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Dye pollution in water system is of concern due to its carcinogenicity and its effect on aesthetic feature. One pollutant of interest is methylene blue (MB), which is a cationic dye widely used in industries. In this study, pyrolysis process was used to convert pineapple waste biomass (PWB) into useful adsorbents such as biochar (BC) and activated carbon (AC) to remove MB in water. BC was produced from pyrolysis of PWB (340 °C, 3 hours) whereas AC was prepared from pyrolysis of PWB (500 °C, 1 hour) impregnated with zinc chloride (ZnCl2). Prior to use, AC-PWB and BC-PWB were characterized for surface area, functional groups and surface morphology. Removal of MB was investigated by varying different parameters i.e. initial MB concentration and contact time, adsorbent dosage and temperature. Results obtained showed that AC-PWB has higher adsorption capacity than BC-PWB. The adsorption capacity and adsorption rate increased with increasing initial concentration of MB, adsorbent dosage and temperature until reached equilibrium condition. As a conclusion, PWB can be used as a useful raw material to produce cheap and environmentally friendly adsorbent to remove dye from solution.

Telomere length (TL) at birth is related to future diseases and long-term health. Bisphenols exhibit toxic effects and can cross the placenta barrier. However, the effect of prenatal exposure to bisphenols on newborn TL remains unknown. We aimed to explore the effects of prenatal exposure to bisphenols (i.e., bisphenol A (BPA), bisphenol B (BPB), bisphenol F (BPF), bisphenol S (BPS), and tetrabromobisphenol A (TBBPA)) on relative TL in newborns. A total of 801 mother–infant pairs were extracted from the Guangxi Zhuang Birth Cohort (GZBC). The relationships between bisphenol levels in maternal serum and relative TL in cord blood were examined by generalized linear models and restricted cubic spline (RCS) models. After adjusting for confounders, we observed a 3.19% (95% CI: -6.08%, -0.21%) reduction in relative cord blood TL among mothers ≥ 28 years with each 1-fold increase of BPS. However, each 1-fold increase of TBBPA, a 3.31% (95% CI: 0.67%, 6.01%) increased in relative cord blood TL among mothers 0.05). This is the first study to show a positive association between serum TBBPA levels and newborn relative TL among younger mothers. However, BPS levels were inversely correlated with TL in fetus born to older mothers. The results suggest fetuses of older pregnant women are more sensitivity to BPS exposure and accelerated aging or BPS-related diseases in later life may stem from early-life exposure.

Bioactive edible swiftlet's nest (ESN) sialylated-mucin (SiaMuc) hydrolysate is produced by alcalase hydrolysis. Enzymatic hydrolysis of ESN breakdown high-valued ESN SiaMuc-glycoprotein into bioactive SiaMuc-glycopeptide. This is a breakthrough for the issue of insolubility and low extraction rate in ESN, and even increases the bioavailability of ESN nutritional functionality and health benefits. Hydrolysis of ESN SiaMuc-glycoprotein was performed for 1 to 4 h and its effect on physicochemical properties, molecular weight (MW) distribution, SiaMuc-glycoprotein and glycopeptide integrity were determined. Other than improvement in solubility and bioavailability as SiaMuc-glycopeptide, results from SDS-PAGE revealed that MW of SiaMuc-glycoprotein decreased from 42.0–148.8 kDa to 17.7–142.7 kDa with increasing hydrolysis period. Further hydrolysis from maximized DH (90 min) showed an insignificant effect on the MW of ESN SiaMuc-glycopeptide and remained constant at 15.2 kDa. This highlights that enzymatic hydrolysis only influences macro SiaMuc-glycoprotein fractions (142.7, 115.3 and 102.7 kDa), while the majority of SiaMuc-glycopeptide fractions from 36.6–98.6 kDa remained intact. Conclusively, alcalase hydrolysis of ESN showed high recovery in the form of bioactive ESN SiaMuc-glycopeptide. Therefore, enzymatic biotechnology is an economic alternative applicable on ESN that broaden industrial utilization by reducing the MW without destroying the quality of bioactive SiaMuc-glycoprotein.

Over the years, much research had been performed on coffee beans due to their vast potential health benefits. Nevertheless, there is yet any study conducted on the bioactivities of drip brewed coffee commonly prepared in cafes. Hence, this work aimed to compare the antibacterial activities of drip coffee from different bean varieties; Coffea arabica, Coffea robusta, and Coffea liberica. The coffee phytocompounds were then tested for their in silico inhibitory potential against bacterial virulence factor, MrkD adhesion protein, responsible for binding to human kidney. Growth inhibition of four urinary tract infection bacteria (Proteus mirabilis, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae) using the coffee extracts were evaluated using Kirby-Bauer disk diffusion and broth microdilution assays. Molecular docking experiment was further conducted to determine the interaction of coffee phytocompounds with MrkD adhesion protein. Among the tested bacteria, K. pneumoniae showed significantly higher susceptibility towards the coffee extracts. C. robusta charted the lowest minimum inhibition concentration (MIC) value of 2000μg/mL followed by C. arabica (4000μg/mL) and C. liberica (>4000μg/mL) against this bacterium. High performance liquid chromatography (HPLC) analysis revealed presence of chlorogenic acid and caffeine in all drip coffees but caffeic acid was found to be absent. Interestingly, chlorogenic acid demonstrated strong binding to an active pocket of MrkD receptor binding domain. This compound interacted with Arg105 residue which was vital in the binding of MrkD to collagen V of the host. In view of that, further investigation should be performed focusing on the inhibition machinery of coffee extracts towards the virulency of K. pneumoniae.

Improving the properties of polyvinyl chloride matrix by the incorporation of carbonaceous filler by melt mixing is an unusual thought in the polymer research. Here we incorporated reduced graphene oxide (RGO) as a filler into plasticized polyvinyl chloride (PPVC) matrix by melt mixing, an eco-friendly method. The effect of addition of filler in the morphology of the PPVC nanocomposites was analyzed by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM) and Raman spectroscopy. The mechanical response of the nanocomposites to an applied stress was studied. A 50% improvement in mechanical properties was obtained at a low filler loading. A decrease in elongation was observed at higher RGO loading. The dynamic mechanical analysis (DMA) of the nanocomposites indicated an increase in glass transition temperature of the PVC up on the addition of RGO. This has confirmed the confinement of PVC chains at the graphene surface. As a result, the storage modulus of the nanocomposites showed an increase up on the addition of the nanofiller. Theoretical values of the storage modulus were calculated using various theoretical equations. The effectiveness of filler on the storage modulus is estimated and is found to be consistent with the results obtained experimentally. POLYM. ENG. SCI., 2017. © 2017 Society of Plastics Engineers

Lead (Pb) is one of the toxic heavy metals that have several toxicological implications including cytotoxicities and oxidative stress. The release of reactive oxygen species (ROS) usually initiates lipid peroxidation and resulting in inflammation and tissue injury. However, the detailed identification of the Pb-produced lipid hydroperoxides has received little attention. Furthermore, the mechanisms behind such effects are less informed. Therefore, this study firstly investigated Pb-produced lipid hydroperoxides in human HepG2 cells using LC/MS. The effects of Pb on the antioxidant enzymes were additionally examined using qPCR and their dependent activities. As a protection trial, the ameliorative effects of rosmarinic (RMA) and ascorbic (ASA) acids on Pb-induced cytotoxicity and oxidative stress and their regulatory effects on Nrf2/Keap1 pathway were investigated. The achieved results confirmed cytotoxicity and oxidative damage of Pb on HepG2 cells. In addition, 20 lipid hydroperoxides (LOOH) were identified including 11 phosphatidylcholine hydroperoxides (PCOOH), 5 triacylglycerol hydroperoxides (TGOOH) and 4 cholesteryl ester hydroperoxides (CEOOH). The most dominant LOOH species were PCOOH 34:2, PCOOH 34:3, PCOOH 38:7, TGOOH 60:14, TGOOH 60:15, CEOOH 18:3 and CEOOH 20:4. Pb significantly downregulated Nrf2-regulated antioxidant enzymes at both the pretranscriptional and functional levels. Co-exposure of HepG2 cells to RMA and ASA significantly reduced Pb-produced adverse outcomes. This protection occurred via activation Nrf2-Keap1 antioxidant pathway.

Polymer-based materials are an important and promising area of research exhibiting strong developments (Sadeghi et al. in J Mol Liq 263:282–287, 2018, [1; Rezakazemi et al. in Progr Energy Combust Sci 66:1–41, 2018 [2]). They play a prominent role in the modern civilization and find application in different industries related to electrical and electronic equipment, chemicals, automotive, spacecraft, energy storage in batteries and supercapacitors and medical to cite a few.

Hematopoietic stem and progenitor cells (HSPCs) are exposed to oxidative damage acquired during ex vivo expansion which affects their therapeutic potency. Efforts to overcome this limitation includes the use of antioxidants. The effects of N-Acetyl-Cysteine (NAC) supplementation for 48 hours on maintenance of ex vivo HSPCs was investigated by examining the cell viability at concentrations of 0.125 µM, 0.25 µM, 0.5 µM, 1.0 µM and 2.0 µM, followed by clonogenicity and oxidative status assessments of lineage-committed progenitors (myeloid, erythroid and pre-B lymphoid) at selected NAC concentrations (0.25 µM, 0.5 µM, 2.0 µM). NAC supplementation significantly (p< 0.05) enhanced viability of HSPC at 0.25 µM, 0.5 µM, 2.0 µM. The clonogenicity of each progenitor was not affected as no significant changes of Colony Forming Units (CFUs) counts was noted between NAC-supplemented group than control. NAC showed no significant effects on reactive oxygen species (ROS), glutathione (GSH) and superoxide dismutase (SOD) levels of respective progenitors as compared to control. Conclusively, NAC shows potential property as antioxidant supplement for ex vivo maintenance of HSPCs by promoting survivability and maintaining clonogenicity.

The weld nugget formation in the resistance spot welding (RSW) of aluminum alloy was investigated in the present study. The nugget formation process was directly observed by using a digital high-speed camera. Numerical simulation was also employed to investigate the nugget formation process. The results showed that for the RSW of two aluminum alloy sheets, a nugget was first formed in the workpiece/workpiece (W/W) interface and grew along the radial direction and axial direction of the sheets, and then it became a large elliptical nugget. For the RSW of three aluminum alloy sheets, two small nuggets were firstly formed in two W/W interfaces and grew along the axial direction and radial direction; finally they fused into one nugget. Besides, there existed a critical welding time, after which the nugget size remained nearly unchanged. This indicates that a long welding time is unnecessary for the RSW of aluminum alloy. In addition, the calculated nugget radius was compared with the experimental results, which showed that the simulation results agreed well with the experimental results.

A novel alternative was developed for the synthesis of polymer–protein conjugates with a controllable number of polymer chains. Human serum albumin (HSA), as a model protein, was grafted by poly(N-isopropyl-acrylamide) (PNIPAM) using N-succinimidyl-3-(2-pyridyldithiol) propionate as a coupling agent at room temperature in aqueous media. The influence of grafting number on the stability of the protein–polymer conjugate against the degradation of enzyme was examined, and the temperature dependent bioactivity was monitored through testing the warfarin-binding affinity. Furthermore, the protein could be recovered by incubating the conjugate under reducing conditions to cause the cleavage of the multiple disulfide bonds.

Solid propellants are well-studied particle reinforced polymer composite materials that are usually subject to complex stress actions. However, their destructive performances under thermo-mechanical coupling loads have been rarely studied. In the present work, the meso-damage process of nitrate ester plasticized polyether (NEPE) propellant under thermo-mechanical coupling loadings was recorded with a home-made apparatus consisting of an in-situ loading system. The stresses, strains, and crack structures of the propellant at different loading times were measured. The numerical parameters including the crack propagation rate, stress intensity factor, fractal dimension, etc., were calculated by the numerical and quantitative analysis method. Based on the quantitative relationships of these parameters, the failure mechanism of the propellant was proposed. A damage model of the NEPE propellant under different initial and loading conditions was established by regression analysis and artificial neural network modeling and validated with experimental data. Our work has provided an important strategy for studying the meso-damage properties of solid propellants in practical applications.

Considering its widespread usage in various fields, such as food, pharmaceutical, medical, cosmetic and polymer composites industries, microcrystalline cellulose (MCC) is becoming impellent due to increasing demand of alternatives to non-renewable and scarce fossil materials. Although it still suffers from some drawbacks, MCC has recently gained more interest owing to its renewability, non-toxicity, economic value, biodegradability, high mechanical properties, high surface area and biocompatibility. New sources, new isolation processes, and new treatments are currently under development to satisfy the increasing demand of producing new types of MCC-based materials on an industrial scale. Therefore, this review assembles the current knowledge on the isolation of MCC from different sources using various procedures, its characterization, and its application in bio-composites. Challenges and future opportunities of MCC-based composites are discussed as well as obstacles remaining for their extensive uses.

Superabsorbent sponge with uniform porous structure was prepared by polyelectrolyte complex (PEC) of polyacrylic acid (PAA) with inorganic polymers, high polymer state polyaluminum chloride (HPSPAC), in combination with freezing-induced phase separation (FIPS). The above superabsorbent sponge was prepared under mild conditions, without strong heat, oxidation, or corrosion, which is an ideal superabsorbent material for drug embedding. Structure analysis and swelling kinetics of the superabsorbent sponge as well as kinetics of the release of the model drug, 4-acetaminophen (AMP), from the sponge were investigated. In addition, effects of the crosslinker HPSPAC, the pH of the solution, and the concentration of NaCl solution on the structure and the swelling property of the sponge and sustained-release kinetics were explored. Further, the relationship between the structure of the superabsorbent sponge and its swelling property as well as sustained drug-release characteristics was investigated. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

A novel polyampholyte superabsorbent polymer-carboxymethyl chitosan-g-poly(acrylic acid-co-dimethyldiallylammonium chloride) (CMCTS-g-(PAA-co-PDMDAAC)) has been prepared through the graft copolymerization of acrylic acid (AA) and dimethyldiallylammonium chloride (DMDAAC) onto the chain of carboxymethyl chitosan. The optimal conditions for synthesizing the polymer with the highest swelling ratio has been identified by studying the water absorption of the polymer prepared under different conditions. The swelling ratio of the prepared polyampholytic polymer was found to be pH dependent, and in particular, the prepared polymer showed peaks in swelling capacity at both acidic condition (pH 3.5) and basic condition (pH 9.5). The effects of the interactions between the charged groups on the polymer backbone as well as the counter ion screening on the non-freezable water content have also been studied by measuring the DSC curve of the swollen hydrogel at different pH values.

A novel hydroxyethyl chitosan-g-poly(acrylic acid-co-Sodium Acrylate) (HECTS-g-(PAA-co-PSA)) superabsorbent polymer was prepared through graft copolymerization of acrylic acid and sodium acrylate onto the chain of hydroxyethyl chitosan. The structure of the polymer was characterized by FTIR. By studying the water absorption of the polymer synthesized under different conditions, the optimal conditions for synthesizing the polymer with the highest swelling ratio was defined. This superabsorbent polymer was further treated by the solvent precipitation method and by the freeze-drying method. We found that the water absorption rate of the treated polymer was greatly increased and the microstructure of the treated polymer was changed from small pores to loose macro pores. The swelling processes of the polymers before and after modification fit first-order dynamic processes. The amount of the residual acrylic acid was greatly decreased after treatments. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Chk1 and Chk2 play major role in cell cycle checkpoint signaling pathway, which are mainly involved in G2/M cell cycle checkpoint signal transduction. Firstly, the siRNA targeting at Chk1 or Chk2 gene was transfected into human gastric cancer BGC823 cells for 24 h before 15 mg/L DADS was added Then, the mRNA and protein expression of Chk1 or Chk2 was detected by Real-time PCR and Western-blot respectively Cell cycle rates and expressions of CDC25C and cyclinB1 were determined by FCM and Western blot respectively. The results showed that the Chk1 or Chk2 expression was inhibited in Chk1 or Chk2 siRNA-transfected group, in which the Chk1 or Chk2 expression at mRNA level was reduced 84.7% and 69.0% respectively and the protein expression of Chk1 or Chk2 was reduced 73.4% and 78.5% respectively as compared with that in empty control group (P 0.05). Western blot showed that although DADS decreased expression of CDC25C and cyclinB1 in untransfected cells, inhibition of expression of CDC25C and cyclinB1 treated by DADS was blocked by Chk1 gene silence (P < 0.05). On the contrary.. Chk2 gene silence can not do so. These results suggest Chk1 gene silence could abrogate G2/M arrest induced by DADS in BGC823 cell line, and Chk1/CDC25C/cyclinB1 pathway was involved at the G2/M arrest induced by DADS

Low threshold, high efficient Raman laser output has been realized from a compact, diode end-pumped, self-stimulating Nd 3+ :GdVO 4 Raman laser. Maximum Raman output power of 100 mW was achieved at a pulse repetition frequency (PRF) of 10 kHz with 1.8 W pump power. The optical efficiency is 5.6% from diode to Raman laser and the slope efficiency is 8%. The lowest threshold for the SRS process is only 400 mW at a PRF of 5 kHz. By generating second harmonics using a LBO crystal, 3 mW 588 nm yellow laser was also produced. A strong blue emission was observed in the Nd 3+ :GdVO 4 crystal when the Raman laser output, we contribute this for the upconversion of the Nd 3+ in the crystal.

A plasmonic nanosensor (using gold nanorods) with inverse sensitivity is presented for circulating cell-free DNA quantification. The inverse sensitivity (i.e. the lower the analyte concentration, the higher the response intensity) is achieved by the unusual DNA concentration-dependent gold nanorod aggregation. This assay method can adjust the dynamic range by controlling the concentration of nanoparticles in solution.

A novel nanofiltration membrane (PEK-C NF membrane) prepared with poly(amidoamine) (PAMAM) dendrimer and trimesoyl chloride (TMC) by in situ interfacial polymerization on phenolphthalein poly(ether ether ketone) (PEK-C) ultrafiltration membrane was investigated. FTIR–ATR, XPS, SEM and contact angle of the water were employed to characterize the chemical and physical changes of resulting membranes. The flux and rejection of resulting membranes increased with increasing concentrations of PAMAM and/or generation numbers of PAMAM for NaCl concentration. Both rejection and flux decrease with an increase of MgSO 4 concentration. The salts rejections order of resulting membrane is MgCl 2 > MgSO 4 > NaCl > Na 2 SO 4 , which shows that resulting membranes were all positively charged NF membrane. Influences of operating temperature on flux and rejection of different solutes show that resulting membrane is thermostable at higher temperature (e.g. 80 °C). The PEK-C NF membrane is especially suitable for separating cationic solutes from others by increasing operating temperature. The pH in the feed increase from 2 to 9 resulted in over two-fold increase in the flux for NaCl solution. Therefore the PEK-C NF membrane is also particularly suitable for treating acidic feed. The studied membrane possesses maximum operating pressure lower than 2.0 MPa and excellent stability during 1080 h (1.5 months) of continuous filtration at 30 °C.

Biosensor detecting techniques have attracted much attention in the content determination of H2O2, which has been used illegally as a food additive. An electrochemical biosensing membrane for the detection of H2O2 was developed with C6-OH of chitosan immobilized cyclodextrin derivates (6-CD–CTS), which possessed a high cyclodextrin loading capacity (2.12 × 10−4 mol/g), as the carrier. The biosensor was prepared through the inclusion of ferrocene as the electron mediator in a hydrophobic cavity of cyclodextrin and crosslinking catalase (CAT) to 2-NH2 of 6-CD–CTS. The ferrocene-included complex was evaluated by ultraviolet–visible spectrophotometry and thermogravimetric analysis. Its electrochemical behavior was also studied. The impact of the reaction conditions on the CAT immobilization capacity was evaluated. When previous membrane was used to detect the concentration of H2O2 (CH2O2), we found that the catalysis of CAT and the signal amplification of ferrocene had a major impact on the cyclic voltammograms. The optimal working pH of the modified electrode was 7.0. The peak current (I) had a linear relationship with the H2O2 concentration (CH2O2) in the range 1.0 × 10−4 to 1.0 × 10−3 mol/L. The linear regression equation was I = 0.00475CH2O2 − 0.03025. The detection limit was 10−6 mol/L. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41499.

We, for the first time, report the intracavity frequency doubling at 1030 nm in an LBO nonlinear optical crystal, at a type-I phase-matching direction of (θ, Φ) = (90°, 13.6°), performed with a double-LD polarization coupled system. With an incident power of 2 W, the maximum output power of 5.62 mW at 515 nm was obtained using a 2 × 2 × 10 mm3 LBO crystal. The threshold was 726 mW. The optical conversion efficiency was 0.28%.

The hot-water extract of Eichhornia crassipes leaves (ECE) was produced and incorporated into the diet of the prawn, Macrobrachium rosenbergii, as an immunostimulant. Survival rates of prawn against Lactococcus garvieae, and its immune parameters including the total haemocyte count (THC), different haemocyte count (DHC), phenoloxidase (PO) activity, respiratory bursts (RBs), superoxide dismutase (SOD) activity, glutathione peroxidase (GPx) activity, transglutaminase (TG) activity, haemolymph coagulation time, and phagocytic activity and clearance efficiency against L. garvieae by M. rosenbergii were determined when prawn (23.0 ± 2.8 g) were fed ECE-containing diets at 0, 1.0, 2.0 and 3.0 g kg(-1). Prawn fed a diet containing ECE at 2.0 and 3.0 g kg(-1) for 12 days showed significantly increased THC, HC, GC, PO activity, RBs, SOD activity, GPx activity, and TG activity, and a significantly decreased coagulation time. The phagocytic activity and clearance efficiency against L. garvieae of prawn fed the ECE-containing diets at 1.0, 2.0, and 3.0 g kg(-1) were significantly higher than those of prawn fed the control diet at 3-12 days. Survival rates of M. rosenbergii fed the diet containing ECE at concentrations of 2 and 3 g kg(-1) were significantly higher than those fed the control diet after challenge with L. garvieae for 48-144 h. The relative percentage survival of prawn fed the 1.0, 2.0, and 3.0 g kg(-1) ECE-containing diets for 12 days were 17.5%, 39.1%, and 52.2%. It was concluded that the ECE can be used as an immunostimulant for prawn through dietary administration to enhance immune responses and resistance of M. rosenbergii against L. garvieae.

Aluminum-doped cupric oxide (CuO:Al) was prepared via an out-diffusion process of Al from an Al-coated substrate into the deposited CuO thin film upon thermal treatment. The effect of the annealing temperature on the structural and optical properties of CuO:Al was investigated in detail. The influence of Al incorporation on the photovoltaic properties was then investigated by preparing a p-CuO:Al/n-Si heterojunction solar cell. A significant improvement in the performance of the solar cell was achieved by controlling the out-diffusion of Al. A novel in situ method to co-dope CuO with Al and titanium (Ti) has been proposed to demonstrate CuO-based solar cells with the front surface field (FSF) design. The FSF design was created by depositing a CuO:Al layer followed by a Ti-doped CuO (CuO:Ti) layer. This is the first successful experimental demonstration of the codoping of a CuO thin film and CuO thin film solar cells with the FSF design. The open circuit voltage (V oc), short circuit current density (J sc) and fill factor (FF) of the fabricated solar cells were significantly higher for the FSF device compared to devices without FSF. The FF of this device improved by 68% through the FSF design and a record efficiency ɳ of 2% was achieved. The improvement of the solar cell properties is mainly attributed to the reduction of surface recombination, which influences the charge carrier collection.

The -Fe 3[110] (112) symmetrical tilt grain boundary model is established by the coincidence site lattice theory. First-principles plane wave ultrasoft pseudopotential method based on the density functional theory is used to calculate the La occupying tendency in -Fe. The results show that La elements tend to be located at grain boundary in the -Fe since the impurity formation energy keeps lowest. On this basis, the electronic structure of La doped in -Fe grain boundary is also calculated. The results indicate that the charges in the system are redistributed to provide more electrons for the grain boundary bonding when the La occupies -Fe grain boundary. Meanwhile, Fe atoms obtain more electrons, and the La doped region combination has the ion-tendency toward strengthening the interaction between La atom and Fe atoms in the adjacent boundary region, and the Fe atom bonds in the grain boundaries and on both sides of the grain boundary also strengthen, which is the reason why the mechanical properties change from the energy point of view. Moreover, La addition also makes the atomic density of states on the grain boundary move to the left, reduce the total energy of the system, and make the grain boundary more stable.

The theoretical effect of barium on calcite crystal growth is widely discussed and investigated. This paper provides a broad analysis of the effect of barium on calcium carbonate scale using a dynamic scale loop (DSL). With a DSL, it is possible to simulate conditions that can be found in oil/gas pipelines in actual pressure and temperature conditions. The DSL measures with high accuracy, small variations in differential pressure over a 1mm/1m flow loop. This paper investigates three cases, simulated with and without barium additions, to provide futher understanding to the existing literature about the effect of barium on calcite scale growth. Effectiveness of scale inhibitors on these cases is also studied.

The behaviour of low-Fe and high-Fe substituted chlorite mineral dispersions was investigated under industrially-relevant, atmospheric leaching conditions typical of low grade, uranium-bearing lateritic ore processing. The main focus was on the influential role played by the clay mineral chemistry. Preferential leaching of Al(III), Fe(II/III) and Mg(II) metal ions over tetrahedral Si species was indicated at pH 1 and 70 °C by supernatant speciation, the kinetics of which was faster at high-Fe than at low-Fe substitution. For the low-Fe chlorite, the incongruent leaching behaviour of Al(III), Fe(II/III) and Mg(II) species was substantially similar. In the case of the high-Fe chlorite however, despite its lower Mg(II) content, Al(III) and Fe(II/III) species leaching rates were relatively lower than that ofMg(II). Crystallo-chemical (XRD, XRF and EM) and spectroscopic (FTIR and XPS) analyses indicated that the incongruent leaching led to significant bulk particle and interfacial layer structures' modification, impacting dramatically upon pulp chemistry, mineralogy and particle interactions.Mineral chemistry-mediated formation of polycondensed, sub-crystalline aluminosilicate gel structures and secondary mineral phases prevailed in the course of leaching. A greater increase in high-Fe pulp particle interactions, in contrast with the low-Fe pulp, was observed during leaching, reflecting remarkably high, time-dependent shear yield stresses, reminiscent of highly viscous gels. The development of viscous gel structures whose strength is strongly dependent upon chlorite mineral chemistry has important implications for the efficacy of aqueous processing of clay-rich lateritic ores. Refereed/Peer-reviewed

We describe a simple and effective method to obtain colloidal surface-functionalized Au nanoparticles. The method is primarily based on irradiation of a gold solution with high-flux X-rays from a synchrotron source in the presence of 11-mercaptoundecanoic acid (MUA). Extensive tests of the products demonstrated high colloidal density as well as excellent stability, shelf life, and biocompatibility. Specific tests with X-ray diffraction, UV-visible spectrometry, visible microscopy, Fourier transform infrared spectroscopy, dark-field visible-light scattering microscopy, and transmission electron microscopy demonstrated that MUA, being an effective surfactant, not only allows tunable size control of the nanoparticles, but also facilitates functionalization. The nanoparticle sizes were 6.45 ± 1.58, 1.83 ± 1.21, 1.52 ± 0.37 and 1.18 ± 0.26 nm with no MUA and with MUA-to-Au ratios of 1:2, 1:1, and 3:1. The MUA additionally enabled functionalization with l-glycine. We thus demonstrated flexibility in controlling the nanoparticle size over a large range with narrow size distribution. Refereed/Peer-reviewed

The role of sulphide and lead in gold dissolution in a cyanide medium has been investigated for pure gold with elemental carbon coatings. Sulphide reduced the dissolution of gold with or without carbon coatings to almost the same extent and this effect became more pronounced at a higher sulphide concentration. The carbon coating slightly reduced the negative effect of sulphide on gold dissolution at around 0.2–5 mg S 2− /L. The negative effect of sulphide on gold dissolution decreased with increasing cyanide concentration. Lead increased the dissolution of gold with or without carbon coatings at a concentration up to 2 mg Pb 2+ /L with the beneficial effect declining over this concentration range. The carbon coating reduced the beneficial effect of lead on gold dissolution. Gold dissolution was retarded at around 5 mg Pb 2+ /L. The positive effect of lead on gold dissolution became more prominent with increasing cyanide concentration. SEM analysis revealed much less erosion of gold occurring with the addition of sulphide. The gold surface showed highly corroded spots scattered across relatively less corroded areas during leaching with the addition of lead, while the gold surface was smooth after leaching with a carbon coating. An XPS investigation indicated the formation of AuS x at the gold surface with the addition of sulphide. Metallic lead or AuPb alloys and lead hydroxide were detected at the gold surface after leaching with the addition of lead. The carbon coating hindered the diffusion of lead to the gold surface and hence reduced the beneficial effect of lead on gold dissolution.

Carbonaceous matter was extracted from ore obtained from Stawell Gold Mine and characterised by microscopic methods and XRD. The carbonaceous matter was predominantly hexagonal crystalline graphite mixed with some minor semi-crystalline graphite or amorphous carbon. It was found that the natural carbonaceous matter had a low gold adsorption capability, dependent on cyanide concentration. No adsorption occurred with > 250 mg/L KCN. Auger studies demonstrated that during grinding, the carbonaceous matter preferentially smeared on iron sulphide rather than alumino-silicate surfaces present in the gold ore. The carbonaceous matter coated unevenly, preferentially at the edges and the defect sites. XPS analysis indicated that when gold foil was ground with the ore, the carbonaceous matter coated on gold surfaces mainly in the form of elemental carbon or graphite. Very limited amounts of organic carbon compounds smeared on the gold foils during grinding. Sulphur species were also present on the gold surfaces after grinding with sulphide ores. The current work shows that the carbonaceous coating had a significant detrimental effect on gold dissolution when gold was pre-ground with the carbonaceous ore. Sulphide coating on gold surfaces appeared to hinder gold dissolution to a lesser extent. The dissolution of gold foils artificially coated with the natural carbonaceous matter extracted from Stawell ore was also substantially retarded. In comparison, graphite had a much lower coating ability on gold. The addition of free carbonaceous matter to pre-ground non-carbonaceous sulphide gold ores did not have much effect on gold cyanidation. However, the carbonaceous matter ground with the non-carbonaceous sulphide ores significantly reduced gold leaching kinetics and recoveries.

Interfacial chemistry and particle interactions of polydispersed chlorite clay mineral dispersions as a function of pH, solid content and ageing time have been investigated in the pH range 2-9 at 25 °C. Particle zeta potential, reflecting interfacial chemistry indicates a strong pH history and solid loading dependency. Zeta potential trends observed from high to low pH sweep show that an isoelectric points of pH ≈ 2.5 and 5, respectively for dilute (0.05 wt.%) and both 8 and 57 wt.% suspension. An electrokinetic potential bifurcation is observed upon reverse pH from low (e.g. 2) to high value (e.g. 9), indicative of pH-mediated interfacial chemistry modification. Particle interactions measured through dispersion shear yield stress show a similar pH-history dependency and compliance with DLVO theory. Supernatant analysis suggests that the suspension pH dependent behaviour may be attributed to the leach of Mg(II), Fe(II/III), Al(III) and Si(IV) ions from the chlorite particles at lower pH. Formation and specific adsorption of hydrolysed metal complexes onto particles which occurs at higher pH values manifest in the observed interfacial chemistry and particle interactions. The findings enable us to accurately rationalise the nature of the inter-particle forces underpinning particle network structure and strength as a function of dispersion conditions during aqueous processing of clay-based minerals. Refereed/Peer-reviewed

The anodic and cathodic behaviour of gold with clay and different carbon coatings was investigated using the potentiodynamic method. The overall dissolution reactions were also examined by combining the anodic and cathodic polarisation curves. The presence of clay coatings affected neither the anodic curve shapes nor the peak positions for gold oxidation nor changed the cathodic curve appearance for oxygen reduction. The peak current densities slightly reduced in the presence of clay coating and this trend became more noticeable with an increase in the coating thickness. Non-conductive clay only acted as a barrier to the diffusion of reagents to the gold surface, but did not galvanically interact with gold. Different carbon coatings, natural carbonaceous matter from Stawell gold ore, activated carbon and graphite, performed similarly in affecting the anodic gold oxidation, i.e., the shift of rest potential to a more anodic position, the narrowing of the first peak region (a more cathodic overpotential region), the shift of current peaks to more anodic positions and the high current densities at high overpotentials over 0.7 V. The carbon coatings changed the wave appearance for oxygen reduction. In the presence of the carbon coatings, the current densities for oxygen reduction became lower at less cathodic potentials and became higher at more cathodic potentials, and the current densities for oxygen reduction increased with an increase in the thickness of the carbon coatings. The presence of the carbon coatings did not change the reaction control mechanisms for either gold oxidation or oxygen reduction. The combination of anodic and cathodic reactions indicated that the carbon coatings significantly reduced the gold oxidation rates with increasing coating thickness, in agreement with the leach results. The oxidation potentials shifted to a more anodic direction with increased thickness of the carbon coatings. The magnitude of the decrease in the gold oxidation rates was comparable for the different carbon coatings at a similar thickness, despite their microstructures, surface areas and activities being significantly different. The results showed that the carbon coatings galvanically interacted with gold.