Subjects -> MINES AND MINING INDUSTRY (Total: 82 journals)
Showing 1 - 42 of 42 Journals sorted alphabetically
American Mineralogist     Hybrid Journal   (Followers: 16)
Applied Earth Science : Transactions of the Institutions of Mining and Metallurgy     Hybrid Journal   (Followers: 4)
Archives of Mining Sciences     Open Access   (Followers: 3)
AusiMM Bulletin     Full-text available via subscription   (Followers: 1)
BHM Berg- und Hüttenmännische Monatshefte     Hybrid Journal   (Followers: 2)
Canadian Mineralogist     Full-text available via subscription   (Followers: 7)
CIM Journal     Hybrid Journal   (Followers: 1)
Clay Minerals     Hybrid Journal   (Followers: 9)
Clays and Clay Minerals     Hybrid Journal   (Followers: 5)
Coal Science and Technology     Full-text available via subscription   (Followers: 3)
Contributions to Mineralogy and Petrology     Hybrid Journal   (Followers: 14)
Environmental Geochemistry and Health     Hybrid Journal   (Followers: 3)
European Journal of Mineralogy     Hybrid Journal   (Followers: 14)
Exploration and Mining Geology     Full-text available via subscription   (Followers: 3)
Extractive Industries and Society     Hybrid Journal   (Followers: 2)
Gems & Gemology     Full-text available via subscription   (Followers: 2)
Geology of Ore Deposits     Hybrid Journal   (Followers: 5)
Geomaterials     Open Access   (Followers: 3)
Geotechnical and Geological Engineering     Hybrid Journal   (Followers: 9)
Ghana Mining Journal     Full-text available via subscription   (Followers: 3)
Gold Bulletin     Hybrid Journal   (Followers: 2)
Inside Mining     Full-text available via subscription  
International Journal of Coal Geology     Hybrid Journal   (Followers: 4)
International Journal of Coal Preparation and Utilization     Hybrid Journal   (Followers: 2)
International Journal of Coal Science & Technology     Open Access   (Followers: 1)
International Journal of Hospitality & Tourism Administration     Hybrid Journal   (Followers: 16)
International Journal of Mineral Processing     Hybrid Journal   (Followers: 8)
International Journal of Minerals, Metallurgy, and Materials     Hybrid Journal   (Followers: 12)
International Journal of Mining and Geo-Engineering     Open Access   (Followers: 4)
International Journal of Mining and Mineral Engineering     Hybrid Journal   (Followers: 8)
International Journal of Mining Engineering and Mineral Processing     Open Access   (Followers: 6)
International Journal of Mining Science and Technology     Open Access   (Followers: 4)
International Journal of Mining, Reclamation and Environment     Hybrid Journal   (Followers: 6)
International Journal of Rock Mechanics and Mining Sciences     Hybrid Journal   (Followers: 9)
Journal of Analytical and Numerical Methods in Mining Engineering     Open Access   (Followers: 1)
Journal of Applied Geophysics     Hybrid Journal   (Followers: 18)
Journal of Central South University     Hybrid Journal   (Followers: 1)
Journal of China Coal Society     Open Access  
Journal of China University of Mining and Technology     Full-text available via subscription   (Followers: 1)
Journal of Convention & Event Tourism     Hybrid Journal   (Followers: 6)
Journal of Geology and Mining Research     Open Access   (Followers: 10)
Journal of Human Resources in Hospitality & Tourism     Hybrid Journal   (Followers: 9)
Journal of Materials Research and Technology     Open Access   (Followers: 2)
Journal of Metamorphic Geology     Hybrid Journal   (Followers: 17)
Journal of Mining Institute     Open Access  
Journal of Mining Science     Hybrid Journal   (Followers: 5)
Journal of Quality Assurance in Hospitality & Tourism     Hybrid Journal   (Followers: 6)
Journal of Sustainable Mining     Open Access   (Followers: 3)
Journal of the Southern African Institute of Mining and Metallurgy     Open Access   (Followers: 6)
Lithology and Mineral Resources     Hybrid Journal   (Followers: 4)
Lithos     Hybrid Journal   (Followers: 11)
Mine Water and the Environment     Hybrid Journal   (Followers: 6)
Mineral Economics     Hybrid Journal   (Followers: 2)
Mineral Processing and Extractive Metallurgy : Transactions of the Institutions of Mining and Metallurgy     Hybrid Journal   (Followers: 14)
Mineral Processing and Extractive Metallurgy Review     Hybrid Journal   (Followers: 5)
Mineralium Deposita     Hybrid Journal   (Followers: 4)
Mineralogia     Open Access   (Followers: 2)
Mineralogical Magazine     Hybrid Journal   (Followers: 1)
Mineralogy and Petrology     Hybrid Journal   (Followers: 5)
Minerals     Open Access   (Followers: 2)
Minerals & Energy - Raw Materials Report     Hybrid Journal   (Followers: 1)
Minerals Engineering     Hybrid Journal   (Followers: 14)
Mining Engineering     Full-text available via subscription   (Followers: 7)
Mining Journal     Full-text available via subscription   (Followers: 4)
Mining Report     Hybrid Journal   (Followers: 3)
Mining Technology : Transactions of the Institutions of Mining and Metallurgy     Hybrid Journal   (Followers: 4)
Mining, Metallurgy & Exploration     Hybrid Journal  
Natural Resources & Engineering     Hybrid Journal  
Natural Resources Research     Hybrid Journal   (Followers: 5)
Neues Jahrbuch für Mineralogie - Abhandlungen     Full-text available via subscription   (Followers: 1)
Physics and Chemistry of Minerals     Hybrid Journal   (Followers: 4)
Podzemni Radovi     Open Access  
Rangeland Journal     Hybrid Journal   (Followers: 4)
Réalités industrielles     Full-text available via subscription  
Rem : Revista Escola de Minas     Open Access  
Resources Policy     Hybrid Journal   (Followers: 4)
Reviews in Mineralogy and Geochemistry     Hybrid Journal   (Followers: 5)
Revista del Instituto de Investigación de la Facultad de Ingeniería Geológica, Minera, Metalurgica y Geográfica     Open Access  
Rock Mechanics and Rock Engineering     Hybrid Journal   (Followers: 9)
Rocks & Minerals     Hybrid Journal   (Followers: 5)
Rudarsko-geološko-naftni Zbornik     Open Access  
Transactions of Nonferrous Metals Society of China     Hybrid Journal   (Followers: 9)
Similar Journals
Journal Cover
Gold Bulletin
Journal Prestige (SJR): 0.461
Citation Impact (citeScore): 2
Number of Followers: 2  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 2364-821X - ISSN (Online) 2190-7579
Published by Springer-Verlag Homepage  [2653 journals]
  • Development of a hydrometallurgical process for the recovery of gold and
           silver powders from anode slime containing copper, nickel, tin, and zinc
    • Abstract: In order to recover gold and silver from anode slimes containing Cu, Ni, Sn, and Zn, an integrated hydrometallurgical process consisting of leaching, solvent extraction, and cementation was developed. All the metals together with 10% of Ag(I) were dissolved by the mixture of HCl and H2O2 at the optimum conditions. Separation of Au (III) together with Sn (II) was performed by Cyanex 272 from the leaching solution with two-stage counter current extraction. Stripping of Au (III) and Sn (II) from the loaded organic phase was sequentially carried out by NH4Cl and NaOH. Cu (II) in the raffinate after Au (III) extraction was separated by LIX 63 with three-stage counter current extraction. Pure Cu (II) solution was recovered from the loaded LIX 63 by stripping with dilute HCl solution. Ag powders with extra high purity were obtained by cementation with copper sheet from the raffinate after Cu (II) separation. Au (III) (99.3%) and 96.8% of Sn (II) were recovered by extraction, and purity of Au (III) and Sn (II) stripping solutions was found to be 99.99%. Au powders with extra high purity were directly synthesized by adding ascorbic acid solution into the NH4Cl stripping solution.
      PubDate: 2019-03-20
      DOI: 10.1007/s13404-019-00254-0
       
  • One-pot synthesized porphyrin-based polymer supported gold nanoparticles
           as efficient catalysts for alkyne hydration and alcohol oxidation in water
           
    • Abstract: The construction of porous organic polymer from 5,10,15,20-tetraphenylporphyrin (TPP) was described using one-pot Friedel-Crafts alkylation reaction. Au was simultaneously loaded on the porphyrin-based polymer denoted as Au/KAPs(DCM-TPP). This polymer-supported Au was fully characterized by many physicochemical methods. It was found to possess BET surface area of 796 m2 g−1, good thermal stability above 250 °C and Au nanoparticles with an average size of 8 nm. It was used as an efficient heterogeneous catalyst for alkyne hydration and alcohol oxidation in water. This Au catalyst exhibited excellent catalytic efficiency and recycling performance without loss of activity at least five times. A new strategy to synthesize polymer-supported Au nanoparticle catalyst was finally provided.
      PubDate: 2019-03-01
      DOI: 10.1007/s13404-018-0249-9
       
  • Development of a novel thermo-responsive hydrogel-coated gold nanorods as
           a drug delivery system
    • Abstract: In this study, at first, gold nanorods (GNRs) were synthesized and then they were coated with a layer of hydrogel composed of poly(N-isopropylacrylamide) (PNIPAM) grafted onto carboxymethyl cellulose (CMC) as a backbone. The chemical structure of GNRs/PNIPAM-g-CMC hydrogel was characterized by Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), atomic-force microscopy (AFM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The swelling properties of the obtained GNRs/PNIPAM-g-CMC hydrogel were studied at different times and temperatures. In addition, drug release from doxorubicin-loaded GNRs/PNIPAM-g-CMC hydrogel was examined at different temperatures during time. The drug release mechanism was studied by first-order, second-order, and Ritger–Peppas models. Finally, the GNRs/PNIPAM-g-CMC hydrogel biocompatibility was tested against L929 mouse fibroblast cells by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) method. Our study suggests that GNRs coated with low-cost hydrogels can be excellent candidate for drug delivery systems.
      PubDate: 2019-03-01
      DOI: 10.1007/s13404-018-0248-x
       
  • Launching low-energy surface plasmons in purple gold (AuAl 2 )
    • Abstract: We confirm that the unusual purple color of the intermetallic compound AuAl2 is of a plasmonic origin by launching surface plasmons (SPs) in thin AuAl2 films. We measure the SP dispersion relation and also use the films to measure the index of refraction of sucrose solutions using standard SP resonance sensing. We find that the SP energy in planar AuAl2 is approximately 2.1 eV, about 0.4 eV lower than in gold, and the material is highly resistant to oxidation. This is close to what is expected from previously reported measurements of the dielectric function of AuAl2. On this basis, we predict that AuAl2 nanoparticles will a have very strong, spectrally nearly uniform light absorbance about an order of magnitude greater than standard carbon black. Such particles may therefore find applications as obscurants or as an alternative to more complex light-absorbing gold structures in areas such as photothermal therapy or solar steam generation, or in plasmonic catalysis.
      PubDate: 2019-03-01
      DOI: 10.1007/s13404-018-0250-3
       
  • Surface plasmon resonance of naked gold nanoparticles for photodynamic
           inactivation of Escherichia coli
    • Abstract: Although antimicrobial photothermal inactivation of naked gold nanostructures using powerful pulsed lasers has been previously studied, there are little reports about their photodynamic antimicrobial properties under the irradiation of low-power density continuous wave lasers. Therefore, this paper attempts to fill this gap. In this paper, we studied the effects of a 40-mW/cm2 continuous Nd:Yag laser at 532 nm and naked gold nanoparticles on inactivation of Escherichia coli ATCC25922. According to our results, 60 min illumination using the Nd:Yag laser caused a 0.15log reduction of the bacterial viability. Also, the employed gold nanoparticles with an average size of 15 nm were toxic to E. coli ATCC 25922 in the concentrations above 0.5 μg/ml. In addition, synergistic effects of 0.5 μg/ml gold nanoparticles and the light illumination led to a 2.43log reduction of the viability after a 60-min exposure and did not show any considerable temperature change on the media. The obtained results were justified based on the possible interaction mechanisms of low-power density laser lights and naked gold nanoparticles. The paper is proposed as a prelude for future research about localized inactivation of resistant pathogens with minimum side effects on neighbor tissues.
      PubDate: 2019-03-01
      DOI: 10.1007/s13404-019-00252-2
       
  • Three new dicyanidoaurate(I)-based complexes exhibiting significant
           antiproliferative property: synthesis and characterization
    • Abstract: The Au(CN)2− ion and its metal-ligand compounds have recently gained considerable interest in industrial applications such as optical diagnostics systems as well as pharmacology with antirheumatic and antitumor activity. Here, [Ni2(N-bishydeten)2][Au(μ-CN)2]3[Au(CN)2]·H2O (C1), [Cu2(N-bishydeten)2][Au(μ-CN)2]3[Au(CN)2]·H2O (C2), and [Zn2(μ-N-bishydetenH)(N-bishydeten)(NC)2Au][Au(CN)2] (C3) were synthesized by reaction of the metal salts with N,N-bis(2-hydroxyethyl)ethylenediamine (N-bisyhdeten) and K[Au(CN)2]. The Au(I) compounds were characterized using elemental analysis and FT-IR. ESI-MS and thermal measurement techniques and their pharmacological properties were also tested. The DNA/bovine serum albumin (BSA) interactions of these compounds were demonstrated by spectrophotometric titration, fluorometric ethidium bromide kinetics, and DNA electrophoresis studies, and the stability of these compounds in physiological solution was also determined. The findings indicate that these compounds displayed a DNA/BSA-binding activity similar to that of cisplatin and exhibited a strong aqueous stability. The Au(I) compounds were potent antiproliferative agents with low necrotic activity and exhibited dose-dependent growth inhibition of cancer cells with IC50 value of 0.12–0.73 μM. Accumulation of p53 and decrease in Bcl-2 in cells exposed to Au(I) compounds may be the main causes for apoptotic effects, such as DNA fragmentation and nuclear collapse. Investigations regarding the mode of action of Au(I) compounds on cells revealed that they reduce the cell migration rate and the level of cytoskeletal proteins, namely CK7 and CK20. On the basis of this evidence, we suggest that strong antiproliferative activity, low necrotic effect, and micromolar dose range observed for Au(I) compounds make them suitable candidates for further pharmacological evaluation as chemotherapeutic agents in colon and cervix cancer.
      PubDate: 2019-03-01
      DOI: 10.1007/s13404-018-00251-9
       
  • Au/CdSe hybrid nanoflowers: a high photocurrent generating
           photoelectrochemical cells
    • Abstract: Photoelectrochemical cell composed of solution-processed nanoflower heterostructure of Au core and eight CdSe petals was investigated for enhanced photocurrent generation. The electrode of CdSe nanorods displayed photocurrent density of 2.1 mA/cm2 whereas the Au core CdSe nanoflower exhibited 4.6 mA/cm2 corresponding to a 119% increase during photoelectrochemical cell performance. Both electrodes showed prompt response to the on/off cycles of light, the photocurrent gain (IPhoton/Idark) in CdSe nanorods is 124.7, while the value is 223.3 for Au/CdSe nanoflower, calculated from the growth-decay curves. Photoresponse time was dramatically improved for Au/CdSe nanoflower samples due to increasing in 66% incident photon-to-current emission. Electron lifetime of 21.63 and 48.71 ns was observed for the electrode of CdSe nanorods and Au/CdSe nanoflowers respectively. The prolonged electron lifetime in the case of the electrode of Au/CdSe nanoflowers was responsible for improving charge separation and as a consequence, higher photocurrent generation.
      PubDate: 2019-03-01
      DOI: 10.1007/s13404-018-0247-y
       
  • Electric field–prevented adsorption of hydrogen on supported gold
           nanoparticles
    • Abstract: The adsorption of hydrogen on the surface of gold nanoparticles deposited on a graphite support was studied in the presence of an external electric field by means of scanning tunneling microscopy (STM) and spectroscopy (STS). Hydrogen was adsorbed from the gas phase onto the surface of gold nanoparticles synthesized by impregnation-precipitation method. During the adsorption process, the STM tip was removed from the surface of the sample so that the measurable tunneling current could not flow, and potential differences of various polarities were applied to the vacuum gap between the sample and the grounded tip. Thus, the system of the STM tip and sample surface formed an asymmetric capacitor inside which an inhomogeneous electric field existed. No hydrogen adsorption was observed in the case of a positive potential difference, while dissociative adsorption of hydrogen took place in the cases of zero and negative potential differences. The ability to control the adsorption process of hydrogen by means of a weak electric field was demonstrated.
      PubDate: 2019-02-12
      DOI: 10.1007/s13404-019-00253-1
       
  • Fluorescent resonance energy transfer of organic fluorescent dyes with
           gold nanoparticles and their analytical application
    • Abstract: We report five effective fluorescence resonance energy transfer (FRET) systems based on gold nanoparticles (AuNPs) and organic fluorescent dyes, including ionic [fluorescein sodium (FS) and Eosin B (EB)] and cationic [rhodamine 6G (Rh6G), acridine orange (AO), and safranine T (ST)] fluorescent dyes. The fluorescence intensity of the five FRET systems demonstrates that efficient quenching is possible. The quenching efficiencies of Rh6G and FS by FRET were nearly 100%, 89% for AO, 60% for EB, and 55% for ST. A series of UV absorbance spectra and fluorescence emission spectra were used to explain the mechanism of fluorescence quenching. We found that there were different degrees of overlap between the absorption spectrum of the AuNPs and the emission spectrum of fluorescence dyes. This outcome indicates that highly efficient FRET is the possible mechanism of fluorescence quenching. We applied the FRET system to establish a sensitive and simple strategy for the determination of mercury (Hg2+). The maximum excitation was at 523 nm (λex = 523 nm). The enhanced fluorescence intensity at 551 nm was proportional to the concentration of Hg2+ with a range of 0.44–100 nmol L−1. The detection limit was 0.13 nM. The linear regression equation was ΔF = 27.05c (nmol L−1) − 79.88, and the regression coefficient was 0.9954. The proposed method has high sensitivity and convenience and does not require complex and expensive instruments.
      PubDate: 2018-12-01
      DOI: 10.1007/s13404-018-0240-5
       
  • Synthesis of gold nanoparticles using Euphorbia tirucalli latex and the
           microwave method
    • Abstract: Uniformly sized and shaped gold nanoparticles (AuNP) were produced by microwave irradiation using Euphorbia tirucalli latex. The AuNPs were characterized by ultraviolet visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering, zeta potential, and transmission electron microscopy (TEM). UV–Vis analysis was employed to detect the characteristic surface plasmon resonance pattern of the AuNPs (550 nm). The carboxylic and polyphenolic groups were associated with the euphol-capped AuNP, which was confirmed using FTIR spectroscopy. The AuNPs studied here show a z-average diameter varying from 35 to 500 ± 0.8 nm. TEM reveals that the particles were spherical and polydispersed. The latex itself is very toxic and can be harmful during manipulation, thus highlighting a negative aspect in it use. However, we have demonstrated that the isolation procedure did not impair the reduction action of the dry latex powder. This study provides a robust solution for the synthesis of stable capped gold nanoparticles. Furthermore, the dried powdered E. tirucalli latex seems to be an attractive capping agent for nanoparticles in drug delivery.
      PubDate: 2018-12-01
      DOI: 10.1007/s13404-018-0231-6
       
  • Effect of M2e peptide–gold nanoparticle conjugates on development of
           anti-influenza antibodies
    • Abstract: Gold nanoparticles (AuNPs) are successfully used as an adjuvant in the design of effective vaccines and in the preparation of high-affinity antibodies to haptens and complete antigens. Here, we assessed the adjuvant properties of AuNPs conjugated to a synthetic M2e peptide of the influenza A virus capsid. The resulting conjugate, a commercial influenza vaccine, and M2e in combination with different adjuvants were used to immunize laboratory mice. The highest titer was detected in the sera of mice immunized with two adjuvants: AuNPs and AuNP-conjugated CpG oligodeoxynucleotide 1826. With this combination, we also recorded increases in the respiratory activity of splenic lymphocytes, in the respiratory activity of peritoneal macrophages, and in the production of proinflammatory cytokines (IL-6 and IFN-γ). The results indicate that simultaneous immunization of the animals with two conjugates—M2e + AuNPs and CpG + AuNPs—activates antibody development. Therefore, the use of AuNPs as an antigen carrier leads to a complete and coordinated immune response from both cellular and humoral immunity.
      PubDate: 2018-12-01
      DOI: 10.1007/s13404-018-0239-y
       
  • Highlights from recent literature
    • PubDate: 2018-12-01
      DOI: 10.1007/s13404-018-0246-z
       
  • Synthesis of gold particles at ionic liquid–ethylene glycol
           interfaces
    • Abstract: The paper presents an investigation of the synthesis of gold particles on liquid–liquid interfaces using room temperature ionic liquids (RTIL) and ethylene glycol at temperatures up to 180 °C. The results show that depending on the RTIL used, the resulting gold particles are of different shape like trigonal and hexagonal plates, single fibers as well as bundles of fibers, and polyhedral and globular particles. This indicates that the shape of gold particles can be tailored by choosing appropriate RTIL. An increase of processing temperature mainly results in the growth of the particles.
      PubDate: 2018-12-01
      DOI: 10.1007/s13404-018-0244-1
       
  • Reduction of sulphur dioxide using carbon monoxide over gold supported
           catalysts
    • Abstract: One percent gold supported on three different metal oxides (TiO2, ZnO and Al2O3) has been evaluated as a catalyst, to reduce sulphur dioxide with carbon monoxide at different reaction temperatures. During the reaction, no carbonyl sulphide was formed and the only sulphur-containing product that was detected was elemental sulphur which condensed as S8 at the reactor exit. High-resolution transmission electron microscopy, X-ray photoemission spectroscopy and powder X-ray diffraction have been used to study the interaction between the metal and the support as well as the size of metal particles before and after the reaction. We found that gold nanoparticles supported on TiO2 had the best performance among all the supported catalysts (86.4% conversion) at a reaction temperature of 300 °C, a feed ratio of CO:SO2 = 2:1 and a gas hourly space velocity of 3600 mL gcat−1 h−1. Au/ZnO and AuAl2O3 were only slightly active for SO2 reduction at a range of temperatures from 50 to 300 °C. After 144 h on stream, the conversion of SO2 over Au/TiO2 was still the same as it was initially. The high activity of the 1% Au/TiO2 catalyst resulted from the size of the gold particles and the strong interaction between the metal and the titania.
      PubDate: 2018-12-01
      DOI: 10.1007/s13404-018-0235-2
       
  • Optimizing of porous silicon alloying process with bimetallic
           nanoparticles
    • Abstract: Bimetallic Ag–Au alloy nanoparticles with a tunable size and composition were synthesized by laser beam power density. A set of Psi substrates with different morphologies fabricated by laser-assisted etching process with laser power density from 10 to 40 mW/cm2 was explored as a substrate for materialization bimetallic Ag–Au alloy nanoparticles by a simple immersion plating process of Psi in a mixture of AgNO3 and HAuCl4 solutions. The materialization of alloy nanoparticles was confirmed by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray analysis (EDS). The results showed that the sizes and distribution of Ag–Au alloy nanoparticle sizes were easily well-ordered by changing the surface morphologies of Psi layer. Pore-like structures with different pores shapes: ultra-fine pores, irregular (grotto form), circular, and star full pore shape (gambling pores) with different sizes were prepared by changing the irradiation laser power density. Bimetallic Ag–Au alloy nanoparticles, phases, crystalline size, specific surface area, and growth sites of Ag–Au alloy nanoparticles were significantly influenced by pore shape. The lower nanoparticle size with higher S.S.A was obtained when the laser power intensity was about 30 mW/cm2.
      PubDate: 2018-12-01
      DOI: 10.1007/s13404-018-0242-3
       
  • Fifty shades of yellow
    • Abstract: The color of ternary Au-Ag-Cu alloys is investigated; a simple and efficient model relying only on the reflectance of gold, silver, and copper is suggested. The alloy color diagram (a⋆,b⋆) based on the alloy proportion (u, v) has the shape of a “wizard’s hat” with special properties. Leuser’s classical triangle can be improved upon these results.
      PubDate: 2018-12-01
      DOI: 10.1007/s13404-018-0245-0
       
  • Dating geologic gold deposits and authenticating a Greek gold tiara, an
           ancient gold chalice, and swimming dragon artifacts of the Chinese Han
           dynasty
    • Abstract: In this work, we present the application of the uranium, thorium–helium (U,Th–He) dating method to two different types of gold objects: geologic gold deposits and archeological gold objects. Direct dating of geologic gold deposits is difficult without assuming contemporaneity between gold and datable hydrothermal minerals. We show that our results indicate that the applied dating method opens a new perspective for the dating of gold deposits without assuming contemporaneity between gold and datable hydrothermal minerals. The second application of our dating method is authenticating archeological gold objects. This is a major problem, as gold is probably the most difficult material in terms of detecting modern forgeries. The feasibility of this application was mentioned in 1996 in an earlier article in Gold Bulletin, Eugster (Gold Bull 29:101–104, 1996). In the past two decades, we applied the U,Th–He dating method to numerous gold antiquities in order to determine the time of their formation or their latest melting process, respectively. Gold always contains traces of uranium and thorium that produce alpha particles by radioactive decay which transform to helium. When gold is molten to manufacture an art object, the helium is lost, but gets stored again when the gold cools down. Thus, the radioactive clock starts anew. Here, we present the results for direct dating of gold deposits and for the authentication of some of the most remarkable artifacts and describe their history.
      PubDate: 2018-12-01
      DOI: 10.1007/s13404-018-0238-z
       
  • Gold nanoparticle trophic transfer from natural biofilm to grazer fish
    • Abstract: Nanoparticle (NP) trophic transfer is reported as an important exposure route for organisms in aquatic ecosystems. This study focused on gold nanoparticle (AuNP, PEG-coated, 10 nm diameter) transfer using an experimental benthic food chain which included two trophic levels: natural river biofilm and grazer fish Hypostomus plecostomus. AuNP biofilm accumulation was assessed via water AuNP concentrations and total biofilm mass. An extended range of six AuNP concentrations in water (0, 0.0048, 0.048, 0.48, 4.8, and 48 mg Au L−1) was set. A dose-dependent relation between gold concentrations in water and natural river biofilm was observed after a 48-h exposure. This pointed out the high propensity of natural biofilms to accumulate gold. Additionally, total biofilm mass appeared to influence AuNP accumulation at the highest exposure levels. This first step enables the set-up of the transfer experiment in which grazer fish were exposed for 21 days to natural biofilms, previously contaminated by low AuNP concentrations in water (NP0.1: 0.48 and NP1: 4.8 mg Au L−1). Gold was quantified in eight fish organs, and histology was observed. Gold was transferred from biofilms to fish; bioaccumulation was organ- and exposure level-dependent. Interestingly, the brain showed significant gold accumulation at the highest exposure level (NP1). Histological observations indicated distinct inflammatory responses in fish liver, spleen, and muscle. The overall results suggest the potential hazards of subchronic nanoparticle exposure in aquatic organisms.
      PubDate: 2018-12-01
      DOI: 10.1007/s13404-018-0241-4
       
  • Wetting ability of human blood in the presence of gold nanoparticles
    • Abstract: Gold nanoparticles are more and more used in bio-medical field for their advantages to be employed as contrast medium for diagnostic images and as targets of disease cells in which thermal-therapy or radiotherapy must be applied. In this contest, a suitable concentration of nanoparticles was added to human blood to study in vitro some physical properties of the treated liquid which is prepared to transport the nanoparticles to the different organs where they can be accumulated by metabolic effects. Measurements indicated that the insertion of gold nanoparticles in the human blood improves the blood wetting ability. In particular, the wetting ability of the blood containing or not gold nanoparticles, with respect to different biocompatible solid surfaces, was investigated. Also, the density, tension surface, and viscosity of the solution at room temperature were measured. Results demonstrated that the introduction of gold nanoparticles in the blood, with size distribution centered at about 50 nm, generally improves the wetting ability and changes other properties of the solution, due to the different distributions of the cohesion and adhesion forces.
      PubDate: 2018-09-01
      DOI: 10.1007/s13404-018-0236-1
       
  • Highlights from recent literature
    • PubDate: 2018-09-01
      DOI: 10.1007/s13404-018-0243-2
       
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
 


Your IP address: 3.235.25.169
 
Home (Search)
API
About JournalTOCs
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-