Gold Products Research Articles

Reduction of Tetrachloroaurate(III) Ions With Bioligands: Role of the Thiol and Amine Functional Groups on the Structure and Optical Features of Gold Nanohybrid Systems.

In this review, the presentation of the synthetic routes of plasmonic gold nanoparticles (Au NPs), fluorescent gold nanoclusters (Au NCs), as well as self-assembled Au-containing thiolated coordination polymers (Au CPs) was highlighted. We exclusively emphasize the gold products that are synthesized by the spontaneous interaction of tetrachloroaurate(III) ions (AuCl4¯) with bioligands using amine and thiolate derivatives, including mainly amino acids. The dominant role of the nature of the applied reducing molecules as well as the experimental conditions (concentration of the precursor metal ion, molar ratio of the AuCl4¯ ions and biomolecules; pH, temperature, etc.) of the syntheses on the size and structure-dependent optical properties of these gold nanohybrid materials have been summarized. While using the same reducing and stabilizing biomolecules, the main differences on the preparation conditions of Au NPs, Au NCs, and Au CPs have been interpreted and the reducing capabilities of various amino acids and thiolates have been compared. Moreover, various fabrication routes of thiol-stabilized plasmonic Au NPs, as well as fluorescent Au NCs and self-assembled Au CPs have been presented via the formation of –(Au(I)-SR)n– periodic structures as intermediates.

The historical experience and practice of fight against tuberculosis in country which is one of the high drug resistant-tuberculosis (DR-TB) burden countries in European Union (EU).

SummaryDespite considerable efforts and quite early initiated anti-tuberculosis (TB) actions, Lithuania still remains one of the European Union (EU) countries with the highest tuberculosis rates, especially multidrug-resistant (MDR) TB. According to the European Centre for Disease Prevention and Control, in 2016, 58 994 cases of TB were reported in 30 EU/European Economic Area (EEA) countries. MDR TB was reported for 3.7% of 36 071 cases with drug susceptibility testing results and continues to be highest in the three Baltic countries - Estonia, Latvia and Lithuania.In this article we present the Lithuanian anti-TB action history review and comparison with other countries in this area of action. Literature review was performed by using documents available in the Martynas Mazvydas Library’s resource, articles of foreign authors and archival materials.According to archaeological studies, tuberculosis was common in Europe including Lithuania in the Middle Ages. Tuberculosis reporting started in Lithuania in 1926. The first tuberculosis sanatorium in Lithuania was opened in 1891. Patients were treated with sun bathing procedures, fresh air and sunlight. Later the treatment included pneumothorax, toracocaustic, toracoplastic, treatment with gold products and other procedures. Lithuania introduced directly observed treatment, short course therapy (DOTS) in 1999, and since 2007 it has been working in accordance with the requirements of this strategy.

REPRESENTATIVE SPENDINGS OF THE MAGISTRATE IN 1577-1583. ON THE EXAMPLE OF LVIV WEEKLY-EXPENDITURES BOOKS

The article analyzes the books of Lviv weekly expenditures. The author has found out that during the period 1577–1583 the funds that were spent on gifts, first of all, wine, elite Lviv fish, oriental goods, precious silver and gold products, were allocated from the city treasury. In Lviv the second half of16th century the gift of wine was an integral part of city politics. The author identifies the costs of 1) wine shipped to the Diet and the royal tribunal; 2) wine for greetings of the most respected persons of the Commonwealth during their arrival or passage through the city (king, voivode, bishop, castle); 3) wine for the so-called "own" persons - the voivodship of Ruthenian and Podilsky, the Lviv elder, the Zemstvo and Grodno judges of the Rus' voivodeship; 4) wine for congratulation on the marriage or birth of children of the state's distinguished persons. The gifts played an essential role in maintaining the social and political network of the city, with their help, the city community managed to solve various problems and to maintain their honour and reputation. The author tries to confirm these theses with specific facts. For example, he states that for the period 1577–1583 the books of city expenditures mention three trips of Lviv rays to meetings of the Seimas. The total cost of a trip to Warsaw in December 1579 amounted to 1002 PLN. 8 ½ gr. The author does not exclude the possibility that one of the consequences of the trip could have been the granting of the privilege of Stefan Batory Lviv to levy a tax on lemons and wines brought to the city. During a trip to the Seimas in 1582, 1212 PLN was spent on gifts, travel, wine-making, payment for accommodation for Lviv rays. 12 gr. The trip resulted in the abolition of the toll, which the king and the Diet had set to raise money to continue the war with Muscovy. Based on the analysis of the available information, the author finds that the Lviv rayons maintained close relations with the highest officials of the Commonwealth and other representatives of their interests, and through gifts and representation, influenced the status and status of their city.

Trace Elements in Ancient Gold Products with PGE Microinclusions from Archaeological Sites of the Urals and North Black Sea Region: LA–ICP–MS Data

Many archaeological gold products of the Urals and North Black Sea region contain microinclusions of platinum group minerals (PGMs). The trace element composition of these products was studied using LA–ICP–MS to reveal their microgeochemical features, the differences in the trace element composition of PGM‐bearing and PGM‐free products, and the source of gold. Owing to the presence of microinclusions of ruthenium, osmium and iridium, the gold products from the Filippovka I grave field and the Phanagoria site are enriched in Os, Ru, Ir and Rh. Among the platinum group elements (PGEs), Pt exhibits the highest contents in the gold products. The gold products are characterized by individual assemblages of Ag and base metals. The gold products with both PGEs and base metals were manufactered from two types of gold: placer‐derived and gold from oxidation zones of polymetallic volcanic‐hosted massive sulphide deposits. It is suggested that cupellation was most common technique of gold refinement.

Gold - Old Drug with New Potentials

Research into gold-based drugs for a range of human diseases has seen a revival in recent years. This article reviews the most important applications of gold products in different fields of human pathology. Au(I) and Au(III) compounds have been re-introduced in clinical practice for targeting the cellular components involved in the onset and progression of viral and parasitic diseases, rheumatoid arthritis and cancer. After some brief historical notes, this article takes into account the applications of gold compounds against Mycobacterium tuberculosis, and also in tuberculosis and in rheumatoid arthritis treatment. The use of gold containing drugs in the cure of cancer are then considered, with special emphasis to the use of nanoparticles and to the photo-thermal cancer therapy. The use of colloidal gold in diagnostics, introduced in the last decade is widely discussed. As a last point a survey on the adverse effects and on the toxicity of the various gold derivatives in use in medicine is presented. In this review, we described the surprisingly broad spectrum of possible uses of gold in diagnostics and in therapeutic approaches to multiple human diseases, ranging from degenerative to infectious diseases, and to cancer. In particular, gold nanoparticles appear as attractive elements in modern clinical medicine, combining high therapeutic properties, high selectivity in targeting cancer cells and low toxicity.

Aminkomplexe des Goldes, Teil 9: Gold(I)-halogenid-Komplexe mit primären und azyklischen sekundären Aminen und ihre Oxidation zu Gold(III)-Derivaten

Abstract The reaction of (tht)AuX (X=Cl or Br; tht=tetrahydrothiophene) with various primary amines L leads to products of the form [L2Au]+X−. Packing diagrams of the corresponding structures are dominated by N–H···X hydrogen bonds and (in some cases) aurophilic contacts. The cyclohexylamine derivative was already known as its dichloromethane ⅔-solvate; we have isolated the solvent-free compound and its pentane ¼-solvate, which all show different packing patterns. With acyclic secondary amines, the products are more varied; LAuX and [L2Au]+[AuX2]− were also found. These gold(I) products were generally formed in satisfactory quantities. The attempted oxidation to Au(III) derivatives with PhICl2 or Br2 proved impossible for the primary amine derivatives [although isopropylamine-trichloridogold(III) was obtained unexpectedly from the corresponding cyanide] and unsatisfactory for the secondary amine derivatives. Products LAuX3 and [L2AuX2]+[AuX4]− were identified but were formed in disappointing yields. In isolated cases protonated products (LH)+[AuCl4]−, (LH+)3[AuCl4]−(Cl−)2 or [(Et2N)2CH]+[AuBr4]− were formed, presumably by involvement of the dichloromethane solvent and/or adventitious water. Here also the yields were poor, and some products arose as mixtures. Direct reaction of amines with AuCl3 or (tht)AuX3 was also unsuccessful. All products were characterized by X-ray structure analysis.

Synthesis of biogenic nano-scale gold products by natural tribes and their inborn antimicrobial activity

Synthesis of biogenic nano-scale gold products by natural tribes and their inborn antimicrobial activity

Synthesis of biogenic nano-scale gold products by natural tribes and their inborn antimicrobial activity

In this paper, we report the green synthesis of gold nanoparticles (AuNPs) using Wright tinctoria seed extract. The biomolecules present in the seed extract is responsible for the formation of AuNPs and they found to play dual role of both reducing as well as capping agents. Appearance of violet colour confirms the AuNPs formation. The surface nature of the synthesised nanoparticle is studied using SEM and TEM analysis. The high crystallinity of AuNPs is observed from the diffraction peaks in XRD profile. FTIR spectrum confirms the presence of different functional groups of biomolecules participated in encapsulating AuNPs. In this work, a possible mechanism of AuNPs formation was also proposed. The synthesised biogenic nano-scale gold particles by natural tribes are tested for its inborn antimicrobial activity. Antimicrobial activity of AuNPs showed better inhibitory activity towards certain pathogens in comparison to other test pathogens.

Assisted laser ablation: silver/gold nanostructures coated with silica

The synthesis processes of metallic nanoparticles have seen a growing interest in recent years, mainly by the potential applications of the phenomenon of localized surface plasmon resonance associated with metallic nanoparticles. This paper shows a fast method to synthesize silver, gold and silver/gold alloy nanoparticles coated with a porous silica shell by the assisted laser ablation method in three steps. The method involves a redox chemical reaction where the reducing agent is supplied in nanometric form by laser ablation. In the first step, a silicon target immersed in water is ablated for several minutes. Later, AgNO3 and HAuCl4 aliquots are added to the solution. The redox reaction between the silver and gold ions and products resulting from ablation process can produce silver, gold or silver/gold alloy nanoparticles coated with a porous silica shell. The influence of the laser pulse energy, ablation time, Ag+ and Au3+ concentration, as well as the Ag+/Au3+ ratio, on optical and structural properties of the nanostructures was investigated. This work represents a step forward in the study of reaction mechanisms that take place during the synthesis of nanoscale materials by the assisted laser ablation technique.

Effect of the composition and production process parameters on the microstructure, residual stresses, and mechanical and corrosion properties of gold alloys used in industrial jewelry processes

Gold alloys, used in the production of both hollow and solid gold chains, influence the optical and mechanical properties of various gold products. Also, the microstructure of the alloys strongly influences the mechanical properties, which have a key role in both the machinability and quality of the plates. In the present work, different compositions of gold alloys and various industrial deformation processes (annealing and rolling steps) were analyzed and optimized. The change in the production parameters and in the compositions of the alloys may lead to the formation of different levels of residual stresses within the material, which can generate a variation in the behavior of gold sheets. The microstructures after the different production processes were analyzed by OM and SEM observations, whereas the variation of mechanical properties by microhardness tests. The residual stresses were evaluated using XRD analysis and the corrosion resistance by potentiodynamic polarization tests. The results showed that with the optimized process, a higher homogeneity of the microstructure, with an increase of the quality of semi-finished products and without ruptures under roller trains, was obtained. Moreover, the grain refiner was changed and a totally non-magnetic gold alloy was developed. Finally, to improve the weldability of the final chains, a different gold welding alloy, with a lower melting point, was developed and optimized.

STUDI IMPLEMENTASI AKUNTANSI PRODUK EMAS MENURUT PSAK 107 DAN 102 PADA PT BANK SYARIAH MANDIRI TBK CABANG JEMBER

This research aims to know the implementation of accounting<br />gold products at PT Bank Syariah Mandiri Tbk Branch Jember<br />that BSM gadai emas and BSM cicil emas based on PSAK 107<br />and 102. This research is a descriptive qualitative research, a<br />method that is done is to interpret and said data concerned<br />with the current situation, attitudes, and opinions that occur in<br />the community, conflict two states / more, the relationship<br />between the variables, the difference between fact, the effect of<br />the condition, and others. Data processing method using<br />interviews and accompanied with documents related to the<br />validity of the data that is triangulation. The results showed<br />that the accounting treatment that contains the recognition,<br />measurement, presentation and recognition of BSM gadai<br />emas products are in accordance with PSAK 107 and BSM cicil<br />emas products are already in accordance with PSAK 102.

Reducing mercury usage in artisanal gold mines using grinding and sieving

Gold extraction in primitive artisanal mines usually involves the over-usage of mercury (Hg). This practice results in significant environmental contamination, but is difficult to eliminate due to its effectiveness. Any alternative must be simple, inexpensive and visually effective. This paper proposes a novel, chemical-free method for extracting gold from gravity middlings which has potential as an effective alternative to Hg amalgamation. This method exploits the differences in relative malleability, rather than density, of gold and waste products by submitting concentrates to grinding in a rod mill. The grind products are separated through a sieve, where flattened gold particles are captured on the oversize while brittle waste reports to the fines. Recoveries often exceeded 90%, with nearly pure raw gold separated after only minutes of grinding. While recently adapted to the modern Yukon placer fields, this method has potential to reduce Hg usage by miners in more primitive settings.

The Phenomenon of the Influence of Gold Melt on Microinclusions of Platinum Group Minerals in Ancient Gold Objects

This study focuses on microinclusions of platinum group minerals (PGMs) in gold objects from the South Urals and North Black Sea archaeological sites. We demonstrate for the first time that melting of gold during archaeometallurgical work affects PGM microinclusions. Desquamation of primary PGM microinclusions with 28–55 wt% Os in the melt and their oxidation by hot air microbubbles results in the formation of secondary particles with 1–20 wt% Os around the primary inclusions. We conclude that the composition only of primary PGM microinclusions in ancient gold products is comparable to the composition of those from natural sources.

Effect of microstructure and residual stresses, generated from different annealing and deformation processes, on the corrosion and mechanical properties of gold welding alloy wires

Gold welding alloys, which are used in the production of both hollow and solid gold chains, affect the optical and mechanical properties of various gold products because the corrosion resistance of the individual links depends on these properties. It is important that welding alloys with high corrosion resistance do not degrade during or after the production process. The mechanical properties of gold welding alloy wires are strongly influenced by the alloy microstructure, which has a key role in both the machinability and the quality of the wires. In the presented work, various physical and mechanical properties of gold originating from different industrial deformation processes are evaluated. Specifically, various plastic deformation grades caused by different annealing and rolling steps are analyzed. The change of the temperature, time, and velocity parameters in the annealing and lamination processes leads to the formation of different levels of residual stresses in the material, which can generate a variation in the corrosion properties of the gold wires. The change in microstructure, due to the different annealing and rolling steps, is analyzed by optical microscope (OM) and SEM observations. The residual stresses are evaluated using XRD analysis, and the variations of the mechanical properties by micro-hardness tests. The corrosion resistance is evaluated by potentiodynamic polarization tests, in which an electrolyte solution is used to simulate human sweat. Small grain size and high homogeneity of the microstructure are preferred for the final products. In this study, the samples that have been produced are shown to have lower levels of residual stresses and feature higher corrosion resistance and more favorable mechanical properties.

Properties of the Master Alloys for White Gold Products with Silicon Contents

Abstract We prepared 8 samples of non-silver and silver-added master alloys containing silicon to confirm the existence ofnickel-silicides. We then prepared products made of 14K and 18K white gold by using the prepared master alloys containing0.25, 0.35, and 0.50 wt% silicon to check for nickel release. We then employed the EN 1811 testing standard to investigatethe nickel release of the white gold products, and we also confirmed the color of the white gold products with an UV-VIS-NIR-color meter. We observed NiSi x residue in all master alloys containing more than 0.50 wt% Si with EDS-nitric acid etching.For the white gold products, we could not confirm the existence of NiSi x through XRD after aqua-regia etching. In the EN1811 test, only the white gold products with 0.25 wt% silicon master alloys successfully passed the nickel release regulations.Moreover, we confirmed that our white gold products showed excellent Lab indices as compared to those of commercial whitegold ones, and the silver-added master alloys offered a larger L index. Our results indicate that employing 0.25 wt% siliconmaster alloys might be suitable for white gold products without nickel-silicide defects and nickel release problems. Key wordsmaster alloy, white gold, silicon content, nickel release, energy dispersive spectroscopy.

Performance of gold etfs and gold fofs: a comparative study

Gold products are considered a highly valuable means of investment in the present scenario of financial markets. There are many alternatives to invest in gold like Gold Exchange Traded Funds (GETFs), Gold Fund of Funds (GFoFs), e-gold, stocks of gold mining companies, gold futures, gold bars, gold coins, gold jewellery, etc. Amongst these, the Gold Exchange Traded Funds (ETF) and Gold Fund of Funds (FoFs) have emerged as the most successful source for investment and ETFs industry has witnessed rapid growth in the last decade. The Gold ETF and Gold FoF provide a convenient way to the investors to intervene in the gold market. This paper attempts to compare the performance of Gold Exchange Traded Funds and Gold Fund of Funds. Return and risk of Gold ETFs has been compared with the return and risk of Gold FoFs. Monthly Net Asset Values (NAVs) for the period from March 2011 to March 2014 were used for both the schemes. The study concluded that the Gold ETFs recorded lesser variability as compared to the Gold FoFs and therefore, the performance of Gold ETFs was better than the performance of Gold FoFs.

Development status and prospect of jewelry industry in China

Chinese economy is developing rapidly in this 21st century. Especially upon the registration of WTO in 2001, Chinese economy has been marketized and globalized and the scale of its economy reached 12.3% of world economy in 2013. After the economic crisis, world economy showed decline but it didn’t affect Chinese market. Consumption of luxurious goods in Chinese emerging market showed dramatic increased and attracted attentions from domestic and international companies.BR Upon the establishment of relations with China, China has been a primary export market for Korea and Korean jewelry companies have been actively entering into Chinese market. Therefore, the objective of this study is to minimize the failure by deeply understanding the status of Chinese jewelry industry and being flexible in responding to rapidly changing Chinese market. The prospect of Chinese jewelry industry will be projected through analyzing the status of jewelry industry and interest level of jewelry industry will be addressed by checking the agendas of jewelry exhibitions or conventions. Overall trend of Chinese consumers will be anticipated through analyzing brand preference, brand product line and positioning map. Furthermore, development tendency of Chinese jewelry industry can be anticipated through analyzing consumption potential and consumption competency of jewelry. The results of this study are as follow. Firstly, China jewelry industry will be expanded from big city to small city, urban area to rural and coast area to inland area. Second, China jewelry market has been developed into a diversified market, however, demand for gold products is still account for a large proportion . Third, with having fast economic growth and large population as a background, jewelry consumption in China is growing rapidly into a superpower. Its potential spending power from current female population will continuously form a consumer market for the next 10 years. BR Importance of this study can be summarized as following.. Accurate calculation was done on Chinese jewelry market which is a subject of many companies entering into China. accurate statistic research on Chinese jewelry market and introduction of Chinese jewelry industry for those companies which are interested in entering Chinese market. This study can be fundamental information for referring upon the consideration of entering Chinese market and systematic introduction of market status of China was made. This research will serve as a foundation of product development for local companies considering entering into Chinese jewelry market as it performed analysis and segmentation on current brand status in China.

The history and economics of gold mining in China

As the largest producer of gold in the world, China's gold reserves are spread across a number of orogenic belts that were constructed around ancient craton margins during various subduction–collision cycles, as well as within the cratonic interior along reactivated paleo-sutures. Among the major gold deposits in China is the unique class of world's richest gold mines in the Jiaodong Peninsula in the eastern part of the North China Craton with an overall endowment of >3000tons. Following the dawn of metal in the third millennium BC in western China, placer gold mining was soon in practice, particularly during the Xia, Shang and Zhou dynasties. During 1096AD, mining techniques were developed to dig underground tunnels and the earliest mineral processing technology was in place to pan gold from crushed rock ores. However, ancient China did not witness any major breakthrough in gold exploitation and production, and the growth in the gold ownership was partly due to the ‘Silk Road’ that enabled the sale of silk products and exquisite artifacts to the west in exchange of gold products. In the modern times, the proven reserves of gold resources in China have steadily increased from 4614.7tons in 2005 up to 6864.79tons in 2010, with a growth rate of 48.76%. In the past ten years, the rate of production increased by 70%, launching China as the top producer of gold in the world in 2008 when the production reached 300tons per year. The gross industrial output of gold industry in China increased sharply from 20.82billion Yuan up to 229.29billion Yuan between 2000 and 2010, registering 9 times growth, and breaking the world record. A simultaneous hike in the proportion of gross value in GDP from 0.21% in 2003 up to 0.58% in 2010 is also recorded.

Dinuclear gold(i) dithio- and diselenophosph(in)ate complexes forming mononuclear gold(iii) oxidative addition complexes and reversible chemical reductive elimination products

Dinuclear gold(i) dithio- and diselenophosph(in)ate complexes were prepared to serve as precursors for subsequent oxidative addition (OA) chemistry following reaction with mild oxidant iodine, I2. The new OA products circumvented the formation of the expected dinuclear Au(ii) complexes, but instead formed novel chelating mononuclear square-planar gold(iii) products of the type [AuI2{E2PR2}] (R = (CH2)2Ph; E = S, 2; E = Se, 3) and [AuI2{Se2P(OR)2}] (R = Et, 4; (i)Pr, 5) directly. We further demonstrate that this process is chemically reversible as all the Au(iii) complexes undergo chemical reductive elimination to the starting dinuclear Au(i) complexes in the presence of SnI2 as determined by (119)Sn and (31)P NMR. The complexes (2-5) were all prepared from the reaction between I2 and the corresponding dinuclear gold(i) precursor material. All new complexes were characterized by (1)H, (31)P, (77)Se (for E = Se) NMR, infrared spectroscopy, elemental analysis and single crystal X-ray diffraction.

Rapid purification of gold nanorods for biomedical applications

Small gold nanorods (GNRs) with longitudinal plasmon absorption in the near-infrared window (700–900nm) are of great interest for in vivo optical applications (e.g., photothermal therapy) and for their high-payload-to-carrier ratio for drug delivery. Common synthetic strategies for GNR production afford spherical and cubical nanoparticles in addition to the desired GNRs. Thus, several methods have been proposed for the selective separation of GNRs from the reaction by-products. For example, centrifugation has been used to separate the high aspect ratio (AR) GNRs (AR>4). However, it is difficult to separate small sized GNRs with low AR (AR≤4) that are particularly promising for biomedical applications. Here, we describe a simple and fast procedure for the separation of small GNRs with AR of 4, and length of 28nm from reaction by-products.The shape separation is achieved through centrifugation according to the following steps:•Isolation of all gold products of the reaction from the excess of cetyltrimethylammonium bromide through a first cycle of centrifugation.•Optimization of the speed and the time of centrifugation for the separation of GNRs from the reaction by-products.•Shape separation of GNRs through a second cycle of centrifugation.The effectiveness of this procedure is documented.