated by single crystal X-ray crystallography, Hirshfeld surface analyses and DFT calculations. The Cu(II) ions in the coordination polymer are five-coordinated bearing slightly twisted square pyramidal coordination environments and are bridged by phenoxy and alkoxy groups. After internalization by tumor cells, the CuCP could be biodegraded and reduced by GSH to generate a large amount of Cu(I), simultaneously depleting GSH. Subsequently, the Cu(I) ions interact with H2O2 to generate toxic ˙OH through a Fenton-like reaction to enhance their anticancer efficacy. Our study provides useful insights into designing smarter metal-based anticancer agents to improve the CDT efficiency in cancer therapy.

One-step fabrication of Cu2O-Cu catalytic electrodes with regular porous array by ultra-fast laser scanning

Highly efficient oxygen evolution reaction (OER) electrocatalysts have been well developed over the past decades, but their large-scale preparation with good performance-to-cost ratio remains a critical challenge. Here we report a simple one-step fabrication method of catalytic electrode using ultra-fast laser scanning. SEM results demonstrate that the samples have a regular porous array microstructure; XRD shows that Cu2O was formed on the surface of Cu substrate, which is in agreement with the large amount of Cu+ detected from XPS. The as-prepared Cu2O-Cu catalyst exhibits excellent OER activity in 1 M NaOH with an over-potential of 384 mV at the current density of 10 mA cm−2 (without iR compensation). During this process, thin Cu(OH)2 passivation layer could be formed with weak crystallinity, which could be easily removed by reduction reactions using cyclic voltammetry and it has minimum side effect on the OER performance of the sample. This approach is ultra-fast, simple, and environmentally friendly, and thus holds great potential in large-scale practical applications of electrocatalysts.

Effect of the microstructural characteristics of die-cast ADC12 alloy controlled by Na and Cu on the mechanical properties of the alloy

The mechanical properties of a die-cast Al–Si–Cu alloy (DC ADC12) were improved using new processing techniques that induce grain refinement and precipitation hardening. Several gravity-cast ADC12 (GC ADC12) samples with different microstructural sizes were also evaluated to better understand the material properties of DC ADC12. The material properties of DC ADC12 indicate that the alloy has both advantages (fine grains) and disadvantages (defects). The mechanical properties of ADC12 can be improved by adding Na before the T5 process. The grain refinement of ADC12 was achieved by introducing Na using benign and inexpensive NaHCO3 rather than metallic Na. The Na elements including sodium oxide retained in the melt cause fine spherical eutectic structures to form in the spherical α-Al matrix by interrupting the Si phase growth. The phenomenon can be detected via a three-dimensional atom probe tomography analysis. Precipitation hardening of the die-cast Al alloy was achieved by subjecting it to T5 treatment and a large amount of Cu, replacing the T6 treatment, for 3 h at 175 °C, because the die casting process can be replaced with the solid solution process in T6 owing to its high cooling rate. Precipitation hardening occurred in the grain-refined DC ADC12-Na sample during the T5 process, which was verified via in situ observation of its microstructure using laser microscopy during the heating and cooling processes. Al2MgCu, CuAl2, and fine Si particles, which were different from the precipitates obtained using the T6 process, were produced in the spherical α-Al phase. The demonstrated techniques resulted in remarkable improvements in the ultimate tensile strength and fracture strain of DC ADC12.

Heavy metals and arsenic in an abandoned barite mining area: ecological risk assessment using biomarkers

This study identifies a source of heavy metal pollution in the Tarnița-Ostra area, Suceava County, Romania, using both chemical and biological techniques. Samples collected from the sterile dumps and the surrounding soil were digested and analyzed for total metals and arsenic by inductively coupled plasma-optical emission spectroscopy (ICP-OES) and atomic absorption spectrometry (AAS). High concentrations of heavy metals, such as copper (3.12 g/kg), arsenic (0.68 g/kg), lead (2.67 g/kg), zinc (0.43 g/kg) and barium (0.54 g/kg), found in that region, may pose a high risk to the environment and public health through the food chain. The large amounts of Cu, Fe, Pb, Zn and As of the collected samples diminished much the germination of wheat (Triticum aestivum L.), used in this study as a marker of toxicity. However, after the removal of the heavy metals by treating the aqueous extracts with sodium hydroxide solutions, the germination parameters returned to normal. The quantification of heavy metal levels by ICP-OES provides a better understanding of the potential ecological risks and contamination status of the tailings dumps. Instead, wheat germination tests can be reliable and inexpensive biological methods to prove the harmful effect of heavy metals and arsenic on plants.

Effect of Reduced Dietary Copper Levels Sourced from Organic and Nanoparticles Forms on Performance and Nutrient Utilization in Giriraja Birds

Background: Copper (Cu) is an essential trace mineral for growth, production and health of poultry. Due to its poor absorption from inorganic source which is common supplemental form, large amount of Cu is excreted in the excreta. This experiment was conducted to assess the bioavailability of Cu from organic and nano sources at lower level of supplementation to reduce the excretion level without compromising the growth performance of chicken. Methods: A total of 420-day-old Giriraja chicks were randomly assigned to 7 treatment groups having 4 replicates each (15 chicks per replicate). The basal diets of both chick (0-6 weeks) and grower phases (7-10 weeks) were supplemented with 20 and 30 ppm of Cu from inorganic source as control (T1), the groups T2, T3 and T4 supplemented with 100, 75 and 50% of control from organic Cu, T5, T6 and T7 treatment diets supplemented with 75, 50 and 25% of control from Cu nanoparticles, respectively. Result: The grower phase and cumulative body weight gain was significantly (p less than 0.05) higher in T2 compared to T1, T6 and T7 groups, while the feed intake in chick phase was lower in T2, T5 and T7 groups as compared to T1, T3, T4 and T6. The chick phase feed conversion ratio was significantly (p less than 0.05) better in T2 and T5 groups compared to T1, T3, T4, T6 and T7, whereas the cumulative FCR was better in T2 and T5 compared to T6 and T7 groups, while it was not affected during grower phase. The dry matter and crude protein metabolizability were significantly (p less than 0.05) higher in T2 and T5, the organic matter and ether extract metabolizability was higher only in T5. The crude fiber and nitrogen free extract was not affected by the treatment diets. Nitrogen excretion was significantly (p less than 0.05) lower and its retention was higher in T2 and T5 treatment groups but was comparable with control. The Cu excretion through excreta was significantly (p less than 0.05) higher and its retention was lower in control as compared to all dietary treatments. Hence, it was concluded that the Cu supplementation from organic or nanoparticles form can be reduced by 50 and 75% of standard, respectively without compromising the growth performance of birds and nutrient digestibility of diets.